Hydraulic systems, construction machinery and pressure compensation valves

Abstract

The hydraulic system comprises a working system and a feedback device. The working system comprises an inlet connected with an oil source and at least two working links arranged in parallel. Each working link comprises an actuator, a control valve and a pressure compensation valve. The pressure compensation valve is connected with the inlet and connected with the actuator through the control valve. The pressure compensation valve has a first control end and a second control end. The first control end and the second control end control the pressure compensation valve to switch to a first valve position in which the oil source is communicated with the control valve and a second valve position in which the inlet is cut off from the control valve. The first control end is connected with the inlet and an outlet of the control valve. The second control end is connected with an inlet of the control valve. The feedback device is used to lead the highest load pressure to the second control end of each working link, so that the pressure difference between the inlet and the outlet of the control valve of each working link of the composite action is equal. Thus, the problem that the light and heavy load actuators cannot work synchronously when the flow is saturated in the hydraulic system with the pressure compensation valve arranged in front of the control valve can be solved.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, and in particular to a hydraulic system, engineering machinery and pressure compensation valve. Background Technology

[0002] Some hydraulic systems of construction machinery include at least two working links connected in parallel, and each working link includes an actuator, a control valve and a pressure compensation valve. The pressure compensation valve is located before the control valve and is connected to the actuator through the control valve to perform pressure compensation and maintain a constant pressure difference across the valve.

[0003] In the aforementioned hydraulic system of the related technology, when the actuators of different working links operate simultaneously and the required flow exceeds the pump's oil supply flow (i.e., flow saturation), the hydraulic oil usually flows to the light-load link first, and only flows to other working links after the light-load link is satisfied. In this case, only the low-pressure actuator can be compensated and operate, while the actuator with a larger load slows down or even stops, causing the actuators of each working link to not operate synchronously, affecting the normal operation of the construction machinery. Summary of the Invention

[0004] This application provides a hydraulic system, engineering machinery, and a pressure compensation valve to solve the problem that in a hydraulic system with a pressure compensation valve installed before the control valve, light and heavy load actuators cannot work synchronously when the flow is saturated.

[0005] The hydraulic system provided in this application includes:

[0006] A working system has an inlet and includes at least two working links. The inlet is connected to an oil source. The at least two working links are arranged in parallel, and each working link includes an actuator, a control valve, and a pressure compensation valve. The actuator is used to drive the actuator of the construction machinery. The pressure compensation valve is connected to the inlet and to the actuator through the control valve. The pressure compensation valve has a first control end and a second control end, which respectively control the pressure compensation valve to switch to a first valve position and a second valve position. When in the first valve position, the pressure compensation valve connects the oil source to the control valve. When in the second valve position, the pressure compensation valve disconnects the inlet from the control valve. The first control end is connected to the inlet and the outlet of the control valve, and the second control end is connected to the inlet of the control valve.

[0007] A feedback device is connected to the outlet of the control valve of each working link and to the second control terminal of each working link to direct the highest load pressure in at least two working links to the second control terminal of each working link, so that when at least two of the at least two working links are combined, the pressure difference between the inlet and outlet of the control valve of each working link in the combined action is equal.

[0008] In some embodiments, the feedback device includes at least two check valves, each check valve corresponding to at least two working links. The inlet of each check valve is connected to the outlet of the control valve of the corresponding working link, and the outlet of each check valve is connected to the second control terminal of the pressure compensation valve of all working links.

[0009] In some embodiments, the pressure at the inlet of the pressure compensation valve, the outlet pressure of the control valve, the inlet pressure of the control valve, and the maximum load pressure have equal effective areas.

[0010] In some embodiments, the pressure compensation valve includes a valve body, a valve core, a guide seat, a connector, a plunger, and a push rod. The guide seat and the connector are disposed at opposite ends of the valve body. The valve core is disposed in the valve body and located between the guide seat and the connector. A first control end is located at one end of the valve core facing the guide seat, and a second control end is located at one end of the valve core facing the connector. The plunger is inserted into a first groove of the valve core and the guide seat. The push rod is inserted into a second groove of the valve core and a third groove of the connector. The inlet communicates with the first groove. The outlet of the control valve communicates with the space of the valve body between the valve core and the guide seat. The inlet of the control valve communicates with the space of the valve body between the valve core and the connector through the second groove. The feedback device communicates with the third groove.

[0011] In some embodiments, the cross-sectional area of ​​the first groove, the difference between the area corresponding to the outer diameter of the valve core's end face facing the guide seat and the cross-sectional area of ​​the first groove, the difference between the area corresponding to the outer diameter of the valve core's end face facing the connector and the cross-sectional area of ​​the third groove, and the cross-sectional area of ​​the third groove are equal.

[0012] In some embodiments, the hydraulic system is configured as at least one of the following:

[0013] A first damping element is provided in the oil passage between the inlet and the first groove;

[0014] A second damper is provided in the oil passage between the outlet of the control valve and the space between the guide seat and the valve core of the valve body;

[0015] A third damper is provided in the oil passage between the inlet of the control valve and the second groove;

[0016] A fourth damper is provided in the oil line between the feedback device and the third groove.

[0017] In some embodiments, the hydraulic system is configured as at least one of the following:

[0018] The valve core is provided with a first oil passage, the first oil passage connects the inlet and the first groove, the first oil passage includes a first damping hole, the first damping is disposed in the first oil passage, or the first damping includes the first damping hole;

[0019] The valve body is provided with a second oil passage, which connects the outlet of the control valve with the space between the guide seat and the valve core of the valve body. The second damping is provided in the second oil passage, or the second oil passage includes a second damping orifice.

[0020] The valve core is provided with a third oil passage, which connects the inlet of the control valve and the second groove. The third damping is provided in the third oil passage, or the third oil passage includes a third damping hole.

[0021] The connector is provided with a fourth oil passage, which connects the feedback device and the third groove. The fourth damping is provided in the fourth oil passage, or the fourth oil passage includes a fourth damping hole.

[0022] In some embodiments, the second groove includes a first groove segment and a second groove segment. The first groove segment is connected to one end of the second groove segment near the guide seat and forms a step between the first and second groove segments. The push rod extends from the second groove segment into the first groove segment and has an abutting surface for abutting against the step so that the push rod and the valve core move together toward the connector.

[0023] In some embodiments, the push rod is eccentrically arranged with respect to the second groove section.

[0024] In some embodiments, the second groove segment is eccentrically arranged with respect to the valve core, and the push rod is concentrically arranged with respect to the valve core.

[0025] In some embodiments, the top rod includes a first rod segment and a second rod segment, which are connected sequentially along the direction from the guide seat to the joint. The first rod segment is located in a first groove segment, and the cross-sectional area of ​​the second rod segment is smaller than that of the first rod segment, such that the connecting surfaces of the first rod segment and the second rod segment form an abutment surface.

[0026] In some embodiments, the top rod further includes a third rod segment connected to the end of the second rod segment away from the guide seat and inserted into a third groove, wherein the cross-sectional area of ​​the third rod segment is larger than that of the second rod segment.

[0027] In some embodiments, the valve core is provided with an oil passage, the inlet and outlet of the pressure compensation valve are connected through the oil passage, and the flow area of ​​the oil passage gradually decreases along the direction from the first control end to the second control end.

[0028] In some embodiments, the oil passage is stepped or conical.

[0029] In some embodiments, a first annular groove is provided on the side of the portion of the plunger that is inserted into the first groove and / or the guide seat; and / or, a second annular groove is provided on the side of the portion of the push rod that is inserted into the third groove.

[0030] In some embodiments, the pressure compensation valve further includes an adjusting element that adjusts the position of the guide seat on the valve body to adjust the displacement of the valve core toward the guide seat.

[0031] The engineering machinery provided in this application includes the hydraulic system of any embodiment of this application.

[0032] The pressure compensation valve provided in this application is the pressure compensation valve of the hydraulic system in any embodiment of this application.

[0033] This application compares the outlet pressure of the control valve, the inlet pressure of the working system, the inlet pressure of the control valve, and the highest load pressure of all working links of the compound action to the pressure compensation valve, controls the opening of the pressure compensation valve, and balances the load. This makes the load of each working link equal, effectively solving the problem that the light and heavy load actuators cannot work synchronously under flow saturation in hydraulic systems using the valve pre-compensation method.

[0034] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a hydraulic schematic diagram of the hydraulic system in the embodiments of this application.

[0037] Figure 2 This is a schematic diagram of the pressure compensation valve in an embodiment of this application.

[0038] Explanation of reference numerals in the attached figures:

[0039] 100. Hydraulic system; 10. Working system; 101. Working link; 102. First working link; 103. Second working link; 20. Feedback device;

[0040] 1. Actuator; 11. Hydraulic cylinder;

[0041] 2. Control valve;

[0042] 3. Pressure compensating valve; 30. Seal; 31. Adjusting component; 311. Screw; 32. Locking component; 321. Nut; 33. End cap; 34. Valve body; 35. Guide seat; 351. Guide groove; 36. Plunger; 361. First annular groove; 37. Valve core; 371. First groove; 372. Second groove; 373. First groove section; 374. Second groove section; 375. Step; 38. Push rod; 381. First rod section; 382. Second rod section; 383, Third rod segment; 384, Abutment surface; 39, Joint; 391, Third groove; 392, Second annular groove; 3a, First oil passage; 3b, Second oil passage; 3c, Third oil passage; 3d, Fourth oil passage; 3e, First damping; 3f, Second damping; 3g, Third damping; 3h, Fourth damping; 3i, Oil passage; 3j, First damping hole; 3k, Third damping hole; 3m, Fourth damping hole; 3n, First control end; 3q, Second control end;

[0043] 4. Check valve. Detailed Implementation

[0044] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0045] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0046] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0047] In the description of this application, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application.

[0048] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0049] Typically, the method of installing a pressure compensation valve upstream of the control valve is called upstream compensation.

[0050] In related technologies, in hydraulic systems employing pre-valve compensation, the first and second control ends of the pressure compensation valve are connected to the outlet and inlet of the control valve, respectively, and the first control end is equipped with a spring. In this case, the compensation pressure is determined by the spring force of the pressure compensation valve. To achieve the compensation effect, the pressure drop generated by the oil flowing through the control valve must reach the compensation pressure. However, in parallel oil circuits, hydraulic oil preferentially flows to the actuator with a lower load (referred to as the light load side). When the flow is insufficient, the actuator with a higher load (referred to as the heavy load side) cannot obtain sufficient flow and therefore cannot achieve the compensation effect. This will lead to the various actuators of the compound action being unable to act synchronously when the flow is saturated, affecting the normal operation of the construction machinery.

[0051] To address the problem that light and heavy load actuators cannot work synchronously when the flow rate is saturated in hydraulic systems employing pre-valve compensation, this application provides a hydraulic system and a pressure compensation valve.

[0052] Figures 1-2 The structure of the hydraulic system and pressure compensation valve in this application is illustrated by way of example.

[0053] See Figures 1-2 In this application, the hydraulic system 100 includes a working system 10 and a feedback device 20.

[0054] The working system 10 has an inlet P and includes at least two working links 101. The inlet P is connected to an oil source. All working links 101 are arranged in parallel, and each working link 101 includes an actuator 1, a control valve 2, and a pressure compensation valve 3. The actuator 1 is used to drive the actuator of the construction machinery. The pressure compensation valve 3 is connected to the inlet P and to the actuator 1 via the control valve 2. The pressure compensation valve 3 has a first control terminal 3n and a second control terminal 3q, which respectively control the pressure compensation valve 3 to switch to a first valve position and a second valve position. In the first valve position, the pressure compensation valve 3 connects the inlet P to the control valve 2; in the second valve position, the pressure compensation valve 3 disconnects the inlet P from the control valve 2. The first control terminal 3n is connected to the inlet P and the outlet of the control valve 2, and the second control terminal 3q is connected to the inlet of the control valve 2.

[0055] Feedback device 20 is connected to the outlet of the control valve 2 of each working link 101 and to the second control terminal 3q of each working link 101, so as to lead the highest load pressure in all working links 101 (i.e., the maximum value of the load pressure of all working links 101) to the second control terminal 3q of each working link 101, so that when at least two of the working links 101 are combined, the pressure difference between the inlet and outlet of the control valve 2 of each working link 101 in the combined action is equal.

[0056] In the above scheme, the first control terminal 3n of the pressure compensation valve 3 is connected not only to the outlet of the control valve 2, but also to the inlet P of the working system 10, so that the inlet pressure of the working system 10 (denoted as P) is... p ) and the outlet pressure of control valve 2 (denoted as P) Ls Together, they act on the first control terminal 3n. Moreover, the second control terminal 3q of the pressure compensation valve 3 is not only connected to the inlet of the control valve 2, but also connected to the outlet of the control valve 2 of all working links 101 through the feedback device 20, so that the highest load pressure (denoted as P) in all working links 101 is... Lmax The pressure of the control valve 2 and the inlet pressure (denoted as P') act together on the second control terminal 3q. In this case, the balance of the pressure compensation valve 3 can be achieved by the inlet pressure P of the working system 10. p With the highest load pressure P Lmax The difference between the pressure difference and the inlet / outlet pressure difference ΔP of the control valve 2 is determined by whether they are equal. In other words, when the pressure compensation valve 3 reaches the equilibrium position, the inlet / outlet pressure difference ΔP of the control valve 2 can be equal to the inlet pressure P of the working system 10. p With the highest load pressure P Lmax The difference. Due to the combined action, the inlet pressure P of the working system 10... p(When there is no pressure drop between the inlet of the working system 10 and the oil source, the inlet pressure of the working system 10 is equal to the oil source pressure, or in other words, equal to the oil pump outlet pressure) and the maximum load pressure P. Lmax The pressure difference is the same for all working links 101 performing the compound action; there is no difference. Therefore, the pressure difference ΔP between the inlet and outlet of control valve 2 is equal to the inlet pressure P of working system 10. p With the highest load pressure P Lmax The difference means that the inlet and outlet pressure difference ΔP of the control valve 2 in each working link 101 is equal. Since the oil flow rate Q flowing through the control valve 2 to the actuator 1 satisfies the formula... K represents the stem stroke of the control valve 2. Therefore, when the inlet and outlet pressure difference ΔP of the control valve 2 in each working link 101 is equal, the amount of oil flowing through each control valve 2 depends only on the stem stroke K of each control valve 2 and is independent of the load size of each actuator 1. In this case, when different working links 101 perform compound actions under flow saturation, the amount of oil can be distributed proportionally according to the stem stroke of the control valve 2 of each working link 101 in the compound action, so that under flow saturation, light and heavy load actuators 1 can work synchronously, effectively preventing the phenomenon of slow or no action of actuator 1 with larger load.

[0057] As can be seen, the above scheme, by controlling the outlet pressure P of valve 2 Ls The inlet pressure P of the working system 10 p The inlet pressure P' of control valve 2 and the highest load pressure P in all working links 101 of the compound action. Lmax These four pressures are compared to the pressure compensation valve 3. By controlling the opening of the pressure compensation valve 3 and balancing the load, it is possible to ensure that each working link 101 can be equally divided and act synchronously under flow saturation conditions. This effectively solves the problem that the light and heavy load actuators of the hydraulic system using the valve pre-compensation method cannot work synchronously under flow saturation conditions, and improves the stability of compound actions. This is beneficial to the normal operation of engineering machinery.

[0058] Moreover, in the above scheme, the pressure compensation valve 3 is still located before the control valve 2. In other words, the hydraulic system 100 still adopts the pre-valve compensation method. Thus, compared with other schemes such as changing the pressure compensation valve 3 to be located after the control valve 2, the structural changes to the working system 10 are less, which is conducive to saving costs.

[0059] In addition, by adopting the above scheme, there is no need to install a spring in the pressure compensation valve 3, which can prevent the compensation function from being affected due to spring failure and is conducive to improving the working reliability of the hydraulic system 100.

[0060] In this application, the feedback device 20 is used to transmit the maximum load pressure P LmaxIt is led to the second control terminal 3q of the pressure compensation valve 3. In order to achieve the corresponding function, the feedback device 20 can adopt various structural forms.

[0061] For example, in some embodiments, the feedback device 20 may include a shuttle valve (not shown) that compares the load pressures of different working links 101 and directs the maximum load pressure obtained from the comparison to the second control terminal 3q of the pressure compensation valve 3, thereby setting the highest load pressure P. Lmax It is led to the second control terminal 3q of the pressure compensation valve 3.

[0062] For example, see Figure 1 In other embodiments, the feedback device 20 includes at least two check valves 4, each corresponding one-to-one with a working link 101 of the working system 10. The inlet of each check valve 4 is connected to the outlet of the control valve 2 of the corresponding working link 101, and the outlet of each check valve 4 is connected to the second control terminal 3q of the pressure compensation valve 3 of all working links 101. Thus, under the combined action of all check valves 4, the feedback device 20 can also compare the load pressures of different working links 101 and direct the maximum load pressure obtained from the comparison to the second control terminal 3q of the pressure compensation valve 3, thereby increasing the maximum load pressure P. Lmax It is led to the second control terminal 3q of the pressure compensation valve 3.

[0063] In addition, to facilitate the operation of pressure compensation valve 3 at the outlet pressure P of control valve 2 Ls The inlet pressure P of the working system 10 p The inlet pressure P' and the maximum load pressure P of control valve 2 Lmax Under the action of [the system], a state of equilibrium is reached. In some embodiments, the pressure compensation valve 3 supplies the inlet pressure P of the working system 10. p The outlet pressure P of control valve 2 Ls The inlet pressure P' and the maximum load pressure P of control valve 2 Lmax The effective area is equal. In this case, as long as the inlet pressure P of the working system 10 is equal... p With the highest load pressure P Lmax If the difference is equal to the pressure difference ΔP between the inlet and outlet of the control valve 2, then the pressure compensation valve 3 can achieve a balanced state. It has a simple structure and is easy to control.

[0064] As an example of the pressure compensation valve 3 in the foregoing embodiments, see Figure 2In some embodiments, the pressure compensation valve 3 includes a valve body 34, a valve core 37, a guide seat 35, a connector 39, a plunger 36, and a push rod 38. The guide seat 35 and the connector 39 are located at opposite ends of the valve body 34. The valve core 37 is disposed within the valve body 34 and is located between the guide seat 35 and the connector 39. A first control end 3n is located at the end of the valve core 37 facing the guide seat 35. A second control end 3q is located at the end of the valve core 37 facing the connector 39. The plunger 36 is inserted into a first groove 371 of the valve core 37 and the guide seat 35. The push rod 38 is inserted into a second groove 372 of the valve core 37 and a third groove 391 of the connector 39. The inlet P of the working system 10 is connected to the first groove 371, the outlet of the control valve 2 is connected to the space between the valve core 37 and the guide seat 35 of the valve body 34, the inlet of the control valve 2 is connected to the space between the valve core 37 and the connector 39 of the valve body 34 through the second groove 372, and the feedback device 20 is connected to the third groove 391.

[0065] The aforementioned pressure compensation valve 3 can introduce the outlet pressure P of the control valve 2. Ls The inlet pressure P of the working system 10 p The inlet pressure P' and the maximum load pressure P of control valve 2 Lmax These four pressure lines are compared and the opening is adjusted to act as a load equalizer. The low-load actuator 1 is throttled to make the load pressure of the low-load actuator 1 the same as that of the high-load actuator 1, so that the loads of each line are equal. This is to prevent the hydraulic oil from preferentially flowing to the low-load actuator 1 when the flow is saturated, which would cause the light and heavy load actuators 1 to be unable to operate synchronously.

[0066] Specifically, by setting a plunger 36 and a push rod 38 at the first control end 3n and the second control end 3q of the valve core 37 respectively, and inserting the plunger 36 and the push rod 38 into the first groove 371 and the second groove 372 of the valve core 37, the outlet pressure P of the control valve 2 is increased. Ls The inlet pressure P of the working system 10 p The inlet pressure P' and the maximum load pressure P of control valve 2 Lmax These four pressures can act on different parts of the valve core 37, so the four pressures can be compared and used together to control the opening of the pressure compensation valve 3.

[0067] Since no spring is installed inside the valve body 34, the compensation function can be prevented from being affected by spring failure, thus effectively improving the working reliability of the pressure compensation valve 3 and the hydraulic system 100.

[0068] Based on the above-described structure of the pressure compensation valve 3, the cross-sectional area (denoted as S1) of the first groove 371 corresponds to the inlet pressure P of the working system 10. pThe difference between the area of ​​the valve core 37 facing the guide seat 35 and the cross-sectional area of ​​the first groove 371 (denoted as S2) of the effective area of ​​the first control end 3n corresponds to the outlet pressure P of the control valve 2. Ls The difference between the area of ​​the valve core 37 facing the connector 39 at the first control end 3n and the cross-sectional area of ​​the third groove 391 (denoted as S3) corresponds to the inlet pressure P' of the control valve 2. The cross-sectional area of ​​the third groove 391 at the second control end 3q (denoted as S4) corresponds to the maximum load pressure P. Lmax In the working area of ​​the second control terminal 3q, in some embodiments, the cross-sectional area of ​​the first groove 371, the difference between the area corresponding to the outer diameter of the end face of the valve core 37 facing the guide seat 35 and the cross-sectional area of ​​the first groove 371, the difference between the area corresponding to the outer diameter of the end face of the valve core 37 facing the connector 39 and the cross-sectional area of ​​the third groove 391, and the cross-sectional area of ​​the third groove 391 are constructed to be equal, that is, S1 = S2 = S3 = S4. In this way, the pressure compensation valve 3 supplies the inlet pressure P of the working system 10. p The outlet pressure P of control valve 2 Ls The inlet pressure P' and the maximum load pressure P of control valve 2 Lmax The effective areas are equal, so that as long as the inlet pressure P of the working system 10 is equal... p With the highest load pressure P Lmax If the difference is equal to the pressure difference ΔP between the inlet and outlet of the control valve 2, then the pressure compensation valve 3 can achieve a balanced state. It has a simple structure and is easy to control.

[0069] See also Figure 2 In some embodiments, the hydraulic system 100 is configured as at least one of the following:

[0070] A first damper 3e is provided on the oil passage between the inlet P of the working system 10 and the first groove 371;

[0071] A second damper 3f is provided in the oil passage between the outlet of the control valve 2 and the space between the guide seat 35 and the valve core 37 of the valve body 34;

[0072] A third damper 3g is provided in the oil line between the inlet of the control valve 2 and the second groove 372;

[0073] A fourth damping 3h is provided on the oil line between the feedback device 20 and the third groove 391.

[0074] By setting at least one of the first damping 3e, the second damping 3f, the third damping 3g, and the fourth damping 3h in the pressure compensation valve 3, the influence of pressure shock on the displacement of the valve core 37 can be reduced, effectively improving the operational stability of the valve core 37, and enabling the pressure compensation valve 3 to perform pressure compensation more accurately and reliably.

[0075] The structural forms of the first damper 3e, the second damper 3f, the third damper 3g, and the fourth damper 3h can be varied.

[0076] For example, as an example of the first damping 3e, see Figure 2 In some embodiments, the valve core 37 is provided with a first oil passage 3a, which connects the inlet P of the working system 10 with the first groove 371. The first oil passage 3a includes a first damping orifice 3j, and a first damper 3e includes a first damping orifice 3j. In this case, the inlet P of the working system 10 and the first groove 371 are connected by the first oil passage 3a on the valve core 37, and the first damper 3e is configured to include a first damping orifice 3j that serves as part of the first oil passage 3a, so that the first damper 3e can reduce the impact force of the oil flowing from the inlet of the working system 10 to the first groove 371 by utilizing the damping effect of the first damping orifice 3j. However, it should be noted that the first damper 3e is not limited to being constructed to include a first damping orifice 3j that serves as part of the first oil passage 3a. For example, instead, the first damper 3e may not be part of the first oil passage 3a, but may be disposed in the first oil passage 3a. In this case, the first damper 3e is a damping element (e.g., a throttle valve, specifically, an adjustable throttle valve) disposed in the first oil passage 3a.

[0077] For example, as an example of the second damping 3f, see [link to relevant documentation]. Figure 2In some embodiments, the valve body 34 is provided with a second oil passage 3b, which connects the outlet of the control valve 2 with the space of the valve body 34 located between the guide seat 35 and the valve core 37. A second damper 3f is disposed in the second oil passage 3b. In this case, the outlet of the control valve 2 and the space of the valve body 34 located between the guide seat 35 and the valve core 37 are connected through the second oil passage 3b on the valve body 34, and the second damper 3f is a damping element (e.g., a throttle valve, specifically, an adjustable throttle valve) disposed in the second oil passage 3b, so that when the oil flows from the outlet of the control valve 2 through the second oil passage 3b to the space of the valve body 34 located between the guide seat 35 and the valve core 37, the second damper 3f can play a damping role and reduce pressure shock. However, it is understood that the second damper 3f is not limited to the damping element in the second oil passage 3b. For example, as an alternative, the second oil passage 3b includes a second damping hole, and the second damper 3f includes a second damping hole. In this case, the second damper 3f is no longer a damping element located in the second oil passage 3b, but is constructed to include a second damping hole as part of the second oil passage 3b.

[0078] For example, as an example of the third damping 3g, see [link to relevant documentation]. Figure 2 In some embodiments, the valve core 37 is provided with a third oil passage 3c, which connects the inlet of the control valve 2 and the second groove 372. The third oil passage 3c includes a third damping orifice 3k, and the third damper 3g includes the third damping orifice 3k. In this case, the inlet of the control valve 2 and the second groove 372 are connected by the third oil passage 3c located on the valve core 37, and the third damper 3g is configured to include the third damping orifice 3k as part of the third oil passage 3c, so that the third damper 3g can reduce the impact force of the oil flowing from the inlet of the control valve 2 to the second groove 372 by utilizing the damping effect of the third damping orifice 3k. However, it should be noted that the third damping 3g is not limited to being constructed to include a third damping orifice 3k that serves as part of the third oil passage 3c. For example, alternatively, the third damping 3g may not be part of the third oil passage 3c, but may be disposed in the third oil passage 3c. In this case, the third damping 3g is a damping element (e.g., a throttle valve, specifically, an adjustable throttle valve) disposed in the third oil passage 3c.

[0079] Additionally, as an example of the fourth damping 3h, see [link to example]. Figure 2 and combined Figure 1In some embodiments, the connector 39 is provided with a fourth oil passage 3d, which connects the feedback device 20 and the third groove 391. The fourth oil passage 3d includes a fourth damping hole 3m, and the fourth damping 3h includes a fourth damping hole 3m. In this case, the feedback device 20 and the third groove 391 are connected by the fourth oil passage 3d on the connector 39, and the fourth damping 3h is configured to include a fourth damping hole 3n that serves as part of the fourth oil passage 3d, so that the fourth damping 3h can reduce the impact force of the oil flowing from the feedback device 20 to the third groove 391 by utilizing the damping effect of the fourth damping hole 3n. However, it should be noted that the fourth damping 3h is not limited to being constructed to include a fourth damping orifice 3n that serves as part of the fourth oil passage 3d. For example, alternatively, the fourth damping 3h may not be part of the fourth oil passage 3d, but may be disposed in the fourth oil passage 3d. In this case, the fourth damping 3h is a damping element (e.g., a throttle valve, specifically, an adjustable throttle valve) disposed in the fourth oil passage 3d.

[0080] See Figure 2 In some embodiments, the second groove 372 includes a first groove segment 373 and a second groove segment 374. The first groove segment 373 is connected to the end of the second groove segment 374 near the guide seat 35, and forms a step 375 between the first and second groove segments 374. The push rod 38 extends from the second groove segment 374 into the first groove segment 373 and has an abutment surface 384. The abutment surface 384 is used to abut against the step 375 so that the push rod 38 and the valve core 37 move together toward the connector 39. Thus, when the push rod 38 moves toward the connector 39 under the action of pressurized oil, the push rod 38 can push the valve core 37 to move together toward the connector 39 through the abutment surface 384 and the step 375, thereby conveniently and reliably realizing the movement of the push rod 38 and the valve core 37 toward the connector 39.

[0081] Furthermore, to facilitate the fit between the abutment surface 384 and the step 375, see [reference needed]. Figure 2 In some embodiments, the push rod 38 is eccentrically arranged with the second groove segment 374. For example, the second groove segment 374 is eccentrically arranged with the valve core 37, and the push rod 38 is concentrically arranged with the valve core 37; or, the second groove segment 374 is concentrically arranged with the valve core 37, and the push rod 38 is eccentrically arranged with the valve core 37. The eccentric arrangement of the push rod 38 and the second groove segment 374 allows the portion of the push rod 38 inserted into the second groove 372 to be pressed against the side wall of the second groove segment 374 under gravity. This facilitates the abutment surface 384 of the push rod 38 against the step 375 of the valve core 37, causing the valve core 37 to move together toward the connector 39. Moreover, the gap between the push rod 38 and the side wall of the second groove 372 also facilitates the smooth flow of oil entering the second groove 372 into the space of the valve body 34 located between the valve core 37 and the connector 39, thereby applying force to the second control end 3q of the valve core 37 toward the connector 39.

[0082] Additionally, to form contact surface 384, see [link / reference]. Figure 2 In some embodiments, the top rod 38 includes a first rod segment 381 and a second rod segment 382, ​​which are sequentially connected along the direction from the guide seat 35 to the joint 39. The first rod segment 381 is located in the first groove segment 373, and the cross-sectional area of ​​the second rod segment 382 is smaller than that of the first rod segment 381, such that the connecting surfaces of the first rod segment 381 and the second rod segment 382 form an abutment surface 384. At this time, the abutment surface 384 is located between the first rod segment 381 with a larger cross-sectional area and the second rod segment 382 with a smaller cross-sectional area, which can easily abut against the step 375.

[0083] Further, see Figure 2 In some embodiments, the push rod 38 includes not only a first rod segment 381 and a second rod segment 382, ​​but also a third rod segment 383. The third rod segment 383 is connected to the end of the second rod segment 382 away from the guide seat 35 and is inserted into the third groove 391. The cross-sectional area of ​​the third rod segment 383 is larger than that of the second rod segment 382. In this case, the push rod 38 forms a structure that is large at both ends and small in the middle, and the second rod segment 382 forms a necked portion, which facilitates the insertion of the push rod 38 into the second groove 372 and the third groove 391, and also facilitates the engagement of the first rod segment 381 and the third rod segment 383 with the second groove 372 and the third groove 391, respectively.

[0084] In the foregoing embodiments, to facilitate the adjustment of the opening degree of the pressure compensation valve 3, see [reference needed]. Figure 2 An oil passage 3i can be provided on the valve core 37. The inlet and outlet of the pressure compensation valve 3 are connected through the oil passage 3i, and the flow area of ​​the oil passage 3i gradually decreases along the direction from the first control end 3n to the second control end 3q. This makes it easier for the valve core 37 to find the balance position more accurately and adjust to the appropriate opening degree during the movement.

[0085] Additionally, see Figure 2 In some embodiments, a first annular groove 361 is provided on the side of the portion of the plunger 36 that is inserted into the first groove 371 and / or the guide seat 35; and / or, a second annular groove 392 is provided on the side of the portion of the push rod 38 that is inserted into the third groove 391. The first annular groove 361 and the second annular groove 392 can play a role in equalizing pressure, improving pressure distribution, and making the pressure distribution more uniform. Moreover, the first annular groove 361 and the second annular groove 392 can play a certain role in sealing, preventing oil leakage and improving operational reliability.

[0086] In the foregoing embodiments, to improve the flexibility of use of the pressure compensation valve 3, see [reference needed]. Figure 2The pressure compensation valve 3 may include a valve body 34, a valve core 37, a guide seat 35, a connector 39, a plunger 36, and a push rod 38, as well as an adjusting element 31. The adjusting element 31 adjusts the position of the guide seat 35 on the valve body 34 to adjust the displacement of the valve core 37 toward the guide seat 35. In this way, the displacement of the valve core 37 toward the guide seat 35 can be flexibly adjusted according to actual conditions. Therefore, the pressure compensation valve 3 has greater flexibility in use, a wider range of applications, and can meet more diverse pressure compensation needs.

[0087] Next, combine Figures 1-2 This application will be further described.

[0088] like Figures 1-2 As shown, in this embodiment, the hydraulic system 100 is a load-sensitive hydraulic system, which includes a working system 10 and a feedback device 20. The working system 10 includes two working links 101, located respectively in... Figure 1 The first working link 102 on the left and located at Figure 1 The second working link 103 on the right side, the first working link 102 and the second working link 103 are arranged in parallel and have the same structure. They all include an actuator 1, a control valve 2 and a pressure compensation valve 3, while the feedback device 20 includes two one-way valves 4.

[0089] In both the first working link 102 and the second working link 103, the pressure compensation valve 3 is located before the control valve 2 and connected to the actuator 1 via the control valve 2. Specifically, as follows... Figure 1 As shown, in this embodiment, the actuator 1 includes a hydraulic cylinder 11. The cylinder rod of the hydraulic cylinder 11 is used to connect to the actuator of the engineering machinery. The rodless chamber of the hydraulic cylinder 11 is connected to the outlet of the control valve 2. The control valve 2 is a proportional directional valve, which combines throttling and reversing functions, and can play a role in throttling and speed regulation. The inlet of the control valve 2 is connected to the outlet of the pressure compensation valve 3. The inlet of the pressure compensation valve 3 is connected to the oil pump (not shown) that provides the oil source through the inlet P of the working system 10. Based on this configuration, in this embodiment, the outlet pressure P of the control valve 2 is... LS The load pressure of actuator 1 is equal to the inlet pressure P' of control valve 2, which is equal to the outlet pressure of pressure compensation valve 3. The inlet pressure of pressure compensation valve 3 is equal to the inlet pressure P of working system 10. p The inlet pressure P of the working system 10 p The pressure is equal to the oil source pressure, meaning that the inlet pressure of pressure compensation valve 3 is equal to the oil source pressure.

[0090] In this embodiment, the pressure compensation valve 3 is a two-position two-way hydraulic control valve with an inlet and an outlet, and a first control terminal 3n and a second control terminal 3q. The first control terminal 3n is used to control the pressure compensation valve 3 to switch to the first valve position, so that the inlet and outlet of the pressure compensation valve 3 are connected, thereby connecting the inlet P of the working system 10 and the inlet of the control valve 2, so that hydraulic oil can flow to the control valve 2 through the pressure compensation valve 3. The second control terminal 3q is used to control the pressure compensation valve 3 to switch to the second valve position, so that the inlet and outlet of the pressure compensation valve 3 are disconnected, thereby cutting off the inlet P of the working system 10 and the inlet of the control valve 2, so that hydraulic oil cannot flow to the control valve 2 through the pressure compensation valve 3.

[0091] Figure 2 The structure of the pressure compensation valve 3 in this embodiment is further illustrated. For ease of description, left and right in the following description are equivalent to each other. Figure 2 The left and right sides are consistent.

[0092] Combination Figure 2 and Figure 1 As can be seen, in this embodiment, the pressure compensation valve 3 is a two-position two-way hydraulic control valve without a spring, which includes a valve body 34, a valve core 37, a guide seat 35, a connector 39, a plunger 36, a push rod 38, an end cap 33, an adjusting member 31, and a locking member 32.

[0093] Among them, such as Figure 2 As shown, the valve body 34 is cylindrical, with a chamber inside and open at both ends axially.

[0094] End caps 33 and connectors 39 are respectively connected to the axial ends of valve body 34, sealing the chamber inside valve body 34. Specifically, in Figure 2 In the middle, the end cap 33 is connected to the left end of the valve body 34, and the connector 39 is connected to the right end of the valve body 34 and extends into the chamber, so that the end cap 33 and the connector 39 respectively close the left and right ports of the chamber.

[0095] The valve core 37, guide seat 35, plunger 36 and push rod 38 are all installed in the chamber of the valve body 34 by means of insertion. The valve core 37 is located between the end cover 33 and the connector 39, the guide seat 35 is located between the end cover 33 and the valve core 37, the plunger 36 is inserted into the guide seat 35 and the valve core 37, and the push rod 38 is inserted into the valve core 37 and the connector 39.

[0096] Specifically, such as Figure 2As shown, in this embodiment, the valve core 37 is cylindrical and concentrically arranged with the chamber of the valve body 34, with its left and right end faces facing the guide seat 35 and the connector 39, respectively. The left and right ends of the valve core 37 are respectively provided with a first groove 371 and a second groove 372. The first groove 371 is recessed to the right from the left end face of the valve core 37, is cylindrical, and concentric with the chamber of the valve body 34. The second groove 372 is recessed to the left from the right end face of the valve core 37, is cylindrical, and includes a first groove segment 373 and a second groove segment 374. The first groove segment 373 and the second groove segment 374 are connected sequentially from left to right, and the inner diameter of the first groove segment 373 is larger than the inner diameter of the second groove segment 374, forming a step 375 between the first groove segment 373 and the second groove segment 374. In this embodiment, the first groove segment 373 is concentric with the chamber of the valve body 34, and the second groove segment 374 is eccentric with respect to the chamber of the valve body 34. At this time, the first groove segment 373 is arranged concentrically with the valve core 37, and the second groove segment 374 is arranged eccentrically with the valve core 37.

[0097] The guide seat 35 is cylindrical and spaced apart from the end cover 33. A sealing element 30 (e.g., a sealing ring) is provided between its outer surface and the inner surface of the cavity to prevent oil leakage. Furthermore, as... Figure 2 As shown, in this embodiment, a guide groove 351 is provided at the right end of the guide seat 35. The guide groove 351 is recessed to the left from the right end face of the guide seat 35, is cylindrical, and is concentric with the cavity. Additionally, as... Figure 2 As shown, in this embodiment, the position of the guide seat 35 within the valve body 34 is limited and adjusted by the adjusting member 31. The adjusting member 31 passes through the end cap 33 and contacts the left end face of the guide seat 35. The adjusting member 31 is movably configured; specifically, in this embodiment, the adjusting member 31 includes a screw 311, which is threadedly connected to the end cap 33 and locked by a locking member 32 (e.g., a nut 321). Thus, when the adjusting member 31 moves axially relative to the valve body 34, the position of the guide seat 35 is adjustable, allowing the guide seat 35 to move closer to or further away from the connector 39. This reduces or increases the maximum displacement of the valve core 37 towards the guide seat 35, enabling the pressure compensation valve 3 to more flexibly meet different pressure compensation requirements.

[0098] The plunger 36 is cylindrical and includes a constant-diameter section. The diameter of the constant-diameter section is uniform throughout, and its axial ends are concentrically inserted into the first groove 371 and the guide groove 351, respectively, and can move within these sections. This allows the plunger 36 to be concentrically inserted into the valve core 37 and the guide seat 35, and to move within the first groove 371 and the guide groove 351. Multiple first annular grooves 361 are provided on the side surfaces of the portion of the constant-diameter section that inserts into the first groove 371 and the guide groove 351, allowing the plunger 36 to engage with the inner walls of the first groove 371 and the guide groove 351 through two sets of first annular grooves 361, respectively. The two sets of first annular grooves 361 provide a good dynamic sealing effect during the movement of the plunger 36. Specifically, the set of first annular grooves 361 that mates with the first groove 371 prevents hydraulic oil from leaking out of the space between the plunger 36 and the bottom wall (opposite to the groove opening) of the first groove 371. The set of first annular grooves 361 that mates with the guide groove 351 prevents hydraulic oil in the space between the guide seat 35 and the valve core 37 of the valve body 34 from flowing into the space between the plunger 36 and the bottom wall of the guide groove 351, so that the plunger 36 and the valve core 37 can move more reliably as desired. Moreover, the two sets of first annular grooves 361 also play a pressure equalization role, distributing the hydraulic oil on the circumferential surface of the plunger 36 to equalize the pressure and make the pressure distribution more uniform. This also helps to improve the movement accuracy of the valve core 37 and the plunger 36, thereby improving the working accuracy and reliability of the pressure compensation valve 3. In this embodiment, each first annular groove 361 is a complete annular shape, and all the first annular grooves 361 are arranged side by side and spaced apart from each other.

[0099] The connector 39 is cylindrical and concentrically inserted into the chamber of the valve body 34. A sealing element 30 is provided on the side of the portion inserted into the chamber to provide a seal and prevent oil leakage. Figure 2 As shown, in this embodiment, a third groove 391 is provided on the left end face of the connector 39, and the third groove 391 is recessed to the right from the left end face of the connector 39. The third groove 391 is cylindrical and concentric with the connector 39. At this time, the third groove 391 is concentric with the valve core 37.

[0100] The top rod 38 is cylindrical and includes a first segment 381, a second segment 382, ​​and a third segment 383. The first segment 381, the second segment 382, ​​and the third segment 383 are connected sequentially from left to right (i.e., from the guide seat 35 to the joint 39). The diameters of the first segment 381 and the third segment 383 are equal and larger than the diameter of the second segment 382. At this point, the cross-sectional areas of the first segment 381 and the third segment 383 are equal and larger than the cross-sectional area of ​​the second segment 382. The second segment 382 forms a necked section, and the connection between the second segment 382 and the first segment 381 forms abutment surface 384. Wherein, as... Figure 2 As shown, the third rod segment 383 is concentrically inserted into the third groove 391 and can move within the third groove 391, allowing the push rod 38 to be movably inserted into the connector 39. The first rod segment 381 and the second rod segment 382 are movably inserted into the second groove 372 of the valve core 37, with the first rod segment 381 located in the first groove segment 373 of the second groove 372, and the abutting surface 384 facing the step 375. This allows the abutting surface 384 to abut against the step 375 during operation, enabling the push rod 38 and the valve core 37 to move together to the right. When movement to the left is required, the left end face of the first rod segment 381 (i.e., the left end face of the push rod 38) can abut against the bottom wall of the first groove segment 373, allowing the push rod 38 to push the valve core 37, moving together to the left.

[0101] like Figure 2 As shown, in this embodiment, the third rod segment 383 has multiple second annular grooves 392 on its side. These multiple second annular grooves 392 are arranged side by side and spaced apart from each other. Each second annular groove 392 is a complete circle. In this way, the push rod 38 can cooperate with the third groove 391 through the second annular groove 392. The second annular groove 392 can play a sealing role to prevent oil leakage into the push rod 38 and the third groove 391. In addition, the second annular groove 392 can play a pressure equalization role, making the pressure distribution more uniform, improving the movement accuracy of the valve core 37 and the push rod 38, and thus improving the working accuracy and reliability of the pressure compensation valve 3.

[0102] In order to achieve connection with the inlet P of the working system 10, the outlet of the control valve 2, the inlet of the control valve 2, and the feedback device 20, such as Figure 2 As shown, in this embodiment, the valve body 34 is provided with an inlet, an outlet, and a second oil passage 3b, and the connector 39 is provided with a fourth oil passage 3d. The inlet and outlet of the pressure compensation valve 3 are both located on the valve body 34 and extend radially along the valve body 34. The outlet and inlet of the pressure compensation valve 3 are arranged alternately from left to right, respectively for communication with the inlet of the control valve 2 and the inlet P of the working system 10. The second oil passage 3b is located on the valve body 34, extending radially along the valve body 34, and is located on the side of the outlet of the pressure compensation valve 3 near the guide seat 35, for communication with the outlet of the control valve 2. The fourth oil passage 3d is located on the connector 39, extending axially along the valve body 34, for communication with the feedback device 20. Thus, the pressure compensation valve 3 can be connected to the inlet of the working system 10, the inlet of the control valve 2, the outlet of the control valve 2, and the feedback device 20 through the inlet, outlet, second oil passage 3b, and fourth oil passage 3d, allowing the corresponding four pressure oils to flow into the pressure compensation valve 3.

[0103] And, as Figure 2As shown, in this embodiment, the valve core 37 is provided with a first oil passage 3a and a third oil passage 3c. The first oil passage 3a connects the inlet of the pressure compensation valve 3 and the space between the bottom of the first groove 371 and the plunger 36, so that the oil at the inlet P of the working system 10 can flow through the first oil passage 3a to the space between the bottom of the first groove 371 and the plunger 36, applying force to the plunger 36 and the valve core 37, thereby increasing the inlet pressure P of the working system 10. p The oil is led to the left end of the valve core 37. The third oil passage 3c connects the outlet of the pressure compensation valve 3 with the second groove 372, so that the pressure oil at the inlet of the control valve 2 can flow through the third oil passage 3c and the second groove 372 to the space between the right end face of the valve core 37 and the connector 39 in the valve body 34, thereby leading the inlet pressure P' of the control valve 2 to the right end of the valve core 37. Moreover, as Figure 2 As shown, in this embodiment, the second oil passage 3b is connected to the space between the left end face of the valve core 37 and the guide seat 35 of the valve body 34. This allows the oil from the control valve 2 to flow through the second oil passage 3b into the space between the left end face of the valve core 37 and the guide seat 35 of the valve body 34, applying force to the left end face of the valve core 37, thereby increasing the outlet pressure P of the control valve 2. LS The oil is directed to the left end of the valve core 37. The fourth oil passage 3d connects with the space between the bottom of the third groove 391 and the push rod 38, allowing the pressure oil flowing from the feedback device 20 to flow through the fourth oil passage 3d to the space between the bottom of the third groove 391 and the push rod 38, thus applying force to the push rod 38, which can move together with the valve core 37, to apply the maximum load pressure P fed back by the feedback device 20. Lmax It is led to the right end of valve core 37.

[0104] Among them, such as Figure 2 As shown, in this embodiment, both the first oil passage 3a and the third oil passage 3c include a transverse section and a longitudinal section, wherein the longitudinal section and the transverse section extend radially and axially, respectively, and are sequentially connected along the oil flow direction. The longitudinal section is constructed as a damping orifice, such that the first oil passage 3a and the second oil passage 3c respectively include a first damping orifice 3j serving as a first damping 3e and a third damping orifice 3k serving as a third damping 3g. The fourth oil passage 3d includes a large-diameter section and a small-diameter section, both extending axially and sequentially connected along the oil flow direction. The small-diameter section is constructed as a damping orifice, such that the fourth oil passage 3d is constructed as a fourth damping orifice 3m serving as a fourth damping 3h. The second oil passage 3b is provided with a damping element serving as a second damping 3f. In this way, the influence of pressure shock on the displacement of the valve core 37 can be reduced.

[0105] It can be seen that, under the action of the first oil passage 3a, the second oil passage 3b, the third oil passage 3c, and the fourth oil passage 3d, the inlet pressure P of the working system 10 can be reduced. pand the outlet pressure P of control valve 2 Ls The pressure is directed to the left end of valve core 37, and the inlet pressure P' and maximum load pressure P of control valve 2 are also connected. Lmax Leading to the right end of valve core 37, thus, Figure 2 The left end of the valve core 37 constitutes the first control end 3n of the pressure compensation valve 3, and the right end of the valve core 37 constitutes the second control end 3q of the pressure compensation valve 3.

[0106] Furthermore, based on the plunger 36 and push rod 38, the inlet pressure P of the working system 10 p and the outlet pressure P of control valve 2 Ls Acting on different parts of the left end of valve core 37, the inlet pressure P' and the maximum load pressure P of valve 2 are controlled. Lmax The pressure is applied to different parts of the right end of the valve core 37, so that the pressure compensation valve 3 can compare the four pressures introduced.

[0107] Among them, such as Figure 2 As shown, the inlet pressure P of the working system 10 p The working part at the left end of the valve core 37 is the bottom of the first groove 371, and the corresponding working area is the cross-sectional area of ​​the first groove 371 (which can be approximately considered equal to the cross-sectional area of ​​the plunger 36), denoted as S1. The outlet pressure P of the control valve 2 is... Ls The operating area at the left end of valve core 37 is the annular end face of the left end of valve core 37. The corresponding operating area is the difference between the area corresponding to the outer diameter of the left end face of valve core 37 and the cross-sectional area of ​​the first groove 371, denoted as S2. The inlet pressure P' of the control valve 2 is applied at the right end of valve core 37. The operating area at the right end of valve core 37 is the annular end face of the right end of valve core 37. The corresponding operating area is the difference between the area corresponding to the outer diameter of the right end face of valve core 37 and the cross-sectional area of ​​the third groove 391, denoted as S3. The maximum load pressure P Lmax The action area at the right end of the valve core 37 corresponds to the part at the right end of the valve core 37 that corresponds to the third groove 391. The corresponding action area is the cross-sectional area of ​​the third groove 391 (which can be approximately considered to be equal to the cross-sectional area of ​​the third rod segment 383 of the push rod 38), and is denoted as S4.

[0108] In this embodiment, the cross-sectional area of ​​the first groove 371 is equal to the cross-sectional area of ​​the third groove 391, and the area corresponding to the outer diameter of the left end face of the valve core 37 is equal to the area corresponding to the outer diameter of the right end face of the valve core 37, and is equal to twice the cross-sectional area of ​​the first groove 371 (third groove 391). Therefore, S1 = S2 = S3 = S4, that is, the inlet pressure P of the working system 10 is equal to the cross-sectional area of ​​the first groove 371 (third groove 391). p The outlet pressure P of control valve 2 Ls The inlet pressure P' and the maximum load pressure P of control valve 2 LmaxThe effective areas on valve core 37 are equal. Therefore, it is only necessary to compare the inlet pressure P of the working system 10. p and the outlet pressure P of control valve 2 Ls The sum of the pressures and the inlet pressure P' of control valve 2 and the maximum load pressure P Lmax The relationship between the sum and magnitude of these values ​​controls the direction and magnitude of movement of valve core 37, switching valve positions and changing the opening degree. Specifically, when the inlet pressure P of the working system 10... p and the outlet pressure P of control valve 2 Ls The sum of these pressures is less than the inlet pressure P' of control valve 2 and the maximum load pressure P. Lmax When the summation occurs, valve core 37 moves to the left, closer to guide seat 35 and away from connector 39, causing pressure compensation valve 3 to switch from the first valve position to the second valve position; when the inlet pressure P of working system 10... p and the outlet pressure P of control valve 2 Ls The sum of these pressures is greater than the inlet pressure P' of control valve 2 and the maximum load pressure P. Lmax When the pressure is equal to the guide seat 35, the valve core 37 moves to the right, away from the guide seat 35 and closer to the connector 39, causing the pressure compensation valve 3 to switch from the second valve position to the first valve position; when the inlet pressure P of the working system 10 is equal to the guide seat 35, the valve core 37 moves to the right, away from the guide seat 35 and closer to the connector 39, causing the pressure compensation valve 3 to switch from the second valve position to p and the outlet pressure P of control valve 2 Ls The sum equals the inlet pressure P' of control valve 2 and the maximum load pressure P. Lmax When the sum is equal, valve core 37 stops moving and reaches the equilibrium position.

[0109] Depend on Figure 2 As can be seen, in this embodiment, the valve core 37 is provided with an oil passage 3i, which connects the inlet and outlet of the pressure compensation valve 3, so that after the pressure compensation valve 3 is opened, the oil can flow smoothly through the pressure compensation valve 3 and flow to the control valve 2. Figure 2 As shown, in this embodiment, the oil passage 3i is located at the shoulder of the valve core 37, and the oil passage 3i has a stepped shape with its cross-sectional area gradually decreasing from left to right (from the first control end 3n to the second control end 3q). Thus, as the valve core 37 moves left and right, the connection area between the inlet and outlet of the pressure compensation valve 3 gradually changes, facilitating precise adjustment of the pressure compensation valve 3's opening. Of course, the oil passage 3i is not limited to a stepped shape; for example, it can also be conical, as long as the cross-sectional area of ​​the oil passage 3i gradually decreases from the first control end 3n to the second control end 3q.

[0110] like Figure 2As shown, in this embodiment, the portion of the valve body 34 located between the inlet and outlet of the pressure compensation valve 3 can close the oil passage 3i, cutting off the inlet and outlet of the pressure compensation valve 3, thus switching the pressure compensation valve 3 to the second valve position. Specifically, as... Figure 2 As shown, when the valve core 37 moves to the left to the side wall of the valve body 34 located between the inlet and outlet of the pressure compensation valve 3, the corresponding side wall closes the oil passage 3i, disconnecting the inlet and outlet of the pressure compensation valve 3. The pressure compensation valve 3 reaches the second valve position, and the pressure oil cannot flow to the control valve 2 through the pressure compensation valve 3. When the valve core 37 moves to the right, the oil passage 3i gradually moves away from the side wall of the valve body 34 located between the inlet and outlet of the pressure compensation valve 3. The flow area gradually increases, and the opening gradually increases until the oil passage 3i completely leaves the side wall of the valve body 34 located between the inlet and outlet of the pressure compensation valve 3. At this point, the opening reaches its maximum, the inlet and outlet of the pressure compensation valve 3 are fully connected, the pressure compensation valve 3 reaches the first valve position, and the pressure oil can flow smoothly to the control valve 2 through the pressure compensation valve 3.

[0111] The structure of the pressure compensation valve 3 and the working system 10 containing the pressure compensation valve 3 has been described above. Next, the feedback device 20 will be introduced.

[0112] Back Figure 1 In this embodiment, the two one-way valves 4 of the feedback device 20 correspond one-to-one with the two working links 101, that is, the two one-way valves 4 correspond to the first working link 102 and the second working link 103, respectively. For example... Figure 1 As shown, the inlets of the two check valves 4 are respectively connected to the outlets of the control valves 2 of their respective working links, and the outlets of the two check valves 4 are both connected to the feedback port PL of the working system 10. At the same time, the second control terminals 3q of the pressure compensation valves 3 of the two working links are also connected to the feedback port PL. In this way, the inlets of the two check valves 4 are respectively connected to the outlets of the control valves 2 of their respective working links, and the outlets of the two check valves 4 are both connected to the second control terminals 3q of the pressure compensation valves 3 of all working links. This allows the feedback device 20 to lead the highest load pressure among the load pressures of the first working link 102 and the second working link 103 to the second control terminals 3q of the pressure compensation valves 3 of the first working link 102 and the second working link 103 to control the pressure compensation valves 3.

[0113] Based on the pressure compensation valve 3 and feedback device 20, this embodiment can effectively avoid the problem of hydraulic oil preferentially flowing to the low-load side when the flow is saturated. The following explanation will take the case where the load pressure of the first working link 102 is higher than the load pressure of the second working link 103 during the combined operation of the first working link 102 and the second working link 103 as an example.

[0114] See Figure 1 For ease of distinction, the inlet pressure P' of the control valve 2 of the first working link 102 and the second working link 103 is respectively designated as P1. ’ and P2 ’ And the load pressure P of the first working link 102 and the second working link 103 will be... Ls Each is counted as P Ls1 and P Ls2 .

[0115] Due to the load pressure P of the first working link 102 Ls1 The load pressure P is higher than that of the second working link 103. Ls2 Therefore, in this embodiment, the highest load pressure P Lmax =P Ls1 .

[0116] Under the above conditions, if the valve core 37 of the pressure compensation valve 3 of the first working link 102 is in force balance, then P p ·S1+P LS1 ·S2=P′1·S3+P Lmax ·S4, because S1=S2=S3=S4, and P Lmax =P LS1 Therefore, we can obtain P. p =P′1, therefore, the pressure difference ΔP1 between the inlet and outlet of the control valve 2 of the first working link 102 is =P′1 - P LS1 =P p -P Lmax .

[0117] In addition, the valve core 37 of the pressure compensation valve 3 of the second working link 103 is balanced, then P p ·S1+P LS2 ·S2=P′2·S3+P Lmax Since S1 = S2 = S3 = S4, we can obtain P. p -P Lmax =P′2-P LS2 Therefore, the pressure difference between the inlet and outlet of the control valve 2 of the second working link 103 is ΔP2 = P′2 - P LS2 =P p -P Lmax Furthermore, since P has already been obtained according to the force balance formula of the pressure compensation valve 3 of the first working link 102, p -P Lmax =ΔP1, therefore, ΔP2 = P′2 - P LS2 =P p -P Lmax =ΔP1.

[0118] It can be seen that the inlet and outlet pressure difference ΔP of the control valve 2 of the first working link 102 and the second working link 103 are equal, both being the inlet pressure P of the working system 10. p With the highest load pressure P Lmax difference.

[0119] Since the oil volume through the control valve 2 of the first working link 102 and the second working link 103 are respectively and Since ΔP1 = ΔP2, the amount of oil flowing to the actuator 1 in the first working link 102 and the second working link 103 depends only on the strokes K1 and K2 of the valve stems of the two control valves 2, and is not affected by the load pressure of different actuators 1. This allows the oil volume to be distributed to each path proportionally according to the stroke of the valve stem of each control valve 2 when the two actuators 1 operate simultaneously under flow saturation, regardless of light or heavy load. This effectively solves the problem that the actuators under light and heavy loads cannot work synchronously when the flow is saturated.

[0120] In fact, we can also analyze from another perspective why this embodiment can solve the problem that light and heavy load actuators cannot work synchronously when the flow is saturated.

[0121] Because each working link 101 will increase the inlet pressure P of the working system 10 p and the outlet pressure P of control valve 2 Ls The pressure is directed to the first control terminal 3n of the pressure compensation valve 3, and the highest load pressure P is... Lmax The inlet pressure P' of control valve 2 is led to the second control terminal 3q of pressure compensation valve 3. Therefore, the pressure difference between the inlet and outlet of pressure compensation valve 3 is P. p -P′=P Lmax -P LS It can be seen that the pressure difference between the inlet and outlet of pressure compensation valve 3 is just right to compensate for the load pressure P of each section. LS With the highest load pressure P Lmax The difference between them is compensated to make the load of each working link 101 equal, thereby avoiding the hydraulic oil from flowing preferentially to the low-load actuator 1, and effectively solving the problem that light and heavy load actuators cannot work synchronously when the flow is saturated.

[0122] Specifically, in this embodiment, the pressure compensation valve 3 of the second working link 103 has an inlet and outlet pressure difference of P. p -P′2=P Lmax -P LS2 =P LS1 -P LS2Therefore, it can be seen that the pressure difference between the inlet and outlet of the pressure compensation valve 3 exactly compensates for the difference in load pressure between the two actuators 1, so that the load of the second working link 103 with a lower load can be equal to the load of the first working link 102, thereby eliminating the influence of the lower load of the actuator 1, and enabling the two working links 101 to be diverted proportionally according to the valve stem stroke of the control valve 2.

[0123] As can be seen, this embodiment achieves this by adjusting the inlet pressure P of the working system 10. p and the outlet pressure P of control valve 2 Ls The pressure is directed to the first control terminal 3n of the pressure compensation valve 3, and the highest load pressure P is... Lmax The inlet pressure P' of the control valve 2 is led to the second control terminal 3q of the pressure compensation valve 3 for comparison, so that the pressure compensation valve 3 of each working link 101 can be adjusted according to the highest load pressure P. Lmax The opening degree is adjusted according to the difference in load pressure between the actuator 1 and its corresponding actuator 1 to balance the load. When flow saturation occurs, each working link 101 can divide the flow equally according to the opening degree of the control valve 2, without being affected by the load of the actuator. This avoids the hydraulic oil from preferentially flowing to the low-load actuator 1, effectively solving the problem that light and heavy load actuators cannot work synchronously when flow saturation occurs, so that the hydraulic system 100 has the function of resisting flow saturation.

[0124] Moreover, in this embodiment, the pressure compensation valve 3 is still located before the control valve 2, and the feedback device 20 is not located inside the pressure compensation valve 3, but outside the pressure compensation valve 3. Therefore, the structure is simple, easy to process, and has a low cost.

[0125] Based on the hydraulic system 100 of the foregoing embodiments, this application also provides an engineering machinery, which includes the hydraulic system 100 of any embodiment of this application. Exemplarily, the engineering machinery is an engineering vehicle such as a crane.

[0126] The above description is merely an exemplary embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A hydraulic system (100), characterized in that, Comprise: a working system (10) having an inlet (P) connected with an oil source and comprising at least two working circuits (101) arranged in parallel, each of the working circuits (101) comprising an actuator (1) for driving connection with an actuating element of a construction machine to drive the actuating element to act, a control valve (2) and a pressure compensation valve (3) connected with the inlet (P) and the actuator (1) through the control valve (2), the pressure compensation valve (3) having a first control end (3n) and a second control end (3q) for controlling the pressure compensation valve (3) to switch to a first valve position and a second valve position respectively, in the first valve position, the pressure compensation valve (3) communicates the oil source with the control valve (2), in the second valve position, the pressure compensation valve (3) cuts off the inlet (P) from the control valve (2), the first control end (3n) is connected with the inlet (P) and an outlet of the control valve (2), the second control end (3q) is connected with an inlet of the control valve (2); and a feedback device (20) connected with an outlet of the control valve (2) of each of the working circuits (101) and the second control end (3q) of each of the working circuits (101) to lead a highest load pressure in the at least two working circuits (101) to the second control end (3q) of each of the working circuits (101) so that when at least two compound actions are performed in the at least two working circuits (101), an inlet-outlet pressure difference of the control valve (2) of each of the working circuits (101) of the compound actions is equal. ​ The pressure compensation valve (3) comprises a valve body (34), a valve core (37), a guide seat (35), a joint (39), a plunger (36) and a top rod (38). The guide seat (35) and the joint (39) are arranged at opposite ends of the valve body (34), the valve core (37) is arranged in the valve body (34) and located between the guide seat (35) and the joint (39), the first control end (3n) is located at one end of the valve core (37) facing the guide seat (35), the second control end (3q) is located at one end of the valve core (37) facing the joint (39), the plunger (36) is inserted into the first recess (371) of the valve core (37) and the guide seat (35), and the top rod (38) is inserted into the second recess (372) of the valve core (37) and the third recess (391) of the joint (39). The inlet (P) is in communication with the first recess (371), the outlet of the control valve (2) is in communication with the space of the valve body (34) between the valve core (37) and the guide seat (35), the inlet of the control valve (2) is in communication with the space of the valve body (34) between the valve core (37) and the joint (39) through the second recess (372), and the feedback device (20) is in communication with the third recess (391).

2. The hydraulic system (100) of claim 1, characterized in that The feedback device (20) comprises at least two one-way valves (4), and the at least two one-way valves (4) correspond to the at least two working links (101) in a one-to-one manner. The inlet of each one-way valve (4) is connected with the outlet of the control valve (2) of the corresponding working link (101), and the outlet of each one-way valve (4) is connected with the second control end (3q) of the pressure compensation valve (3) of all working links (101).

3. The hydraulic system (100) of claim 1, characterized in that, The action areas of the pressure of the inlet (P), the outlet pressure of the control valve (2), the inlet pressure of the control valve (2) and the highest load pressure of the pressure compensation valve (3) are equal.

4. The hydraulic system (100) according to any one of claims 1-3, characterized in that, The cross-sectional area of the first recess (371), the area corresponding to the outer diameter of the end face of the valve core (37) facing the guide seat (35) and the difference between the cross-sectional area of the first recess (371) and the cross-sectional area of the third recess (391), the area corresponding to the outer diameter of the end face of the valve core (37) facing the joint (39) and the difference between the cross-sectional area of the third recess (391) and the cross-sectional area of the third recess (391) are equal.

5. The hydraulic system (100) according to any one of claims 1-3, characterized in that, The hydraulic system (100) is configured as at least one of the following: A first damper (3e) is arranged on an oil path between the inlet (P) and the first recess (371); A second damper (3f) is arranged on an oil path between the outlet of the control valve (2) and the space of the valve body (34) between the guide seat (35) and the valve core (37); A third damper (3g) is arranged on an oil path between the inlet of the control valve (2) and the second recess (372); A fourth damping (3h) is arranged on an oil path between the feedback device (20) and the third groove (391).

6. The hydraulic system (100) of claim 5, characterized in that The hydraulic system (100) is configured as at least one of: The valve core (37) is provided with a first oil passage (3a) which communicates the inlet (P) with the first groove (371), the first oil passage (3a) comprises a first damping hole (3j), the first damping (3e) is arranged in the first oil passage (3a), or the first damping (3e) comprises the first damping hole (3j); The valve body (34) is provided with a second oil passage (3b) which communicates the outlet of the control valve (2) with the space of the valve body (34) between the guide seat (35) and the valve core (37), the second damping (3f) is arranged in the second oil passage (3b), or the second oil passage (3b) comprises a second damping hole, and the second damping (3f) comprises the second damping hole; The valve core (37) is provided with a third oil passage (3c) which communicates the inlet of the control valve (2) with the second groove (372), the third damping (3g) is arranged in the third oil passage (3c), or the third oil passage (3c) comprises a third damping hole (3k), and the third damping (3g) comprises the third damping hole (3k); The joint (39) is provided with a fourth oil passage (3d) which communicates the feedback device (20) with the third groove (391), the fourth damping (3h) is arranged in the fourth oil passage (3d), or the fourth oil passage (3d) comprises a fourth damping hole (3m), and the fourth damping (3h) comprises the fourth damping hole (3m).

7. The hydraulic system (100) according to any one of claims 1-3, characterized in that, The second groove (372) comprises a first groove section (373) and a second groove section (374), the first groove section (373) is connected to one end of the second groove section (374) close to the guide seat (35) and forms a step (375) with the second groove section (374), the top rod (38) extends into the first groove section (373) from the second groove section (374) and has an abutting surface (384), the abutting surface (384) is used for abutting on the step (375) to make the top rod (38) and the valve core (37) move together towards the joint (39).

8. The hydraulic system (100) of claim 7, characterized by The top rod (38) and the second groove section (374) are arranged eccentrically.

9. The hydraulic system (100) of claim 8, characterized in that The second groove section (374) and the valve core (37) are arranged eccentrically, and the top rod (38) and the valve core (37) are arranged concentrically.

10. The hydraulic system (100) of claim 7, characterized in that, The ejector rod (38) comprises a first rod section (381) and a second rod section (382), which are connected in sequence along the direction from the guide seat (35) to the joint (39), the first rod section (381) is located in the first groove section (373), and the cross-sectional area of the second rod section (382) is smaller than that of the first rod section (381), so that the connecting surface of the first rod section (381) and the second rod section (382) forms the abutting surface (384).

11. The hydraulic system (100) of claim 10, characterized in that The ejector rod (38) further comprises a third rod section (383), which is connected to one end of the second rod section (382) away from the guide seat (35) and is inserted into the third groove (391), and the cross-sectional area of the third rod section (383) is larger than that of the second rod section (382).

12. The hydraulic system (100) according to any one of claims 1-3, characterized in that, The valve core (37) is provided with an oil passing channel (3i), the inlet and the outlet of the pressure compensation valve (3) are communicated through the oil passing channel (3i), and the flow area of the oil passing channel (3i) gradually decreases along the direction from the first control end (3n) to the second control end (3q).

13. The hydraulic system (100) of claim 12, characterized by The oil passing channel (3i) is in a stepped or tapered shape.

14. The hydraulic system (100) according to any one of claims 1-3, characterized in that, The side surface of the part of the plunger (36) inserted into the first groove (371) and / or the guide seat (35) is provided with a first annular groove (361); and / or, the side surface of the part of the ejector rod (38) inserted into the third groove (391) is provided with a second annular groove (392).

15. The hydraulic system (100) according to any one of claims 1-3, characterized in that, The pressure compensation valve (3) further comprises an adjusting member (31), which adjusts the position of the guide seat (35) on the valve body (34) to adjust the displacement of the valve core (37) towards the guide seat (35).

16. A working machine characterized by The hydraulic system (100) comprises the hydraulic system (100) according to any one of claims 1-15. The hydraulic system (100) comprises the hydraulic system (100) according to any one of claims 1-15.

17. A pressure compensated valve (3) characterized by The pressure compensation valve (3) is used for connecting with the inlet (P) of the working system (10) of the hydraulic system (100) connected with the oil source, and connecting with the actuator (1) of the working link (101) of the working system (10) through the operating valve (2) of the hydraulic system (100), the pressure compensation valve (3) has a first control end (3n) and a second control end (3q), the first control end (3n) and the second control end (3q) control the pressure compensation valve (3) to switch to the first valve position and the second valve position respectively, when the pressure compensation valve (3) is in the first valve position, the oil source is communicated with the operating valve (2), when the pressure compensation valve (3) is in the second valve position, the inlet (P) is cut off with the operating valve (2), the first control end (3n) is used for connecting with the inlet (P) and the outlet of the operating valve (2), the second control end (3q) is used for connecting with the inlet of the operating valve (2), the pressure compensation valve (3) comprises a valve body (34), a valve core (37), a guide seat (35), a joint (39), a plunger (36) and a top rod (38), the guide seat (35) and the joint (39) are arranged at opposite ends of the valve body (34), the valve core (37) is arranged in the valve body (34) and located between the guide seat (35) and the joint (39), the first control end (3n) is located at one end of the valve core (37) facing the guide seat (35), the second control end (3q) is located at one end of the valve core (37) facing the joint (39), the plunger (36) is inserted into the first recess (371) of the valve core (37) and the guide seat (35), and the top rod (38) is inserted into the second recess (372) of the valve core (37) and the third recess (391) of the joint (39), the first recess (371) is used for communicating with the inlet (P), the space of the valve body (34) between the valve core (37) and the guide seat (35) is used for communicating with the outlet of the operating valve (2), the space of the valve body (34) between the valve core (37) and the joint (39) is communicated with the inlet of the operating valve (2) through the second recess (372), and the third recess (391) is used for communicating with the feedback device (20) of the hydraulic system (100), the feedback device (20) is connected with the outlets of the operating valves (2) of the working links (101) in parallel of the working system (10) and connected with the second control ends (3q) of the working links (101), so that the highest load pressure in at least two working links (101) is introduced to the second control ends (3q) of the working links (101), and when at least two composite actions of the at least two working links (101) occur, the pressure difference between the inlet and the outlet of the operating valve (2) of each working link (101) of the composite action is equal.

18. Pressure-compensated valve (3) according to claim 17, characterized in that An acting area of the pressure compensating valve (3) for the pressure of the inlet (P), the outlet pressure of the control valve (2), the inlet pressure of the control valve (2) and the highest load pressure is equal.

19. Pressure compensated valve (3) according to any of claims 17-18, characterized in that A cross-sectional area of the first groove (371), a difference between an outer diameter of an end surface of the valve core (37) facing the guide seat (35) and a cross-sectional area of the first groove (371), a difference between an outer diameter of an end surface of the valve core (37) facing the joint (39) and a cross-sectional area of the third groove (391), and the cross-sectional area of the third groove (391) are equal.

20. Pressure compensated valve (3) according to any of claims 17-18, characterized in that The pressure compensating valve (3) is configured as at least one of: A first damper (3e) is provided on an oil passage between the first groove (371) and the inlet (P); A second damper (3f) is provided on an oil passage between a space of the valve body (34) between the guide seat (35) and the valve core (37) and the outlet of the control valve (2); A third damper (3g) is provided on an oil passage between the second groove (372) and the inlet of the control valve (2); A fourth damper (3h) is provided on an oil passage between the third groove (391) and the feedback device (20).

21. Pressure-compensated valve (3) according to claim 20, characterized in that The pressure compensating valve (3) is configured as at least one of: A first oil passage (3a) is provided on the valve core (37), the first oil passage (3a) connecting the inlet (P) and the first groove (371), the first oil passage (3a) including a first damper hole (3j), the first damper (3e) being provided in the first oil passage (3a) or the first damper (3e) including the first damper hole (3j); A second oil passage (3b) is provided on the valve body (34), the second oil passage (3b) connecting the outlet of the control valve (2) and a space of the valve body (34) between the guide seat (35) and the valve core (37), the second damper (3f) being provided in the second oil passage (3b) or the second oil passage (3b) including a second damper hole, the second damper (3f) including the second damper hole; A third oil passage (3c) is provided on the valve core (37), the third oil passage (3c) connecting the inlet of the control valve (2) and the second groove (372), the third damper (3g) being provided in the third oil passage (3c) or the third oil passage (3c) including a third damper hole (3k), the third damper (3g) including the third damper hole (3k); A fourth oil passage (3d) is provided on the joint (39), the fourth oil passage (3d) connecting the feedback device (20) and the third groove (391), the fourth damper (3h) being provided in the fourth oil passage (3d) or the fourth oil passage (3d) including a fourth damper hole (3m), the fourth damper (3h) including the fourth damper hole (3m).

22. Pressure-compensating valve (3) according to any one of claims 17-18, characterized in that The second groove (372) comprises a first groove section (373) and a second groove section (374), the first groove section (373) is connected to one end of the second groove section (374) close to the guide seat (35), and a step (375) is formed between the first groove section (373) and the second groove section (374), the ejector rod (38) extends into the first groove section (373) from the second groove section (374) and has an abutting surface (384) for abutting against the step (375) to move the ejector rod (38) and the valve core (37) together towards the joint (39).

23. Pressure-compensated valve (3) according to claim 22, characterized in that The ejector rod (38) is arranged eccentrically with the second groove section (374).

24. Pressure-compensated valve (3) according to claim 23, characterized in that The second groove section (374) is arranged eccentrically with the valve core (37), and the ejector rod (38) is arranged concentrically with the valve core (37).

25. Pressure-compensated valve (3) according to claim 22, characterized in that The ejector rod (38) comprises a first rod section (381) and a second rod section (382), the first rod section (381) and the second rod section (382) are connected in sequence along the direction from the guide seat (35) to the joint (39), the first rod section (381) is located in the first groove section (373), and the cross-sectional area of the second rod section (382) is smaller than that of the first rod section (381), so that the connecting surface of the first rod section (381) and the second rod section (382) forms the abutting surface (384).

26. Pressure-compensated valve (3) according to claim 25, characterized in that The ejector rod (38) further comprises a third rod section (383), the third rod section (383) is connected to one end of the second rod section (382) away from the guide seat (35) and is inserted into the third groove (391), and the cross-sectional area of the third rod section (383) is larger than that of the second rod section (382).

27. Pressure compensating valve (3) according to any of claims 17-18, characterized in that An oil passing channel (3i) is arranged on the valve core (37), the inlet and the outlet of the pressure compensation valve (3) are communicated through the oil passing channel (3i), and the flow area of the oil passing channel (3i) gradually decreases along the direction from the first control end (3n) to the second control end (3q).

28. Pressure-compensated valve (3) according to claim 27, characterized in that The oil passing channel (3i) is in a stepped or tapered shape.

29. Pressure compensating valve (3) according to any of claims 17-18, characterized in that A first annular groove (361) is arranged on the side surface of the part of the plunger (36) inserted into the first groove (371) and / or the guide seat (35); and / or, a second annular groove (392) is arranged on the side surface of the part of the ejector rod (38) inserted into the third groove (391).

30. The pressure-compensating valve (3) according to any of claims 17-18, characterized in that The pressure compensation valve (3) further comprises an adjusting member (31), the adjusting member (31) adjusts the position of the guide seat (35) on the valve body (34) to adjust the displacement of the valve core (37) towards the guide seat (35).

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