A closed hydraulic motor-mechanical linear actuator driving circuit with centralized oil supply

Abstract

The application is a hydraulic motor-mechanical linear actuator closed drive circuit with centralized oil supply characteristics, comprising a plurality of hydraulic motor-mechanical linear actuator control oil paths arranged in parallel and a continuous variable pump / motor power device connected thereto, a motor drivingly connected to a first hydraulic motor-mechanical linear actuator, a first control oil path and a second control oil path connected to the motor inlet and outlet respectively, an external interface of the first control oil path and the second control oil path respectively arranged to connect two four-way logic switch control valves, four-way logic switch control valves arranged at the inlet and outlet of the continuous variable pump / motor power device, and the four-way logic switch control valves at the inlet and outlet of the continuous variable pump / motor power device respectively connected to the second control oil path in each hydraulic motor-mechanical linear actuator control oil path and the four-way logic switch control valves arranged at the external interfaces of the first control oil path and the second control oil path.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic control technology, specifically a closed-loop drive circuit of hydraulic motor-mechanical linear actuator that can have centralized oil supply in a hydraulic system. Background Technology

[0002] In open-loop pump control systems, the pump output flow is still distributed to the actuators via a multi-way valve. To ensure reliable operation of actuators under different loads, load compensators or priority logic valves are often added to distribute the flow, increasing throttling losses. Closed-loop volumetric control directly replaces valve control with a pump-controlled cylinder and pump-controlled motor circuit that eliminates throttling losses, improving system efficiency and representing a cutting-edge direction in fluid transmission and control research. However, in closed-loop pump control systems, each actuator is driven by at least one pump. Applying this to equipment like excavators that require multiple hydraulic actuators results in high installed power and high installation costs. Furthermore, the oil in a closed-loop system does not return to the tank, leading to poor heat dissipation and potentially overheating. Additionally, asymmetric actuators in closed-loop pump control systems suffer from flow mismatch, requiring a small-capacity replenishing pump to replenish oil and flush the oil circuit for cooling, complicating the system structure. The pumps in closed-loop circuits are relatively small, limiting the system's application to smaller machinery and making it less suitable for medium to large-sized equipment.

[0003] Single-rod hydraulic cylinders are the most common linear actuators in hydraulic systems due to their simple structure, reliable operation, and high transmission efficiency. However, due to structural design issues, the two chambers of this device have asymmetrical areas, leading to flow mismatch during operation and affecting the overall system performance. Currently, electric cylinders are a cutting-edge research direction in this field. However, due to the power density limitations of motors, electric cylinders may malfunction under heavy loads or load shocks. Therefore, hydraulic drives remain the primary method in medium and large-scale equipment.

[0004] Chinese patent CN204959857U discloses a hydraulic powertrain technology for excavators, which reduces the number of oil supply pumps used and enables multiple actuators to be driven by a small number of oil supply pumps. However, this solution does not achieve independent control of individual actuators by the oil supply pumps when the oil supply is collectively supplied. The use of control valve groups also increases system resistance and oil consumption. Chinese patent CN115163582A discloses a distributed independent variable speed closed-loop pump-controlled hydraulic system for excavators. This system uses an integrated electro-hydraulic actuator of four pump-controlled hydraulic systems to achieve independent execution of the actuators. However, the number of oil supply pumps used is not reduced, increasing the installed power. Summary of the Invention

[0005] To address the problem in existing closed-loop pump control systems that require a one-to-one correspondence between the motor pump and the actuator, the technical solution adopted in this invention is as follows: A closed-loop drive circuit for a hydraulic motor-mechanical linear actuator with centralized oil supply features includes control oil circuits for multiple hydraulic motor-mechanical linear actuators connected in parallel and power sources connected to them respectively. The power source is a continuous variable pump / motor power unit. It includes control oil circuits for at least two hydraulic motor-mechanical linear actuators connected in parallel. Each control oil circuit includes a first hydraulic motor-mechanical linear actuator, a motor, a four-way logic switch control valve, a first control oil circuit, and a second control oil circuit. The motor drives the first hydraulic motor-mechanical linear actuator. The first and second control oil circuits are respectively connected to the motor's inlet and outlet. The external interfaces of the first and second control oil circuits are respectively connected to two four-way logic switches. The continuous variable pump / motor power unit includes a speed-regulating motor and its driven first and second continuous variable pumps / motors. Four-way logic switch control valves are installed at the inlet and outlet of the continuous variable pump / motor power unit. The four-way logic switch control valve at the outlet of the continuous variable pump / motor power unit is connected to a four-way logic switch control valve at the external interface of the second control circuit in the control oil circuit of each hydraulic motor-mechanical linear actuator. The four-way logic switch control valve at the inlet of the continuous variable pump / motor power unit is connected to a four-way logic switch control valve at the external interface of the first control oil circuit in the control oil circuit of each hydraulic motor-mechanical linear actuator. The four-way logic switch control valves are used to achieve four connection states: State 1: When port P is connected to port T, port B is disconnected from port T; State 2: When port P is disconnected from port T, port B is disconnected from port T; State 3: When port P is disconnected from port T, port B is connected to port T; State 4: When port P is connected to port T, port B is connected to port T.

[0006] The motor is either a continuous variable motor or a fixed-displacement motor.

[0007] The four-way logic switch control valve is either a four-position four-way directional valve or two two-position two-way solenoid switch valves connected in parallel.

[0008] A speed-regulating motor is one of the following: an AC asynchronous motor, a stepper motor, a DC motor, or a servo motor.

[0009] The control circuit of the hydraulic motor-mechanical linear actuator also includes: a first relief valve, a second relief valve, and a flow regeneration switch valve. The first relief valve, the second relief valve, and the flow regeneration switch valve are respectively connected between the first control circuit and the second control circuit.

[0010] The control circuit of the hydraulic motor-mechanical linear actuator also includes: a hydraulic lock, the outlet of which is connected to the first control circuit and the second control circuit respectively, and the inlet of the first hydraulic control check valve and the second hydraulic control check valve is equipped with an oil replenishment device.

[0011] The first type of hydraulic motor-mechanical linear actuator includes a reducer, rolling bearings, balls, a nut, a lead screw, and a push rod. One side of the reducer is connected to the motor drive via a coupling, and the other side is connected to the lead screw via a coupling. The rolling bearings are fitted onto the lead screw, the balls are fitted between the lead screw and the nut, and the nut is connected to the push rod.

[0012] The hydraulic lock consists of a first hydraulically controlled check valve and a second hydraulically controlled check valve. The control oil circuit of the first hydraulically controlled check valve is connected to the second control oil circuit, and the control oil circuit of the second hydraulically controlled check valve is connected to the first control oil circuit. The oil outlet of the first hydraulically controlled check valve is connected to the first control oil circuit, and the oil outlet of the second hydraulically controlled check valve is connected to the second control oil circuit. The oil inlets of the first and second hydraulically controlled check valves are connected together to a replenishing oil device.

[0013] The oil replenishment device includes an accumulator, a first two-position two-way switch valve, an electric motor, a one-way metering pump, and a third relief valve. The electric motor is connected to the one-way metering pump. The oil inlet of the third relief valve is connected in parallel with the A port of the two-position two-way switch valve at the oil outlet of the one-way metering pump. The accumulator is connected to the B port of the two-position two-way switch valve.

[0014] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: This invention discloses a closed-loop drive circuit for a hydraulic motor-mechanical linear actuator with centralized oil supply. Specifically, it uses a continuous variable pump / motor to drive the actuator, achieving the effect of controlling multiple drivers with a small number of pumps / motors. This gives the closed-loop pump control system the advantages of an open system. While eliminating throttling losses, the system can operate with fewer pumps than the number of actuators, reducing energy consumption and installed power, improving work efficiency, and lowering manufacturing costs. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure and connection components of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure and connection composition of Embodiment 2 of the present invention; Figure 3This is a schematic diagram of the structure and connection composition of Embodiment 3 of the present invention; Figure 4 This is a schematic diagram of a hydraulic motor-mechanical linear actuator. Figure 5 This is a schematic diagram of a four-way valve. Figure 6 This is a schematic diagram of the connection of a two-position, two-way solenoid valve.

[0017] Explanation of reference numerals in the attached figures: 1- Control circuit of hydraulic motor-mechanical linear actuator (Part I); 2- Hydraulic motor-mechanical linear actuator (Part I); 3- Reducer; 4- Rolling bearing; 5- Ball bearing; 6- Nut; 7- Lead screw; 8- Push rod; 9- Continuous variable motor (Part I); 10- Relief valve (Part I); 11- Relief valve (Part II); 12- Flow regeneration switch valve; 13- Hydraulic lock; 14- Pilot-operated check valve (Part I); 15- Pilot-operated check valve (Part II); 16- Four-position four-way directional valve (Part I); 17- Four-position four-way directional valve (Part II); 18- Control circuit (Part I); 19- Control circuit (Part II); 20- Continuous variable pump / motor power unit; 21- Four-position four-way directional valve (Part III); 22- Part IV 23-4-position directional control valve; 24-speed regulating motor; 25-Continuous variable pump / motor (I); 26-Continuous variable pump / motor (II); 27-Main oil circuit (III); 28-Main oil circuit (IV); 29-Main oil circuit (II); 30-Main oil replenishment device; 31-Accumulator; 32-Two-position 2-way switch valve (I); 33-Motor; 34-One-way fixed displacement pump; 35-Relief valve (III); 36-Replenishment circuit; 37-Control oil circuit for hydraulic motor-mechanical linear actuator (II); 38-Control oil circuit for hydraulic motor-mechanical linear actuator (III); 39-Fixed displacement motor; 40-Two-position 2-way switch valve (II); 41-Two-position 2-way switch valve (III). Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The purpose of this invention is to use one or more variable pumps / motors to control multiple drives, so that the system can eliminate throttling losses while possessing the advantages of both closed and open pump control systems, reducing energy loss and installed power, improving working efficiency, and reducing manufacturing costs.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1, as shown in the appendix Figure 1 As shown, a closed-loop drive circuit for a hydraulic motor-mechanical linear actuator with centralized oil supply features includes a control oil circuit 1 for the first hydraulic motor-mechanical linear actuator, a control oil circuit 37 for the second hydraulic motor-mechanical linear actuator, a control oil circuit 38 for the third hydraulic motor-mechanical linear actuator, a continuous variable pump / motor power unit 20, and an oil replenishment device 30. The control oil circuit and the power unit constitute a closed loop.

[0022] The control circuit 37 of the second hydraulic motor-mechanical linear actuator and the control circuit 38 of the third hydraulic motor-mechanical linear actuator are the same as the control circuit 1 of the first hydraulic motor-mechanical linear actuator. The three circuits are connected in parallel. During operation, one circuit can work alone, or the number of control circuits can be increased to work simultaneously. The number of circuits depends on the working conditions.

[0023] The control circuit 1 of the hydraulic motor-mechanical linear actuator includes the hydraulic motor-mechanical linear actuator 2, the continuous variable motor 9, the relief valve 10, the relief valve 11, the flow regeneration switch valve 12, the hydraulic lock 13, the four-position four-way directional valve 16, the four-position four-way directional valve 17, the control circuit 18, and the control circuit 19. The continuous variable motor 9 is connected to the control circuit 18 and the control circuit 19. The direction and speed of the hydraulic oil in the two control circuits are controlled to adjust the direction and speed of the continuous variable motor 9, thereby controlling the extension or retraction and the speed of the hydraulic motor-mechanical linear actuator 2.

[0024] As attached Figure 4 As shown, the first hydraulic motor-mechanical linear actuator 2 includes a reducer 3, rolling bearings 4, balls 5, a nut 6, a lead screw 7, and a push rod 8. The first continuous variable motor 9 drives the reducer 3, which in turn drives the balls 5 and the lead screw 7 to rotate via a mechanical connection. The reducer 3 can be a gear reducer or a belt reducer. During this process, since the lead screw 7 is fixed, the balls 5 push the nut 6 to make linear motion under the rotation of the lead screw 7. The nut 6 further drives the push rod 8 to complete the extension and retraction of the actuator and the speed of the action.

[0025] The inlet of the first relief valve 10 is connected to the first control oil circuit 18, and the outlet of the first relief valve 10 is connected to the second control oil circuit 19. The inlet of the second relief valve 11 is connected to the second control oil circuit 19, and the outlet of the second relief valve 11 is connected to the first control oil circuit 18. The first relief valve 10 and the second relief valve 11 act as safety valves and pressure maintaining valves in the circuit. The flow regeneration switch valve 12 is connected to the first control oil circuit 18 and the second control oil circuit 19. When high-pressure oil is introduced into the first control oil circuit 18 or the second control oil circuit 19, low-pressure oil is introduced into the other control oil circuit. At this time, the flow regeneration switch valve 12 opens, allowing high-pressure oil to enter the low-pressure oil circuit through the valve, compensating for insufficient oil in the low-pressure oil circuit and playing the role of flow regeneration.

[0026] The hydraulic lock 13 includes a first hydraulically controlled check valve 14 and a second hydraulically controlled check valve 15. The control oil circuit of the first hydraulically controlled check valve 14 is connected to the second control oil circuit 19, the control oil circuit of the second hydraulically controlled check valve 15 is connected to the first control oil circuit 18, the oil outlet of the first hydraulically controlled check valve 14 is connected to the first control oil circuit 18, the oil outlet of the second hydraulically controlled check valve 15 is connected to the second control oil circuit 19, and the oil inlets of the first hydraulically controlled check valve 14 and the second hydraulically controlled check valve 15 are connected in parallel on the oil replenishment circuit. When high-pressure oil is supplied to the first control oil circuit 18 and low-pressure oil is supplied to the second control oil circuit 19, the high-pressure oil causes the valve core switch of the second hydraulic control check valve 15 to open, and the oil circuit compensation device operates. The compensation oil flows into the low-pressure oil circuit through the second hydraulic control check valve 15 to complete the oil replenishment. When high-pressure oil is supplied to the second control oil circuit 19 and low-pressure oil is supplied to the first control oil circuit 18, the high-pressure oil causes the valve core switch of the first hydraulic control check valve 14 to open, and the oil circuit compensation device operates. The compensation oil flows into the low-pressure oil circuit through the first hydraulic control check valve 14 to complete the oil replenishment.

[0027] As attached Figure 5 The schematic diagram of the four-way four-position valve shown is combined with the attached diagram. Figure 1 As shown, ports A and B of the first four-way directional valve 16 are connected to the first control oil circuit 18, ports A and B of the second four-way directional valve 17 are connected to the second control oil circuit 19, the first continuous variable motor 9 is connected to the first four-way directional valve 16 through the first control oil circuit 18, and the first continuous variable motor 9 is connected to the second four-way directional valve 17 through the second control oil circuit 19.

[0028] The continuous variable pump / motor power unit 20 includes a third four-position four-way directional valve 21, a speed-regulating motor 23, a first continuous variable pump / motor 24, a second continuous variable pump / motor 25, a fourth four-position four-way directional valve 22, a first main oil passage 29, a second main oil passage 28, a third main oil passage 26, and a fourth main oil passage 27. The speed-regulating motor 23 is mechanically or via a coupling to the first and second continuous variable pumps / motors 24 and 25, and is used to drive the continuous variable pumps / motors. The speed-regulating motor 23 is one of an AC asynchronous motor, a stepper motor, a DC motor, or a servo motor. The variable pump / motor is a liquid-driven variable pump / motor. Figure 1 The system consists of two continuous variable pumps / motors operating, but depending on the operating conditions, one continuous variable pump / motor may operate, or both may operate simultaneously.

[0029] The two oil ports of the first continuous variable pump / motor 24 are connected to the P port of the third four-way directional valve 21 and the A port of the fourth four-way directional valve 22, respectively. The two oil ports of the second continuous variable pump / motor 25 are connected to the T port of the third four-way directional valve 21 and the B port of the fourth four-way directional valve 22, respectively. Port A of the third four-way directional valve 21 is connected to the third main oil circuit 26; Port B of the third four-way directional valve 21 is connected to the fourth main oil circuit 27; Port P of the fourth four-way directional valve 22 is connected to the first main oil circuit 29; Port T of the fourth four-way directional valve 22 is connected to the second main oil circuit 28; The first continuous variable pump / motor 24 is connected to the first main oil circuit 29 through the fourth four-way directional valve 22; The first continuous variable pump / motor 24 is connected to the third main oil circuit 26 through the third four-way directional valve 21; The second continuous variable pump / motor 25 is connected to the second main oil circuit 28 through the third four-way directional valve 22; The second continuous variable pump / motor 25 is connected to the fourth main oil circuit 27 through the third four-way directional valve 21.

[0030] Main oil circuit I 29 is connected to port T of directional valve I 16 (four-way, four-position). Main oil circuit II 28 is connected to port P of directional valve I 16 (four-way, four-position). Main oil circuit III 26 is connected to port P of directional valve II 17 (four-way, four-position). Main oil circuit IV 27 is connected to port T of directional valve II 17 (four-way, four-position). Main oil circuit I 29 is connected to control oil circuit I 18 via directional valve I 16 (four-way, four-position). Main oil circuit II 28 is connected to... I. The four-position four-way directional valve 16 is connected to the first control oil circuit 18. The third main oil circuit 26 is connected to the second control oil circuit 19 through the second four-position four-way directional valve 17. The fourth main oil circuit 27 is connected to the second control oil circuit 19 through the second four-position four-way directional valve 17. The first hydraulic motor-mechanical linear actuator 2 is driven by the speed regulating motor 23, the first continuous variable pump / motor 24, and / or the second continuous variable pump / motor 25.

[0031] The oil replenishment device 30 includes an accumulator 31, a first two-position two-way switch valve 32, a motor 33, a one-way metering pump 34, a third relief valve 35, and an oil replenishment circuit 36. The motor 33 is connected to the one-way metering pump 34, and the motor 33 drives the one-way metering pump 34 to work. The oil inlet of the one-way metering pump 34 is connected to the oil tank. The oil inlet of the third relief valve 35 is connected in parallel with port A of the first two-position two-way switch valve 32 to the oil outlet of the one-way metering pump 34. The oil outlet of the third relief valve 35 is connected to the oil tank and acts as a safety valve. The oil replenishment circuit 36 ​​is connected in parallel with the accumulator 31 to port B of the first two-position two-way switch valve 32. The accumulator 31 can provide pressurized oil when replenishing the system. The oil replenishment circuit connects to the oil inlets of the first hydraulic control check valve 14 and the second hydraulic control check valve 15 to provide the system compensation pressure oil.

[0032] Example 2, as Figure 2 As shown, the difference from Embodiment 1 is that in this implementation mode, the continuous variable motor in the control oil circuit 38 of the third hydraulic motor-mechanical linear actuator is replaced with a fixed motor 39, while the control oil circuits of the other two hydraulic motor-mechanical linear actuators are still continuously variable motors.

[0033] Example 3, as Figure 3 , Figure 5 , Figure 6 As shown, the difference from Embodiment 1 is that the four-position four-way directional valve, such as the I four-position four-way directional valve 16, is replaced by two identical two-position two-way solenoid valves: the II two-position two-way valve 40 and the III two-position two-way valve 41. The implementation principle is the same as that of the four-position four-way directional valve. Port A' is equivalent to port A, port B' is equivalent to port B, port P' is equivalent to port P, and port T' is equivalent to port T. When the P port and A port of the four-position four-way directional valve are connected, only the A' and P' ports of the left two-position two-way solenoid valve need to be connected. When the T port and B port of the four-position four-way directional valve are connected, only the B' and T' ports of the right two-position two-way solenoid valve need to be connected. When the P port and A port, and the T port and B port of the four-position four-way directional valve are all connected, both two-position two-way solenoid valves need to be connected. The implementation principle is the same.

[0034] Operating mode 1: A continuous variable pump / motor drives an actuator.

[0035] In this implementation mode, the first continuous variable pump / motor 24 operates, the third four-position four-way directional valve 21 and the fourth four-position four-way directional valve 22 are connected to the leftmost position, and the P port and A port are connected, connecting the first continuous variable pump / motor 24 to the first main oil circuit 29 and the third main oil circuit 26. The first four-position four-way directional valve 16 and the second four-position four-way directional valve 17 are also connected to the leftmost position, and the P port and A port are connected, forming a complete closed loop. In this loop, the first continuous variable pump / motor 24 supplies oil to the first continuous variable motor 9, and the first continuous variable motor 9 controls the extension and retraction of the first hydraulic motor-mechanical linear actuator 2 and the speed of the movement. The second continuous variable pump / motor 25 can be used, with the same principle as when the first continuous variable pump / motor 24 is used; alternatively, other actuators in the control oil circuit can be selected, with the same principle as the control oil circuit 1 of the first hydraulic motor-mechanical linear actuator.

[0036] Operating mode 2: Multiple continuous variable pumps / motors drive one actuator.

[0037] In this implementation mode, the first continuous variable pump / motor 24 and the second continuous variable pump / motor 25 operate, jointly driving the first hydraulic motor-mechanical linear actuator 2 in the first control oil circuit 18. In this case, the third four-position four-way directional valve 21 and the fourth four-position four-way directional valve 22 are connected to the rightmost position, connecting ports P and A, B and T. The first continuous variable pump / motor 24 is connected to the first main oil circuit 29 and the third main oil circuit 26, and the second continuous variable pump / motor 25 is connected to the second main oil circuit 28 and the fourth main oil circuit 27. The first four-position four-way directional valve 16 and the second four-position four-way directional valve 17 are also connected to the rightmost position, connecting ports P and A, B and T, forming a closed loop. By adjusting the first continuous variable pump / motor 24 and the second continuous variable pump / motor 25, the flow rate in the oil circuit is controlled, thereby controlling the extension and retraction movements and the speed of the first hydraulic motor-mechanical linear actuator 2. The actuators of other hydraulic circuits can be driven by the first continuous variable pump / motor 24 and the second continuous variable pump / motor 25, in the same principle as driving the first hydraulic motor-mechanical linear actuator 2.

[0038] Operating mode 3: One continuous variable pump / motor drives multiple actuators.

[0039] In this implementation mode, the first continuous variable pump / motor 24 operates, simultaneously driving the auxiliary... Figure 1The first hydraulic motor-mechanical linear actuator 2 is located in one of the three oil circuits. In this case, the third four-position four-way directional valve 21 and the fourth four-position four-way directional valve 22 are connected to the leftmost position, with port P and port A connected. This connects the first continuous variable pump / motor 24 to the first main oil circuit 29 and the third main oil circuit 26. The four-position four-way directional valves in the three control oil circuits are connected to the leftmost position, with port P and port A connected, forming a complete closed loop. The first continuous variable pump / motor 24 supplies oil to these three control oil circuits. By adjusting the continuous variable motor connected to the hydraulic motor-mechanical linear actuator, the flow rate of the pressurized oil in this circuit is distributed, thereby controlling the simultaneous extension and retraction of the actuators in different oil circuits and the speed of the action. The second continuous variable pump / motor 25 can also be used, with the same principle.

[0040] Operating mode 4: Multiple continuous variable pumps / motors jointly drive multiple actuators.

[0041] In this implementation mode, the first continuous variable pump / motor 24 and the second continuous variable pump / motor 25 drive the auxiliary Figure 1 The first hydraulic motor-mechanical linear actuator 2 operates on the three oil circuits. All four-way directional valves in the system are connected to the rightmost position, connecting ports P and A, and ports B and T. The first continuous variable pump / motor 24 is connected to the first main oil circuit 29 and the third main oil circuit 26. The second continuous variable pump / motor 25 is connected to the second main oil circuit 28 and the fourth main oil circuit 27. By adjusting the continuous variable motor connected to the hydraulic motor-mechanical linear actuator, the flow rate of the pressurized oil in each circuit is distributed, thereby controlling the simultaneous extension and retraction of the actuators in different oil circuits, as well as the speed of the movements. Under this operating condition, the load-bearing capacity is relatively large.

[0042] Operating mode 5: One continuous variable pump / motor drives one actuator, and another continuous variable pump / motor drives the remaining actuators.

[0043] In this implementation mode, the first continuous variable pump / motor 24 drives the hydraulic motor-mechanical linear actuator of the first hydraulic motor-mechanical linear actuator control circuit 1, and the second continuous variable pump / motor 25 drives the hydraulic motor-mechanical linear actuators of the second hydraulic motor-mechanical linear actuator control circuit 37 and the third hydraulic motor-mechanical linear actuator control circuit 38. At this time, the third four-position four-way directional valve 21 and the fourth four-position four-way directional valve 22 are connected to the rightmost position, so that ports P and A, and ports B and T are all connected. The first continuous variable pump / motor 24 is connected to the first main oil circuit 29 and the third main oil circuit 26, and the second continuous variable pump / motor 25 is connected to the second main oil circuit 28 and the fourth main oil circuit 27. The first four-position four-way directional valve 16 of the control circuit 1 of the first hydraulic motor-mechanical linear actuator switches to connect ports T and B, and the second four-position four-way directional valve 17 switches to the leftmost position, so that... Ports P and A are connected to form a closed loop; the four-position four-way directional valves in the control oil circuit 37 of the second hydraulic motor-mechanical linear actuator and the control oil circuit 38 of the third hydraulic motor-mechanical linear actuator, which are connected to the main oil circuit 27 of the fourth hydraulic circuit, are reversed to connect ports T and B; the four-position four-way directional valves in the control oil circuit 37 of the second hydraulic motor-mechanical linear actuator and the control oil circuit 38 of the third hydraulic motor-mechanical linear actuator, which are connected to the main oil circuit 28 of the second hydraulic motor-mechanical linear actuator, are reversed to the leftmost position to connect ports P and A, thus forming a closed loop. At this time, the first continuous variable pump / motor 24 can independently drive the extension and retraction of the hydraulic motor-mechanical linear actuator in the control oil circuit 1 of the first hydraulic motor-mechanical linear actuator, as well as the speed of the action; the second continuous variable pump / motor 25 drives the hydraulic motor-mechanical linear actuator in the control oil circuit 37 of the second hydraulic motor-mechanical linear actuator and the control oil circuit 38 of the third hydraulic motor-mechanical linear actuator. By adjusting the continuous variable motor connected to the hydraulic motor-mechanical linear actuator, the flow rate of the pressure oil in the control oil circuit 37 of the second hydraulic motor-mechanical linear actuator and the control oil circuit 38 of the third hydraulic motor-mechanical linear actuator is distributed, thereby controlling the extension and retraction of the actuator in these two oil circuits and the speed of the action. When the hydraulic motor-mechanical linear actuator in control circuit 1 of the first hydraulic motor-mechanical linear actuator extends or retracts, the hydraulic motor-mechanical linear actuators in control circuits 37 of the second hydraulic motor-mechanical linear actuator and 38 of the third hydraulic motor-mechanical linear actuator can also extend or retract without interference. The principle is the same when the hydraulic motor-mechanical linear actuators in control circuits 1 and 37 of the first hydraulic motor-mechanical linear actuator are driven by the first continuous variable pump / motor 24, and when the hydraulic motor-mechanical linear actuator in control circuit 38 of the third hydraulic motor-mechanical linear actuator is driven by the second continuous variable pump / motor 25.

[0044] Operating mode six: The motor connected to one actuator is changed to a fixed-displacement motor, while the other motors remain continuous variable motors.

[0045] As attached Figure 2 As shown, in this implementation mode, the continuously variable motor in the control circuit 38 of the third hydraulic motor-mechanical linear actuator is replaced with a fixed displacement motor 39, while the control circuits of the other two hydraulic motor-mechanical linear actuators remain continuously variable motors. In this case, the first continuously variable pump / motor 24 can be driven alone, or the first continuously variable pump / motor 24 and the second continuously variable pump / motor 25 can be driven together. The flow rate of the continuously variable pump / motor can be adjusted to control the extension and retraction actions and the speed of the hydraulic motor-mechanical linear actuator in the control circuit of the hydraulic motor-mechanical linear actuator.

[0046] When the hydraulic motor-mechanical linear actuators of the control circuits of the three hydraulic motor-mechanical linear actuators are simultaneously driven by the first continuous variable pump / motor 24, or when the first continuous variable pump / motor 24 and the second continuous variable pump / motor 25 jointly drive the hydraulic motor-mechanical linear actuators of the three hydraulic motor-mechanical linear actuators, the flow rate of the continuous variable motor in the control circuit 1 of the continuous variable pump / motor and the control circuit 37 of the first hydraulic motor-mechanical linear actuator and the second hydraulic motor-mechanical linear actuator is adjusted to match the flow rate in the control circuit 38 of the third hydraulic motor-mechanical linear actuator where the fixed displacement motor 39 is located, thereby controlling the extension and retraction actions and the speed of the three hydraulic motor-mechanical linear actuators.

[0047] When the first continuous variable pump / motor 24 drives the hydraulic motor-mechanical linear actuator in the control oil circuit 38 of the third hydraulic motor-mechanical linear actuator, and the second continuous variable pump / motor 25 drives the other two hydraulic motor-mechanical linear actuators, it is only necessary to adjust the flow rate of the first continuous variable pump / motor 24 to match the flow rate of the oil circuit where the fixed displacement motor 39 is located, thereby controlling the extension and retraction actions and the speed of the hydraulic motor-mechanical linear actuator in the control oil circuit 38 of the third hydraulic motor-mechanical linear actuator.

[0048] When the second continuous variable pump / motor 25 drives the hydraulic motor-mechanical linear actuator in control circuit 1 of the first hydraulic motor-mechanical linear actuator, and the first continuous variable pump / motor 24 drives the hydraulic motor-mechanical linear actuators in control circuit 38 of the third hydraulic motor-mechanical linear actuator and control circuit 37 of the second hydraulic motor-mechanical linear actuator, the flow rate in the continuous variable motor control circuit of the first variable pump / motor 24 and control circuit 37 of the second hydraulic motor-mechanical linear actuator is adjusted to match the flow rate in control circuit 38 of the third hydraulic motor-mechanical linear actuator where the fixed displacement motor 39 is located. This controls the extension and retraction actions and the speed of the hydraulic motor-mechanical linear actuators in control circuit 38 of the third hydraulic motor-mechanical linear actuator and control circuit 37 of the second hydraulic motor-mechanical linear actuator.

Claims

1. A closed-loop drive circuit for a hydraulic motor-mechanical linear actuator with centralized oil supply, comprising control oil circuits for multiple hydraulic motor-mechanical linear actuators connected in parallel and power sources connected to them respectively, characterized in that: The power source is a continuous variable pump / motor power unit (20), which includes at least two parallel hydraulic motor-mechanical linear actuator control oil circuits. The control oil circuit of the hydraulic motor-mechanical linear actuator includes a first hydraulic motor-mechanical linear actuator (2), a motor, a four-way logic switch control valve, a first control oil circuit (18), and a second control oil circuit (19). The motor drive is connected to the first hydraulic motor-mechanical linear actuator (2). The first control oil circuit (18) and the second control oil circuit (19) are respectively connected to the motor inlet and outlet. The external interface of the first control oil circuit (18) is connected to a four-way logic switch control valve, and the external interface of the second control oil circuit (19) is connected to another four-way logic switch control valve. A total of two four-way logic switch control valves are configured in the two control oil circuits. The power unit (20) includes a speed-regulating motor (23) and its driven first continuous variable pump / motor (24) and second continuous variable pump / motor (25). The inlet and outlet of the continuous variable pump / motor power unit (20) are respectively equipped with four-way logic switch control valves. The four-way logic switch control valve at the outlet of the continuous variable pump / motor power unit (20) is connected to the four-way logic switch control valve at the external interface of the second control circuit (19) in the control oil circuit of each hydraulic motor-mechanical linear actuator. The four-way logic switch control valve at the inlet of the continuous variable pump / motor power unit (20) is connected to the four-way logic switch control valve at the external interface of the first control oil circuit (18) in the control oil circuit of each hydraulic motor-mechanical linear actuator. The four-way logic switch control valves are used to achieve four connection states, namely: State 1: When port P is connected to port T, port B is disconnected from port T; State 2: When port P is disconnected from port T, port B is disconnected from port T; State 3: When port P is disconnected from port T, port B is connected to port T; State 4: When port P is connected to port T, port B is connected to port T.

2. The closed-loop drive circuit of a hydraulic motor-mechanical linear actuator with centralized oil supply as described in claim 1, characterized in that: The motor is a first-order continuous variable motor (9) or / and a fixed-displacement motor (39).

3. A closed-loop drive circuit for a hydraulic motor-mechanical linear actuator with centralized oil supply as described in claim 1, characterized in that: The four-way logic switch control valve is either a four-position four-way directional valve or two two-position two-way solenoid switch valves connected in parallel.

4. A closed-loop drive circuit for a hydraulic motor-mechanical linear actuator with centralized oil supply as described in any one of claims 1-3, characterized in that: The speed-regulating motor (23) is one of an AC asynchronous motor, a stepper motor, a DC motor, or a servo motor.

5. A closed-loop drive circuit for a hydraulic motor-mechanical linear actuator with centralized oil supply as described in any one of claims 1-3, characterized in that: The control circuit of the hydraulic motor-mechanical linear actuator also includes: a first relief valve (10), a second relief valve (11), and a flow regeneration switch valve (12). The first relief valve (10), the second relief valve (11), and the flow regeneration switch valve (12) are respectively connected between the first control circuit (18) and the second control circuit (19).

6. A closed-loop drive circuit for a hydraulic motor-mechanical linear actuator with centralized oil supply as described in any one of claims 1-3, characterized in that: The control circuit of the hydraulic motor-mechanical linear actuator also includes a hydraulic lock (13), which is composed of a first hydraulic control check valve (14) and a second hydraulic control check valve (15). The outlet of the hydraulic lock (13) is connected to the first control circuit (18) and the second control circuit (19) respectively, and the inlets of the first hydraulic control check valve (14) and the second hydraulic control check valve (15) are connected to the oil replenishment device (30).

7. A closed-loop drive circuit for a hydraulic motor-mechanical linear actuator with centralized oil supply as described in any one of claims 1-3, characterized in that: The first hydraulic motor-mechanical linear actuator (2) includes a reducer (3), rolling bearings (4), balls (5), nuts (6), lead screws (7), and push rods (8); one side of the reducer is connected to the motor drive via a coupling, and the other side is connected to the lead screw via a coupling. The rolling bearings are sleeved on the lead screw, the balls are fitted between the lead screw and the nut, and the nut is connected to the push rod.

8. A closed-loop drive circuit for a hydraulic motor-mechanical linear actuator with centralized oil supply as described in claim 6, characterized in that: The hydraulic lock (13) consists of a first hydraulic control check valve (14) and a second hydraulic control check valve (15). The control oil circuit of the first hydraulic control check valve (14) is connected to the second control oil circuit (19), the control oil circuit of the second hydraulic control check valve (15) is connected to the first control oil circuit (18), the oil outlet of the first hydraulic control check valve (14) is connected to the first control oil circuit (18), the oil outlet of the second hydraulic control check valve (15) is connected to the second control oil circuit (19), and the oil inlets of the first hydraulic control check valve (14) and the second hydraulic control check valve (15) are connected to the oil replenishment device (30).

9. A closed-loop drive circuit for a hydraulic motor-mechanical linear actuator with centralized oil supply as described in claim 8, characterized in that: The oil replenishment device (30) includes an accumulator (31), a first two-position two-way switch valve (32), a motor (33), a one-way metering pump (34), and a third overflow valve (35). The motor (33) is connected to the one-way metering pump (34). The oil inlet of the third overflow valve (35) is connected in parallel with the A port of the first two-position two-way switch valve (32) at the oil outlet of the one-way metering pump (34). The accumulator (31) is connected to the B port of the first two-position two-way switch valve (32).

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