A dual-mode flow control device for a hydraulic system

Abstract

The invention discloses a dual-mode flow control device for a hydraulic system, belongs to the technical field of hydraulic system control devices for excavators, and solves the problem that the conventional hydraulic system for excavators has only one external feedback flow control mode, which affects the life of a hydraulic pump; the control device includes an oil tank, a multi-way valve and a pilot valve, the multi-way valve is connected to the pilot valve through a plurality of control loops, the pilot valve is connected to the oil tank through a pilot oil return loop, and also includes a selection solenoid valve and an adjustable pressure reducing valve, the selection solenoid valve is connected to the multi-way valve through a first feedback loop, the selection solenoid valve is connected to the adjustable pressure reducing valve through a second feedback loop, the selection solenoid valve is connected to the hydraulic pump through a final feedback loop, the adjustable pressure reducing valve is connected to the hydraulic pump through a feedback oil supply loop, and the pilot valve is connected to the hydraulic pump through a pilot oil supply loop. The invention can select different control modes according to the working conditions of the actuator, reduce the number of times the hydraulic pump swash plate is adjusted and worn, and improve the life of the hydraulic pump.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic system control devices for excavators, and more specifically, to a dual-mode flow control device for a hydraulic system. Background Art

[0002] Conventionally, an excavator hydraulic system has only one external feedback flow control mode, that is, follow-up fuzzy flow control. The multi-way valve forms a feedback signal based on the flow demand of the actuator and transmits it to the hydraulic pump. The hydraulic pump adjusts the angle of the swash plate according to the feedback signal to complete the flow supply control. This feedback signal changes frequently, and the swash plate of the hydraulic pump also follows the frequent adjustments and frequent wear, thus affecting the life of the hydraulic pump. This flow control mode is still desirable if there are multiple actuators in the complex action. If it is a single actuator action, such as crushing, drilling, etc., the flow demand is relatively fixed, and this control mode is not the best. Summary of the invention

[0003] The purpose of the present invention is to provide a dual-mode flow control device for a hydraulic system, which uses a selection solenoid valve to select the best flow control mode, thereby ultimately reducing the wear of the hydraulic pump and effectively increasing the life of the hydraulic pump.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A dual-mode flow control device for a hydraulic system comprises an oil tank, a multi-way valve and a pilot valve, wherein the multi-way valve is connected to the pilot valve through a plurality of control circuits, and the pilot valve is connected to the oil tank through a pilot oil return circuit. The device also comprises a selection solenoid valve and an adjustable pressure reducing valve, wherein the selection solenoid valve is connected to the multi-way valve through a first feedback circuit, the selection solenoid valve is connected to the adjustable pressure reducing valve through a second feedback circuit, the selection solenoid valve is connected to a hydraulic pump through a final feedback circuit, the adjustable pressure reducing valve is connected to the hydraulic pump through a feedback oil supply circuit, and the pilot valve is connected to the hydraulic pump through a pilot oil supply circuit.

[0006] Furthermore, the oil port P of the multi-way valve is connected to the oil port D1 of the hydraulic pump to form a high-pressure oil supply circuit, and the oil port R of the multi-way valve is connected to the oil port of the oil tank to form a main oil return circuit.

[0007] Furthermore, the oil port xa1 of the pilot valve is connected to the oil port a1 of the multi-way valve to form a first control loop.

[0008] Furthermore, the oil port xb1 of the pilot valve is connected to the oil port b1 of the multi-way valve to form a second control loop.

[0009] Furthermore, the oil port xa2 of the pilot valve is connected to the oil port a2 of the multi-way valve to form a third control loop.

[0010] Furthermore, the oil port xb2 of the pilot valve is connected to the oil port b2 of the multi-way valve to form a fourth control loop.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] A dual-mode flow control device for a hydraulic system of the present invention provides two flow modes for selection, namely, following fuzzy flow control and specified precise flow control. By selecting the flow control mode by selecting the solenoid valve, the optimal flow control mode can be selected according to the working condition of the actuator, which can ultimately reduce the wear of the hydraulic pump and effectively increase the life of the hydraulic pump. At the same time, precise flow control can effectively reduce energy loss and achieve energy-saving effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0014] Figure 1 is a structural principle diagram of the dual-mode flow control device of the present invention;

[0015] In the figure, 1. oil tank, 2. multi-way valve, 3. pilot valve, 4. pilot oil return circuit, 5. selection solenoid valve, 6. adjustable pressure reducing valve, 7. first feedback circuit, 8. second feedback circuit, 9. final feedback circuit, 10. feedback oil supply circuit, 11. pilot oil supply circuit, 12. high-pressure oil supply circuit, 13. main oil return circuit, 14. first control circuit, 15. second control circuit, 16. third control circuit, 17. fourth control circuit, 18. hydraulic pump. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further described in detail below in conjunction with specific implementation methods, but does not constitute any limitation to the present invention.

[0017] Reference Figure 1As shown, a dual-mode flow control device for a hydraulic system includes an oil tank 1, a multi-way valve 2 and a pilot valve 3. The multi-way valve 2 is connected to the pilot valve 3 through multiple control circuits, and the pilot valve 3 is connected to the oil tank 1 through a pilot oil return circuit 4. It also includes a selection solenoid valve 5 and an adjustable pressure reducing valve 6. The selection solenoid valve 5 is connected to the multi-way valve 2 through a first feedback circuit 7, the selection solenoid valve 5 is connected to the adjustable pressure reducing valve 6 through a second feedback circuit 8, the selection solenoid valve 5 is connected to the hydraulic pump 18 through a final feedback circuit 9, the adjustable pressure reducing valve 6 is connected to the hydraulic pump 18 through a feedback oil supply circuit 10, and the pilot valve 3 is connected to the hydraulic pump 18 through a pilot oil supply circuit 11. The oil port P of the multi-way valve 2 is connected to the oil port D1 of the hydraulic pump 18 to form a high-pressure oil supply circuit 12, and the oil port R of the multi-way valve 2 is connected to the oil port of the oil tank 1 to form a main oil return circuit 13.

[0018] Specifically, the oil port xa1 of the pilot valve 3 is connected with the oil port a1 of the multi-way valve 2 to form a first control circuit 14, the oil port xb1 of the pilot valve 3 is connected with the oil port b1 of the multi-way valve 2 to form a second control circuit 15, the oil port xa2 of the pilot valve 3 is connected with the oil port a2 of the multi-way valve 2 to form a third control circuit 16, and the oil port xb2 of the pilot valve 3 is connected with the oil port b2 of the multi-way valve 2 to form a fourth control circuit 17.

[0019] A dual-mode flow control device for a hydraulic system in the present invention provides two flow control modes, namely, following fuzzy flow control and specified precise flow control. The flow control mode is selected by selecting the solenoid valve 5. Under normal conditions, the following fuzzy flow control mode is selected by default, and the specified precise flow control mode is switched when the button for selecting the solenoid valve 5 is pressed.

[0020] When the machine is in the state of starting, when it is in the state of compound action of multiple actuators, the solenoid valve 5 is selected by default to connect the first feedback loop 7 and the final feedback loop 9. At this time, the machine is in the following fuzzy flow control mode. The multi-way valve 2 generates a feedback signal, which enters the first feedback loop 7 through the oil port PN and flows through the selected solenoid valve 5 to the final feedback loop 9, and finally enters the oil port pi1 of the hydraulic pump 18. The hydraulic pump 18 adjusts the swash plate angle according to this signal, thereby completing a flow control. New feedback signals are continuously generated during the working process, and the hydraulic pump 18 also follows and continuously adjusts the swash plate angle to complete the flow control.

[0021] If the machine is in a single actuator action or a predictable flow demand stable action condition, press the button of the selection solenoid valve 5 to connect the selection solenoid valve 5 to the second feedback loop 8 and the final feedback loop 9. At this time, the machine is in the specified precise flow control mode. The oil in the feedback oil supply loop 10 outputs the expected feedback signal oil after passing through the adjustable pressure reducing valve 6. The oil passes through the second feedback loop 8, flows through the selection solenoid valve 5 to the final feedback loop 9, and finally enters the oil port pi1 of the hydraulic pump 18. The hydraulic pump 18 adjusts the swash plate angle according to this signal, thereby completing the flow control. Since the feedback signal is a specified precise value adjusted by the adjustable pressure reducing valve 6, after approval, only one precise feedback signal needs to be input for one working condition, and the hydraulic pump 18 does not need to repeatedly adjust the swash plate angle during operation.

[0022] A dual-mode flow control device for a hydraulic system of the present invention has a simple structure and is easy to manufacture. It can select the optimal flow control mode according to the working conditions, and can ultimately reduce the wear of the hydraulic pump 18, effectively increasing the life of the hydraulic pump 18. At the same time, precise flow control can effectively reduce energy loss and achieve energy-saving effects. It has the characteristics of reliable performance, high cost performance, and objective social benefits.

[0023] The above description is only a preferred embodiment of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A dual-mode flow control device for a hydraulic system, comprising an oil tank (1), a multi-way valve (2) and a pilot valve (3), wherein the multi-way valve (2) is connected to the pilot valve (3) via a plurality of control circuits, and the pilot valve (3) is connected to the oil tank (1) via a pilot oil return circuit (4), characterized in that: The invention also comprises a selection solenoid valve (5) and an adjustable pressure reducing valve (6), wherein the selection solenoid valve (5) is connected to the multi-way valve (2) via a first feedback loop (7), the selection solenoid valve (5) is connected to the adjustable pressure reducing valve (6) via a second feedback loop (8), the selection solenoid valve (5) is connected to a hydraulic pump (18) via a final feedback loop (9), the adjustable pressure reducing valve (6) is connected to the hydraulic pump (18) via a feedback oil supply loop (10), and the pilot valve (3) is connected to the hydraulic pump via a pilot oil supply loop (11). (18) connected; the oil port xa1 of the pilot valve (3) is connected to the oil port a1 of the multi-way valve (2) to form a first control circuit (14), the oil port xb1 of the pilot valve (3) is connected to the oil port b1 of the multi-way valve (2) to form a second control circuit (15), the oil port xa2 of the pilot valve (3) is connected to the oil port a2 of the multi-way valve (2) to form a third control circuit (16), and the oil port xb2 of the pilot valve (3) is connected to the oil port b2 of the multi-way valve (2) to form a fourth control circuit (17); When the machine is in the starting state and in the multi-actuator compound action state, the solenoid valve (5) is selected to connect the first feedback loop (7) and the final feedback loop (9) in the default state, and the multi-way valve (2) generates a feedback signal which enters the first feedback loop (7) through the oil port PN, flows through the selection solenoid valve (5) to the final feedback loop (9), and finally enters the oil port pi1 of the hydraulic pump (18). The hydraulic pump (18) adjusts the swash plate angle according to the signal, thereby completing a flow control. During the working process, new feedback signals are continuously generated, and the hydraulic pump (18) also continuously adjusts the swash plate angle to complete the flow control. When the machine is in a single actuator action or a predictable flow demand stable action condition, the button of the selection solenoid valve (5) is pressed to connect the selection solenoid valve (5) to the second feedback loop (8) and the final feedback loop (9). The oil in the feedback oil supply loop (10) outputs an expected feedback signal after passing through the adjustable pressure reducing valve (6). The oil passes through the second feedback loop (8), flows through the selection solenoid valve (5) to the final feedback loop (9), and is finally input into the oil port pi1 of the hydraulic pump (18). The hydraulic pump (18) adjusts the swash plate angle according to the signal, thereby completing the flow control.

2. A dual-mode flow control device for a hydraulic system according to claim 1, characterized in that: The oil port P of the multi-way valve (2) is connected to the oil port D1 of the hydraulic pump (18) to form a high-pressure oil supply circuit (12), and the oil port R of the multi-way valve (2) is connected to the oil port of the oil tank (1) to form a main oil return circuit (13).

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