Compensation pressure difference variable pump control valve with load-sensitive function

Abstract

The utility model discloses a load-sensitive function pump control valve with variable compensation pressure difference. The load-sensitive function pump control valve comprises a valve body, a valve sleeve, a valve core and a proportional pressure reducing valve, a port P, a port C, a port L, a port A, a sleeve mounting hole and a core mounting hole are formed in the valve body, the sleeve mounting hole and the core mounting hole are coaxially formed, the proportional pressure reducing valve is inserted into the port A, the valve sleeve is located in the sleeve mounting hole, the valve core is located in the core mounting hole, one end of the valve core is in sliding connection with the valve body, and the other end of the valve core extends into the valve sleeve and is in sliding connection with the valve sleeve. A load sensitive cavity acting on the valve element is formed in the valve sleeve. A pressure acting cavity and a proportional pressure reducing cavity are formed in the valve body, the pressure acting cavity is located at the end, away from the valve sleeve, of the valve element, and the proportional pressure reducing cavity is connected with the L port through a proportional pressure reducing valve and communicated with the P port through a damping hole. A reset spring connected with the valve element is arranged in the valve sleeve. The hydraulic system has the advantage that the energy consumption of the hydraulic system can be reduced.

Description

Technical Field

[0001] This utility model belongs to the field of hydraulic load-sensitive control systems, and particularly relates to a load-sensitive pump control valve with variable differential pressure compensation. Background Technology

[0002] A load-sensitive control system is a hydraulic circuit that senses the pressure and flow demand of a hydraulic system and then adjusts the output flow and pressure to meet the required levels. Load-sensitive control systems offer advantages such as low power loss and high efficiency. High efficiency and low power loss translate to energy savings and lower heat generation in the hydraulic system, reducing cooling costs and resulting in an energy-efficient, cost-effective overall system.

[0003] A load-sensitive control system requires the variable pump to have load-sensitive control functionality, and the corresponding pump control valve also needs to have load-sensitive control functionality. The load-sensitive control functions of the pump and valve work together to achieve the load-sensitive control function of the entire hydraulic system.

[0004] The pump control valve is a key component for variable displacement pumps to achieve load-sensing functionality. The existing pump control valve is a two-position, three-way hydraulically controlled proportional directional valve, and its control principle diagram is shown below. Figure 6 As shown, the left end of the pump control valve is acted upon by the pressure at pump outlet B, and the right end by the pressure at load port X. Simultaneously, a pressure regulating spring acts on the right end. If the pump outlet B pressure is too high, the valve core of the pump control valve moves to the right, and the pressure at port B enters the right end of the variable displacement piston of the variable pump, pushing the piston to the left, thus reducing the pump displacement and outlet flow rate. If the pump outlet B pressure is too low, the valve core of the load-sensitive function pump control valve moves to the left, and the oil at the right end of the variable displacement piston of the variable pump leaks into port L (returning to the oil tank). The spring on the left side of the variable displacement piston pushes the piston to the right, increasing the pump displacement and outlet flow rate. Overall, the difference between the pump outlet pressure B and the load pressure X is equal to the preload of the pressure regulating spring. This pressure difference is the compensation pressure difference of the load-sensitive system. Adjusting the preload of the pressure regulating spring can adjust the compensation pressure difference. Once the preload of the pressure regulating spring is fixed, the compensation pressure difference will be fixed, thus making the pressure difference across the valve core of the load-sensitive multi-way valve constant. This makes the flow rate through the valve core proportional to the opening area of ​​the valve core, thereby achieving the load-sensitive function.

[0005] In existing pump control valves, the preload of the pressure regulating spring is a fixed value after it is set, which is not convenient to adjust again. Regardless of whether the flow rate is high or low, including standby mode, the compensation pressure difference is a constant value. This pressure difference multiplied by the flow rate is the power loss of the hydraulic system. When the system is in standby or the working flow rate is low, the fixed compensation pressure difference results in a large power loss, which is not conducive to reducing the energy consumption of the hydraulic system. Utility Model Content

[0006] The purpose of this invention is to provide a load-sensitive pump control valve with variable differential pressure compensation. This invention has the advantage of reducing energy consumption in hydraulic systems.

[0007] The technical solution of this utility model is: a load-sensitive pump control valve with variable differential pressure compensation, comprising a valve body, a valve sleeve, a valve core, and a proportional pressure reducing valve;

[0008] The valve body is provided with a P port, a C port, an L port, an A port, a sleeve mounting hole, and a core mounting hole. The sleeve mounting hole and the core mounting hole are coaxially arranged. The proportional pressure reducing valve is inserted into the A port. The valve sleeve is located in the sleeve mounting hole, and the valve core is located in the core mounting hole. One end of the valve core is slidably connected to the valve body, and the other end of the valve core extends into the valve sleeve and is slidably connected to the valve sleeve. A load-sensitive chamber acting on the valve core is formed inside the valve sleeve.

[0009] The valve body is provided with a pressure-acting chamber and a proportional pressure-reducing chamber. The pressure-acting chamber is located at the end of the valve core away from the valve sleeve. The proportional pressure-reducing chamber is connected to port L through a proportional pressure-reducing valve and port P through a damping orifice.

[0010] The valve sleeve is equipped with a return spring that connects to the valve core;

[0011] When the valve core moves toward the valve sleeve, port C is disconnected from port L and port P is connected to port C; when the valve core moves toward the pressure chamber, port C is connected to port L and port P is disconnected from port C.

[0012] In the aforementioned load-sensitive pump control valve with variable differential pressure compensation, from the pressure-acting chamber to the valve sleeve, the outer circumferential surface of the valve core is sequentially provided with a first annular groove, a second annular groove, and an annular boss. The first annular groove is used to realize the connection and disconnection between port P and port C, and the second annular groove is used to realize the connection and disconnection between port C and port L. An axial hole is provided on the end face of the valve core near the pressure-acting chamber, and the bottom surface of the axial hole extends beyond the annular boss. A radial hole is provided on the bottom surface of the first annular groove, and the radial hole connects the axial hole and port P. The end face of the annular boss facing the pressure-acting chamber is connected to port L. The proportional pressure-reducing chamber is located between the annular boss and the valve sleeve. There is a radial damping hole on the right side of the annular boss, and the damping hole connects the axial hole and the proportional pressure-reducing chamber.

[0013] In the aforementioned load-sensitive pump control valve with variable differential pressure compensation, there are multiple radial holes, and at least one radial hole is always connected to port P.

[0014] In the aforementioned load-sensitive pump control valve with variable differential pressure compensation, the valve sleeve has an annular groove, and an elastic retaining ring for the bore is provided in the groove. The return spring is located between the elastic retaining ring for the bore and the valve core.

[0015] In the aforementioned load-sensitive pump control valve with variable differential pressure compensation, the valve sleeve is threaded to the valve body, and a sealing ring is provided between the valve sleeve and the valve body.

[0016] Compared with the prior art, this utility model has a pressure-acting chamber, a proportional pressure-reducing chamber, and a load-sensitive chamber. The proportional pressure-reducing chamber is connected to the pressure-acting chamber through a damping orifice. The pressure-acting chamber is always connected to the pump outlet B. The load-sensitive chamber is always connected to the load pressure. The proportional pressure-reducing chamber is connected to the pump's return oil tank through a proportional pressure-reducing valve. The valve core is simultaneously subjected to the oil pressure inside the pressure-acting chamber, the proportional pressure-reducing chamber, and the load-sensitive chamber to achieve balance. The difference between the pump outlet B pressure and the load X pressure depends on the pressure of the proportional pressure-reducing chamber. A type B hydraulic half-bridge can be constructed through the proportional pressure-reducing valve and the damping orifice. By changing the current input to the proportional pressure-reducing valve, the oil pressure of the proportional pressure-reducing chamber is changed. Therefore, the difference between the pump outlet B pressure and the load X pressure is variable, that is, the compensation pressure difference is variable.

[0017] During the operation of a load-sensitive system, when the system oil flow rate is large, the pressure difference between the P port pressure and the load must be sufficiently large to achieve a large flow capacity due to the limited valve core opening area. When the system oil flow rate is low, the valve core opening area is relatively large, and the designed flow capacity can be achieved even with a lower compensation pressure difference. When the system is in standby mode, the power loss is equal to the product of the compensation pressure difference and the standby flow rate. Reducing the pressure difference between the P port pressure and the load can reduce the system's standby power loss.

[0018] Load-sensitive pump control valves can adjust and compensate for differential pressure in real time, thereby reducing power loss and improving the efficiency of the hydraulic system under various operating conditions. When the pump output flow is low, the compensation differential pressure is reduced to minimize power loss caused by excessive compensation differential pressure at low flow rates. Conversely, when the pump output flow is high, the compensation differential pressure is increased to increase the oil flow rate through the valve, achieving optimal matching between the compensation differential pressure and the oil flow rate, thus avoiding excessive power loss caused by differential pressure mismatch. When the pump is in standby mode, the compensation differential pressure can be reduced to zero, thereby minimizing standby pressure and reducing standby power loss.

[0019] In summary, this utility model has the advantage of reducing the energy consumption of hydraulic systems. Attached Figure Description

[0020] Figure 1 This is a front view schematic diagram of this utility model.

[0021] Figure 2 This is a front view schematic diagram of the valve body.

[0022] Figure 3 This is a front view of the valve sleeve.

[0023] Figure 4 This is a front view schematic diagram of the valve core.

[0024] Figure 5 This is a hydraulic schematic diagram of this utility model.

[0025] Figure 6This is a hydraulic schematic diagram of an existing pump-controlled valve.

[0026] The labels in the attached diagram are as follows: 1-valve body, 2-valve sleeve, 3-valve core, 4-proportional pressure reducing valve, 5-sleeve mounting hole, 6-core mounting hole, 7-load sensitive chamber, 8-damping hole, 9-pressure acting chamber, 10-proportional pressure reducing chamber, 11-reset spring, 12-first annular groove, 13-second annular groove, 14-annular boss, 15-axial hole, 16-radial hole, 17-groove, 18-elastic retaining ring for hole, 19-sealing ring. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0028] Example. A load-sensitive functional pump control valve with variable differential pressure compensation, such as... Figure 1 As shown, it includes valve body 1, valve sleeve 2, valve core 3, and proportional pressure reducing valve 4.

[0029] The valve body 1 is provided with a P port, a C port, an L port, an A port, a sleeve mounting hole 5, and a core mounting hole 6. The P port, C port, L port, and A port are respectively located at... Figure 1 As shown in P, C, L, and A. The core mounting hole 6 can be machined directly as a blind hole, i.e., closed at the left end, or it can be machined as a through hole with a screw plug at the left end.

[0030] The sleeve mounting hole 5 and the core mounting hole 6 are coaxially arranged, with the sleeve mounting hole 5 located to the right of the core mounting hole 6, and one end of the valve sleeve 2 is screwed into the sleeve mounting hole 5.

[0031] The proportional pressure reducing valve 4 is inserted into port A. The valve core 3 is located in the core mounting hole 6. One end of the valve core 3 is slidably connected to the valve body 1, and the other end of the valve core 3 extends into the valve sleeve 2 and is slidably connected to the valve sleeve 2. The seal between the valve core 3 and the valve sleeve 2 can be achieved by a clearance fit or by a sealing element.

[0032] A load-sensitive cavity 7 acting on the right end of the valve core 3 is formed within the valve sleeve 2. An annular groove 17 is formed within the valve sleeve 2, and an elastic retaining ring 18 is provided within the groove 17. A return spring 11 is provided between the elastic retaining ring 18 and the valve core 3. The valve sleeve 2 is screwed to the valve body 1, and a sealing ring 19 is provided between the valve sleeve 2 and the valve body 1.

[0033] The return spring 11 is used to help the valve core 3 return to its original position. The spring's limit is restricted by an elastic retaining ring through the hole, resulting in a simple and efficient structure. Since the return spring 11 has a small elastic force, the pressure it exerts on the valve core 3 can be considered close to zero.

[0034] The valve body 1 is provided with a pressure-acting chamber 9 and a proportional pressure-reducing chamber 10. The pressure-acting chamber 9 is located at the end of the valve core 3 away from the valve sleeve 2. The proportional pressure-reducing chamber 10 is connected to port L through the proportional pressure-reducing valve 4 and port P through the damping hole 8.

[0035] In the initial state, when the valve core 3 is close to the pressure chamber 9, port C is connected to port L and port P is disconnected from port C. When the valve core 3 moves towards the valve sleeve 2, port C is disconnected from port L and port P is connected to port C.

[0036] The valve core 3 is cylindrical. From left to right, the outer circumference of the valve core 3 is provided with a first annular groove 12, a second annular groove 13, and an annular boss 14. The first annular groove 12 is used to realize the connection and disconnection between port P and port C, and the second annular groove 13 is used to realize the connection and disconnection between port C and port L. The area on the right side of the annular boss 14 is equal to the area of ​​the end face of the valve core 3.

[0037] An axial hole 15 is provided on the left end face of the valve core 3. The bottom surface of the axial hole 15 extends to the right beyond the annular boss 14. A radial hole 16 is provided on the bottom surface of the first annular groove 12. The radial hole 16 connects the axial hole 15 and the P port. The end face of the annular boss 14 facing the pressure chamber 9 is connected to the L port. The proportional pressure reducing chamber 10 is located between the annular boss 14 and the valve sleeve 2. The damping hole 8 connects the axial hole 15 and the proportional pressure reducing chamber 10. The damping hole 8 is located on the right side of the annular boss 14.

[0038] There are multiple radial holes 16, and at least one radial hole 16 is always connected to port P. When the valve core moves to the left, all radial holes 16 are connected to port P, and when the valve core moves to the right, at least one radial hole 16 is connected to port C.

[0039] Usage: Connect port P to pump outlet B, port C to the right end of the pump's variable piston, port L to the pump's return oil tank, and valve sleeve to load port X, i.e., load sensing chamber 7 is connected to the load oil pressure.

[0040] Working principle: such as Figure 1 As shown,

[0041] For pressure chamber 9: Pressure chamber 9 is connected to pump outlet B through axial hole 15, radial hole 16 and port P. The oil action area at the left end of valve core 3 is S1, the oil pressure at pump outlet B is P1, and the force to the right on valve core 3 is F1 = P1 * S1.

[0042] For the proportional pressure reducing chamber 10: the oil in the pressure acting chamber 9 enters the proportional pressure reducing chamber 10 sequentially through the axial hole 15 and the damping hole 8. The proportional pressure reducing chamber 10 is connected to port L through the proportional pressure reducing valve 4, so that the oil pressure P2 is maintained in the proportional pressure reducing chamber 10, and the valve core 3 is subjected to a force to the left F2 = P2 * S2, where S2 is the area on the right side of the annular boss 14, S2 = S1, and F2 = P2 * S1.

[0043] For the load-sensitive chamber 7: When the load oil enters, the oil pressure P3 causes the valve core 3 to be subjected to a force to the left, F3 = P3 * S1.

[0044] F1 = F2 + F3 + F 弹 F 弹 This represents the spring force acting on the right end of valve core 3. Its value is small and can be ignored in the principle analysis. Therefore, we can obtain F1 = F2 + F3, that is, P1*S1 = P2*S1 + P3*S1. Canceling S1 on both sides, we get P1 = P2 + P3.

[0045] If P1 > P2 + P3, the pressure at port P is too high, causing valve core 3 to move to the right. Port C and port P are connected through the first annular groove 12, and port C is disconnected from port L. The oil at pump outlet B enters port C through the first annular groove 12 in sequence, that is, it enters the right end of the variable piston, pushing the variable piston to the left, reducing the pump's displacement, thereby reducing the pressure at port P.

[0046] If P1 < P2 + P3, the pressure at port P is too low, causing valve core 3 to move to the left. The oil at port C connects to port L through the second annular groove 13, disconnecting port C and port P. The pressure at port C decreases, and the variable piston moves to the right under the action of the matching spring, which reduces the pump's displacement and thus increases the pressure at port P.

[0047] Ultimately, the pressure at port P remains balanced with the sum of pressures P2 and P3, where P2 = P1 - P3, meaning P2 equals the pressure difference between port P and the load pressure. Changing the pressure of P2 will alter the pressure difference between port P and the load, thus enabling adjustable and controllable pressure differential compensation. Changing the pressure of P2 is achieved through the proportional pressure reducing valve 4.

[0048] The proportional pressure reducing chamber pressure control function is realized by adopting the B-type hydraulic half-bridge method. The damping orifice 8 is the fixed damping orifice of the B-type half-bridge, and the proportional pressure reducing valve is the variable damping of the B-type half-bridge. The two work together to form the B-type half-bridge. The oil at port P enters the proportional pressure reducing chamber 10 through the damping orifice 8, and then is unloaded to port L through the proportional pressure reducing valve 4.

[0049] The oil pressure in the proportional pressure reducing chamber 10 acts on the valve core of the proportional pressure reducing valve 4. This force is balanced with the force generated by the proportional electromagnet in the proportional pressure reducing valve 4. By maintaining a constant current in the proportional electromagnet, the pressure in the proportional pressure reducing chamber remains constant. Changing the current in the proportional electromagnet can change the pressure in the proportional pressure reducing chamber 10.

[0050] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

Claims

1. A load-sensitive pump control valve with variable differential pressure compensation, characterized in that: It includes a valve body (1), a valve sleeve (2), a valve core (3), and a proportional pressure reducing valve (4); The valve body (1) is provided with a P port, a C port, an L port, an A port, a sleeve mounting hole (5) and a core mounting hole (6). The sleeve mounting hole (5) and the core mounting hole (6) are coaxially arranged. The proportional pressure reducing valve (4) is inserted into the A port. The valve sleeve (2) is located in the sleeve mounting hole (5). The valve core (3) is located in the core mounting hole (6). One end of the valve core (3) is slidably connected to the valve body (1). The other end of the valve core (3) extends into the valve sleeve (2) and is slidably connected to the valve sleeve (2). A load-sensitive cavity (7) acting on the valve core (3) is formed in the valve sleeve (2). The valve body (1) is provided with a pressure-acting chamber (9) and a proportional pressure-reducing chamber (10). The pressure-acting chamber (9) is located at the end of the valve core (3) away from the valve sleeve (2). The proportional pressure-reducing chamber (10) is connected to port L through the proportional pressure-reducing valve (4). The proportional pressure-reducing chamber (10) is connected to port P through the damping hole (8). The valve sleeve (2) is equipped with a return spring (11) that connects to the valve core (3); When the valve core (3) moves toward the valve sleeve (2), port C is disconnected from port L and port P is connected to port C; when the valve core (3) moves toward the pressure chamber (9), port C is connected to port L and port P is disconnected from port C.

2. The load-sensitive pump control valve with variable differential pressure compensation according to claim 1, characterized in that: From the pressure chamber (9) to the valve sleeve (2), the outer circumferential surface of the valve core (3) is provided with a first annular groove (12), a second annular groove (13) and an annular boss (14) in sequence. The first annular groove (12) is used to realize the connection and disconnection between the P port and the C port, and the second annular groove (13) is used to realize the connection and disconnection between the C port and the L port. The end face of the valve core (3) near the pressure chamber (9) is provided with an axial hole (15). The bottom surface of the axial hole (15) extends beyond the annular boss (14). The bottom surface of the first annular groove (12) is provided with a radial hole (16). The radial hole (16) connects the axial hole (15) and the P port. The end face of the annular boss (14) facing the pressure chamber (9) connects to the L port. The proportional pressure reducing chamber (10) is located between the annular boss (14) and the valve sleeve (2). The right side of the annular boss (14) is provided with a radial damping hole (8). The damping hole (8) connects the axial hole (15) and the proportional pressure reducing chamber (10).

3. The load-sensitive pump control valve with variable differential pressure compensation according to claim 2, characterized in that: There are multiple radial holes (16), and at least one radial hole (16) is always connected to port P.

4. The load-sensitive pump control valve with variable differential pressure compensation according to claim 1, characterized in that: The valve sleeve (2) has an annular groove (17) inside, and an elastic retaining ring (18) for holes is provided in the groove (17). The return spring (11) is located between the elastic retaining ring (18) for holes and the valve core (3).

5. The load-sensitive pump control valve with variable differential pressure compensation according to claim 1, characterized in that: The valve sleeve (2) is threadedly connected to the valve body (1), and a sealing ring (19) is provided between the valve sleeve (2) and the valve body (1).

6. The load-sensitive pump control valve with variable differential pressure compensation according to claim 1, characterized in that: The valve core (3) and valve sleeve (2) are sealed by a gap fit or by a sealing element.

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