Apparatus for improving excavating operation characteristic and grading operation characteristic of excavator

Abstract

Disclosed is an apparatus for improving excavating operation characteristic and grading operation characteristic of an excavator. The apparatus includes a solenoid valve group and a hydraulically controlled selector valve. An oil controlling output A1 of the solenoid valve group is configured in series with oil controlling input a1 of the hydraulic control valve. An oil controlling output A2 of the solenoid valve group is configured in series with a pilot control end XBa2 of a multi-port valve group. An oil return port T1 of the solenoid valve group is connected to the hydraulic oil tank. An oil controlling output b1 of the hydraulically controlled selector valve is connected to a pilot control end XAb2 of the multiplexer valve group, and an oil return port T2 of the hydraulically controlled selector valve is connected with the hydraulic oil tank. The apparatus improves operational efficiency and control comfortability.

Claims

1. An apparatus for improving excavating operation characteristic and grading operation characteristic of an excavator including a boom, a stick, and a bucket, the apparatus comprising: a hydraulic oil tank (3), a right control lever valve (5), a left control lever valve (6), a multiplexer valve group (8), a solenoid valve group (4) and a hydraulically controlled selector valve (7), wherein: the right control lever valve (5) has a BOOM UP end functioned to control the boom to be up, and is connected with each of: an oil controlling inlet (P1) of the solenoid valve group (4) and a pilot control end (XBb1) of the multiplexer valve group (8), that are configured in parallel; the left control lever valve (6) has an ARM DUMP end functioned to control the stick to dump, and connected with each of: an oil controlling inlet (P2) of the solenoid valve group (4) and a pilot control end (XBa1) of the multiplexer valve group (8), that are configured in parallel; and an oil controlling output (A1) of the solenoid valve group (4) is configured in series with an oil controlling input (a1) of the hydraulic control valve (7), an oil controlling output (A2) of the solenoid valve group (4) is configured in series with a pilot control end (XBa2) of the multiplexer valve group (8), and an oil return port (T1) of the solenoid valve group (4) is connected to the hydraulic oil tank (3); the hydraulically controlled selector valve (7) is configured in a boom confluence control circuit to control the boom operation and configured to detect a control pressure signal of a stick excavation; and the hydraulically controlled selector valve (7) is configured to detect the control pressure signal of the stick excavation during the excavation operation, and configured to disconnect the boom confluence control circuit, while a double pump confluence circuit corresponding to a double hydraulic pump (1) is used only for the stick excavation, based on the control pressure value of the stick excavation.

2. The apparatus of claim 1, wherein: the left control lever valve (6) is configured, via an ARM CROWD end, to connect with each of: pilot control ends (XAa2) and (XAa1) of the multiplexer valve group (8) and a pressure detecting end (a2) of the hydraulically controlled selector valve (7), that are configured in parallel; and an oil controlling output (b1) of the hydraulically controlled selector valve (7) is connected to a pilot control end (XAb2) of the multiplexer valve group (8), and an oil return port (T2) of the hydraulically controlled selector valve (7) is connected with the hydraulic oil tank (3).

3. The apparatus of claim 1, further comprising a double hydraulic pump (1), a gear pump (2), a stick cylinder (9), and a boom cylinder (10), wherein: the double hydraulic pump (1) and the gear pump (2) are configured in series by a mechanical connecting mechanism and then connected to an oil inlet (B.sub.1) at one end, an other end of the oil inlet (B.sub.1) is connected to the hydraulic oil tank (3), and oil passages (P.sub.1) and (P.sub.2) of the double hydraulic pump (1) are connected to an input port of the multiplexer valve group (8), (Aa1) of the multiplexer valve group (8) is connected to a rod-less chamber of the stick cylinder (9), (Ba1) of the multiplexer valve group (8) is connected to a rod chamber of the stick cylinder (9), (Ab1) of the multiplexer valve group (8) is connected to a rod-less chamber of the boom cylinder (10), and (Bb1) of the multiplexer valve group (8) is connected to a rod chamber of the boom cylinder (10), an oil return port (R.sub.2) of the multiplexer valve group (8) is connected to the hydraulic oil tank (3).

4. The apparatus of claim 3, wherein: an oil controlling output (A.sub.3) of the gear pump (2) is respectively connected with each of: (P.sub.R) end of the right control lever valve (5) and (P.sub.L) end of the left control lever valve (6), that are configured in parallel, and T.sub.R end of the right control lever valve (5) is configured in parallel with (T.sub.L) end of the left control lever valve (6) and then connected with the hydraulic oil tank (3) in series.

5. The apparatus of claim 1, wherein: the solenoid valve group (4) is configured to control: both the boom confluence control circuit and a stick confluence control circuit, to allow the excavator to switch between an excavation operation and a grading operation, in response to a control signal received by the solenoid valve group (4).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram illustrating a hydraulic process in accordance with various disclosed embodiments;

(2) FIG. 2 is schematic diagram illustrating flow directions of hydraulic oil passages in a standard excavation mode when a hydraulically controlled selector valve does not change direction in accordance with various disclosed embodiments;

(3) FIG. 3 is schematic diagram illustrating flow directions of hydraulic oil passages in a standard excavation mode when the hydraulically controlled selector valve changes direction in accordance with various disclosed embodiments;

(4) FIG. 4 is a schematic diagram illustrating flow directions of hydraulic oil passages in a grading operation mode during a stick excavation operation in accordance with various disclosed embodiments; and

(5) FIG. 5 is a schematic diagram illustrating flow directions of hydraulic oil passages in a grading operation mode during a stick swing operation in accordance with various disclosed embodiments.

REFERENCE SIGN LIST

(6) Double hydraulic pump 1 Gear pump 2 Hydraulic oil tank 3 Solenoid valve group 4 Right control lever valve 5 Left control lever valve 6 Hydraulically controlled selector valve 7 Multiplexer valve group 8 Stick cylinder 9 Boom cylinder 10

DETAILED DESCRIPTION

(7) Reference will now be made in detail to exemplary embodiments of the disclosure, which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

(8) As shown FIGS. 1-5, the disclosed apparatus includes a double hydraulic pump 1, a gear pump 2, a hydraulic oil tank 3, a right control lever valve 5, a left control lever valve 6, a multiplexer valve group 8, a stick cylinder 9, and a boom cylinder 10.

(9) The double hydraulic pump 1 and the gear pump 2 are configured in series by a mechanical connecting means and then connected to an oil inlet B.sub.1 at one end. The other end of the oil net B.sub.1 is connected to the hydraulic oil tank 3. OH passages P.sub.1 and P.sub.2 of the double hydraulic pump 1 are connected to an input port of the multiplexer valve group 8. Aa1 of the multiplexer valve group 8 is connected to a rod-less chamber of the slick cylinder 9, Ba1 of the multiplexer valve group 8 is connected to a rod chamber of the stick cylinder 9; Ab1 of the multiplexer valve group 8 is connected to a rod-less chamber of the boom cylinder 10; and Bb1 of the multiplexer valve group 8 is connected to a rod chamber of the boom cylinder 10.

(10) An oil return port R.sub.2 of the multiplexer valve group 8 is connected to the hydraulic oil tank 3. An oil controlling output A.sub.3 of the gear pump 2 is configured in parallel respectively with P.sub.R end of the right control lever valve 5 and P.sub.L end of the left control lever valve 6. T.sub.R end of the right control lever valve 5 is configured in parallel with T.sub.L end of the left control lever valve 6 and then connected with the hydraulic oil tank 3 in series.

(11) The disclosed apparatus also includes a solenoid valve group 4 and a hydraulically controlled selector valve 7. The right control lever valve 5 is configured, via a BOOM UP end, in parallel with an oil controlling inlet P1 of the solenoid valve group 4 and a pilot control end XBa1 of the multiplexer valve group 8. The left control lever valve 6 is configured, via an ARM DUMP end, in parallel with an oil controlling inlet P2 of the solenoid valve group 4 and a pilot control end XBa1 of the multiplexer valve group 8. An oil controlling output A1 of the solenoid valve group 4 is configured in series with oil controlling input a1 of the hydraulic control valve 7.

(12) An oil controlling output A2 of the solenoid valve group 4 is configured in series with a pilot control end XBa2 of the multi-port valve group 8. An oil return port T1 of the solenoid valve group 4 is connected to the hydraulic oil tank 3. The left control lever valve 6 is configured, via an ARM CROWD end, in parallel with pilot control ends XAa2 and XAa1 of the multiplexer valve group 8 and a pressure detecting end a2 of the hydraulically controlled selector valve 7.

(13) An oil controlling output b1 of the hydraulically controlled selector valve 7 is connected to a pilot control end XAb2 of the multiplexer valve group 8. An oil return port T2 of the hydraulically controlled selector valve 7 is connected with the hydraulic oil tank 3.

(14) An electrical signal controlling end of the solenoid valve group 4 is connected with a controller. Via commands from an operator, a switching between a disconnected mode and a connected mode of the solenoid valve group 4 is achieved. When the controller sends out a signal to connect the solenoid valve group 4, the solenoid valve group 4 disconnects a boom lifting confluence circuit and increases a stick swinging confluence circuit to achieve a grading operation mode. When the controller sends out a signal to disconnect the solenoid valve group 4, a valve spool is restored to a middle position, a boom lifting confluence circuit is restored, and a stick swinging confluence circuit is disconnected to perform a standard excavation mode.

(15) When entering a standard excavation mode, a pressure detecting end of the hydraulically controlled selector valve 7 detects a control pressure signal of a stick excavation. When a control pressure value of the stick excavation is smaller than a change-direction pressure of the hydraulically controlled selector valve 7, the hydraulically controlled selector valve 7 does not change its direction. Hydraulic oil of a pilot control oil passage controlling a boom cylinder 10 and a stick cylinder 9 is entirely supplied by a double pump after confluence. When the control pressure value of the stick excavation reaches the change-direction pressure of the hydraulically controlled selector valve 7, the hydraulically controlled selector valve 7 changes its direction, a boom confluence control circuit is disconnected and oil is independently supplied to a boom by a single pump, while a stick excavation double pump confluence circuit is maintained. In this manner, power utilization efficiency of a hydraulic pump is achieved and hydraulic oil of the hydraulic pump is more allocated to the stick cylinder to perform the excavation operation.

(16) When entering a grading operation mode, an operator may change a control mode by sending the controller a change-direction command to the solenoid valve group 4 via an operational button. After receiving the command, the solenoid valve group 4 changes its direction, the pilot control oil passage changes allocation of a double pump confluence, a confluence control circuit of boom lifting (e.g., a piston rod of boom cylinder extends out) hydraulic oil is disconnected and is replaced by using a single pump to supply oil, stick excavation (e.g., a piston rod of the stick cylinder 9 extends out) maintains double pump confluence, and a hydraulic oil passage of stick swinging (e.g., a piston rod of the stick cylinder 9 recovers) is increased with the double pump confluence. Speed for recovering the stick cylinder is improved to achieve fast reciprocating speed of the stick during grading operation. Because boom lifting confluence is cancelled and boom lifting is steady, impact of traffic to the boom is reduced to achieve requirements for smooth and fine grading operation.

(17) Other applications, advantages, alternations, modifications, or equivalents to the disclosed embodiments are obvious to those skilled in the art.