PERSONAL WATERCRAFT

Abstract

A personal watercraft propelled by a jet stream includes a boat body, a jet pump, a tunnel, a tunnel opening and a thrust propulsion device. The jet pump includes an impeller disposed at a rear portion of the boat body and generates a propulsive force, and an impeller shaft that rotates the impeller. The tunnel extends in the boat body. The tunnel opening is located at one end of the tunnel, disposed in front of the jet pump, directed in a thrust direction, and opened in the boat body at a position equal to or lower than a virtual plane extending in a horizontal direction along a rotation axis of the impeller. The thrust propulsion device generates a propulsive force in the thrust direction by causing a fluid to flow from an inside of the tunnel to an outside of the boat body through the tunnel opening.

Claims

1. A personal watercraft propelled by a jet stream, the personal watercraft comprising: a boat body; a jet pump including an impeller that is disposed at a rear portion of the boat body and generates a propulsive force, and an impeller shaft that rotates the impeller; a tunnel extending in the boat body; a tunnel opening located at one end of the tunnel, disposed in front of the jet pump, directed in a thrust direction intersecting a front-rear direction of the boat body, and opened in the boat body at a position equal to or lower than a virtual plane extending in a horizontal direction along a rotation axis of the impeller; and a thrust propulsion device that generates a propulsive force in the thrust direction by causing a fluid to flow from an inside of the tunnel to an outside of the boat body through the tunnel opening.

2. The personal watercraft according to claim 1, wherein the tunnel extends linearly in a direction orthogonal to a front-rear direction of the boat body and a vertical direction of the boat body, the tunnel opening is opened in the boat body at both ends of the tunnel, and the thrust propulsion device includes a propeller disposed in the tunnel and rotating in the tunnel.

3. The personal watercraft according to claim 1, wherein the tunnel and the tunnel opening are disposed at positions overlapping an extension line of a rotation axis of the impeller in a side view of the boat body.

4. The personal watercraft according to claim 1, wherein the tunnel opening is disposed in front of a center of gravity of the boat body.

5. The personal watercraft according to claim 1, wherein the tunnel opening is opened at a position above a water surface when the personal watercraft is planing.

6. The personal watercraft according to claim 1, further comprising: a drive source that is disposed in the boat body and applies a rotational driving force to the impeller shaft; and an energy storage body that is disposed in the boat body and stores energy supplied to the drive source, wherein the tunnel is disposed in front of the drive source or the energy storage body.

7. The personal watercraft according to claim 1, wherein the thrust propulsion device includes an electric motor for obtaining the propulsive force in the thrust direction and a battery that supplies driving power to the electric motor, and at least one of the electric motor and the battery is attached to an upper surface of the tunnel.

8. The personal watercraft according to claim 1, wherein the thrust propulsion device includes an electric motor for obtaining the propulsive force in the thrust direction and a battery that supplies driving electric power to the electric motor, and at least one of the electric motor and the battery is attached to a tunnel wall forming the tunnel.

9. The personal watercraft according to claim 1, wherein the thrust propulsion device includes one or a plurality of electric motors for obtaining the propulsive force in the thrust direction and one or a plurality of batteries for supplying driving power to the one or the plurality of electric motors, and the one or the plurality of electric motors and the one or the plurality of batteries are disposed above the tunnel and side by side along an axial direction of the tunnel.

10. The personal watercraft according to claim 1, wherein the thrust propulsion device includes: a propeller that is disposed in the tunnel and rotates around a tunnel axis; an electric motor having a rotation axis in a direction intersecting the tunnel axis; and a power transmission portion that converts a rotational force around the rotation axis output by the electric motor into a rotational force around the tunnel axis and transmits the rotational force to the propeller.

11. The personal watercraft according to claim 2, wherein the thrust propulsion device includes an electric motor that rotationally drives the propeller, and the electric motor is disposed to be inclined with respect to a vertical line passing through an axis of the tunnel.

12. The personal watercraft according to claim 11, further comprising: a luggage room disposed at a front portion in the boat body; and an electric motor for obtaining the propulsive force in the thrust direction, wherein the electric motor is disposed at a position vertically overlapping the luggage room.

13. The personal watercraft according to claim 1, further comprising: a luggage room disposed at a front portion in the boat body; an electric motor for obtaining the propulsive force in the thrust direction; and a cover that covers a protruding portion of the electric motor to the luggage room.

14. The personal watercraft according to claim 1, further comprising: a drive source that applies a rotational driving force to the impeller shaft; an electric motor for obtaining the propulsive force in the thrust direction; and a partition wall that partitions an area in which the drive source is accommodated and an area in which the electric motor is disposed.

15. A personal watercraft propelled by a jet stream, the personal watercraft comprising: a boat body; a jet pump including an impeller that is disposed at a rear portion of the boat body and generates a propulsive force, and an impeller shaft that rotates the impeller; and a side thruster that generates a water flow in a thrust direction intersecting a front-rear direction of the boat body relative to the boat body, and has a water flow generation position set at a height position equal to or lower than a virtual line extending in an extending direction of the impeller shaft in front of the impeller.

16. A personal watercraft propelled by a jet stream, the personal watercraft comprising: a boat body; a jet pump including an impeller that is disposed at a rear portion of the boat body and generates a propulsive force, and an impeller shaft that rotates the impeller; a stabilizer disposed at a rear portion and on a side portion of the boat body; and a side thruster that generates a water flow in a thrust direction intersecting a front-rear direction of the boat body relative to the boat body, and has a water flow generation position located in front of the impeller and below the stabilizer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 is a partially broken side view of a personal watercraft according to an embodiment of the present disclosure.

[0006] FIG. 2 is a plan view of the personal watercraft.

[0007] FIG. 3 is a side view of the personal watercraft with a virtual plane extending in a horizontal direction along a rotation axis of an impeller.

[0008] FIG. 4 is a schematic view illustrating a state of planing, turning, and lateral movement of the personal watercraft.

[0009] FIGS. 5A and 5B are side views illustrating another example of an installation position of a tunnel opening, and FIG. 5C is a side view illustrating a position of the tunnel opening when the personal watercraft is planing.

[0010] FIG. 6 is a diagram illustrating a configuration of a thrust propulsion device.

[0011] FIG. 7 is a view illustrating a state in which a thruster motor is attached to the tunnel.

[0012] FIG. 8 is a view illustrating an example of attachment of a battery to a tunnel.

[0013] FIG. 9 is a cross-sectional view of a front portion of the personal watercraft, illustrating a positional relationship between a luggage room and the thrust propulsion device.

[0014] FIG. 10 is a view illustrating a modification of the arrangement of the thrust propulsion device.

DETAILED DESCRIPTION

[0015] Hereinafter, an embodiment of a personal watercraft 1 according to the present disclosure will be described with reference to the drawings. In the drawings, front, rear, left, and right directions are indicated, and these directions coincide with directions viewed from the passenger riding on the personal watercraft 1. The front-rear direction is a direction connecting the bow and the stern of a boat body 10, where the bow side is the front and the stern side is the rear. The left-right direction is a width direction of the boat body 10 and is a direction orthogonal to the front-rear direction and the vertical direction. In the embodiment described below, an example will be described in which the personal watercraft 1 is a jet propulsion personal watercraft that navigates on the water in reaction to a jet stream ejected backward.

Overall Structure of Personal Watercraft

[0016] FIG. 1 is a partially broken side view of a personal watercraft 1 according to an embodiment of the present disclosure, and FIG. 2 is a plan view of the personal watercraft 1 as viewed from above. The personal watercraft (PWC) 1 is a straddle-type jet propulsion watercraft that is propelled by a jet stream. The personal watercraft 1 includes a boat body 10, and a main propulsion device 2 and a thrust propulsion device 3 as propulsion devices for applying a propulsive force to the boat body 10. The main propulsion device 2 mainly generates a propulsive force in the front-rear direction. The thrust propulsion device 3 generates a propulsive force in the left-right direction, and is also referred to as a side thruster.

[0017] The boat body 10 includes a hull 11, a deck 12 covering an upper surface of the hull 11, and a gunnel line 10G. The main propulsion device 2 and the thrust propulsion device 3 are housed inside the hull 11. The gunnel line 10G is a joint portion that connects the hull 11 and the deck 12 over the entire circumference of the boat body 10.

[0018] The deck 12 is provided with a steering wheel 13, a passenger seat 14, a display panel 15, and a front hatch 16. The steering wheel 13 is attached slightly forward of the center in the front-rear direction of the boat body 10. The steering wheel 13 includes a throttle lever and is operated by a driver M to steer the personal watercraft 1. The passenger seat 14 is disposed at a substantially center position of the deck 12 between the front and rear and the left and right, and is a seat on which the driver M and the passenger ride. The display panel 15 is disposed in front of the steering wheel 13 and displays various types of information related to navigation of the personal watercraft 1, such as a navigation speed, a remaining amount of fuel, and an operation mode. The front hatch 16 is a door for opening and closing an upper surface opening of a luggage room 6 illustrated in FIG. 9. A front bumper 17 is attached to a front portion of the boat body 10. The front bumper 17 serves to mitigate impact when the personal watercraft 1 collides with an obstacle or the like during operation.

[0019] FIG. 3 is a side view of the personal watercraft 1. In FIG. 3, structural parts of the boat body 10, which are omitted in FIG. 1, are described. Hull 11 includes a bottom surface portion 111, a side surface portion 112, and a chine 113. The bottom surface portion 111 is a wall constituting a boat bottom 11A of the boat body 10, and has a V-shape or a U-shape having a large angle in a cross-sectional view in the left-right direction. The side surface portions 112 are walls extending upward from left and right upper end edges of the bottom surface portion 111. The chine 113 is a boundary line between the bottom surface portion 111 and the side surface portion 112.

[0020] The boat body 10 further includes a stabilizer 18 and stripe strips 19. The stabilizer 18 is a fin-shaped member that is attached to a side surface near a rear end of the hull 11, extends in the front-rear direction, and protrudes laterally. The stabilizer 18 functions to suppress rolling of the boat body 10. The stripe strips 19 are provided on the bottom surface portion 111 of the hull 11 and extend in the front-rear direction. The stripe strips 19 are ridges having a substantially triangular cross-sectional shape in the left-right direction, and contribute to stability of navigation of the boat body 10.

[0021] The main propulsion device 2 is an engine-type propulsion device, and includes an engine 21 as a drive source and a jet pump 4 that generates a jet stream. The engine 21 is housed in an engine room ER provided inside the hull 11. The engine 21 is disposed at a position along a center line CL of the boat body 10 and slightly rearward from the center in the front-rear direction. The jet pump 4 is disposed at a position along the center line CL and at a rear portion of the boat body 10.

[0022] The engine 21 is an internal combustion engine. The engine 21 generates power for driving the jet pump 4. The engine 21 is, for example, a water-cooled 4-stroke multicylinder engine using gasoline as fuel. The engine 21 includes a crankshaft 22 extending in the front-rear direction as an output shaft. A fuel tank 23 is disposed in front of the engine 21 in the engine room ER. The fuel tank 23 is an example of an energy storage body that stores fuel (energy) to be supplied to the engine 21. The main propulsion device 2 may be an electric propulsion device. In this case, an electric motor is used as a drive source of the jet pump 4, and a battery is used as an energy storage body.

[0023] The jet pump 4 is disposed behind the engine 21 and includes an impeller shaft 41 and an impeller 42. The impeller shaft 41 extends in the front-rear direction along the center line CL and is connected to the crankshaft 22. When the crankshaft 22 rotates about the axis by driving of the engine 21, a rotational driving force is applied to the impeller shaft 41. The impeller 42 is attached to a rear end of the impeller shaft 41. The impeller 42 rotates around an axis to generate a jet stream. The rotation axis of the impeller 42 is the impeller shaft 41, and the impeller 42 rotates by the rotation of the impeller shaft 41 to generate a jet stream.

[0024] The boat body 10 includes an impeller passage 47 in which the jet pump 4 is arranged. The impeller passage 47 includes a water inlet 48 as a water inlet. The water inlet 48 is formed at the center of the bottom surface portion 111 of the hull 11 in the left-right width direction. The impeller passage 47 is formed so as to penetrate the rear portion of the hull 11 in the front-rear direction along the center line CL. In order to apply a propulsive force to the personal watercraft 1, the jet pump 4 pressurizes and accelerates the water taken in the impeller passage 47 and injects the water rearward.

[0025] The jet pump 4 further includes a venturi nozzle 43, a jet nozzle 44, and a reverse bucket 46. The venturi nozzle 43 and the jet nozzle 44 pressurize and accelerate the water sent from the impeller 42 to generate a jet stream. The venturi nozzle 43 gradually narrows a flow path cross-sectional area of the impeller passage 47 rearward to increase the flow velocity of the water flow. The jet nozzle 44 has an injection port 45 that opens rearward as an outlet for a jet stream. The jet nozzle 44 is connected to a rear end of the venturi nozzle 43 so as to be swingable left and right. The jet nozzle 44 is driven to swing by a nozzle motor 44M. When the jet nozzle 44 swings, the direction of the injection port 45 and an injection direction of the jet stream from the injection port 45 are changed to the left and right.

[0026] The reverse bucket 46 has a function of switching the propulsion direction of the personal watercraft 1 forward or backward. The reverse bucket 46 is disposed near the injection port 45, and is attached to the jet nozzle 44 so as to be rotatable about an axis extending in the left-right direction. When the reverse bucket 46 descends so as to cover the injection port 45, the propulsion direction of the personal watercraft 1 is changed backward.

[0027] The thrust propulsion device 3 generates a water flow directed in a thrust direction, that is, an auxiliary water flow directed rightward or leftward from the front portion of the boat body 10. This auxiliary water flow imparts a propulsive force in the left-right direction to the boat body 10. The thrust direction is a direction intersecting with both the front-rear direction and the vertical direction of the boat body 10, and is desirably a direction orthogonal thereto. In the present embodiment, an example in which the water flow in the thrust direction generated by the thrust propulsion device 3 is a water flow injected in the left-right direction is illustrated, but the water flow may be a water flow in a direction inclined with respect to the left-right direction.

[0028] The boat body 10 includes a tunnel 5 at a position corresponding to the thrust propulsion device 3. The tunnel 5 is a passage extending so as to linearly penetrate the hull 11 in the thrust direction, in the left-right direction in the present embodiment, at the front portion of the boat body 10. The tunnel 5 has openings at both ends of the tunnel 5. As illustrated in FIG. 2, a first tunnel opening 5A is opened at one end of the tunnel 5, and a second tunnel opening 5B is opened at the other end of the tunnel 5. The first tunnel opening 5A opens on a left side surface of a front portion of the hull 11. The second tunnel opening 5B opens on a right side surface of the front portion of the hull 11. The first tunnel opening 5A and the second tunnel opening 5B are disposed in front of the jet pump 4, and are both directed in the thrust direction.

[0029] The thrust propulsion device 3 generates a propulsive force in the thrust direction by causing a fluid to flow from the inside of the tunnel 5 to the outside of the boat body 10 via the first tunnel opening 5A or the second tunnel opening 5B. The fluid may be water (sea water) in a water landing area of the personal watercraft 1 or air. Examples of the mode of generating the propulsive force include a mode of ejecting the fluid sucked from one of the tunnel openings 5A and 5B from the other, and a mode depending on the suction force of the fluid generated in any one of the tunnel openings 5A and 5B.

[0030] The thrust propulsion device 3 includes a thruster motor 51, a propeller 52, a gear mechanism 53 and a battery 54. The thruster motor 51 is an electric motor for obtaining a propulsive force in a thrust direction, and rotationally drives the propeller 52. The propeller 52 is disposed in the tunnel 5 and rotates in the tunnel 5. The propeller 52 is attached to a propeller shaft 52S extending in the left-right direction. The gear mechanism 53 transmits the rotational force generated by the thruster motor 51 to the propeller shaft 52S. When the thruster motor 51 is driven, the propeller shaft 52S rotates via the gear mechanism 53, whereby the propeller 52 rotates about the propeller shaft 52S. The rotation of the propeller 52 causes the fluid in the tunnel 5 to flow to generate a propulsive force in the thrust direction. The battery 54 supplies driving power to the thruster motor 51. As the battery 54, a secondary battery can be used.

[0031] FIG. 4 is a view schematically illustrating an operation mode of the personal watercraft 1. In FIG. 4, operation modes of sliding, turning, and lateral movement are illustrated. In the sliding mode, the personal watercraft 1 is propelled forward by a backward propulsive force F1 generated by the main propulsion device 2. In the sliding mode, the thrust propulsion device 3 does not operate. Note that, when the reverse bucket 46 is operated to cover the injection port 45, the personal watercraft 1 is propelled rearward.

[0032] In the turning mode, the main propulsion device 2 is deactivated and the thrust propulsion device 3 is activated. For example, as illustrated in FIG. 4, when the thrust propulsion device 3 operates so as to generate a thrust propulsive force F2 from the first tunnel opening 5A, the personal watercraft 1 stationary turns clockwise about the center of gravity G of the boat body 10 as the center of rotation. Conversely, when the thrust propulsive force is generated from the second tunnel opening 5B, the personal watercraft 1 turns counterclockwise.

[0033] In the lateral travel mode, both the main propulsion device 2 and the thrust propulsion device 3 are activated and both generate the propulsive force in the thrust direction. For example, when the personal watercraft 1 is laterally moved rightward, the thrust propulsion device 3 generates the thrust propulsive force F2 from the first tunnel opening 5A similarly to the turning mode. The main propulsion device 2 swings the jet nozzle 44 to move the backward propulsive force F1 leftward and generate a thrust propulsive force F3. That is, an injection direction of the jet stream from the jet nozzle 44 is changed leftward by the nozzle motor 44M, and the thrust propulsive force F3 directed leftward is generated. The personal watercraft 1 laterally moves rightward by the two thrust propulsive forces F2 and F3 generated across the center of gravity G. In the case of leftward lateral movement, the thrust propulsion device 3 generates the thrust propulsive force F2 from the second tunnel opening 5B, and the main propulsion device 2 generates the thrust propulsive force F3 directed rightward.

Details of Tunnel and Tunnel Openings

[0034] Detailed structures of the tunnel 5 and the tunnel openings 5A and 5B described above and variations thereof will be further described. Referring to FIGS. 1 and 3, a line extending forward along the impeller shaft 41, which is the rotation axis of the impeller 42, is defined as an extension line EL. A virtual horizontal plane extending in the horizontal direction along the extension line EL is defined as a virtual plane VP. At least one of the first tunnel opening 5A and the second tunnel opening 5B is opened in the boat body 10 at a position equal to or lower than the virtual plane VP. Note that, although FIG. 3 is a side view of the personal watercraft 1 as viewed from the left side, only the virtual plane VP is illustrated three-dimensionally.

[0035] The position equal to or lower than the virtual plane VP includes a position where the height positions of the tunnel openings 5A and 5B overlap the virtual plane VP or a position below the virtual plane VP without overlapping the virtual plane VP. By employing such a positional relationship, it is easy to maintain the tunnel openings 5A and 5B at a position below the water surface when the personal watercraft 1 stands still or is planing at a low speed. Therefore, the propulsive force in the thrust direction can be stably generated. FIGS. 1 to 3 illustrate an example in which the tunnel 5 has a circular cross section, the tunnel openings 5A and 5B are circular openings, and the height position of the center point of the circular shape substantially coincides with the virtual plane VP. In other words, the tunnel openings 5A and 5B are arranged so that the extension line EL passes through the center points of the tunnel openings 5A and 5B in a side view of the boat body 10.

[0036] The jet propulsion direction by the main propulsion device 2 is on an axis obtained by extending the impeller shaft 41 rearward. By arranging the tunnel openings 5A and 5B, the axis in the jet propulsion direction and the axis in the thrust propulsion direction by the thrust propulsion device 3 are located on the same virtual plane VP. Furthermore, the central axis of the tunnel 5 is also located on the virtual plane VP. Therefore, it is possible to suppress the deviation in the height direction between the jet propulsion direction and the thrust propulsion direction. Such an arrangement contributes to stable movement of the personal watercraft 1 in the lateral movement mode illustrated in FIG. 4.

[0037] Even if the center points of the tunnel openings 5A and 5B do not coincide with the extension line EL, it is desirable to open the tunnel openings 5A and 5B at positions where the center points and the extension line EL overlap with each other. According to this aspect, the vertical width of the boat body 10 can be made compact as compared with the case where the tunnel openings 5A and 5B are disposed below the extension line EL. That is, even if the tunnel 5 having a large inner diameter to some extent is provided on the boat body 10, a required distance can be provided between the boat bottom 11A and the tunnel 5, and the size of the vertical width of the boat body 10 can be easily suppressed. In addition, it is desirable that not only the tunnel openings 5A and 5B but also at least the end region of the tunnel 5 overlap the extension line EL. In the present embodiment, since the tunnel 5 extends linearly in the left-right direction, not only the end region of the tunnel 5 but also the entire tunnel 5 exists at a position overlapping the extension line EL.

[0038] FIGS. 5A and 5B are side views illustrating other examples of installation positions of the tunnel openings 5A and 5B. FIG. 5A illustrates an example in which the tunnel opening 5A (5B) is disposed below the extension line EL of the impeller shaft 41 and above the boat bottom 11A in the side view of the boat body 10. According to the modification of FIG. 5A, the tunnel openings 5A and 5B are more easily maintained at the position below the water surface. FIG. 5B is a modification in which the vicinity of an upper end of the tunnel opening 5A overlaps with the extension line EL. A mode may be employed in which the vicinity of a lower end of the tunnel opening 5A overlaps the extension line EL.

[0039] The present embodiment illustrates an example in which the tunnel 5 extends linearly in the left-right direction, and both ends of the tunnel 5 are the tunnel openings 5A and 5B. According to this aspect, by the fluid sucked from the tunnel opening 5A or 5B at one end of the tunnel 5 being discharged from the tunnel opening 5A or 5B at the other end by the operation of the thrust propulsion device 3, it is possible to obtain the thrust propulsive force in the extension line direction of the central axis of the tunnel 5, that is, in the left-right direction. Since the tunnel 5 extends linearly, the flow path resistance of the fluid from one end to the other end of the tunnel 5 can be reduced as compared with a case where the tunnel 5 extends non-linearly. Therefore, it is easy to discharge the fluid that generates the propulsive force in the thrust direction while suppressing the resistance in the tunnel 5.

[0040] It is sufficient if at least one of the tunnel openings 5A and 5B is directed in the thrust direction. For example, it is assumed that the second tunnel opening 5B is exclusively used as a fluid intake port and the first tunnel opening 5A is exclusively used as a fluid ejection port. In this case, the first tunnel opening 5A is opened so as to be directed in the thrust direction, but the second tunnel opening 5B is not necessarily directed in the thrust direction, and may be directed in a direction suitable for taking in the fluid.

[0041] In addition, in the configuration assumed above, only the first tunnel opening 5A may be disposed at a position equal to or lower than the virtual plane VP. For example, the second tunnel opening 5B may be opened on the boat body 10 at a position higher than the water surface, and the air taken in from the second tunnel opening 5B may be ejected from the first tunnel opening 5A to obtain the thrust propulsive force. Alternatively, the second tunnel opening 5B may be opened downward on the bottom surface portion 111 of the hull 11. Furthermore, the second tunnel opening 5B serving as a fluid intake port may be disposed on the side surface portion 112 of the hull 11, and the first tunnel opening 5A serving as an ejection port may be opened downward in the bottom surface portion 111. In this case, the thrust propulsive force is obtained by a reaction force when the fluid is sucked from the second tunnel opening 5B. As described above, the two tunnel openings 5A and 5B may be opened in the boat body 10 with different heights or different orientations.

[0042] The tunnel 5 need not be in a mode of being parallel to the left-right direction which is the ship width direction. The tunnel 5 may have an inclination in the front-rear direction with respect to the left-right direction, and the tunnel 5 may have an inclination in the up-down direction. In this case, when the tunnel 5 is linear, the opening positions of the first tunnel opening 5A and the second tunnel openings 5B are shifted in the front-rear direction or the up-down direction. In addition, the tunnel 5 is not limited to a linear shape, and may include a curved portion or a bent portion. For example, the tunnel 5 curved in an arc shape or a U shape and the tunnel 5 bent in an L shape can be exemplified. Furthermore, the tunnel 5 may be in a mode that a plurality of tunnels 5 is provided, or a plurality of first tunnel openings 5A and second tunnel openings 5B are provided by forming a tunnel 5 branched into two or more branches at both ends.

[0043] FIG. 3 illustrates the center of gravity G of the boat body 10. The center of gravity G depends on the arrangement of a heavy device such as the engine 21, but is located substantially near the center of the boat body 10 in the front-rear direction. The tunnel openings 5A and 5B are disposed in front of the center of gravity G. Further, the thrust propulsion device 3 including the thruster motor 51 is also arranged in front of the center of gravity G. In this arrangement, the thrust propulsive force is applied to easily rotate the personal watercraft 1 about the center of gravity G in the turning mode illustrated in FIG. 4. By increasing the distance in the front-rear direction between the tunnel openings 5A and 5B and the center of gravity G, the personal watercraft 1 can be turned with a small thrust propulsive force.

[0044] FIG. 5C is a side view illustrating the position of the tunnel opening 5A (5B) during normal planing of the personal watercraft 1, that is, high-speed planing. The tunnel openings 5A and 5B are opened at positions above the water surface WS during normal planing of the personal watercraft 1. The tunnel openings 5A and 5B are openings directed in the thrust direction. Therefore, when the tunnel openings 5A and 5B are located in the water at the time of planing, propulsion resistance is generated. In the present embodiment, the tunnel openings 5A and 5B are located above the water surface during normal planing of the personal watercraft 1. Therefore, the portion of the tunnel 5 does not become a propulsion resistance, and does not deteriorate the traveling performance of the personal watercraft 1.

[0045] As described above based on FIG. 3, boat body 10 includes a chine 113, a stabilizer 18 and stripe strips 19. The positional relationship between these and tunnel openings 5A and 5B will be described. The tunnel openings 5A and 5B are located below the chine 113. This arrangement makes it easy to position the tunnel openings 5A and 5B below the water surface when the personal watercraft 1 is stationary or is planing at a low speed. Note that the chine 113, which is a boundary between the bottom surface portion 111 and the side surface portion 112 of the hull 11, is not a straight line extending back and forth at the same height position. The tunnel openings 5A and 5B only need to be disposed below the uppermost portion of the chine 113 extending in the front-rear direction.

[0046] The tunnel openings 5A and 5B are opened at positions equal to or lower than the height position of the stabilizer 18 in a side view. In other words, the tunnel openings 5A and 5B are desirably disposed at positions overlapping with the height position of the stabilizer 18, particularly at positions lower than the height position of the stabilizer 18. The stabilizer 18 is a fin-shaped member, and often faces a draft surface of the boat body 10. That is, the height position of the stabilizer 18 is substantially the draft surface of the boat body 10. Therefore, by opening the tunnel openings 5A and 5B at a position equal to or lower than the height position of the stabilizer 18, particularly at a position lower than the stabilizer 18, the tunnel openings 5A and 5B can be easily positioned below the water surface.

[0047] The tunnel openings 5A and 5B are opened at positions above the stripe strips 19 in a side view. The stripe strips 19 extend in the front-rear direction at the bottom surface portion 111 of the hull 11. During normal planing of the personal watercraft 1, the stripe strips 19 are mostly located above the water surface. When the tunnel openings 5A and 5B are disposed above the stripe strips 19, the tunnel openings 5A and 5B are easily located on the water surface during normal planing of the personal watercraft 1. Therefore, it is possible to suppress the tunnel openings 5A and 5B from becoming a propulsion resistance.

[0048] Next, a positional relationship between the engine 21 or the fuel tank 23 and the tunnel 5 will be described. The tunnel 5 is disposed in front of the engine 21 and the fuel tank 23. With this arrangement, the tunnel 5 can be arranged in such a mode that interference with the engine 21 and the fuel tank 23 does not occur. In the present embodiment, the engine 21 and the fuel tank 23 are arranged side by side in the front-rear direction near the center of the boat body 10 in the front-rear direction. By disposing heavy objects such as the engine 21 and the fuel tank 23 close to the center, it is possible to contribute to improvement of the steerability of the personal watercraft 1.

[0049] As a modification, the tunnel 5 can be disposed in front of the engine 21 and behind the fuel tank 23. According to this modification, it is not necessary to ensure a space for disposing the thrust propulsion device 3 including the tunnel 5 in front of the fuel tank 23. Therefore, there is an advantage that the front portion of the boat body 10 can be used as an arrangement space of a storage and other devices.

Details of Thrust Propulsion Device

[0050] A detailed structure of the thrust propulsion device 3 will be described with reference to FIGS. 6 to 8. FIG. 6 is a view schematically illustrating an arrangement example of the thrust propulsion device 3 with respect to the tunnel 5. FIG. 7 is a cross-sectional view in a direction orthogonal to the tunnel axis TL of FIG. 6. The thruster motor 51 is disposed outside the tunnel 5 at a central position in the left-right direction of the tunnel 5. The output shaft 51S of the thruster motor 51 penetrates a tunnel wall 50 of the tunnel 5 and enters the tunnel 5. The thruster motor 51 is disposed with respect to the tunnel 5 so that a rotation axis RL of the output shaft 51S is orthogonal to the tunnel axis TL.

[0051] The propeller shaft 52S serving as a rotation axis of the propeller 52 extends along the tunnel axis TL. That is, the rotation axis RL of the output shaft 51S and the axis of the propeller shaft 52S intersect in an orthogonal manner. The gear mechanism 53 is arranged in the tunnel 5 and is constituted of, for example, a gear box provided with a bevel gear. The gear mechanism 53 converts the rotational force around the rotation axis RL output from the thruster motor 51 into a rotational force around the tunnel axis TL and transmits the rotational force to the propeller 52. That is, the gear mechanism 53 receives the input of the rotational force from the rotation axis RL of the output shaft 51S of the thruster motor 51, converts the rotation axis direction by 90, and then transmits the rotational force to the propeller shaft 52S. The interposition of the gear mechanism 53 can increase the degree of freedom in designing the mounting position of the thruster motor 51.

[0052] As illustrated in FIG. 7, the thruster motor 51 is disposed so that the rotation axis RL is inclined by about 45with respect to a vertical line TV passing through the tunnel axis TL. The inclination angle of the rotation axis RL with respect to the vertical line TV may be appropriately set in consideration of other devices and members present in the boat body 10. Due to the inclined arrangement of the thruster motors 51, the vertical width occupied by the thrust propulsion device 3 in the boat body 10 can be suppressed, and the thrust propulsion device 3 can be easily accommodated in the boat body 10.

[0053] A flow direction of the fluid in the tunnel 5, that is, an injection direction of the fluid is determined by a rotation direction of the output shaft 51S of the thruster motor 51. For example, when the thruster motor 51 rotates the output shaft 51S in a predetermined forward rotation direction and rotates the propeller 52, the fluid is taken in from the first tunnel opening 5A and injected rightward from the second tunnel opening 5B as indicated by an arrow in FIG. 6. A reaction force due to the injection serves as a thrust propulsive force for moving the personal watercraft 1 leftward. On the other hand, when the thruster motor 51 rotates the output shaft 51S in a reverse rotation direction opposite to the forward rotation direction and rotates the propeller 52 in a reverse rotation direction, the fluid is taken in from the second tunnel opening 5B and injected leftward from the first tunnel opening 5A. A reaction force due to the injection serves as a thrust propulsive force for moving the personal watercraft 1 rightward.

[0054] FIG. 2 illustrates an example in which the battery 54 that supplies driving power to the thruster motor 51 is disposed behind the thruster motor 51. On the other hand, FIG. 6 illustrates an example in which a first battery 54A and a second battery 54B as the battery 54 are attached to an upper surface of the tunnel 5. Note that the upper surface is an outer peripheral surface above the tunnel axis TL of the tunnel 5 illustrated in FIG. 7. In the present embodiment, not only the battery 54 but also the thruster motor 51 is attached to the upper surface of the tunnel 5. When the thruster motor 51 and the battery 54 are disposed below the tunnel 5, it is necessary to ensure a housing space for the thruster motor 51 and the battery 54 between the tunnel 5 and the boat bottom 11A. According to the aspect of FIG. 7, it is not necessary to ensure the housing space, and as a result, the tunnel openings 5A and 5B can be easily disposed below the water surface. Note that at least one of the thruster motor 51 and the battery 54 may be attached to the upper surface of the tunnel 5.

[0055] The thruster motor 51 and the battery 54 are directly attached to the tunnel wall 50 forming the tunnel 5. When the thruster motor 51 and the battery 54 are disposed in the boat body 10, a support member for positioning and fixing the thruster motor 51 and the battery 54 is required. According to the present embodiment, the tunnel wall 50 is used as a wall for attaching the thruster motor 51 and the battery 54. Therefore, the support member is unnecessary, and the number of parts can be reduced. Note that at least one of the thruster motor 51 and the battery 54 may be directly attached to the tunnel wall 50.

[0056] At least one of the thruster motor 51 or the battery 54 may be attached to the tunnel 5 via a predetermined support member. FIG. 8 illustrates an example in which the battery 54 is attached to the tunnel 5 via a pedestal 55 as a support member. The pedestal 55 is attached near a top surface of the tunnel 5. The pedestal 55 has a flange portion 56 wider than the battery 54 on an upper surface. The battery 54 is placed on the flange portion 56. According to the aspect of FIG. 8, stable attachment of the battery 54 is completed only by placing and fixing the battery 54 on the flange portion 56, so that attachment workability can be improved.

[0057] The thruster motor 51 may also be attached to the tunnel 5 using a member similar to the pedestal 55. In addition, the thruster motor 51 may be attached inside the tunnel 5 via an appropriate support member. In this case, the thruster motor 51 may be in an attaching mode in which the rotation axis RL and the tunnel axis TL thereof are in the same direction.

[0058] As illustrated in FIG. 6, the thruster motor 51 and the two batteries 54A and 54B are arranged above the tunnel 5 in an extending direction of the tunnel axis TL, that is, along the left-right direction. Specifically, the first battery 54A and the second battery 54B are disposed with the thruster motor 51 disposed at the center in the left-right direction of the tunnel 5 interposed therebetween. According to this aspect, a space above the tunnel 5 in the boat body 10 can be effectively used for arrangement of the thrust propulsion device 3. Further, the two batteries 54A and 54B can be arranged in a well-balanced manner, and the length of the power supply cable to the thruster motor 51 can be shortened. The thruster motor 51 may be disposed at a position deviated from the center position in the left-right direction of the tunnel 5, or a plurality of thruster motors 51 may be disposed. In addition, one battery 54 may be disposed in the tunnel 5, or three or more batteries 54 may be disposed in the tunnel 5. Furthermore, the arrangement order of the thruster motor 51 and the two batteries 54A and 54B may be appropriately changed.

[0059] The thrust propulsion device 3 is not limited to the aspect using the thruster motor 51 and the propeller 52 described above, and only needs to be a device that generates a pressure difference or a flow in the fluid in the tunnel 5. That is, the aspect of the thrust propulsion device 3 is not limited as long as the fluid can be ejected from the tunnel openings 5A and 5B to the outside of the ship or the fluid outside the ship can be sucked into the ship through the tunnel openings 5A and 5B.

[0060] Specifically, the thrust propulsion device 3 may be a device including an axial rotary blade or a centrifugal rotary blade. The axial rotary blade rotates to axially direct the surrounding fluid. The centrifugal rotary blade rotates to direct the surrounding fluid radially outward. In addition, the thrust propulsion device 3 may be a positive displacement pump such as a gear pump or a reciprocating pump such as a reciprocating pump. Furthermore, the thrust propulsion device 3 may include an injection nozzle capable of injecting a fluid at a high pressure.

Other Specific Configuration Examples

[0061] FIG. 9 is a cross-sectional view of a front portion of the personal watercraft 1 including a luggage room 6. The luggage room 6 is disposed at a front portion of the boat body 10 to accommodate luggage of the driver M and the passenger, accessories of the personal watercraft 1, and the like. The luggage room 6 is defined by a luggage room wall 61. On the upper surface of the luggage room wall 61, a luggage room opening 62 for loading and unloading luggage is opened. The front hatch 16 illustrated in FIG. 1 constantly closes the luggage room opening 62. The front hatch 16 is rotated around a hinge 16H to open the luggage room opening 62.

[0062] FIG. 9 illustrates an example in which the thrust propulsion device 3 is installed in the luggage room 6. Specifically, the tunnel 5 is disposed in a mode of penetrating the luggage room wall 61, and the thruster motor 51 is attached in an inclined state with respect to the tunnel 5. As a result, the thruster motor 51 is disposed at a position overlapping the luggage room 6 in the vertical direction. The thruster motor 51 is mounted relative to the tunnel 5 in an inclined manner rather than in an upright manner. For this reason, even when the thruster motor 51 enters the area of the luggage room 6, it is easy to ensure the capacity of the luggage room 6.

[0063] A cover 51C is attached to the thruster motor 51. The cover 51C covers a protruding portion of the thruster motor 51 to the luggage room 6. Accordingly, it is possible to prevent the driver M or the passenger who has accessed the luggage room 6 from touching the thruster motor 51. The cover 51C is preferably detachable for maintenance of the thruster motor 51 and the like. Instead of the arrangement of FIG. 9, for example, the tunnel 5 and the thruster motor 51 may be arranged between the luggage room 6 and the fuel tank 23.

[0064] It is desirable that the thruster motor 51 and an area of the engine room ER, which is an area for accommodating the engine 21 as a drive source of the personal watercraft 1, be partitioned by a partition wall. In the example of FIG. 9, a part of the luggage room wall 61 is a partition wall 61W that functions as the partition wall. The luggage room wall 61 can be said to be a wall that partitions the engine room ER and the luggage room 6. The partition wall 61 W is a standing wall positioned between the tunnel 5 to which the thruster motor 51 is attached and the fuel tank 23. Since the partition wall 61 W is interposed, there is an advantage that the thruster motor 51 can be thermally isolated even if the engine 21 generates heat during planing. Instead of using a part of the luggage room wall 61 as the partition wall 61 W, a separate partition wall 61 W may be disposed between the thruster motor 51 and the engine 21.

[0065] FIG. 10 is a view illustrating a modification of the arrangement of the thrust propulsion device 3. FIG. 10 illustrates an example in which the fuel tank 23 and the tunnel 5 are disposed in a mode of vertically overlapping each other. The fuel tank 23 has a substantially rectangular shape and has a recess 231 in which one of lower corners is recessed upward. The tunnel 5 is disposed in a space created by the formation of the recess 231. The thruster motor 51 is attached to the tunnel 5 in a mode of extending obliquely upward from the recess 231. According to this modification, the thrust propulsion device 3 can be disposed by efficiently utilizing a space in the boat body 10.

[0066] An operation mode of the thrust propulsion device 3 by an occupant will be exemplified. Examples thereof include a mode in which the thruster motor 51 is driven in accordance with an operation state of a first operation device disposed on the steering wheel 13, a mode in which the thruster motor 51 is driven by an operation of a second operation device provided separately from the steering wheel 13, and the like. The first operation device may be a throttle operation device that instructs output of the engine 21 or a steering wheel 13 itself that instructs a steering direction. Examples of the second operation device include an operation device such as a joystick.

[0067] Regardless of an operation state of the steering wheel 13 as the first operation device, control such as switching between driving and stopping of the thruster motor 51 and output change may be performed according to the operation on the second operation device. Note that, when the steering wheel 13 is operated simultaneously with the second operation device, the boat body 10 may be in a mode of being controlled based on an operation of one of the steering wheel 13 and the second operation device. For example, when the steering wheel 13 is operated simultaneously with the second operation device, the steering wheel 13 may be prioritized over the second operation device. That is, the operation of the second operation device may be invalidated, and the boat body 10 may be navigated based on the operation of the steering wheel 13.

Summary of Present Disclosure

[0068] The specific embodiments described above include a disclosure having the following configurations.

[0069] A personal watercraft according to a first aspect of the present disclosure includes a boat body, a jet pump including an impeller that is disposed at a rear portion of the boat body and generates a propulsive force, and an impeller shaft that rotates the impeller, a tunnel extending in the boat body, a tunnel opening located at one end of the tunnel, disposed in front of the jet pump, directed in a thrust direction intersecting a front-rear direction of the boat body, and opened in the boat body at a position equal to or lower than a virtual plane extending in a horizontal direction along a rotation axis of the impeller, and a thrust propulsion device that generates a propulsive force in the thrust direction by causing a fluid to flow from an inside of the tunnel to an outside of the boat body through the tunnel opening.

[0070] The position of the impeller is set below the water surface in order to obtain the propulsive force of the boat. According to the first aspect, the tunnel opening serving as an outlet of a fluid that generates a propulsive force is located at a position equal to or lower than the virtual plane extending in the horizontal direction along the rotation axis of the impeller. Thus, when the watercraft is stationary or is planing at a low speed, the tunnel opening can be easily maintained at a position below the water surface, and the propulsive force in the thrust direction can be stably generated.

[0071] A personal watercraft according to a second aspect is the personal watercraft according to the first aspect, in which the tunnel extends linearly in a direction orthogonal to a front-rear direction of the boat body and a vertical direction of the boat body, the tunnel opening is opened in the boat body at both ends of the tunnel, and the thrust propulsion device includes a propeller disposed in the tunnel and rotating in the tunnel.

[0072] According to the second aspect, the thrust propulsion device discharges a fluid sucked from the tunnel opening at one end from the tunnel opening at the other end, so that a thrust propulsive force in an extension line direction of the one end can be obtained. Since the tunnel extends linearly, a channel resistance from one end to the other end can be reduced as compared with a case where the tunnel extends non-linearly. Therefore, it is easy to discharge the fluid that generates the propulsive force in the thrust direction while suppressing the resistance in the tunnel.

[0073] A personal watercraft according to a third aspect is the personal watercraft according to the first or second aspect, in which the tunnel and the tunnel opening are disposed at positions overlapping an extension line of a rotation axis of the impeller in a side view of the boat body.

[0074] According to the third aspect, it is possible to make a vertical width of the boat body compact as compared with a case where the tunnel opening is disposed below the extension line of the rotation axis of the impeller. That is, even if a tunnel having a large tunnel diameter to some extent is provided, a required distance can be provided between the boat bottom and the tunnel, and the size of the vertical width of the boat body can be easily suppressed.

[0075] A personal watercraft according to a fourth aspect is the personal watercraft according to the first to third aspects, in which the tunnel opening is disposed in front of a center of gravity of the boat body.

[0076] According to the fourth aspect, the tunnel opening is disposed in front of the center of gravity. With this arrangement, it is easy to rotate the watercraft around the center of gravity by applying the thrust propulsive force.

[0077] A personal watercraft according to a fifth aspect is the personal watercraft according to any one of the first to fourth aspects, in which the tunnel opening is opened at a position above a water surface when the personal watercraft is planing.

[0078] According to the fifth aspect, the tunnel opening is located above the water surface during normal planing of the watercraft. Therefore, the tunnel portion does not become a propulsion resistance, and the traveling performance of the watercraft is not deteriorated.

[0079] A personal watercraft according to a sixth aspect is the personal watercraft according to any one of the first to fifth aspects, further including a drive source that is disposed in the boat body and applies a rotational driving force to the impeller shaft, and an energy storage body that is disposed in the boat body and stores energy supplied to the drive source, in which the tunnel is disposed in front of the drive source or the energy storage body.

[0080] According to the sixth aspect, it is easy to arrange the tunnel in a mode in which interference with the drive source or the energy storage body does not occur.

[0081] A personal watercraft according to a seventh aspect is the personal watercraft according to any one of the first to sixth aspects, in which the thrust propulsion device includes an electric motor for obtaining the propulsive force in the thrust direction and a battery that supplies driving power to the electric motor, and at least one of the electric motor and the battery is attached to an upper surface of the tunnel.

[0082] When the electric motor or the battery is disposed below the tunnel, it is necessary to ensure a housing space for the motor or the battery between the tunnel and the bottom surface of the boat body. According to the seventh aspect, it is not necessary to ensure the housing space, and it is easy to arrange the tunnel below the water surface.

[0083] A personal watercraft according to an eighth aspect is the personal watercraft according to any one of the first to sixth aspects, in the thrust propulsion device includes an electric motor for obtaining the propulsive force in the thrust direction and a battery that supplies driving electric power to the electric motor, and at least one of the electric motor and the battery is attached to a tunnel wall forming the tunnel.

[0084] According to the eighth aspect, a tunnel wall is utilized as a wall for attachment of the electric motor or the battery. Therefore, it is easy to reduce the number of components.

[0085] A personal watercraft according to a ninth aspect is the personal watercraft according to any one of the first to sixth aspects, in which the thrust propulsion device includes one or a plurality of electric motors for obtaining the propulsive force in the thrust direction and one or a plurality of batteries for supplying driving power to the one or the plurality of electric motors, and the one or the plurality of electric motors and the one or the plurality of batteries are disposed above the tunnel and side by side along an axial direction of the tunnel.

[0086] According to the ninth aspect, a space above the tunnel in the boat body can be effectively utilized.

[0087] A personal watercraft according to a tenth aspect is the personal watercraft according to any one of the first to ninth aspects, in which the thrust propulsion device includes a propeller that is disposed in the tunnel and rotates around a tunnel axis, an electric motor having a rotation axis in a direction intersecting the tunnel axis, and a power transmission portion that converts a rotational force around the rotation axis output by the electric motor into a rotational force around the tunnel axis and transmits the rotational force to the propeller.

[0088] According to the tenth aspect, by providing the power transmission portion, the degree of freedom in designing a mounting position of the electric motor can be increased.

[0089] A personal watercraft according to an eleventh aspect is the personal watercraft according to the second aspect, in which the thrust propulsion device includes an electric motor that rotationally drives the propeller, and the electric motor is disposed to be inclined with respect to a vertical line passing through an axis of the tunnel.

[0090] According to the eleventh aspect, the inclined arrangement of the electric motor can suppress the vertical width occupied by the thrust propulsion device, and the thrust propulsion device can be easily accommodated in the boat body.

[0091] A personal watercraft according to a twelfth aspect is the personal watercraft according to any one of the first to eleventh aspects, further including a luggage room disposed at a front portion in the boat body, and an electric motor for obtaining the propulsive force in the thrust direction, in which the electric motor is disposed at a position vertically overlapping the luggage room.

[0092] According to the twelfth aspect, even if the electric motor enters an area of the luggage room, the electric motor is disposed to be inclined, so that it is easy to ensure the capacity of the luggage room.

[0093] A personal watercraft according to a thirteenth aspect is the personal watercraft according to any one of the first to eleventh aspects, further including a luggage room disposed at a front portion in the boat body, an electric motor for obtaining the propulsive force in the thrust direction, and a cover that covers a protruding portion of the electric motor to the luggage room.

[0094] According to the thirteenth aspect, it is possible to prevent a passenger who has accessed the luggage room from touching the electric motor.

[0095] A personal watercraft according to a fourteenth aspect is the personal watercraft according to any one of the first to thirteenth aspects, further including a drive source that applies a rotational driving force to the impeller shaft, an electric motor for obtaining the propulsive force in the thrust direction, and a partition wall that partitions an area in which the drive source is accommodated and an area in which the electric motor is disposed.

[0096] According to the fourteenth aspect, since the partition wall is provided, it is easy to thermally isolate the electric motor even if the drive source generates heat.

[0097] A personal watercraft according to a fifteenth aspect is a personal watercraft propelled by a jet stream, the personal watercraft including a boat body, a jet pump including an impeller that is disposed at a rear portion of the boat body and generates a propulsive force, and an impeller shaft that rotates the impeller, and a side thruster that generates a water flow in a thrust direction intersecting a front-rear direction of the boat body relative to the boat body, and has a water flow generation position set at a height position equal to or lower than a virtual line extending in an extending direction of the impeller shaft in front of the impeller.

[0098] According to the fifteenth aspect, the side thruster that generates the water flow is disposed at a height position equal to or lower than a virtual line extending in the extending direction of the impeller shaft. Thus, when the watercraft is stationary or is planing at a low speed, the side thruster can be easily maintained at a position below the water surface, and the propulsive force in the thrust direction can be stably generated.

[0099] A personal watercraft according to a sixteenth aspect is a personal watercraft propelled by a jet stream, the personal watercraft including a boat body, a jet pump including an impeller that is disposed at a rear portion of the boat body and generates a propulsive force, and an impeller shaft that rotates the impeller, a stabilizer disposed at a rear portion and on a side portion of the boat body, and a side thruster that generates a water flow in a thrust direction intersecting a front-rear direction of the boat body relative to the boat body, and has a water flow generation position located in front of the impeller and below the stabilizer.

[0100] The stabilizer is attached near a draft surface of the boat body. According to the sixteenth aspect, the side thruster is disposed below the stabilizer. Therefore, when the watercraft is stationary or is planing at a low speed, the side thruster can be easily maintained at a position below the water surface, and the propulsive force in the thrust direction can be stably generated.