FLUSH TOILET APPARATUS

Abstract

The present invention provides a flush toilet apparatus that includes a flush toilet body including a bowl and having a rim water ejection port, a drain trap pipeline, and a jet water ejection port; a flush water tank body; a rim drain valve; and a jet drain valve, in which the flush toilet apparatus has an exhaust path along which air of an air layer formed in an upstream side of a jet water conduit is discharged, in which the rim-water-ejection drain port and the jet-water-ejection drain port are each provided at a position higher than the lower end of the rim water ejection port, and in which flush water is supplied into the jet water conduit after a flush is started and before the jet drain valve is opened.

Claims

1. A flush toilet apparatus that flushes with flush water stored in a flush water tank, the flush toilet apparatus comprising: a flush toilet body that includes a bowl and has a rim water ejection port provided in an upper portion of the bowl, a drain trap pipeline extending from a lower portion of the bowl, and a jet water ejection port provided to face an inlet of the drain trap pipeline; a flush water tank body that stores flush water for flushing the bowl of the flush toilet body; a rim drain valve that stops or allows flush water to be ejected through the rim water ejection port via a rim water conduit provided in the flush toilet body, the rim drain valve being provided at a rim-water-ejection drain port formed in the flush water tank body; and a jet drain valve that stops or allows flush water to be ejected through the jet water ejection port via a jet water conduit provided in the flush toilet body, the jet drain valve being provided at a jet-water-ejection drain port formed in the flush water tank body, wherein the flush toilet apparatus has an exhaust path along which air of an air layer formed in an upstream side of the jet water conduit is discharged, wherein the rim-water-ejection drain port and the jet-water-ejection drain port are each provided at a position higher than a lower end of the rim water ejection port, and wherein flush water is supplied into the jet water conduit after a flush is started and before the jet drain valve is opened.

2. The flush toilet apparatus according to claim 1, wherein flush water is supplied into the jet water conduit by, after a flush is started and before the jet drain valve is opened, opening the rim drain valve to allow flush water to be ejected through the rim water ejection port and to thereby allow flush water to flow in through the jet water ejection port.

3. The flush toilet apparatus according to claim 2, wherein supply of flush water into the jet water conduit causes a water level in the jet water conduit to rise, and, at a point of time when the jet drain valve is opened, a water level in the drain trap pipeline rises to be higher than a water level in the jet water conduit.

4. The flush toilet apparatus according to claim 1, wherein a cross-sectional area of the jet water ejection port is larger than a cross-sectional area of the rim water ejection port.

5. The flush toilet apparatus according to claim 4, wherein ejection of flush water through the rim water ejection port forms a swirling flow on an inner wall surface of the bowl, and the swirling flow makes one or more revolutions in the bowl.

6. The flush toilet apparatus according to claim 1, wherein the jet drain valve is opened when or after a water level in the jet water conduit rises to a highest position.

7. The flush toilet apparatus according to claim 1, wherein one end of the exhaust path in communication with an inside of the jet water conduit is open at a position higher than a water surface that has risen in the jet water conduit due to supply of flush water into the jet water conduit.

8. The flush toilet apparatus according to claim 7, wherein one end of the exhaust path is open upward in a ceiling surface of the jet water conduit.

9. The flush toilet apparatus according to claim 1, wherein the exhaust path is configured such that an inside of the jet water conduit is in communication with outside air.

10. The flush toilet apparatus according to claim 9, wherein the exhaust path is configured such that an inside of the jet water conduit and an air layer in the flush water tank body are in communication with each other.

11. The flush toilet apparatus according to claim 1, wherein the jet water conduit is configured such that an air layer remains inside the jet water conduit even in a state in which flush water has been supplied into the jet water conduit before the jet drain valve is opened.

12. The flush toilet apparatus according to claim 1, wherein the jet water conduit is configured such that an air pocket is formed inside the jet water conduit after the jet drain valve is opened.

13. The flush toilet apparatus according to claim 1, wherein the rim drain valve and the jet drain valve are configured to be driven based on drive inputs that differ from each other, and wherein one end side of the exhaust path is open inside the jet water conduit, and another end side of the exhaust path is open in an atmospheric region.

14. The flush toilet apparatus according to claim 13, wherein the one end side of the exhaust path is open inside an upstream region located directly under the jet drain valve or inside an intermediate region extending forward from the upstream region in plan view.

15. The flush toilet apparatus according to claim 14, wherein a downstream region extending to the jet water ejection port is connected to the intermediate region, and wherein a water surface formed, after the jet drain valve is opened and flush water reaches the jet water ejection port, by a water flow of flush water in the upstream region in which the one end side of the exhaust path is open or in the intermediate region is determined depending on a position at which the one end side of the exhaust path is open, and an enclosed water flow of flush water is formed from the upstream region to the jet water ejection port via the intermediate region and the downstream region.

16. The flush toilet apparatus according to claim 15, wherein, after the jet drain valve is opened and flush water reaches the jet water ejection port, a flow rate of flush water that flows in the upstream region is larger than a flow rate of flush water that flows in the intermediate region, and a flow rate of flush water that flows in the intermediate region is larger than a flow rate of flush water that flows in the downstream region.

17. The flush toilet apparatus according to claim 13, wherein the exhaust path is formed by a pipeline member that is formed integrally with the rim drain valve and/or the jet drain valve, and wherein the other end side of the exhaust path is open in an upper-side space inside the flush water tank body.

18. The flush toilet apparatus according to claim 13, wherein the exhaust path is provided with a check valve.

19. The flush toilet apparatus according to claim 13, wherein the other end side of the exhaust path is open in a space outside the flush water tank body.

20. The flush toilet apparatus according to claim 13, wherein the one end side of the exhaust path is located above a water level of retained water.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] FIG. 1 is a top view illustrating a general configuration of a flush toilet apparatus according to a first embodiment of the present invention.

[0053] FIG. 2 is a side sectional view illustrating a general configuration of the flush toilet apparatus according to the first embodiment of the present invention.

[0054] FIG. 3 is a block diagram illustrating a flush-water supply system in the flush toilet apparatus according to the first embodiment of the present invention.

[0055] FIG. 4 is a front sectional view illustrating an internal configuration of a flush water tank body included in the flush toilet apparatus according to the first embodiment of the present invention.

[0056] FIG. 5 is a time chart illustrating an operation of the flush toilet apparatus according to the first embodiment of the present invention.

[0057] FIG. 6 is a partial sectional view illustrating an exhaust path according to a modification in the flush toilet apparatus according to the first embodiment of the present invention.

[0058] FIG. 7 is a block diagram illustrating a flush toilet apparatus according to a second embodiment of the present invention.

[0059] FIG. 8 is a sectional view illustrating a general configuration of a flush water tank included in the flush toilet apparatus according to the second embodiment of the present invention.

[0060] FIG. 9 is a sectional view illustrating a structure of a ball tap incorporated in the flush water tank in the flush toilet apparatus according to the second embodiment of the present invention.

[0061] FIG. 10 is a sectional view illustrating a structure of a hydraulic drive mechanism incorporated in the flush water tank in the flush toilet apparatus according to the second embodiment of the present invention.

[0062] FIG. 11 is a schematic side view illustrating a jet water conduit extending from the flush water tank to a jet water ejection port in the flush toilet apparatus according to the second embodiment of the present invention.

[0063] FIG. 12 is a schematic vertical cross-sectional view illustrating the jet water conduit extending from the flush water tank to the jet water ejection port in the flush toilet apparatus according to the second embodiment of the present invention.

[0064] FIG. 13 is a sectional view taken along line XIII-XIII in FIG. 12.

[0065] FIG. 14 is a sectional view taken along line XIV-XIV in FIG. 12.

[0066] FIG. 15 is a sectional view taken along line XV-XV in FIG. 11.

[0067] FIG. 16A is a schematic view illustrating elapse of time of jet water ejection in a comparative example configuration (existing type).

[0068] FIG. 16B is a schematic view illustrating elapse of time of jet water ejection in a comparative example configuration (existing type).

[0069] FIG. 16C is a schematic view illustrating elapse of time of jet water ejection in a comparative example configuration (existing type).

[0070] FIG. 17A is a schematic view illustrating elapse of time of jet water ejection in the second embodiment of the present invention.

[0071] FIG. 17B is a schematic view illustrating elapse of time of jet water ejection in the second embodiment of the present invention.

[0072] FIG. 17C is a schematic view illustrating elapse of time of jet water ejection in the second embodiment of the present invention.

[0073] FIG. 18 is a schematic diagram for describing an operation of the flush toilet apparatus according to the second embodiment of the present invention.

[0074] FIG. 19 is a schematic diagram for describing an operation of the flush toilet apparatus according to the second embodiment of the present invention.

[0075] FIG. 20 is a schematic diagram for describing an operation of the flush toilet apparatus according to the second embodiment of the present invention.

[0076] FIG. 21 is a schematic diagram for describing an operation of the flush toilet apparatus according to the second embodiment of the present invention.

[0077] FIG. 22 is a time chart illustrating an operation of the flush toilet apparatus according to the second embodiment of the present invention.

[0078] FIG. 23 is a sectional view illustrating a general configuration of a flush water tank included in a flush toilet apparatus according to a third embodiment of the present invention.

[0079] FIG. 24 is a schematic diagram for describing an operation of the flush water tank in the flush toilet apparatus according to the third embodiment of the present invention.

[0080] FIG. 25 is a time chart illustrating an operation of the flush toilet apparatus according to the third embodiment of the present invention.

[0081] FIG. 26 is a sectional view illustrating a general configuration of a flush water tank included in a flush toilet apparatus according to a fourth embodiment of the present invention.

[0082] FIG. 27 is a time chart illustrating an operation of the flush toilet apparatus according to the fourth embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0083] Next, a flush toilet apparatus according to embodiments of the present invention will be described with reference to the accompanying drawings.

[0084] FIG. 1 is a top view illustrating a general configuration of a flush toilet apparatus according to a first embodiment of the present invention. FIG. 2 is a side sectional view illustrating a general configuration of the flush toilet apparatus according to the first embodiment of the present invention. FIG. 3 is a block diagram illustrating a flush-water supply system in the flush toilet apparatus according to the first embodiment of the present invention. FIG. 4 is a front sectional view illustrating an internal configuration of a flush water tank body included in the flush toilet apparatus according to the first embodiment of the present invention.

[0085] As illustrated in FIG. 1 and FIG. 2, a flush toilet apparatus 1 according to the first embodiment of the present invention is constituted by a flush toilet body 2 and a flush water tank body 4 that is disposed behind the flush toilet body 2. The flush toilet apparatus 1 according to the present embodiment is configured such that a lever handle 4a provided at the flush water tank body 4 is operated after use to perform a flush. In FIG. 1 and FIG. 2, illustration of a drain valve and other components included inside the flush water tank body 4 is omitted.

[0086] The flush toilet body 2 includes a bowl 2a and a drain trap pipeline 2b extending from a lower portion of the bowl 2a. A rim water ejection port 2c is provided in an upper edge portion of the bowl 2a, and a jet water ejection port 2d is provided in a lower portion of the bowl 2a. In a toilet flush, flush water is ejected at a predetermined timing through each of the rim water ejection port 2c and the jet water ejection port 2d, and a waste receiving surface of the bowl 2a is flushed while waste and the flush water in the bowl 2a are discharged to the drain trap pipeline 2b. The waste and the flush water discharged to the drain trap pipeline 2b are discharged to a sewage pipe (not illustrated) through a drain socket (not illustrated). The present embodiment is configured such that the cross-sectional area of the jet water ejection port 2d is larger than the cross-sectional area of the rim water ejection port 2c. If a plurality of the rim water ejection ports 2c are provided, it is preferable to configure such that the cross-sectional area of the jet water ejection port 2d is larger than the total of the cross-sectional areas of the rim water ejection ports 2c.

[0087] As illustrated in FIG. 3, flush water is supplied to the flush water tank body 4 from a water supply source 6, such as water supply, and the supplied flush water is stored in the flush water tank body 4. The flush water tank body 4 includes a rim drain valve 8 and a jet drain valve 10 that are incorporated therein and is configured to stop or allow flush water to be ejected through a drain port provided in a bottom portion of the flush water tank body 4.

[0088] In the present embodiment, the flush water discharged as a result of the rim drain valve 8 being opened passes through a rim water conduit 2e formed inside the flush toilet body 2 and is ejected through the rim water ejection port 2c. The flush water discharged as a result of the jet drain valve 10 being opened passes through a jet water conduit 2f formed inside the flush toilet body 2 and is ejected through the jet water ejection port 2d.

[0089] Next, with reference to FIG. 3 and FIG. 4, an internal structure of the flush water tank body 4 will be described.

[0090] As illustrated in FIG. 3 and FIG. 4, an inner tank 14 is disposed inside the flush water tank body 4. Inside the flush water tank body 4, there are also provided the rim drain valve 8 that is disposed outside the inner tank 14 and inside the flush water tank body 4, the jet drain valve 10 that is disposed inside the inner tank 14, a ball tap 16 that is a water supply valve, and a hydraulic drive mechanism 18.

[0091] The flush water tank body 4 and the inner tank 14 are containers configured to store flush water that should be supplied to the flush toilet body 2. In the present embodiment, the flush water tank body 4 is made of ceramic, and the inner tank 14 disposed inside the flush water tank body 4 is made of resin. In the present specification, the flush water stored inside the flush water tank body 4 includes flush water stored inside the inner tank 14 in addition to flush water stored in (outside the inner tank 14) the flush water tank body 4.

[0092] As illustrated in FIG. 1 and FIG. 4, a rim-water-ejection drain port 4b and a jet-water-ejection drain port 4c are provided in a bottom surface of the flush water tank body 4, and these drain ports are each configured to have a circular shape in the present embodiment. In the present embodiment, as illustrated in FIG. 2, the rim-water-ejection drain port 4b and the jet-water-ejection drain port 4c (only the jet-water-ejection drain port 4c is illustrated in FIG. 2) are formed at the same height as the height of an upper end surface of the bowl 2a, and the rim water ejection port 2c is formed below the upper end surface of the bowl 2a. Accordingly, in the present embodiment, each of the rim-water-ejection drain port 4b and the jet-water-ejection drain port 4c is provided at a position higher than the lower end of the rim water ejection port 2c.

[0093] Further, in the present embodiment, it is configured such that the flush water stored inside the flush water tank body 4 (and outside the inner tank 14) flows into the rim water conduit 2e of the flush toilet body 2 through the rim-water-ejection drain port 4b and the flush water stored inside the inner tank 14 flows into the jet water conduit 2f of the flush toilet body 2 through the jet-water-ejection drain port 4c. However, the inner tank 14 can be omitted, and, in this case, the flush water stored in a (undivided) single space inside the flush water tank body 4 is supplied to the flush toilet body 2 through each of the rim-water-ejection drain port 4b and the jet-water-ejection drain port 4c.

[0094] As illustrated in FIG. 4, the inner tank 14 is disposed on the bottom surface of the flush water tank body 4, and the bottom surface of the inner tank 14 has a circular discharge port 14a. The discharge port 14a of the inner tank 14 is arranged concentrically to be aligned with the jet-water-ejection drain port 4c provided in the flush water tank body 4. That is, in the present embodiment, the center of the circular jet-water-ejection drain port 4c coincides with the circular discharge port 14a in top view. Therefore, the flush water in the inner tank 14 is ejected through the discharge port 14a of the inner tank 14 and the jet-water-ejection drain port 4c of the flush water tank body 4 and flows into the jet water conduit 2f of the flush toilet body 2.

[0095] Further, in the present embodiment, the discharge port 14a of the inner tank 14 is formed by a drain-port formation member 14b constituted by a member that is separate from a body part of the inner tank 14. The drain-port formation member 14b is a tubular member and is attached to the bottom surface of the inner tank 14 in a watertight manner to form the discharge port 14a at the inner side of the drain-port formation member 14b. A sheet surface is provided at the upper end of the drain-port formation member 14b, and the discharge port 14a is closed by the jet drain valve 10 being seated on the seat surface. Accordingly, in the present embodiment, the seat surface on which the jet drain valve 10 is to be seated is constituted by a member that is separate from the inner tank 14.

[0096] In addition, an overflow pipe 15, which is an exhaust path, is attached to a side surface of the drain-port formation member 14b. The overflow pipe 15, which is a pipe that is bent into an L-shape, extends from the side surface of the drain-port formation member 14b and is open upward above the upper end of the inner tank 14. Consequently, a space inside the drain-port formation member 14b is in communication with outside air above a water surface in the inner tank 14 through the overflow pipe 15.

[0097] With this overflow pipe 15, when the water level of the flush water in the flush water tank body 4 exceeds the height of the overflow pipe 15, flush water flows into the overflow pipe 15 and is discharged to the jet water conduit 2f through the drain-port formation member 14b. Meanwhile, when, for example, flush water flows into the jet water conduit 2f, air of an air layer formed at an upstream end portion of the jet water conduit 2f is discharged to outside air through the overflow pipe 15. That is, in a standby state of the flush toilet apparatus 1, the upstream end portion of the jet water conduit 2f is filled with flush water to a water level W2 (FIG. 2, FIG. 4), and an air layer is formed between the water level W2 and the jet drain valve 10. When flush water flows into the air layer, the air in the air layer is pushed out to be discharged through the overflow pipe 15.

[0098] That is, the lower end of the overflow pipe 15 is in communication with an opening 15a provided in an inner peripheral surface of the drain-port formation member 14b, and the opening 15a is provided at a position below the jet drain valve 10 and higher than the water level W2 in the upstream end portion of the jet water conduit 2f. As described above, the overflow pipe 15 causes the inside of the jet water conduit 2f and the air layer in the flush water tank body 4 to be in communication with each other. Consequently, the inside of the jet water conduit 2f is in communication with outside air.

[0099] Next, as illustrated in FIG. 4, the rim drain valve 8 is a valve body that is disposed to open and close the rim-water-ejection drain port 4b provided in the flush water tank body 4, and the rim-water-ejection drain port 4b is opened as a result of the rim drain valve 8 being pulled upward. Consequently, the flush water in the flush water tank body 4 is discharged to the rim water conduit 2e (FIG. 1) of the flush toilet body 2 and is ejected through the rim water ejection port 2c. Therefore, the rim drain valve 8 is provided at the rim-water-ejection drain port 4b formed in the flush water tank body 4 and stops or allows flush water to be ejected through the rim water ejection port 2c via the rim water conduit 2e provided in the flush toilet body 2.

[0100] In the present embodiment, a user rotates the lever handle 4a provided at the flush water tank body 4 to pull a ball chain 8a (FIG. 4) coupled to the rim drain valve 8, and the rim drain valve 8 is pulled up. As a modification, the present invention also can be configured such that, to perform a flush, the rim drain valve 8 is pulled up on the basis of a control signal from a remote control device (not illustrated) or a detection signal from a human sensor (not illustrated).

[0101] The jet drain valve 10 is provided at the jet-water-ejection drain port 4c formed in the flush water tank body 4 and stops or allows flush water to be ejected through the jet water ejection port 2d via the jet water conduit 2f provided in the flush toilet body 2. That is, pulling the jet drain valve 10 upward separates the jet drain valve 10 from the seat surface of the discharge port 14a and opens the discharge port 14a. Consequently, the flush water in the inner tank 14 flows into the jet water conduit 2f (FIG. 1) through the discharge port 14a and the jet-water-ejection drain port 4c of the flush water tank body 4.

[0102] As described above, pulling up the jet drain valve 10 allows the flush water in the inner tank 14 to be discharged through the discharge port 14a, to flow into the jet water conduit 2f (FIG. 1) of the flush toilet body 2 through the jet-water-ejection drain port 4c, and to be ejected through the jet water ejection port 2d. If the inner tank 14 is omitted, the jet-water-ejection drain port 4c is opened and closed directly by the jet drain valve 10 to discharge the flush water in the flush water tank body 4.

[0103] As illustrated in FIG. 4, the jet drain valve 10 in the present embodiment is configured to be pulled up by the hydraulic drive mechanism 18 from the discharge port 14a. That is, the jet drain valve 10 is a valve body that includes a valve shaft 10a extending upward, and the valve shaft 10a is pulled up by the hydraulic drive mechanism 18. When pulled up to a predetermined height, the jet drain valve 10 is separated from the hydraulic drive mechanism 18 and descends slowly, and the discharge port 14a is closed. A configuration of the hydraulic drive mechanism 18 will be described later.

[0104] Further, the ball tap 16, which is a water supply valve, is configured such that flush water supplied from the water supply source 6 flows into the ball tap 16 through an inflow pipe 16a and such that the ball tap 16 switches between supply and stop of flush water that should be stored in the flush water tank body 4 and the inner tank 14.

[0105] As illustrated in FIG. 4, the inflow pipe 16a and an outflow pipe 16b are connected to the ball tap 16, and a valve seat 20b is opened and closed by a main valve body 20a incorporated in the ball tap 16. The ball tap 16 includes a float 22 and an arm 24 that is rotated by the float 22. The float 22 included in the ball tap 16 is actuated in conjunction with a water level in the flush water tank body 4, and, when the float 22 descends to a predetermined position, the incorporated main valve body 20a is opened, and flush water is supplied to the hydraulic drive mechanism 18.

[0106] That is, the main valve body 20a is disposed inside the ball tap 16 to open and close the valve seat 20b, and it is configured such that, when the main valve body 20a is opened, the tap water that has flowed in from the inflow pipe 16a flows out to the outflow pipe 16b through the valve seat 20b. The outflow pipe 16b is connected the hydraulic drive mechanism 18.

[0107] The main valve body 20a is a diaphragm-type valve body having a substantially disk shape and is mounted in the ball tap 16 so as to be capable of being seated on and separated from the valve seat 20b. Inside the ball tap 16, a pressure chamber 20c is formed at a side opposite to the valve seat 20b with respect to the main valve body 20a. A pilot valve port (not illustrated) is provided in the ball tap 16 so as to be in communication with the inside of the pressure chamber 20c. When the pilot valve port (not illustrated) is closed and a pressure in the pressure chamber 20c increases, the main valve body 20a is pressed against the valve seat 20b by the pressure and is seated on the valve seat 20b.

[0108] The float 22 is supported by the arm 24 with a pilot valve (not illustrated) coupled to the arm 24, and it is configured such that the pilot valve is moved with a rotation of the arm 24. In the present embodiment, the float 22 is disposed in the flush water tank body 4 and is moved upward and downward in response to the water level inside the flush water tank body 4. Thus, in a state in which the water level inside the flush water tank body 4 has risen to a predetermined water level or higher, the float 22 is pushed upward, and the pilot valve (not illustrated) is consequently moved to close the pilot valve port (not illustrated) provided in the ball tap 16. Meanwhile, when the flush water inside the flush water tank body 4 is drained and the water level drops, the float 22 moves downward, and the pilot valve port (not illustrated) is opened. Therefore, during a toilet-flush standby time in which the water level inside the flush water tank body 4 is higher than a predetermined water level, the pilot valve port (not illustrated) of the ball tap 16 is in a state of being closed.

[0109] The tap water that has flown from the inflow pipe 16a into the ball tap 16 flows into the pressure chamber 20c. Here, in a state in which the pilot valve port (not illustrated) is closed, the pressure in the pressure chamber 20c increases. When the pressure in the pressure chamber 20c increases as described above, the main valve body 20a is pressed toward the valve seat 20b by the pressure, and the valve seat 20b is closed by the main valve body 20a.

[0110] Meanwhile, when the rim drain valve 8 is opened by a flushing operation and the water level in the flush water tank body 4 becomes lower than a predetermined water level, the float 22 descends, the pilot valve (not illustrated) moves, and the pilot valve port (not illustrated) is opened. When the pilot valve port (not illustrated) is opened, the pressure in the pressure chamber 20c decreases. Consequently, the main valve body 20a is moved to be separated from the valve seat 20b, and the valve seat 20b is opened. As described above, in a state in which the pilot valve port (not illustrated) is opened, the pressure in the pressure chamber 20c does not increase, and the valve seat 20b is thus in a state of being opened.

[0111] Next, the configuration of the hydraulic drive mechanism 18 will be described with reference to FIG. 4.

[0112] The hydraulic drive mechanism 18 is configured to drive the jet drain valve 10 by utilizing a water supply pressure of flush water supplied from the water supply to the flush water tank body 4. Specifically, the hydraulic drive mechanism 18 includes a cylinder 18a into which the water supplied from the ball tap 16 flows, a piston 18b that is slidably disposed in the cylinder 18a, and a rod 28 that protrudes from the lower end of the cylinder 18a and drives the jet drain valve 10. Further, a spring 18c is disposed inside the cylinder 18a and downwardly urges the piston 18b, and a packing is attached to the piston 18b to ensure watertightness between an inner wall surface of the cylinder 18a and the piston 18b. A clutch mechanism 30 is provided at the lower end of the rod 28, and the rod 28 and the valve shaft 10a of the jet drain valve 10 are coupled to and separated from each other by the clutch mechanism 30.

[0113] The cylinder 18a, which is a cylindrical member, is disposed with the axis thereof extending in the vertical direction and receives the piston 18b in the inside thereof such that the piston 18b is slidable. The outflow pipe 16b extending from the ball tap 16 is connected to a lower end portion of the cylinder 18a such that the flush water that has flowed out from the ball tap 16 flows into the cylinder 18a. Therefore, the piston 18b in the cylinder 18a is pushed up against the urging force of the spring 18c by the water that has flowed into the cylinder 18a.

[0114] An outflow hole is provided in an upper end portion of the cylinder 18a, and a water supply pipe 32 is connected to the outflow hole. Therefore, when water flows into the cylinder 18a through the outflow pipe 16b connected to a lower portion of the cylinder 18a, the piston 18b is pushed upward from the lower portion of the cylinder 18a. When the piston 18b is pushed up to a position above the outflow hole, the water that has flowed into the cylinder 18a flows out to the water supply pipe 32 through the outflow hole. The flush water that has flowed into the water supply pipe 32 flows into the inner tank 14.

[0115] The rod 28 is a rod-shaped member connected to a lower surface of the piston 18b and extends to protrude downward from the inside of the cylinder 18a through a through hole formed in a bottom surface of the cylinder 18a. The valve shaft 10a of the jet drain valve 10 is connected to the lower end of the rod 28 via the clutch mechanism 30, and the rod 28 couples the piston 18b to the jet drain valve 10. Thus, when water flows into the cylinder 18a and the piston 18b is pushed up, the rod 28 connected to the piston 18b lifts the jet drain valve 10 upward, and the jet drain valve 10 is opened.

[0116] A gap is provided between the rod 28 that protrudes from below the cylinder 18a and an inner wall of the through hole of the cylinder 18a, and part of water that has flowed into the cylinder 18a flows out through the gap. The water that has flowed out through the gap flows into the inner tank 14. Since the gap is relatively narrow and flow path resistance is large, the pressure in the cylinder 18a is increased, even in a state in which water flows out through the gap, by the water that flows into the cylinder 18a from the outflow pipe 16b, and the piston 18b is pushed up against the urging force of the spring 18c.

[0117] Further, the clutch mechanism 30 detachably couples the rod 28 to the jet drain valve 10. The clutch mechanism 30 is configured to separate the valve shaft 10a of the jet drain valve 10 from the rod 28 when the jet drain valve 10 is lifted together with the rod 28 by a predetermined distance. In a state in which the clutch mechanism 30 is separated, the jet drain valve 10 is not in conjunction with a movement of the piston 18b and the rod 28, and the jet drain valve 10 descends with a drop in the water level in the inner tank 14, and the discharge port 14a of the inner tank 14 is closed.

[0118] Next, newly referring to FIG. 5, an operation of the flush toilet apparatus 1 according to the first embodiment of the present invention will be described.

[0119] FIG. 5 is a time chart illustrating an operation of the flush toilet apparatus 1 according to the first embodiment of the present invention and illustrates, in order from the upper stage, the state of jet water ejection, the state of rim water ejection, the state of the ball tap, and the water level in each portion.

[0120] First, in a toilet-flush standby state, the rim-water-ejection drain port 4b of the flush water tank body 4 and the discharge port 14a of the inner tank 14 are closed by the rim drain valve 8 and the jet drain valve 10, respectively. In the standby state, an initial water level in the flush water tank body 4 is higher than a predetermined water level. Consequently, the pilot valve port (not illustrated) of the ball tap 16 (FIG. 4) is in a state of being closed, and the valve seat 20b is closed by the main valve body 20a. Further, as illustrated in FIG. 2, in the standby state (before the time t1 in FIG. 5), a water level W1 of retained water in the bowl 2a, the water level W2 in the upstream end portion of the jet water conduit 2f, and a water level W3 in the drain trap pipeline 2b are identical to each other and coincide with the height of a top portion 2g of the drain trap pipeline 2b.

[0121] Since the water level W2 in the upstream end portion of the jet water conduit 2f is positioned below the jet-water-ejection drain port 4c of the flush water tank body 4, an air layer is present between the water surface in the upstream end portion of the jet water conduit 2f and the jet-water-ejection drain port 4c in the standby state.

[0122] Next, when a user rotates the lever handle 4a (FIG. 4) of the flush water tank body 4 at the time t1 in FIG. 5 to perform a toilet flush, the ball chain 8a connected to the lever handle 4a pulls up the rim drain valve 8. Consequently, the rim drain valve 8 is separated from the rim-water-ejection drain port 4b, and the rim-water-ejection drain port 4b is opened. When the rim-water-ejection drain port 4b is opened, the flush water stored inside the flush water tank body 4 (outside the inner tank 14) flows into the rim water conduit 2e (FIG. 1) through the rim-water-ejection drain port 4b and is ejected through the rim water ejection port 2c. The rim water ejection through the rim water ejection port 2c forms a swirling flow on the waste receiving surface of the bowl 2a, and the waste receiving surface is flushed. The ejection of flush water through the rim water ejection port 2c forms a swirling flow on an inner wall surface of the bowl 2a, the swirling flow makes one or more revolutions in the bowl 2a, and the bowl 2a is thoroughly flushed.

[0123] The flush water ejected through the rim water ejection port 2c first flows into the bowl 2a, and the water level W1 of the retained water in the bowl 2a rises. When the water level W1 of the retained water in the bowl 2a rises, the water level W3 in the drain trap pipeline 2b also rises with a delay since the bowl 2a and the drain trap pipeline 2b are in communication with each other through an inlet of the drain trap pipeline 2b. Further, when the water level W1 of the retained water in the bowl 2a rises, flush water flows into the jet water conduit 2f through the jet water ejection port 2d since the bowl 2a and the jet water conduit 2f are in communication with each other through the jet water ejection port 2d. Thus, the water level W2 in the upstream end portion of the jet water conduit 2f also rises with a delay after the water level W1 of the retained water in the bowl 2a rises.

[0124] As described above, after a flush is started at the time t1, flush water is supplied into the jet water conduit 2f before the jet drain valve is opened (time t2 in FIG. 5) in the present embodiment. That is, in the present embodiment, flush water is supplied into the jet water conduit 2f by, after a flush is started and before the jet drain valve 10 is opened (time t2 in FIG. 5), opening (time t1 in FIG. 5) the rim drain valve 8 to allow flush water to be ejected through the rim water ejection port 2c and to thereby allow flush water to flow into the jet water conduit 2f through the jet water ejection port 2d.

[0125] As a result of flush water being thus supplied into the jet water conduit 2f, the water level W2 in the upstream end portion of the jet water conduit 2f rises. Here, as described above, the air layer is present between the water surface in the upstream end portion of the jet water conduit 2f and the jet-water-ejection drain port 4c. Therefore, when the water level W2 in the upstream end portion of the jet water conduit 2f rises, the air in the air layer is discharged to outside air (above the water surface in the flush water tank body 4) through the overflow pipe 15, which is an exhaust path.

[0126] However, even in a state in which the water level W2 has risen to a highest position before the jet drain valve 10 is opened, the water level W2 is at a position lower than the jet-water-ejection drain port 4c, and the air layer remains. That is, the jet water conduit 2f is configured such that the air layer remains inside the jet water conduit 2f even in a state in which flush water has been supplied into the jet water conduit 2f before the jet drain valve 10 is opened. The opening 15a provided in the inner peripheral surface of the drain-port formation member 14b in communication with the overflow pipe 15 is still at a position higher than the water level W2 even in a state in which the water level W2 in the upstream end portion of the jet water conduit 2f has risen. Therefore, a rise in the water level W2 does not cause flush water to intrude from the lower end of the overflow pipe 15.

[0127] As described above, after water ejection through the rim water ejection port 2c is started and before the jet drain valve 10 is opened, the water level W2 rises, and the water level W3 in the drain trap pipeline 2b also rises. As illustrated in FIG. 5, the rise in the water level W3 in the drain trap pipeline 2b increases faster than the rise in the water level W2. As described above, supply of flush water into the jet water conduit 2f causes the water level W2 in the jet water conduit 2f to rise and, at the point of time (time t2 in FIG. 5) when the jet drain valve 10 is opened, causes the water level W3 in the drain trap pipeline 2b to rise to be higher than the water level W2 in the jet water conduit 2f.

[0128] Meanwhile, discharge of flush water through the rim-water-ejection drain port 4b causes the water level in the flush water tank body 4 to drop. Consequently, the float 22 of the ball tap 16 (FIG. 4) descends, and the pilot valve port (not illustrated) is opened. As a result, the pressure in the pressure chamber 20c decreases, and the main valve body 20a is opened and allows flush water to be supplied to the hydraulic drive mechanism 18 (FIG. 4) through the outflow pipe 16b.

[0129] When flush water is supplied to the hydraulic drive mechanism 18, the flush water that has flowed into the cylinder 18a pushes up the piston 18b against the urging force of the spring 18c. Consequently, the rod 28 coupled to the piston 18b pulls up the valve shaft 10a of the jet drain valve 10, and the discharge port 14a of the inner tank 14 is opened. That is, the jet drain valve 10 is driven and opened by a water supply pressure of the tap water supplied via the ball tap 16.

[0130] Consequently, the discharge port 14a is opened at the time t2 in FIG. 5, and the flush water stored in the inner tank 14 flows into the jet water conduit 2f (FIG. 2) through the discharge port 14a and the jet-water-ejection drain port 4c and is ejected through the jet water ejection port 2d. Further, jet water ejection through the jet water ejection port 2d fills the inside of the drain trap pipeline 2b with water and induces a siphon action. Due to generation of the siphon action, the retained water and waste in the bowl 2a are suctioned into the drain trap pipeline 2b and discharged to a sewage pipe (not illustrated).

[0131] That is, as illustrated in FIG. 5, when the discharge port 14a is opened at the time t2 and flush water is ejected through the jet water ejection port 2d, the water level W3 in the drain trap pipeline 2b rises in a short period, and the inside of the drain trap pipeline 2b is filled with water. Consequently, a siphon action is generated, and the retained water in the bowl 2a is thus suctioned into the drain trap pipeline 2b, and the water level W1 of the retained water in the bowl 2a drops. As described above, the water level W3 in the drain trap pipeline 2b has risen before the jet drain valve 10 is opened. The inside of the drain trap pipeline 2b is thus filled with water early when jet water ejection is started, and the time from the start of jet water ejection to generation of a siphon action is shortened. (The graph of the water level W2 between the time t2 to the time t3 in FIG. 5 roughly illustrates the water level W2 since it is difficult to precisely specify the water level W2 in the upstream end portion of the jet water conduit 2f in a state in which the jet drain valve 10 is opened and in which flush water has flowed into the jet water conduit 2f through the jet-water-ejection drain port 4c.)

[0132] As described above, the water level W2 in the upstream end portion of the jet water conduit 2f has risen before the jet drain valve 10 is opened, and the air layer above the water level W2 has been reduced. Therefore, the air layer at the upstream end of the jet water conduit 2f may be filled with water in a short time when the jet drain valve 10 is opened, and flush water may be ejected early through the jet water ejection port 2d. In the present embodiment, the jet drain valve 10 is opened at the timing when the water level in the jet water conduit 2f rises to a highest position or after the timing.

[0133] As described above, in the flush toilet apparatus 1 according to the present embodiment, a siphon action may be generated in the drain trap pipeline 2b early after the jet drain valve 10 is opened. In particular, the water head pressure of the flush water that is discharged early through the jet-water-ejection drain port 4c (discharge port 14a) is high since the water level in the inner tank 14 is high. In the present embodiment, since it is configured such that the air layer at the upstream end of the jet water conduit 2f is relatively small, the flush water with a high water head pressure immediately after drainage is started may be not easily wasted for filling the air layer. As a result, the flush water with a high water head pressure may be effectively utilized for a toilet flush, and an instantaneous flow rate of flush water ejected through the jet water ejection port 2d may be increased. The jet water conduit 2f is configured such that an air pocket is formed inside the jet water conduit 2f in the vicinity of a ceiling surface of the jet water conduit 2f even after the jet drain valve 10 is opened. Therefore, an effective volume of the jet water conduit 2f may be reduced, and flush water that is wasted before a siphon action is started may be reduced.

[0134] Meanwhile, when the jet drain valve 10 is pulled up together with the piston 18b of the hydraulic drive mechanism 18 to a predetermined height, the valve shaft 10a of the jet drain valve 10 is separated from the rod 28 by the clutch mechanism 30 (FIG. 4). Consequently, the jet drain valve 10 descends toward the discharge port 14a with a drop in the water level in the inner tank 14. Then, at the time t3 in FIG. 5, the jet drain valve 10 is seated at the discharge port 14a, and the discharge port 14a is closed. Consequently, jet water ejection through the jet water ejection port 2d is stopped.

[0135] When the jet drain valve 10 is closed and jet water ejection is stopped, the siphon action in the drain trap pipeline 2b stops, and the flush water in the bowl 2a is not suctioned into the drain trap pipeline 2b. Meanwhile, since water ejection through the rim water ejection port 2c is continued, the water level W1 in the bowl 2a starts to rise after the jet drain valve 10 is closed. Along with this, the water level W2 in the jet water conduit 2f also rises. In addition, the stop of the siphon action causes the water level W3 in the drain trap pipeline 2b to rapidly drop.

[0136] In a state in which the main valve body 20a of the ball tap 16 is opened, the flush water supplied from the water supply source 6 (water supply) is supplied to the hydraulic drive mechanism 18 via the ball tap 16 and flows into the inner tank 14 through the water supply pipe 32 (FIG. 4) connected to the cylinder 18a. Therefore, after jet water ejection is stopped at the time t3 in FIG. 5, the water level in the inner tank 14 is caused to rise by the flush water that flows in from the water supply pipe 32.

[0137] Meanwhile, since the rim drain valve 8 is still in a state of being opened, the flush water in the flush water tank body 4 flows out through the rim-water-ejection drain port 4b, and the water level in the flush water tank body 4 continues to drop. When the water level in the flush water tank body 4 drops to a predetermined dead water level at the time t4 in FIG. 5, the rim drain valve 8 is seated at the rim-water-ejection drain port 4b, and the rim drain valve 8 is closed. Consequently, rim water ejection through the rim water ejection port 2c is stopped. At the time t4 when rim water ejection is stopped, the water level W1 in the bowl 2a, the water level W2 in the jet water conduit 2f, and the water level W3 in the drain trap pipeline 2b return to respective water levels in the standby state.

[0138] Further, since the main valve body 20a of the ball tap 16 is maintained in the state of being opened even after the rim drain valve 8 is closed, the flush water supplied from the water supply source 6 (water supply) flows into the inner tank 14 from the water supply pipe 32 via the ball tap 16 and the hydraulic drive mechanism 18. Consequently, the water level in the inner tank 14 rises. When the inner tank 14 is filled with water at the time t5 in FIG. 5, the flush water that has flowed into the inner tank 14 from the water supply pipe 32 overflows and flows into the flush water tank body 4. Consequently, the water level in the flush water tank body 4 starts to rise.

[0139] Next, when the water level in the flush water tank body 4 rises to a predetermined water level, the float 22 of the ball tap 16 rises, and the pilot valve (not illustrated) is closed. When the pilot valve is closed as described above, the pressure in the pressure chamber 20c increases. Then, at the time t6 in FIG. 5, the main valve body 20a is pressed by the pressure in the pressure chamber 20c to be seated on the valve seat 20b, and the main valve body 20a is closed. Consequently, water supply to the hydraulic drive mechanism 18 from the water supply source 6 via the ball tap 16 is stopped, and supply of flush water into the inner tank 14 is stopped.

[0140] When water supply to the hydraulic drive mechanism 18 is stopped, the piston 18b (FIG. 4) in the cylinder 18a that has been pushed up by the water supply is pushed down by the urging force of the spring 18c. Along with this, the rod 28 attached to the piston 18b also descends. When the rod 28 descends to a predetermined position, the clutch mechanism 30 couples the rod 28 again to the valve shaft 10a of the jet drain valve 10. Through the above operations, a single toilet flush ends, and the flush toilet apparatus 1 returns to the toilet-flush standby state.

[0141] According to the flush toilet apparatus 1 in the first embodiment of the present invention, since there are included the rim drain valve 8, which stops or allows flush water to be ejected through the rim water ejection port 2c, and the jet drain valve 10, which stops or allows flush water to be ejected through the jet water ejection port 2d, the timing of ejecting flush water through each of the ejection ports may be precisely set, and flush water may be effectively utilized. According to the flush toilet apparatus 1 in the present embodiment, since the overflow pipe 15, which is an exhaust path along which the air of the air layer in the jet water conduit 2f is discharged, is included and flush water is supplied into the jet water conduit 2f after a flush is started and before the jet drain valve 10 is opened, the air in the jet water conduit 2f is discharged, and the water level W2 in the jet water conduit 2f rises. As a result, flush water may be ejected through the jet water ejection port 2d early after the jet drain valve 10 is opened, and jet water ejection may be started at a desired timing. Consequently, it is possible to ensure sufficient flushing performance and also achieve water saving by effectively utilizing the flush water stored in the flush water tank.

[0142] In addition, according to the flush toilet apparatus 1 in the present embodiment, since flush water is supplied into the jet water conduit 2f by opening the rim drain valve 8 to allow flush water to be ejected through the rim water ejection port 2c before the jet drain valve 10 is opened, the water level in the jet water conduit 2f may be caused to rise without a special configuration for supplying flush water into the jet water conduit 2f.

[0143] Further, according to the flush toilet apparatus 1 in the present embodiment, since the water level in the drain trap pipeline 2b rises to be higher than the water level in the jet water conduit 2f, the air remaining in the drain trap pipeline 2b may be discharged early, and a siphon action may be started in the drain trap pipeline 2b early after jet water ejection is started. Consequently, a siphon action may be started with a less amount of flush water, and water saving may be achieved.

[0144] According to the flush toilet apparatus 1 in the present embodiment, since the cross-sectional area of the jet water ejection port 2d is larger than the cross-sectional area of the rim water ejection port 2c, water ejection may be performed at a large flow rate through the jet water ejection port 2d, and a siphon action may be generated in the drain trap pipeline 2b in a short period. Consequently, a siphon action may be started with a less amount of flush water, and water saving may be achieved.

[0145] Further, according to the flush toilet apparatus 1 in the present embodiment, since water ejection through the rim water ejection port 2c forms a swirling flow and the swirling flow makes one or more revolutions in the bowl 2a, the inner wall surface of the bowl 2a may be thoroughly flushed while water saving is achieved.

[0146] According to the flush toilet apparatus 1 in the present embodiment, since the jet drain valve 10 is opened when or after the water level W2 in the jet water conduit 2f rises to a highest position, the jet drain valve 10 is opened after exhaustion of the air of the air layer in the jet water conduit 2f is completed. Consequently, mixing of the air in the air layer into flush water may be suppressed, and generation of an abnormal noise at the time of jet water ejection may be suppressed.

[0147] Further, according to the flush toilet apparatus 1 in the present embodiment, since one end of the overflow pipe 15 is open at a position higher than the water level W2 that has risen in the jet water conduit 2f due to supply of flush water into the jet water conduit 2f, air may be exhausted even in a state in which the water level W2 in the jet water conduit 2f has risen, and the water level W2 in the jet water conduit 2f may be easily caused to rise.

[0148] According to the flush toilet apparatus 1 in the present embodiment, since the overflow pipe 15, which is an exhaust path, is configured such that the inside of the jet water conduit 2f and the air layer, which is outside air, in the flush water tank body 4 are in communication with each other, the air in the jet water conduit 2f may be easily discharged.

[0149] Further, according to the flush toilet apparatus 1 in the present embodiment, since the air layer remains inside the jet water conduit 2f even in a state in which flush water has been supplied into the jet water conduit 2f before the jet drain valve 10 is opened, an infiltration of flush water into the overflow pipe 15 may be avoided.

[0150] According to the flush toilet apparatus 1 in the present embodiment, since the jet water conduit 2f is configured such that an air pocket is formed inside the jet water conduit 2f after the jet drain valve 10 is opened, an effective volume of the jet water conduit 2f may be reduced, and wasted flush water may be reduced.

[0151] While the flush toilet apparatus according to the first embodiment of the present invention has been described above, the above-described embodiment can be variously modified. In particular, in the above-described embodiment, the hydraulic drive mechanism 18 is used to open the jet drain valve 10 to thereby open the jet drain valve 10 after the rim drain valve 8 is opened. In contrast, as a modification, the rim drain valve 8 and/or the jet drain valve 10 may be configured to be opened using power of a motor (not illustrated), and the motor may be actuated such that the jet drain valve 10 is opened with a delay. Alternatively, the rim drain valve 8 and the jet drain valve 10 may be each configured to be pulled up by a ball chain or the like connected to the lever handle 4a, and the present invention can be configured such that the ball chain or the like attached to the jet drain valve 10 is lengthened to cause the jet drain valve 10 to be opened after the rim drain valve 8 is opened.

[0152] In addition, while the air of the air layer in the upstream end portion of the jet water conduit 2f is exhausted through the overflow pipe 15 in the above-described embodiment, a pipe for exhausting air can be separately provided as a modification. In the modification illustrated in FIG. 6, an opening 34 is provided in a horizontal surface of the upper end of the bowl 2a of the flush toilet body 2, and an exhaust pipe 36 is attached to the opening 34 to ensure an exhaust path. That is, the opening 34 provided in the horizontal surface of the upper end of the bowl 2a is in communication with the jet water conduit 2f provided in the flush toilet body 2. The exhaust pipe 36 is mounted so as to extend vertically upward from the opening 34 to serve as an exhaust path. Thus, one end of the exhaust path is open upward in the ceiling surface of the jet water conduit in the present modification. That is, with one end of the exhaust path being open upward in the ceiling surface of the jet water conduit, even when flush water in the jet water conduit 2f intrudes into the exhaust path, the flush water is discharged immediately, and a stable air passage may be ensured.

Second Embodiment

[0153] Next, a flush toilet apparatus according to a second embodiment of the present invention will be described with reference to the accompanying drawings.

[0154] FIG. 7 is a block diagram illustrating the flush toilet apparatus according to the second embodiment of the present invention. FIG. 8 is a sectional view illustrating a general configuration of a flush water tank included in the flush toilet apparatus according to the second embodiment of the present invention. FIG. 9 is a sectional view illustrating a structure of a ball tap incorporated in the flush water tank in the flush toilet apparatus according to the second embodiment of the present invention. FIG. 10 is a sectional view illustrating a structure of a hydraulic drive mechanism incorporated in the flush water tank in the flush toilet apparatus according to the second embodiment of the present invention.

Basic Configuration

[0155] As illustrated in FIG. 7, a flush toilet apparatus 101 according to an embodiment of the present invention includes a flush toilet body 102, which is a flush toilet bowl, and a flush water tank 104, which is a flush water tank body disposed behind the flush toilet body 102. The flush toilet apparatus 101 according to the present embodiment is configured such that a lever handle 104a provided at the flush water tank 104 is operated after use to perform a flush. As a modification, the present invention can be configured such that a flush is performed on the basis of a control signal from a remote control device (not illustrated) or a detection signal from a human sensor (not illustrated).

[0156] The flush toilet body 102 includes a bowl 102a and a drain trap pipeline 102c extending from a lower portion of the bowl 102a. A rim water ejection port 102d is provided in an upper edge portion of the bowl 102a, and a jet water ejection port 102e is provided in a lower portion of the bowl 102a. In a toilet flush, flush water is ejected at a predetermined timing through each of the rim water ejection port 102d and the jet water ejection port 102e, and a waste receiving surface of the bowl 102a is flushed while waste and the flush water in the bowl 102a are discharged to the drain trap pipeline 102c. The waste and the flush water discharged to the drain trap pipeline 102c are discharged to a sewage pipe (not illustrated) through a drain socket (not illustrated).

[0157] Flush water is supplied to the flush water tank 104 from a water supply source 106, such as water supply, via a stop valve 108. The supplied flush water is stored to a predetermined water level in the flush water tank 104. The stop valve 108 is provided to stop supply of flush water to the flush water tank 104 at the time of maintenance or the like and is in a state of open during a normal time. A first drain valve 110, which is a rim drain valve, and a second drain valve 112, which is a jet drain valve, are incorporated in the flush water tank 104 and are configured to open and close a first drain port 104b, which is a rim-water-ejection drain port, and a second drain port 104c, which is a jet-water-ejection drain port, respectively, the first drain port 104b and the second drain port 104c each being provided in a bottom portion of the flush water tank 104. The flush water tank 104 may be integrated with the flush toilet body 102 and may be separate from the flush toilet body 102.

[0158] Flush water that flows out through the first drain port 104b passes through a rim water conduit 102f formed inside the flush toilet body 102 and is ejected through the rim water ejection port 102d. That is, the flush water tank 104 is located above the rim water ejection port 102d. Therefore, the first drain valve 110 switches between stop and ejection of flush water through the rim water ejection port 102d by closing and opening the first drain port 104b provided in the flush water tank 104. The flush water that flows out through the second drain port 104c passes through a jet water conduit 102g formed inside the flush toilet body 2 and is ejected through the jet water ejection port 102e. Therefore, the second drain valve 112 switches between stop and ejection of flush water through the jet water ejection port 102e by closing and opening the second drain port 104c provided in the flush water tank 104.

Internal Structure

[0159] Next, an internal structure of the flush water tank 104 will be described with reference to FIG. 8.

[0160] As illustrated in FIG. 8, the flush water tank 104 includes the first drain valve 110 that opens and closes the first drain port 104b, the second drain valve 112 that opens and closes the second drain port 104c, a ball tap 114 that is a delay mechanism, and a hydraulic drive mechanism 116.

[0161] The flush water tank 104 is a tank configured to store flush water that should be supplied to the flush toilet body 102, and the first drain port 104b and the second drain port 104c for discharging the stored flush water to the flush toilet body 102 are each formed in a bottom portion of the flush water tank 104.

[0162] The first drain valve 110 is a valve body that is disposed to open and close the first drain port 104b, and the first drain valve 110 is pulled upward to open the first drain port 104b. Consequently, the flush water in the flush water tank 104 is discharged to the rim water conduit 102f (FIG. 7) of the flush toilet body 102 and is ejected through the rim water ejection port 102d.

[0163] In the present embodiment, a user rotates the lever handle 104a, which is provided at the flush water tank 104, to pull a ball chain 110a (schematically illustrated in FIG. 8) coupled to the first drain valve 110, and the first drain valve 110 is pulled up. In the present embodiment, the first drain valve 110 is a valve body that includes a floating ball 110b and is configured such that, after pulled up from the first drain port 104b and opened, the first drain valve 110 descends slowly with a drop in the water level in the flush water tank 104 and is closed when the water level drops to a predetermined water level.

[0164] The second drain valve 112 is a valve body that is disposed to open and close the second drain port 104c, and the second drain valve 112 is pulled upward to open the second drain port 104c. Consequently, the flush water in the flush water tank 104 is discharged to the jet water conduit 102g (FIG. 7) of the flush toilet body 102 and is ejected through the jet water ejection port 102e.

[0165] In the present embodiment, the second drain valve 112 is configured to be pulled up by the hydraulic drive mechanism 116 (by using an operation of the hydraulic drive mechanism 116 as a drive input) from the second drain port 104c. The second drain valve 112 is a valve body that includes a valve shaft 112a extending upward and a floating ball 112b, and the valve shaft 112a is pulled up by the hydraulic drive mechanism 116. When pulled up to a predetermined height, the second drain valve 112 is separated from the hydraulic drive mechanism 116 and descends slowly with a drop in the water level in the flush water tank 104, and the second drain port 104c is closed.

[0166] In the present embodiment, since the floating ball 112b of the second drain valve 112 is attached to a position higher than the floating ball 110b of the first drain valve 110, the second drain valve 112 is seated at the second drain port 104c in a state in which the water level in the flush water tank 104 is relatively high, and the second drain port 104c is closed. That is, when the first drain valve 110 and the second drain valve 112 descend with a drop in the water level in the flush water tank 104, the second drain valve 112 is first seated at the second drain port 104c, and the second drain port 104c is closed.

[0167] The ball tap 114, which is a delay mechanism, is configured such that the flush water supplied from the water supply source 106 flows into the ball tap 114 through an inflow pipe 114a, and the operation of the hydraulic drive mechanism 116 is delayed by the operation of the ball tap 114. As a result, in the present embodiment, the second drain valve 112 is opened with a delay (the degree of the delay is adjustable by structural design of the ball tap 114) after the first drain valve 110 is opened.

Ball Tap 114

[0168] Next, a configuration of the ball tap 114 will be described with reference to FIG. 9.

[0169] As illustrated in FIG. 9, the ball tap 114 includes a body portion 118 to which the inflow pipe 114a and an outflow pipe 114b are connected, a main valve body 120 that is disposed in the body portion 118, a valve seat 122 on which the main valve body 120 is to be seated, an arm portion 126 that is rotated by a float 124, and a pilot valve 128 that is moved by a rotation of the arm portion 126. That is, the ball tap 114 includes the float 124 that is actuated in conjunction with a water level in the flush water tank 104 and is configured to supply flush water to the hydraulic drive mechanism 116 when the float 124 descends to a predetermined position (adjustable by structural design).

[0170] The body portion 118 is a member in which a connecting portion for the inflow pipe 114a is provided at a lower portion thereof and a connecting portion for the outflow pipe 114b is provided at one side thereof. The valve seat 122 is formed inside the body portion 118, and the valve seat 122 is in communication with the outflow pipe 114b connected to the connecting portion. Further, the main valve body 120 is disposed inside the body portion 118 to open and close the valve seat 122, and it is configured such that, when the main valve body 120 is opened, the tap water that has flowed in from the inflow pipe 114a flows out to the outflow pipe 114b through the valve seat 122. The outflow pipe 114b is connected to the hydraulic drive mechanism 116.

[0171] The main valve body 120 is a diaphragm-type valve body having a substantially disk shape and is mounted in the body portion 118 to be capable of being seated on and separated from the valve seat 122. A bleed hole 120a is provided in a peripheral portion of the main valve body 120. Inside the body portion 118, a pressure chamber 118a is formed at a side (the left side in FIG. 9) opposite to the valve seat 122 with respect to the main valve body 120. That is, the pressure chamber 118a is demarcated by an inner wall surface of the body portion 118 and the main valve body 120, and, when the pressure in the pressure chamber 118a increases, the main valve body 120 is pressed against the valve seat 122 by the pressure and is seated on the valve seat 122.

[0172] Further, a pressure passage 118b extends upward so as to be in communication with the pressure chamber 118a provided in the body portion 118, and a pilot valve port 128a is provided in the upper end of the pressure passage 118b. The pilot valve port 128a is open upward and is configured to be opened and closed by the pilot valve 128.

[0173] Meanwhile, the float 124 is supported by the arm portion 126, and the arm portion 126 is rotatably supported by a support shaft 126a. Further, the pilot valve 128 is coupled to the arm portion 126, and it is configured such that the pilot valve 128 is moved in the up-down direction with a rotation of the arm portion 126.

[0174] Consequently, in a state in which the water level in the flush water tank 104 has risen to a predetermined set water level L101 or higher, the float 124 is pushed upward, the pilot valve 128 is consequently moved downward to be seated at the pilot valve port 128a, and the pilot valve port 128a is closed. Meanwhile, when the flush water in the flush water tank 104 is drained and the water level in the flush water tank 104 drops, the float 124 moves downward, the pilot valve 128 moves upward, and the pilot valve port 128a is opened. (Therefore, during the toilet flush standby time, in which the water level in the flush water tank 104 is higher than the set water level L101, the pilot valve port 128a of the body portion 118 is in a state of being closed.)

[0175] The tap water that has flowed into the body portion 118 from the inflow pipe 114a flows into an annular space at the periphery of the valve seat 122 and flows from here into the pressure chamber 118a through the bleed hole 120a of the main valve body 120.

[0176] Here, in a state in which the pilot valve port 128a is closed by the pilot valve 128, a path along which the tap water that has flowed into the pressure chamber 118a through the bleed hole 120a flows out is not present, and the pressure in the pressure chamber 118a increases. When the pressure in the pressure chamber 118a increases as described above, the main valve body 120 is pressed toward (toward the right side in FIG. 9) the valve seat 122 by the pressure, and the valve seat 122 is closed by the main valve body 120.

[0177] Meanwhile, when the first drain valve 110 is opened by a flushing operation and the water level in the flush water tank 104 drops to be lower than the set water level L101, the float 124 moves downward, the pilot valve 128 moves upward, and the pilot valve port 128a is opened. When the pilot valve port 128a is opened, the water in the pressure chamber 118a flows out through the pilot valve port 128a, and the pressure in the pressure chamber 118a decreases. Consequently, the main valve body 120 is moved to be separated from the valve seat 122 (toward the left side in FIG. 9), and the valve seat 122 is opened. As described above, the pressure in the pressure chamber 118a does not increase in a state in which the pilot valve port 128a is opened, and the valve seat 122 is thus in a state of being opened.

Hydraulic Drive Mechanism 116

[0178] Next, a configuration of the hydraulic drive mechanism 116 will be described with reference to FIG. 10.

[0179] The hydraulic drive mechanism 116 is configured to drive the second drain valve 112 by utilizing a water supply pressure of flush water supplied to the flush water tank from the water supply. Specifically, the hydraulic drive mechanism 116 includes a cylinder 116a into which the water supplied from the ball tap 114 flows, a piston 116b that is slidably disposed in the cylinder 116a, and a rod 130 that protrudes from the lower end of the cylinder 116a and drives the second drain valve 112. A spring 116c is disposed inside the cylinder 116a and urges the piston 116b downwardly. A packing is attached to the piston 116b to ensure watertightness between an inner wall surface of the cylinder 116a and the piston 116b. A clutch mechanism 132 is provided at the lower end of the rod 130, and the rod 130 and the valve shaft 112a of the second drain valve 112 are coupled to/separated from each other by the clutch mechanism 132.

[0180] The cylinder 116a is a cylindrical member and is disposed such that the axis thereof is directed in the vertical direction, and the piston 116b is slidably received inside the cylinder 116a. The outflow pipe 114b extending from the ball tap 114 is connected to a lower end portion of the cylinder 116a such that the flush water flowing out from the ball tap 114 flows into the cylinder 116a. Therefore, the piston 116b in the cylinder 116a is configured to be pushed up against the urging force of the spring 116c by the water that flows into the cylinder 116a.

[0181] An outflow hole is provided in an upper end portion of the cylinder 116a, and a water supply pipe 134 is in communication with the inside of the cylinder 116a through the outflow hole. Accordingly, when water flows into the cylinder 116a from the outflow pipe 114b connected to a lower portion of the cylinder 116a, the piston 116b is pushed upward from the lower portion of the cylinder 116a, and, when the piston 116b is pushed up to a position above the outflow hole, the water that flows into the cylinder 116a flows out to the water supply pipe 134 through the outflow hole. The flush water that has flowed into the water supply pipe 134 falls into the flush water tank 104, and the flush water is consequently supplied to the flush water tank 104.

[0182] The rod 130 is a rod-shaped member that is connected to a lower surface of the piston 116b and extends to protrude downward from the inside of the cylinder 116a through a through hole formed in a bottom surface of the cylinder 116a. The valve shaft 112a of the second drain valve 112 is connected to the lower end of the rod 130 via the clutch mechanism 132. That is, the rod 130 couples the piston 116b and the second drain valve 112 to each other via the clutch mechanism 132. Thus, when water flows into the cylinder 116a and the piston 116b is pushed up, the rod 130 connected to the piston 116b lifts the second drain valve 112 upward, and the second drain valve 112 is opened.

[0183] A gap is provided between the rod 130 protruding from below the cylinder 116a and an inner wall of the through hole of the cylinder 116a, and part of the water that flows into the cylinder 116a flows out also through the gap. The water that flows out through the gap flows into the flush water tank 104. However, since the gap is relatively narrow and flow path resistance is large, the pressure in the cylinder 116a is increased, even in a state in which water flows out through the gap, by the water that flows into the cylinder 116a from the outflow pipe 114b, and the piston 116b is pushed up against the urging force of the spring 116c.

[0184] Further, the clutch mechanism 132 detachably couples the rod 130 and the second drain valve 112 to each other. Specifically, the clutch mechanism 132 is configured to separate the valve shaft 112a of the second drain valve 112 from the rod 130 when the second drain valve 112 is lifted together with the rod 130 by a predetermined distance. In the separated state, the second drain valve 112 is not in conjunction with a movement of the piston 116b and an upper portion of the rod 130 and thus descends with a drop in the water level in the flush water tank 104.

Jet Water Conduit 102g

[0185] Next, FIG. 11 and FIG. 12 are a schematic side view and a schematic vertical cross-sectional view, respectively, illustrating the jet water conduit 102g extending from the flush water tank 104 to the jet water ejection port 102e.

[0186] As illustrated in FIG. 11, the jet water ejection port 102e is provided at the front side of a lower portion of the bowl 102a.

[0187] As illustrated in FIG. 11 and FIG. 12, the jet water conduit 102g has an upstream region 161 that is located directly under the second drain valve 112, an intermediate region 162 that extends forward from the upstream region 161 in plan view, and a downstream region 163 that extends, below the water level of the retained water, sideward from a front region of the intermediate region 162 and that reaches the jet water ejection port 102e by avoiding a lower portion of the bowl 102a and the drain trap pipeline 102c.

[0188] In the present embodiment, a vertical cross-section of the upstream region 161 perpendicular to the front-rear direction has a maximum value in a cross-section along line XIII-XIII in FIG. 12 located at the most downstream side of the upstream region 161, and the maximum value is approximately 2400 mm.sup.2. The cross-section along line XIII-XIII is illustrated in FIG. 13.

[0189] In the present embodiment, a vertical cross-section of the intermediate region 162 perpendicular to the front-rear direction has a maximum value in a cross-section along line XIV-XIV in FIG. 12 located in the vicinity of a rear end portion of a toilet seat surface, and the maximum value is approximately 7300 mm.sup.2. The cross-section along line XIV-XIV is illustrated in FIG. 14.

[0190] In the present embodiment, a vertical cross-section of the downstream region 163 perpendicular to a flow path direction has a maximum value in a cross-section along line XV-XV in FIG. 11 located at a connecting portion (a transition portion from the intermediate region 162) connected to the intermediate region 162, and the maximum value is approximately 2000 mm.sup.2. The cross-section along line XV-XV is illustrated in FIG. 15.

[0191] With the above dimensional relationships, (1) the maximum value (FIG. 14) of the vertical cross-section of the intermediate region 162 perpendicular to the front-rear direction is larger than the maximum value (FIG. 13) of the vertical cross-section of the upstream region 161 perpendicular to the front-rear direction, (2) the maximum value (FIG. 14) of the vertical cross-section of the intermediate region 162 perpendicular to the front-rear direction is larger than the maximum value (FIG. 15) of the vertical cross-section of the downstream region 163 perpendicular to the flow path direction, and (3) the maximum value (FIG. 13) of the vertical cross-section of the upstream region 161 perpendicular to the front-rear direction is larger than the maximum value (FIG. 15) of the vertical cross-section of the downstream region 163 perpendicular to the flow path direction.

[0192] In the present embodiment, after the second drain valve 112 is opened and flush water reaches the jet water ejection port 102e, the flow rate of flush water that flows in the upstream region 161 is larger than the flow rate of flush water that flows in the intermediate region 162, and the flow rate of flush water that flows in the intermediate region 162 is larger than the flow rate of flush water that flows in the downstream region 163.

[0193] Further, as schematically (functionally) illustrated in FIG. 11 and FIG. 12, a pipeline member 170 is provided as one example of an air vent path, which is an exhaust path, in the present embodiment. The lower end side (one end side) of the pipeline member 170 is open inside the intermediate region 162, and the upper end side (the other end side) of the pipeline member 170 is open in an atmospheric region. Consequently, the intermediate region 162 is not filled with water (a state in which air remains in part of the intermediate region 162 is continued) during a period from when the second drain valve 112 is opened to when the second drain valve 112 is closed. More specifically, after flush water reaches the jet water ejection port 102e, a water surface formed by a water flow of flush water in the intermediate region 162, in which the lower end side of the pipeline member 170 (air vent path) is open, is determined depending on a position at which the lower end side of the pipeline member 170 is open. This is because the air present above a lower end side of the pipeline member 170 easily remains since the pipeline member 170 loses an air vent function after the lower end side is submerged. Meanwhile, even in such an air remaining state, an enclosed water flow of flush water is formed (and maintained) from the upstream region 161 to the jet water ejection port 102e via the intermediate region 162 and the downstream region 163 in the present embodiment.

[0194] Illustrating this, as illustrated in FIG. 16A to FIG. 16C, the intermediate region 162 is filled with water in a comparative example (conventional type) within a period from when the second drain valve 112 is opened to when the second drain valve 112 is closed while, as illustrated in FIG. 17A to FIG. 17C, the intermediate region 162 is not filled with water in the present embodiment.

[0195] Consequently, as obvious from the comparison between FIG. 16C and FIG. 17C, the water head pressure in the flush water tank 104 may be efficiently utilized for jet water ejection.

Basic Operation

[0196] Next, an operation of the flush toilet apparatus 101 according to the second embodiment of the present invention will be described with reference to FIG. 18 to FIG. 22.

[0197] FIG. 18 to FIG. 21 are schematic views for describing an operation of the flush toilet apparatus 101 according to the second embodiment of the present invention. FIG. 22 is a time chart illustrating an operation of the flush toilet apparatus 101 according to the second embodiment of the present invention.

[0198] First, as illustrated in FIG. 8, the first drain port 104b and the second drain port 104c of the flush water tank 104 are closed by the first drain valve 110 and the second drain valve 112, respectively, in the toilet-flush standby state. In this standby state, an initial water level L102 in the flush water tank 104 is higher than the predetermined set water level L101 (a reason for the initial water level L102 being higher than the set water level L101 will be described later). Consequently, the pilot valve port 128a of the body portion 118 (FIG. 9) of the ball tap 114 is in a state of being closed, and the valve seat 122 is closed by the main valve body 120.

[0199] Next, when a user rotates the lever handle 104a of the flush water tank 104 at the time t101 in FIG. 22 to perform a toilet flush, the ball chain 110a connected to the lever handle 104a pulls up the first drain valve 110. Consequently, as illustrated in FIG. 18, the first drain valve 110 is separated from the first drain port 104b, and the first drain port 104b is opened.

[0200] When the first drain port 104b is opened, the flush water stored in the flush water tank 104 flows into the rim water conduit 102f (FIG. 7) through the first drain port 104b and is ejected through the rim water ejection port 102d. The rim water ejection through the rim water ejection port 102d forms a swirling flow on the waste receiving surface of the bowl 102a, and the waste receiving surface is flushed.

[0201] Discharging of the flush water through the first drain port 104b causes the water level in the flush water tank 104 to drop. When the water level in the flush water tank 104 drops to be lower than the set water level L101 at the time t102 in FIG. 22, the float 124 of the ball tap 114 descends, and the pilot valve 128 (FIG. 9) is opened. Consequently, the pressure in the pressure chamber 118a decreases and the main valve body 120 is opened, and, as illustrated in FIG. 19, water supply to the hydraulic drive mechanism 116 is started.

[0202] When flush water is supplied to the hydraulic drive mechanism 116, the flush water that has flowed into the cylinder 116a (FIG. 10) pushes up the piston 116b against the urging force of the spring 116c. Consequently, the rod 130 coupled to the piston 116b pulls up the valve shaft 112a of the second drain valve 112, and the second drain port 104c is opened. That is, the second drain valve 112 is driven and opened by an operation (a drive input that differs from pulling of the ball chain 110a by a user) of the hydraulic drive mechanism 116 based on the water supply pressure of the tap water supplied via the ball tap 114.

[0203] When the second drain port 104c is opened, the flush water stored in the flush water tank 104 flows into the jet water conduit 102g (FIG. 7) through the second drain port 104c and is ejected through the jet water ejection port 102e (refer to FIG. 17). The inside of the drain trap pipeline 102c is filled with water by the jet water ejection through the jet water ejection port 102e, and a siphon action is induced. Due to generation of the siphon action, retained water and waste in the bowl 102a are suctioned into the drain trap pipeline 102c and discharged to a sewage pipe (not illustrated).

[0204] When the second drain valve 112 is pulled up together with the piston 116b of the hydraulic drive mechanism 116 to a predetermined height, the valve shaft 112a of the second drain valve 112 is separated from the rod 130 by the clutch mechanism 132 (FIG. 10). Consequently, the second drain valve 112 descends toward the second drain port 104c. Then, at the time t103 in FIG. 22, the second drain valve 112 is seated at the second drain port 104c as illustrated in FIG. 20, and the second drain port 104c is closed. Consequently, jet water ejection through the jet water ejection port 102e is stopped. Since, as described above, the floating ball 112b of the second drain valve 112 is attached to a relatively high position, the second drain valve 112 is seated at the second drain port 104c earlier than the first drain valve 110.

[0205] In the state illustrated in FIG. 20, the main valve body 120 of the ball tap 114 is in a state of being opened, and the flush water supplied from the water supply source 106 (water supply) is thus supplied to the hydraulic drive mechanism 116 via the ball tap 114 and flows into the flush water tank 104 from the water supply pipe 134 connected to the cylinder 116a.

[0206] Meanwhile, since the first drain valve 110 is still in the state of being opened, the flush water in the flush water tank 104 flows out through the first drain port 104b and is ejected through the rim water ejection port 102d. After jet water ejection is stopped at the time t103 in FIG. 22, the flush water that is ejected through the rim water ejection port 102d is utilized as refill water for returning a water level in the bowl 102a to a water level of retained water in the standby state.

[0207] Here, in the present embodiment, the flow rate of flush water that flows out through the first drain port 104b is adjusted to be larger than the flow rate of flush water that flows into the flush water tank 104 from the water supply pipe 134. Therefore, in the state illustrated in FIG. 20, the water level in the flush water tank 104 drops, and the first drain valve 110 also descends with the drop in the water level. When the water level in the flush water tank 104 drops to a dead water level DWL at the time t104 in FIG. 22, the first drain valve 110 is seated at the first drain port 104b as illustrated in FIG. 21, and the first drain valve 110 is closed. Consequently, rim water ejection through the rim water ejection port 102d is stopped.

[0208] Further, the main valve body 120 of the ball tap 114 is maintained in the state of being opened even after the first drain valve 110 is closed. The flush water supplied from the water supply source 106 (water supply) thus flows into the flush water tank 104 via the ball tap 114, the hydraulic drive mechanism 116, and the water supply pipe 134. Consequently, the water level in the flush water tank 104 rises. When the water level in the flush water tank 104 rises to the set water level L101 at the time t105 in FIG. 22, the float 124 of the ball tap 114 rises, and the pilot valve 128 (FIG. 9) is closed.

[0209] When the pilot valve 128 is closed, the pressure in the pressure chamber 118a increases since the flush water that has flowed into the pressure chamber 118a through the bleed hole 120a provided in the main valve body 120 of the ball tap 114 is disabled to flow out. Then, at the time t106 in FIG. 22, the main valve body 120 is pressed by the pressure in the pressure chamber 118a to be seated on the valve seat 122, and the main valve body 120 is closed. Consequently, water supply to the hydraulic drive mechanism 116 from the water supply source 106 via the ball tap 114 is stopped, and supply of flush water into the flush water tank 104 is stopped.

[0210] When water supply to the hydraulic drive mechanism 116 is stopped, the piston 116b (FIG. 10) that has been pushed up by the water supply in the cylinder 116a is pushed down by the urging force of the spring 116c. Along with this, the rod 130 attached to the piston 116b also descends. When the rod 130 descends to a predetermined position, the clutch mechanism 132 couples the rod 130 again to the valve shaft 112a of the second drain valve 112. Through the above operations, a single toilet flush ends, and the flush toilet apparatus 101 returns to the toilet-flush standby state illustrated in FIG. 8.

[0211] As described above, according to the present embodiment, a desired time lag may be provided between a timing (the time t105 in FIG. 22) when the water level in the flush water tank 104 rises to the set water level L101 and the pilot valve 128 is closed and a timing (the time t106 in FIG. 22) when the main valve body 120 of the ball tap 114 is closed. Then supply of flush water is continued since the main valve body 120 is opened during a period from the time t105 to the time t106, and, at the point of time when the main valve body 120 is closed at the time t106, the water level in the flush water tank 104 becomes the initial water level L102 higher than the set water level L101.

[0212] As a result, the initial water level L102 in the flush water tank 104 in the standby state of the flush toilet apparatus 101 becomes higher than the predetermined set water level L101 at which the pilot valve 128 is closed. Therefore, at the point of time (the time t101 in FIG. 22) when the lever handle 104a is operated in the standby state by a user, the main valve body 120 of the ball tap 114 is not opened since the water level in the flush water tank 104 is higher than the set water level L101.

[0213] When a predetermined amount of flush water is discharged as rim ejection water through the first drain port 104b during a period from the time t101 to the time t102 and the water level in the flush water tank 104 drops to the set water level L101, the pilot valve 128 is opened, and the main valve body 120 of the ball tap 114 is also opened. Consequently, at the time t102, water supply to the hydraulic drive mechanism 116 is started, the second drain valve 112 is opened by an operation of the hydraulic drive mechanism 116, and jet water ejection is started.

[0214] As described above, according to the flush toilet apparatus in the second embodiment of the present invention, since stop and ejection of flush water through the rim water ejection port 102d are switched by the first drain valve 110 and stop and ejection of flush water through the jet water ejection port 102e are switched by the second drain valve 112, it may be possible to freely set the time of rim water ejection and the time of jet water ejection independently and possible to flush the bowl 102a of the flush toilet body 102 effectively with a less amount of flush water (FIG. 7).

[0215] In particular, since the first drain valve 110 and the second drain valve 112 are driven on the basis of drive inputs that differ from each other (pulling-up of the ball chain 110a by a rotational of the lever handle 104a/an operation of the hydraulic drive mechanism 116 based on the water supply pressure of flush water (tap water) supplied via the ball tap 114), it may be possible to flexibly adjust the timing of opening and closing the first drain port 104b and the timing of opening and closing the second drain port 104c and possible to effectively achieve an effect of suppressing wasted water.

[0216] In addition, since the second drain valve 112 is opened utilizing the water supply pressure of flush water by the hydraulic drive mechanism 116, there is no need to pull up the drain valve by electric power of a motor or the like, and it may be possible to set a valve opening time without using a complex mechanism for opening the drain valve.

[0217] According to the flush toilet apparatus in the present embodiment, since the second drain valve 112 is opened (FIG. 22) later than the first drain valve 110 by the ball tap 114, which is a delay mechanism, it may be possible to start water ejection through each of the rim water ejection port 102d and the jet water ejection port 102e at a necessary time in accordance with a configuration of the flush toilet body 102 and possible to flush the bowl 102a effectively while suppressing the amount of flush water.

[0218] Further, according to the flush toilet apparatus 101 in the present embodiment, since the second drain valve 112 is opened by the hydraulic drive mechanism 116, it may be possible to control the time of starting water ejection through the jet water ejection port 102e by controlling the time (the time t102 in FIG. 22) of supplying flush water to the hydraulic drive mechanism 116 and possible to freely set the time of starting jet water ejection.

[0219] In addition, according to the flush toilet apparatus in the present embodiment, since flush water is supplied to the hydraulic drive mechanism 116 when the float 124 of the ball tap 114 descends to a predetermined position, it may be possible to start supply of flush water to the hydraulic drive mechanism 116 at an appropriate time on the basis of the water level in the flush water tank 104 and start water ejection through the jet water ejection port 102e.

Operational Effects Relating to Jet Water Ejection

[0220] Further, according to the flush toilet apparatus in the present embodiment, since there is provided the pipeline member 170 (air vent path) whose lower end side (one end side) is open inside the jet water conduit 102g extending from the second drain valve 112 to the jet water ejection port 102e and whose upper end side (other end side) is open in an atmospheric region, it may possible to achieve a form in which part of air remains in the jet water conduit 102g (since an air vent function is lost after a lower end side of the pipeline member 170 is submerged, the air present above the lower end side easily remains) while maintaining an enclosed state of the water flow in the jet water conduit 102g (consequently, the water head pressure in the flush water tank 104 may be utilized for jet water ejection) and possible to achieve efficient utilization of flush water.

[0221] In particular, since the lower end side of the pipeline member 170 is open inside the intermediate region 162 in the present embodiment, performance and design flexibility in arrangement of the pipeline member 170 may be high, and the air vent function may be desirably achieved easily.

[0222] In the present embodiment, the downstream region 163 is connected to the intermediate region 162, the water surface formed, after the second drain valve 112 is opened and flush water reaches the jet water ejection port 102e, by the water flow of the flush water in the intermediate region 162, in which the lower end side of the pipeline member 170 is open, is determined depending on a position at which the lower end side of the pipeline member 170 is open, and an enclosed water flow of flush water is formed from the upstream region 161 to the jet water ejection port 102e via the intermediate region 162 and the downstream region 163. Consequently, the enclosed state of the water flow in the jet water conduit 102g may be maintained reliably, and the water head pressure in the flush water tank 104 may be reliably utilized for jet water ejection.

[0223] In the present embodiment, employing the dimensional relationships, in which the maximum value of the vertical cross-section of the intermediate region 162 perpendicular to the front-rear direction is larger than the maximum value of the vertical cross-section of the upstream region 161 perpendicular to the front-rear direction and is larger than the maximum value of the vertical cross-section of the downstream region 163 perpendicular to the flow path direction, may also contribute to achieve a form in which part of internal air remains in the intermediate region 162 while the enclosed state of the water flow in the jet water conduit 102g is maintained (consequently, the water head pressure in the flush water tank 104 may be utilized for jet water ejection).

[0224] According to the flush toilet apparatus in the present embodiment, since, after the second drain valve 112 is opened and flush water reaches the jet water ejection port 102e, the flow rate of flush water that flows in the upstream region 161 is larger than the flow rate of flush water that flows in the intermediate region 162 and the flow rate of flush water that flows in the intermediate region 162 is larger than the flow rate of flush water that flows in the downstream region 163, the enclosed state of the water flow of flush water in the jet water conduit 102g may be more reliably maintained, and the water head pressure in the flush water tank 104 may be more reliably utilized for jet water ejection.

Operational Effects Relating to Rim Water Ejection

[0225] According to the flush toilet apparatus in the present embodiment, since the flush water tank 104 is located above the rim water ejection port 102d, the water head pressure in the flush water tank 104 may be utilized also for rim water ejection efficiently.

Supplement Relating to Pipeline Member

[0226] At least at the time of filing of the present application, the lower end side of the pipeline member 170 is not limited to be in a form of being open in the intermediate region 162 and may be open in the upstream region 161 located directly under the second drain valve 112. Operational effects substantially the same as those in the former may be obtained also in the latter.

[0227] The pipeline member 170 is preferably formed integrally with the first drain valve 110 and/or the second drain valve 112, and, in this case, the upper end side of the pipeline member 170 is preferably open in an upper-side space inside the flush water tank 104. Consequently, a space in which the pipeline member 170 is arranged may be absorbed by a space in which the flush water tank 104 is arranged.

[0228] The pipeline member 170 is preferably provided with a check valve (in particular, when the upper end opening of the pipeline member 170 is at a position lower than a (initial) tank water level). In this case, generation of an undesired air backflow may be effectively avoided. (The check valve may be omitted when the upper end opening of the pipeline member 170 is at a position higher than the (initial) tank water level.)

[0229] Further, the pipeline member 170 is preferably an overflow pipe. Consequently, the function as an air vent path and the function as an overflow pipe may be served by a single member, and cost reduction and space saving may be achieved.

[0230] Alternatively, instead of independently providing the pipeline member 170, an air vent path may be constituted by, for example, an internal pipeline present inside the first drain valve 110 and/or the second drain valve 112.

[0231] Such an internal pipeline is also preferably provided with a check valve (in particular, when the upper end opening of the internal pipeline is at a position lower than a (initial) tank water level). Also in this case, generation of an undesired air backflow may be effectively avoided. (The check valve may be omitted when the upper end opening of the internal pipeline is at a position higher than the (initial) tank water level.)

[0232] Further, the upper end side of the pipeline member 170 or the internal pipeline may be open in a space outside the flush water tank 104. Also in this case, the pipeline member 170 or the internal pipeline is preferably provided with a check valve, and, consequently, generation of an undesired air backflow may be effectively avoided.

[0233] The lower end side of the pipeline member 170 or the internal pipeline is preferably located above the water level of the retained water.

Third Embodiment

[0234] Next, a flush toilet apparatus according to a third embodiment of the present invention will be described with reference to FIG. 23 to FIG. 25.

[0235] The flush toilet apparatus according to the present embodiment differs from the flush toilet apparatus according to the above-described second embodiment in terms of the configuration of the delay mechanism provided in the flush water tank. Therefore, only the configuration and operations in the third embodiment of the present invention differing from those in the second embodiment will be described below, and description of the same configurations is omitted by giving identical signs thereto.

[0236] FIG. 23 is a sectional view illustrating a general configuration of a flush water tank included in the flush toilet apparatus according to the third embodiment of the present invention. FIG. 24 is a schematic view for describing an operation of the flush water tank in the flush toilet apparatus according to the third embodiment of the present invention. FIG. 25 is a time chart illustrating an operation of the flush toilet apparatus according to the third embodiment of the present invention.

[0237] As illustrated in FIG. 23, the flush water tank 104 provided in the flush toilet apparatus according to the present embodiment includes the first drain valve 110, the second drain valve 112, the ball tap 114, and the hydraulic drive mechanism 116. As with the above-described second embodiment, the ball tap 114 includes the float 124, and the ball tap 114 is also the same as that in the second embodiment in that the pilot valve is opened and closed by the float 124 and the main valve body of the ball tap 114 is opened and closed. Here, in the present embodiment, a small tank 140 disposed to surround the float 124 of the ball tap 114 is provided, as a delay mechanism, in addition to the ball tap 114.

[0238] The small tank 140 is a small-sized tank that is disposed in the flush water tank 104 so as to surround the float 124, and the float 124 is moved upward and downward in response to a water level in the small tank 140. In the standby state of the flush toilet apparatus illustrated in FIG. 23, the small tank 140 is disposed in the flush water tank 104 in a state in which the entirety of the small tank 140 is submerged. That is, the small tank 140 has a box shape whose upper side is open to receive the float 124 from above, and the upper end of the small tank 140 is disposed at a position lower than the initial water level L102 in the flush water tank 104. Therefore, in the standby state illustrated in FIG. 23, the entirety of the small tank 140 is submerged in the flush water in the flush water tank 104, and the inside of the small tank 140 is filled with the flush water.

[0239] Further, the bottom surface of the small tank 140 has a discharge hole 140a, and the discharge hole 140a is configured to be opened and closed by a check valve float 142 provided at the bottom surface of the small tank 140. The check valve float 142 includes a float portion that receives buoyancy due to the flush water in the flush water tank 104, and a packing for closing the discharge hole 140a. The check valve float 142 is attached to the bottom surface of the small tank 140 to be movable upward and downward to open and close the discharge hole 140a.

[0240] That is, the check valve float 142 is configured to be pushed upward by the buoyancy received by the float portion. Therefore, in a state in which the water level of the flush water in the flush water tank 104 is higher than the bottom surface of the small tank 140, the packing of the check valve float 142 is pressed against the discharge hole 140a of the bottom surface of the small tank 140 by the buoyancy, and the discharge hole 140a is closed. Meanwhile, when the water level in the flush water tank 104 drops, the check valve float 142 also descends due to its own weight, the discharge hole 140a is opened, and the flush water in the small tank 140 is discharged into the flush water tank 104.

[0241] With such a configuration, when the water level in the flush water tank 104 drops, the water level in the small tank 140 drops later than the water level in the flush water tank 104. Since the float 124 of the ball tap 114 descends in conjunction with a drop in the water level in the small tank 140, the main valve body of the ball tap 114 is opened later than a drop in the water level in the flush water tank 104. On the basis of this operation, supply of flush water to the hydraulic drive mechanism 116, that is, opening of the second drain valve 112 is delayed.

[0242] Next, an operation of the flush toilet apparatus according to the third embodiment of the present invention will be described with reference to FIG. 24 and FIG. 25.

[0243] First, when a user rotates the lever handle 104a of the flush water tank 104 at the time t111 in FIG. 25 to perform a toilet flush, the ball chain 110a connected to the lever handle 104a pulls up the first drain valve 110.

[0244] Consequently, the first drain port 104b is opened, and the flush water in the flush water tank 104 is ejected through the rim water ejection port 102d.

[0245] Discharging of the flush water through the first drain port 104b causes the water level in the flush water tank 104 to drop. However, the water level in the small tank 140 does not change since the discharge hole 140a of the small tank 140 is closed by the check valve float 142 in a state in which the water level in the flush water tank 104 is higher than the bottom surface of the small tank 140. Therefore, the float 124 in the small tank 140 also does not descend, and the main valve body of the ball tap 114 is maintained in the state of being closed.

[0246] When the water level in the flush water tank 104 further drops to be lower than the bottom surface of the small tank 140, the check valve float 142 of the small tank 140 is opened, and the flush water in the small tank 140 also starts to flow out through the discharge hole 140a. When the water level in the small tank 140 drops to be lower than a predetermined set water level L103 at the time t112 in FIG. 25, the float 124 of the ball tap 114 descends as illustrated in FIG. 24, and the pilot valve is opened. Consequently, the main valve body 120 of the ball tap 114 is opened, and water supply to the hydraulic drive mechanism 116 is started. When water supply to the hydraulic drive mechanism 116 is performed, the second drain valve 112 is pulled up by an operation of the hydraulic drive mechanism 116 based on a water supply pressure, and water ejection through the jet water ejection port 102e is started (refer to FIG. 17).

[0247] An operation in which the second drain valve 112 is closed at the time t113 and an operation in which the first drain valve 110 is closed at the time t114 after water ejection through the jet water ejection port 102e is started at the time t112 are the same as those in the above-described second embodiment, and description thereof is thus omitted.

[0248] After the first drain valve 110 is closed at the time t114, the water level in the flush water tank 104 rises. Then, in a state in which the water level in the flush water tank 104 has risen to be higher than the bottom surface of the small tank 140, the discharge hole 140a of the small tank 140 is closed by the buoyancy that acts on the check valve float 142, and the water level in the small tank 140 does not rise. When the water level in the flush water tank 104 further rises and the water level in the flush water tank 104 becomes higher than the upper end of the small tank 140, flush water flows into the small tank 140, and the water level in the small tank 140 also rises.

[0249] When the water level in the small tank 140 becomes higher than the predetermined set water level L103 at the time t115, the pilot valve is closed. Then, at the time t116, the main valve body of the ball tap 114 is closed, and water supply to the hydraulic drive mechanism 116 is stopped. Consequently, the rod extending from the piston 116b of the hydraulic drive mechanism 116 descends, and the rod is coupled again to the valve shaft of the second drain valve 112 by the operation of the clutch mechanism 132. Through the above operations, a single toilet flush ends, and the flush toilet apparatus returns to the toilet-flush standby state illustrated in FIG. 23.

[0250] According to the flush toilet apparatus in the third embodiment of the present invention, the delay mechanism includes the small tank 140 and the check valve float 142, and flush water is supplied to the hydraulic drive mechanism 116 when the water level in the small tank 140 drops to be lower than the predetermined set water level L103 (FIG. 24). Therefore, it may be possible by adjusting the configurations and the like of the small tank 140 and other components to freely set the timing of supplying flush water to the hydraulic drive mechanism 116 and possible to start water ejection at a timing suitable for a flush.

[0251] Next, a flush toilet apparatus according to a fourth embodiment of the present invention will be described with reference to FIG. 26 and FIG. 27.

[0252] The flush toilet apparatus according to the present embodiment differs from the flush toilet apparatus according to the above-described second embodiment in terms of the configuration of the delay mechanism provided in the flush water tank. Therefore, only the configuration and operations in the fourth embodiment of the present invention differing from those in the second embodiment will be described below, and description of the same configurations is omitted by giving identical signs thereto.

[0253] FIG. 26 is a sectional view illustrating a general configuration of a flush water tank included in the flush toilet apparatus according to the fourth embodiment of the present invention. FIG. 27 is a time chart illustrating an operation of the flush toilet apparatus according to the fourth embodiment of the present invention.

[0254] As illustrated in FIG. 26, the flush water tank 104 included in the flush toilet apparatus according to the present embodiment includes the first drain valve 110, the second drain valve 112, a first ball tap 150, a second ball tap 152, and the hydraulic drive mechanism 116.

[0255] As with the ball tap 114 in the above-described second embodiment, the first ball tap 150 is configured to be actuated in conjunction with a water level in the flush water tank 104 and cause water supply into the flush water tank to start. That is, the first ball tap 150 includes the float 124, and the pilot valve is opened and closed by the float 124 moving upward and downward in conjunction with a water level in the flush water tank 104, and the main valve body of the first ball tap 150 is opened and closed.

[0256] Further, in the present embodiment, the second ball tap 152 is provided, as a delay mechanism, in addition to the first ball tap 150.

[0257] The second ball tap 152 is provided at the downstream side of the first ball tap 150 and at the upstream side of the hydraulic drive mechanism 116, and supply of flush water to the second ball tap 152 is started when the main valve body of the first ball tap 150 is opened. The second ball tap 152 also includes a float 156 and is configured to open and close the main valve body incorporated therein in conjunction with a water level in the flush water tank 104. That is, the structure of the second ball tap 152 is also the same as the structure of the ball tap 114 in the above-described second embodiment.

[0258] In addition, a water supply port 158 is provided in a pipeline between the first ball tap 150 and the second ball tap 152. In a state in which the first ball tap 150 is opened and the second ball tap 152 is closed, the total amount of the flush water that has flown out from the first ball tap 150 is ejected through the water supply port 158 and flows into the flush water tank 104.

[0259] The first ball tap 150 is configured such that the main valve body is opened when the water level in the flush water tank 104 drops to a predetermined first water level L104, and the second ball tap 152 is configured such that the main valve body is opened when the water level in the flush water tank 104 drops to a second water level L105 lower than the first water level L104. Therefore, the second ball tap 152 is configured to be opened with a delay after the first drain valve 110 is opened and the water level in the flush water tank 104 starts to drop. When the second ball tap 152 is opened, water supply to the hydraulic drive mechanism 116 is started.

[0260] Next, an operation of the flush toilet apparatus according to the fourth embodiment of the present invention will be described with reference to FIG. 27.

[0261] First, when a user rotates the lever handle 104a of the flush water tank 104 at the time t121 in FIG. 27 to perform a toilet flush, the ball chain 110a connected to the lever handle 104a pulls up the first drain valve 110. Consequently, the first drain port 104b is opened, and the flush water in the flush water tank 104 is ejected through the rim water ejection port.

[0262] Discharging of the flush water through the first drain port 104b causes the water level in the flush water tank 104 to drop. When the water level in the flush water tank 104 drops to the predetermined first water level L104, the main valve body of the first ball tap 150 is opened. Since the main valve body of the second ball tap 152 is not opened in this state, the total amount of the flush water that has been supplied from the water supply source and that has passed through the first ball tap 150 flows into the flush water tank 104 through the water supply port 158.

[0263] Here, in the present embodiment, the flow rate of flush water that is discharged through the first drain port 104b is adjusted to be larger than the flow rate of flush water that flows into the flush water tank 104 through the water supply port 158. Therefore, the water level in the flush water tank 104 drops even after the first ball tap 150 is opened.

[0264] When the water level in the flush water tank 104 further drops and reaches the predetermined second water level L105, the main valve body of the second ball tap 152 is also opened. Consequently, water supply to the hydraulic drive mechanism 116 is started at the time t122 in FIG. 27. When water supply to the hydraulic drive mechanism 116 is started, the second drain valve 112 is pulled up by the operation of the hydraulic drive mechanism 116, and water ejection through the jet water ejection port 102e is started.

[0265] The flush water supplied to the hydraulic drive mechanism 116 flows into the flush water tank 104 through the cylinder of the hydraulic drive mechanism 116. In a state in which the main valve body of the first ball tap 150 and the main valve body of the second ball tap 152 are opened, part of the flush water that is to be supplied to the flush water tank 104 flows into the flush water tank 104 through the water supply port 158, and the remainder of the flush water flows into the flush water tank 104 through the cylinder of the hydraulic drive mechanism 116.

[0266] When the second drain valve 112 is pulled up to a predetermined height after the time t122, the second drain valve 112 is separated from the rod of the hydraulic drive mechanism 116 by the clutch mechanism 132, and the second drain valve 112 starts to descend. Then, at the time t123 in FIG. 27, the second drain valve 112 is seated at the second drain port 104c, and water ejection through the jet water ejection port 102e is stopped. Since the opened state of each of the first ball tap 150 and the second ball tap 152 is maintained even after the second drain valve 112 is closed, flush water continues to flow into the flush water tank 104 from the water supply port 158 and the hydraulic drive mechanism 116.

[0267] Since the first drain valve 110 is opened even after the second drain valve 112 is closed, the water level in the flush water tank 104 drops even when flush water flows into the flush water tank 104. When the water level in the flush water tank 104 drops to a predetermined dead water level at the time t124 in FIG. 27, the first drain valve 110 is seated at the first drain port 104b, and water ejection through the rim water ejection port 102d is stopped. As a result of the first drain valve 110 being closed, the water level in the flush water tank 104 starts to rise.

[0268] When the water level in the flush water tank 104 exceeds the second water level L105 at the time t125, the main valve body of the second ball tap 152 is closed. Consequently, the total amount of the flush water supplied from the water supply source flows into the flush water tank 104 through the water supply port 158. Since supply of flush water to the hydraulic drive mechanism 116 from the second ball tap 152 is stopped, the rod extending from the piston 116b of the hydraulic drive mechanism 116 descends, and the rod is coupled again to the valve shaft of the second drain valve 112 by the clutch mechanism 132.

[0269] Further, when the water level in the flush water tank 104 exceeds the first water level L104 at the time t126, the main valve body of the first ball tap 150 is closed, and supply of flush water to the flush water tank 104 is also stopped. Consequently, supply of flush water into the flush water tank 104 from the water supply source is stopped. Through the above operations, a single toilet flush ends, and the flush toilet apparatus returns to the toilet-flush standby state illustrated in FIG. 26.

[0270] According to the flush toilet apparatus in the fourth embodiment of the present invention, there are included the first ball tap 150 that causes water supply into the flush water tank 104 to start (the time t121 in FIG. 27) at the first water level L104 and the second ball tap 152 that causes supply of flush water to the hydraulic drive mechanism 116 to start (the time t122 in FIG. 27) at the second water level L105 lower than the first water level L104. Therefore, it may be possible to freely set the timing of supplying flush water to the hydraulic drive mechanism 116 by setting (adjusting), for example, the float 156 of the second ball tap 152 and possible to start water ejection at a timing suitable for a flush.

[0271] Although embodiments of the present invention have been described above, the above-described embodiments can be variously changed. In particular, although jet water ejection is started with a delay after rim water ejection is started in the above-described embodiments, the present invention can be configured such that rim water ejection is started after jet water ejection is started. In this case, the present invention is configured such that the first drain valve for switching between stop and ejection of flush water through the rim water ejection port is opened by the hydraulic drive mechanism.

[0272] In addition, although the first drain port and the second drain port of the flush water tank are separately provided in the above-described embodiments, these drain ports may be configured to overlap each other in top view. In this case, for example, the present invention can be configured such that the first drain port and the second drain port are provided concentrically and such that the inner-side drain port is opened and closed by a circular drain valve and the outer-side drain port is opened and closed by a toroidal plate-shaped drain valve.

[0273] The invention of the present application includes the following features (invention).

[Feature 1]

[0274] A flush toilet apparatus that flushes with flush water stored in a flush water tank, the flush toilet apparatus including: [0275] a flush toilet body that includes a bowl and has a drain trap pipeline extending from a lower portion of the bowl; [0276] a flush water tank that is disposed behind the flush toilet body and stores flush water for flushing the bowl of the flush toilet body; [0277] a first drain valve that switches between stop and ejection of flush water through a rim water ejection port provided in an upper edge portion of the bowl by closing and opening a first drain port provided in the flush water tank; and [0278] a second drain valve that switches between stop and ejection of flush water through a jet water ejection port provided in a lower portion of the bowl by closing and opening a second drain port provided in the flush water tank, [0279] in which the first drain valve and the second drain valve are driven based on drive inputs (not a common drive input) that differ from each other, and [0280] in which an air vent path whose one end side is open inside a jet water conduit extending from the second drain valve to the jet water ejection port and whose another end side is open in an atmospheric region is provided.

[Feature 2]

[0281] The flush toilet apparatus according to Feature 1, [0282] in which the one end side of the air vent path is open inside an upstream region located directly under the second drain valve or inside an intermediate region extending forward from the upstream region in plan view.

[Feature 3]

[0283] The flush toilet apparatus according to Feature 2, [0284] in which a downstream region extending to the jet water ejection port is connected to the intermediate region, [0285] in which a water surface formed, after the second drain valve is opened and flush water reaches the jet water ejection port, by a water flow of flush water in the upstream region in which the one end side of the air vent path is open or in the intermediate region is determined depending on a position at which the one end side of the air vent path is open, and [0286] in which an enclosed water flow of flush water is formed from the upstream region to the jet water ejection port via the intermediate region and the downstream region.

[Feature 4]

[0287] The flush toilet apparatus according to Feature 2 or 3, [0288] in which, after the second drain valve is opened and flush water reaches the jet water ejection port, [0289] a flow rate of flush water that flows in the upstream region is larger than a flow rate of flush water that flows in the intermediate region, and [0290] a flow rate of flush water that flows in the intermediate region is larger than a flow rate of flush water that flows in the downstream region.

[Feature 5]

[0291] The flush toilet apparatus according to any one of Features 1 to 4, [0292] in which the air vent path is formed by a pipeline member that is formed integrally with the first drain valve and/or the second drain valve, and [0293] in which the other end side of the air vent path is open in an upper-side space inside the flush water tank body.

[Feature 6]

[0294] The flush toilet apparatus according to any one of Features 1 to 5, [0295] in which the air vent path is provided with a check valve.

[Feature 7]

[0296] The flush toilet apparatus according to Feature 5, [0297] in which the pipeline member is an overflow pipe.

[Feature 8]

[0298] The flush toilet apparatus according to any one of Features 1 to 4, [0299] in which the other end side of the air vent path is open in a space outside the flush water tank.

[Feature 9]

[0300] The flush toilet apparatus according to any one of Features 1 to 8, [0301] in which the one end side of the air vent path is located above a water level of retained water.

[Feature 10]

[0302] The flush toilet apparatus according to Feature 8 or 9, [0303] in which the air vent path is provided with a check valve.