Valve bank and hydraulic system

Abstract

The invention relates to the technical field of hydraulic pressure, in particular to a valve bank and a hydraulic system. The invention discloses a valve group, which is arranged aiming at an actuating mechanism and comprises an oil inlet path for introducing pressure oil to a pressure oil port p of a reversing valve; the reversing valve is used for controlling oil inlet and outlet of the executing mechanism, is positioned on an oil inlet path and is used for controlling on-off and flow of the oil inlet path; the compensation valve is located on the oil inlet way and located on the downstream of the reversing valve, the pressure of an inlet p3 of the compensation valve is introduced into one end of the compensation valve, a control cavity is formed in the other end of the compensation valve, and the compensation valve slides under the action of the pressure at the two ends to control the opening area of the oil inlet way; and the switching valve controls the control cavity to communicate with the load-sensitive oil port P0 or the oil drainage port Dr. The technical problem that in the prior art, a hydraulic system can only work in a single mode and cannot be switched to give consideration to controllability and pressure loss is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic technology, in particular to a valve group and a hydraulic system. BACKGROUND

[0002] The existing hydraulic control system of walking machinery, which is typical of excavators, can be mainly divided into two types according to principles: load-sensitive system and open-center system. In the load-sensitive system, the pressure difference before and after the reversing control valve is constant, and the flow rate can be controlled by the opening degree of the valve core; in the open-center system, the flow rate is determined by the pump, and the opening degree of the control valve core does not determine the flow rate.

[0003] The document with the application number CN201610778205.1 discloses a full-power adaptive load-sensitive multi-way reversing valve, which includes an oil inlet joint and a reversing joint. The reversing joint is provided with no less than one, the oil inlet joint and the reversing joint are communicated, the other side of the reversing joint is provided with a power adaptive valve block, the oil inlet joint, the reversing joint and the power adaptive valve block form a parallel structure circuit, a pressure compensation valve is arranged in the reversing joint, the pressure compensation valve is arranged between the P port and the LS port of the reversing joint, and the use of the pressure compensation valve ensures that each working oil port can work smoothly at the same time under the condition of insufficient flow. The parallel structure circuit ensures that each actuator moves independently and does not interfere with each other. When the pressure is higher than the power change point, the flow rate decreases, and when the flow rate is saturated, because of the action of the pressure compensation valve, the pressure difference at the opening of the reversing valve is reduced in proportion, which leads to the synchronous decrease of the flow rate, maintains the proportion of the area of the opening of the reversing valve, and each oil port can work smoothly at the same time and is not affected by the load. As can be seen from the above application, the advantages of the load-sensitive system are that the movement speed of the actuator is not affected by the load, and the micro-control operation is good, and the disadvantages are that there is a fixed pressure loss, and the power loss is large under large flow rate.

[0004] For example, the file with application number CN202210609006.3 discloses a hydraulic system, the first oil supply oil way includes a first open center oil way and a first bypass oil way from the first valve body section, the first open center oil way and the first bypass oil way pass through all valve body sections, the first open center oil way is configured to communicate the first oil supply oil way with the oil tank in the case that all function valves on the first oil supply oil way are in the neutral position, and the first bypass oil way is configured to supply oil to downstream function valves in the case that the function valves on the first oil supply oil way are in action. The second oil supply oil way includes a second open center oil way and a second bypass oil way from the first valve body section, the second open center oil way and the second bypass oil way pass through all valve body sections, the second open center oil way is configured to communicate the second oil supply oil way with the oil tank in the case that all function valves on the second oil supply oil way are in the neutral position, and the second bypass oil way is configured to supply oil to downstream function valves in the case that the function valves on the second oil supply oil way are in action. The open center system disclosed in the above application has the advantages of no fixed pressure loss, relatively small power loss, and energy saving advantage especially under large flow. The disadvantages are that the speed of the actuator is greatly affected by the load, and the micro-control operability is poor. The load sensing system and the open center system described above can only work in a single mode and cannot be switched to balance the control performance and pressure loss. SUMMARY

[0005] In order to solve the technical problem that the hydraulic system in the prior art can only work in a single mode and cannot be switched to balance the control performance and pressure loss, the present application provides a valve group and a hydraulic system, which solve the above technical problems.

[0006] The technical scheme of the present application is as follows: The present application provides a valve group, which is arranged for an actuator, comprising: An oil inlet oil way is arranged to introduce pressure oil to a pressure oil port p of a reversing valve; The reversing valve is arranged to control the oil inlet and outlet of the actuator, and is arranged on the oil inlet oil way to control the on-off and flow of the oil inlet oil way; The compensation valve is arranged on the oil inlet oil way and downstream of the reversing valve, one end of the compensation valve is arranged to introduce pressure to an inlet p3 thereof, and the other end forms a control chamber, and the compensation valve is arranged to slide to control the opening area of the oil inlet oil way under the pressure of both ends; The switching valve is arranged to control the control chamber to communicate with a load sensing oil port P0 or a drain port Dr.

[0007] According to one embodiment of the present application, in the initial state, the switching valve controls the control chamber to communicate with the load sensing oil port P0, and after reversing under the action of the first pilot pressure, the switching valve controls the control chamber to communicate with the drain port Dr.

[0008] According to one embodiment of the present application, the inlet p3 and the outlet p4 of the compensation valve are both communicated with the oil inlet oil line, and the compensation valve further has a sensing outlet c which is unidirectionally communicated with the load-sensitive oil port P0.

[0009] According to one embodiment of the present application, the compensation valve has a disconnection position, an intermediate position and a communication position which are sequentially set, when the compensation valve is in the disconnection position, the oil ports of the compensation valve are not communicated with each other, when the compensation valve is in the intermediate position, the inlet p3 and the outlet p4 of the compensation valve are small-area communicated, when the compensation valve is in the communication position, the inlet p3 and the outlet p4 are large-area communicated, the inlet p3 is communicated with the sensing outlet c, and the inlet p3 pushes the compensation valve to the communication position.

[0010] According to one embodiment of the present application, a logic valve is further included, which is located on the oil inlet oil line and downstream of the compensation valve, and the logic valve controls the opening area of the oil inlet oil line.

[0011] According to one embodiment of the present application, under the action of the second pilot pressure, the logic valve is switched from the large-area communication to the small-area communication.

[0012] According to one embodiment of the present application, a check valve is arranged on the oil inlet oil line, or a check valve is integrated in the logic valve.

[0013] According to one embodiment of the present application, a valve body is further included, and the reversing valve, the compensation valve, the switching valve and the logic valve are integrated in the valve body.

[0014] The present application further provides a hydraulic system, comprising: an oil source P for providing pressure oil; at least one valve group, and the oil inlet oil line is communicated with the oil source P; an actuator which is correspondingly arranged with the valve group, and the valve group controls the oil inlet and outlet of the actuator.

[0015] According to one embodiment of the present application, the reversing valve further includes two working oil ports and a return oil port t, the two working oil ports are communicated with the actuator, when the reversing valve is in the intermediate position, the reversing valve controls the oil inlet oil line to be disconnected, and the oil ports are not communicated with each other, when the reversing valve is in the working position, the reversing valve controls the oil inlet oil line to be communicated, one working oil port is for oil inlet, and the other working oil port is for oil return.

[0016] Based on the above technical solutions, the present application can achieve the following technical effects: The valve group of the present application controls the pressure of the control cavity of the compensation valve through the switching valve, when the switching valve controls the control cavity of the compensation valve to communicate with the load sensing oil port P0, the flow distribution relationship can be controlled through the compensation valve, the proportion of the movement speed of each actuator can be accurately controlled through the reversing valve, and the fixed flow ratio control mode is realized; when the switching valve controls the control cavity of the compensation valve to communicate with the drain port Dr, the control cavity is in a low pressure state, the compensation valve is disabled, and the priority relationship of the flow distribution of different actuators is no longer controlled, but the larger opening area is always maintained, so that the oil inlet pressure loss is reduced, and the fixed opening area control mode is realized; in this way, in actual use, the valve group can work in the fixed flow ratio control mode in the micro-control working condition, and the valve group can work in the fixed opening area control mode in the full-speed working condition, the valve group of the present application can realize the switching of the control mode, and both the control performance and the pressure loss are considered; The valve group of the present application is also provided with a logic valve, when the valve group adopts the fixed opening area control mode, the flow distribution relationship can be controlled through the logic valve. The logic valve is in a large-area communication state in the initial state, when the switching valve is in the initial state, the control cavity communicates with the load sensing oil port, at this time, the logic valve can not participate in the flow distribution; when the switching valve is reversed under the action of the first pilot pressure, the compensation valve no longer controls the priority relationship of the flow distribution of different actuators, but always maintains a larger opening area, at this time, the flow distribution relationship can be controlled by the action of the second pilot pressure on the logic valve; The sensing outlet c of the compensation valve of the valve group of the present application unidirectionally communicates with the load sensing oil port P0, then the outlet oil port p2 pressure of each valve group reversing valve, that is, the pressure of the inlet p3 of the compensation valve, the highest pressure in it is unidirectionally output from the load sensing oil port P0 from the inlet p3 of the compensation valve to the sensing outlet c of the compensation valve, the pressure of the load sensing oil port P0 is transmitted to the oil source P, the outlet pressure of the oil source P is adjusted to maintain a fixed pressure difference with the pressure of the load sensing oil port P0, in this way, the pressure difference between the inlet oil port p1 and the outlet oil port p2 of the reversing valve corresponding to the valve group which communicates with the oil inlet line is kept constant, the flow from the inlet oil port p1 to the outlet oil port p2 of the reversing valve is only related to the opening area of the inlet oil port p1 and the outlet oil port p2 of the reversing valve, that is, the movement speed of the actuator is only related to the opening area of the inlet oil port p1 and the outlet oil port p2 of the reversing valve, and is not related to the load pressure; The valve group of the present application is provided with a check valve on the oil inlet line; or, the check valve is integrated in the logic valve, which can play a role in load holding, and can prevent the backflow of oil when the pressure of the working oil port is higher than the pressure of the oil source; The hydraulic system of the present application can switch the working mode of the valve group under micro-control working condition and full-speed working condition. Under micro-control working condition, the opening area of the oil inlet oil way is controlled by the compensation valve: the opening area is larger under single-action working condition, reducing the oil inlet pressure loss; under compound-action working condition, the opening area of the oil inlet of the low-load valve group is adjusted to control the priority relationship of the flow distribution of different actuators. Under full-speed working condition, the opening area of the oil inlet oil way is controlled by the logic valve: the opening area is larger under single-action working condition, reducing the oil inlet pressure loss; under compound-action working condition, the opening area is smaller, realizing reasonable flow distribution. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 the hydraulic principle diagram of the valve group of the present application; Figure 2 the hydraulic principle diagram of the hydraulic system of the present application; In the figure: 1-oil inlet oil way; 2-reversing valve; 3-compensation valve; 4-switching valve; 5-logic valve; 6-first check valve; 7-second check valve. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not intended to limit the present application and its application or use in any way. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0019] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise, and furthermore, it should be understood that when the terms "comprise" and / or "include" are used in the specification, there is a feature, step, operation, device, component and / or combination thereof.

[0020] The foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and practice described. Accordingly, all such variations are intended to be included within the scope of the present application as defined in the following claims, along with full equivalents thereof.

[0021] In the description of the present application, it is to be understood that the orientation or positional relationships indicated by terms such as "front", "back", "up", "down", "left", "right", "lateral", "vertical", "horizontal", "top", "bottom", and the like are generally based on the orientation or positional relationships shown in the drawings, and are merely intended to facilitate the description and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be construed as limiting the scope of protection of the present application. The orientation terms "inner", "outer" refer to the inner and outer relative to the contour of the components themselves.

[0022] For the convenience of description, spatial relative terms such as "over", "above", "upper surface", "upper", and the like can be used herein to describe the spatial positional relationship of one device or feature with respect to other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device as described in the drawings. For example, if the device in the drawings is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0023] In addition, it should be noted that the use of the terms "first", "second", and the like do not have a special meaning, and are used only to facilitate the distinction between corresponding parts, and therefore cannot be construed as limiting the scope of protection of the present application.

[0024] As Figure 1As shown, the embodiment proposes a valve group for an actuator, which comprises an oil inlet oil path 1, a reversing valve 2, a compensation valve 3 and a switching valve 4. The oil inlet oil path 1 is used to introduce pressure oil to a pressure oil port p of the reversing valve 2. The reversing valve 2 is located on the oil inlet oil path 1 and controls the on-off and flow of the oil inlet oil path 1. The reversing valve 2 also controls the oil inlet and outlet of the actuator. The compensation valve 3 is located on the oil inlet oil path 1 and downstream of the reversing valve 2. The compensation valve 3 controls the opening area of the oil inlet oil path 1 under the action of pressure at both ends. The switching valve 4 controls the force on the end of the compensation valve 3 to switch the working mode of the valve group.

[0025] The first end of the oil inlet oil path 1 is connected to an oil source P. The second end of the oil inlet oil path 1 is in communication with the pressure oil port p of the reversing valve 2, which is used to deliver pressure oil to the reversing valve 2 and then to the corresponding actuator under the control of the reversing valve 2.

[0026] The reversing valve 2 is located on the oil inlet oil path 1. On the one hand, the reversing valve 2 controls the on-off of the oil inlet oil path 1. On the other hand, the reversing valve 2 controls the oil inlet and outlet of the corresponding actuator. The reversing valve 2 has an oil inlet port p1, an oil outlet port p2, a pressure oil port p, a return oil port t, a working oil port a and a working oil port b. The oil inlet port p1 and the oil outlet port p2 are in communication with the oil inlet oil path 1. The pressure oil port p is in communication with the second end of the oil inlet oil path 1. The return oil port t is in communication with an oil tank T. The working oil port a and the working oil port b are in communication with the working oil port A and the working oil port B of the actuator, respectively. In the initial state, the reversing valve 2 is in the neutral position, and each oil port is not in communication. Therefore, the oil inlet oil path 1 is in the off state, and the actuator does not work. When the reversing valve 2 is switched to the first working position, the oil inlet port p1 is in communication with the oil outlet port p2, the pressure oil port p is in communication with the working oil port a, and the working oil port b is in communication with the return oil port t. Therefore, the oil inlet oil path 1 is in the on state, the working oil port A of the actuator is in oil inlet, and the working oil port B is in oil return. When the reversing valve 2 is switched to the second working position, the oil inlet port p1 is in communication with the oil outlet port p2, the pressure oil port p is in communication with the working oil port b, and the working oil port a is in communication with the return oil port t. Therefore, the oil inlet oil path 1 is in the on state, the working oil port B of the actuator is in oil inlet, and the working oil port A is in oil return.

[0027] As a preferred technical solution of the embodiment, the reversing valve 2 is switched under the action of pilot pressure at both ends. Specifically, the two ends of the reversing valve 2 are in communication with oil port XA and oil port XB, respectively. The oil port XA and the oil port XB introduce pilot pressure, respectively. The opening area of the oil inlet port p1 to the oil outlet port p2 of the reversing valve 2 is adjusted by the pilot pressure introduced by the oil port XA and the oil port XB, so as to control the flow of the oil inlet port p1 to the oil outlet port p2 of the reversing valve, that is, to control the movement speed of the corresponding actuator. When neither the oil port XA nor the oil port XB introduces pilot pressure, the reversing valve 2 is in the neutral position. When the oil port XA introduces pilot pressure, the reversing valve 2 is switched to the first working position. When the oil port XB introduces pilot pressure, the reversing valve 2 is switched to the second working position.

[0028] The compensation valve 3 is arranged on the oil inlet oil way 1, and the compensation valve 3 is communicated with the reversing valve 2. Specifically, the compensation valve 3 has an inlet p3 and an outlet p4, both of which are communicated with the oil inlet oil way 1, and the compensation valve 3 slides to control the opening area of the oil inlet oil way 1 under the pressure of both ends.

[0029] As a preferred technical solution of the embodiment, one end of the compensation valve 3 introduces the pressure of the inlet p3, and the other end forms a control cavity, and the compensation valve 3 slides under the pressure of the inlet p3 and the control cavity. The pressure of the inlet p3 of the compensation valve 3 drives the compensation valve to change position towards a large opening area.

[0030] As a preferred technical solution of the embodiment, the compensation valve 3 has a sensing outlet c, which is communicated with the load-sensitive oil port P0. The compensation valve 3 has a disconnection position, an intermediate position and a communication position arranged in sequence. When the compensation valve 3 is in the disconnection position, the inlet p3, the outlet p4 and the sensing outlet c are not communicated; when the compensation valve 3 is in the intermediate position, the inlet p3 and the outlet p4 are communicated in a small area, and the inlet p3 and the sensing outlet c are not communicated; when the compensation valve 3 is in the communication position, the inlet p3 and the outlet p4 are communicated in a large area, and the inlet p3 and the sensing outlet c are communicated. The pressure of the inlet p3 drives the compensation valve 3 to change position towards the communication position.

[0031] As a preferred technical solution of the embodiment, a second one-way valve 7 is arranged on the oil way communicated with the load-sensitive oil port P0 and the sensing outlet c, which can control the one-way flow of the oil in the sensing outlet c to the load-sensitive oil port P0, and prevent the oil from flowing from P0 to the sensing outlet c and then to the inlet p3, thereby interfering with the flow distribution.

[0032] The switching valve 4 controls the pressure of the control cavity of the compensation valve 3. Specifically, the switching valve 4 controls the control cavity of the compensation valve 3 to be communicated with the load-sensitive oil port P0 or the oil drain port Dr. When the switching valve 4 controls the control cavity of the compensation valve 3 to be communicated with the load-sensitive oil port P0, the valve group is in a fixed flow ratio control mode, and the compensation valve 3 controls the flow distribution relationship; when the switching valve 4 controls the control cavity of the compensation valve 3 to be communicated with the oil drain port Dr, the valve group is in a fixed opening area control mode, and the compensation valve 3 is invalid, and a logic valve 5 is required to control the flow distribution relationship.

[0033] Specifically, the switching valve 4 can be provided as a two-position three-way valve, the switching valve 4 has an oil port d, an oil port e and an oil port f, the oil port d is communicated with the control chamber of the compensation valve 3, the oil port e is communicated with the load sensing oil port P0, and the oil port f is communicated with the drain port Dr. In the initial state, the switching valve 4 controls the oil port d and the oil port e to be communicated, that is, the control chamber of the compensation valve 3 is communicated with the load sensing oil port P0, and the control chamber of the compensation valve 3 introduces the oil pressure of the load sensing oil port P0; after the switching valve 4 is reversed, the control oil port d and the oil port f are communicated, that is, the control chamber of the compensation valve 3 is communicated with the drain port Dr, and the control chamber of the compensation valve 3 is in a low pressure state.

[0034] As a preferred technical solution of the embodiment, the switching valve 4 is reversed under the control of the first pilot pressure, one end of the switching valve 4 is provided with a resilient member, the end pilot chamber is communicated with the drain port Dr and is in a low pressure state, and the other end of the switching valve 4 is communicated with the oil port X0. In the initial state, the oil port X0 does not introduce the first pilot pressure, and the switching valve 4 is in the initial position under the action of the resilient member; when the oil port X0 introduces the first pilot pressure, the switching valve 4 is reversed by overcoming the action of the resilient member.

[0035] The logic valve 5 is further provided on the oil inlet oil path 1, when the switching valve 4 controls the control chamber of the compensation valve 3 to be communicated with the drain port Dr, the compensation valve 3 is disabled, and the logic valve 5 is required to control the flow distribution relationship. The logic valve 5 is located downstream of the compensation valve 3, the logic valve 5 has an oil port p5 and an oil port p6, and the oil port p5 and the oil port p6 are both communicated with the oil inlet oil path 1. In the initial state, the oil port p5 and the oil port p6 of the logic valve 5 are in a large-area communication state; after the logic valve 5 is reversed, the oil port p5 and the oil port p6 of the logic valve 5 are in a small-area communication state.

[0036] As a preferred technical solution of the embodiment, the working position of the logic valve 5 is controlled by the second pilot pressure. One end of the logic valve 5 is provided with a resilient member, the pilot chamber is further communicated with the drain port Dr and is in a low pressure state, and the other end of the logic valve 5 is communicated with the oil port Pn. In the initial state, the oil port Pn does not introduce the second pilot pressure, and the logic valve 5 is in the initial position under the action of the resilient member; when the oil port Pn introduces the second pilot pressure, the logic valve 5 is reversed by overcoming the action of the resilient member.

[0037] As a preferred technical solution of the embodiment, in order to control the oil flow direction and prevent the oil from flowing in the reverse direction, the first one-way valve 6 is provided on the oil inlet oil path 1. The first one-way valve 6 is located between the oil port p4 of the compensation valve 3 and the oil port p5 of the logic valve 5. In addition, the first one-way valve 6 can be integrated in the logic valve 5.

[0038] As a preferred technical solution of the embodiment, the valve group can be integrated, and the valve group can include a valve body, and the corresponding reversing valve 2, compensation valve 3, switching valve 4 and logic valve 5 are integrated in the valve body.

[0039] Based on the above technical solution, the valve group in this embodiment controls whether the compensation valve 3 works through the switching valve 4: In micro-control mode, the switching valve 4 controls the load-sensitive oil port P0 to connect with the control chamber of the compensation valve 3, and the compensation valve 3 plays the role of controlling the opening area of ​​the oil inlet circuit 1. At this time, the valve group is in working mode one, that is, fixed flow ratio control mode; In full-speed mode, the switching valve 4 controls the control chamber of the compensation valve 3 to connect with the drain port Dr, so that the compensation valve 3 is disabled and no longer controls the priority relationship of flow distribution of different actuators, but always maintains a larger opening area, thereby reducing the inlet pressure loss. At this time, the valve group switches to working mode two, that is, fixed opening area control mode. In this mode, the flow distribution relationship is controlled by the logic valve 5.

[0040] like Figure 2 As shown, this embodiment also provides a hydraulic system, including an oil source P, a valve group, and an actuator. There is at least one valve group, and the actuator is correspondingly configured with respect to the valve group. The oil inlet passage 1 of the valve group is connected to the oil source P, and the valve group controls the oil flow to and from the corresponding actuator. The oil source P can be divided into oil source P1 and oil source P2.

[0041] This hydraulic system is used to control the excavator's movements. The excavator includes multiple actuators such as right travel, left travel, swing, boom 1, boom 2, bucket, spare bucket, stick, stick (regenerator), and bulldozing. Except for right travel and left travel, each actuator is equipped with corresponding features such as... Figure 1 The valve assembly shown, Figure 2 The symbols for the compensation valve 3, switching valve 4, logic valve 5, etc., are simplified to a speed control valve, which is controlled by the first pilot pressure introduced by oil port X0 and the second pilot pressure introduced by oil port Pn.

[0042] Based on the above technical solution, in the hydraulic system of this embodiment, when the first pilot pressure is not introduced at oil port X0, the switching valve 4 is in the initial position, oil port d and oil port e of the switching valve 4 are connected, and the control chamber of the compensation valve 3 is connected to the load-sensitive oil port P0. At this time, the following situations exist: When only one actuator is in motion, the pressure at the inlet p3 of the compensation valve 3 pushes the compensation valve 3 to switch to the connected position. The inlet p3 of the compensation valve 3 is connected to the outlet p4 and the sensing outlet c. The pressure at the inlet p3 is output as the pressure at the oil port P0 through the sensing outlet c. The opening area connecting the inlet p3 and the outlet p4 is the largest, and the pressure loss is the smallest. When multiple actuators operate, and the pressure at the inlet p3 of the compensation valve 3 of the valve group corresponding to the actuator is the highest among all valve groups, then it is the same as case (1); When the pressure of the inlet p3 of the compensation valve 3 corresponding to the actuator of the valve group is not the highest among all valve groups, the pressure of the instant load sensing oil port P0 is higher than the pressure of the oil port p3 of the compensation valve 3, the pressure of the oil port p3 drives the compensation valve 3 to switch to the off position, the inlet p3, the outlet p4 and the sensing outlet c of the compensation valve 3 are not connected, the oil flows from the inlet oil port p1 to the outlet oil port p2 of the switching valve 2, so that the pressure of the inlet p3 of the compensation valve 3 rises until the pressure of the inlet p3 of the compensation valve 3 reaches the same as the pressure of the load sensing oil port P0, the compensation valve 3 switches to the intermediate position, the inlet p3 and the outlet p4 are connected, so that the pressure of the inlet p3 of the compensation valve 3 no longer rises, and the compensation valve 3 remains in the intermediate position to reach the equilibrium state, at this time, the opening area of the connection between the inlet p3 and the outlet p4 of the compensation valve 3 is small, and the pressure loss is large. Since the pressure difference between the inlet oil port p1 and the outlet oil port p2 of the switching valve 1 of each valve group is the pressure difference between the oil source P and the load sensing oil port P0, the flow distribution relationship of each valve group is determined by the opening area of the connection between the inlet oil port p1 and the outlet oil port p2 of the switching valve 1, that is, when the oil port X0 is not introduced into the first pilot pressure, the relatively accurate flow distribution control can be realized.

[0043] When the oil port X0 is introduced into the first pilot pressure, the switching valve 4 switches, the oil port d and the oil port f of the switching valve 4 are connected, the pressure acting on the control chamber of the compensation valve 3 is the pressure of the drain port Dr, which is basically 0, so that no matter how many actuators are in action at the same time, no matter whether the pressure of the inlet p3 of the compensation valve 3 of the valve group is the highest among all valve groups, the compensation valve 3 will switch to the connected position to ensure that the opening area of the connection between the inlet p3 and the outlet p4 is the largest and the pressure loss is the smallest. That is, when the oil port X0 is introduced into the first pilot pressure, the compensation valve 3 no longer functions, achieving the effect of switching the working mode and reducing the pressure loss.

[0044] As for the logic valve 5, its position is controlled by the second pilot pressure introduced by the oil port Pn. When only the actuator of the valve group is in action, the oil port Pn is not introduced into the second pilot pressure, the opening area of the connection between the oil port p5 and the oil port p6 of the logic valve 5 is large, and the pressure loss is small; when multiple actuators are in composite action, if the load of the actuator corresponding to the valve group is low, it may lead to a large flow allocated to the actuator, or even all the flow is allocated to the actuator, resulting in uncoordinated composite action, at this time, the second pilot pressure is introduced into the oil port Pn to switch the logic valve 5, the opening area of the connection between the oil port p5 and the oil port p6 is small, so that the flow allocated to the actuator corresponding to the valve group is reduced, improving the coordination of the composite action. The first check valve 6 plays a role in load holding, and can prevent the backflow of oil when the working oil port pressure is higher than the pump pressure.

[0045] The embodiments of the present application are described in detail above with reference to the accompanying drawings, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application.

Claims

1. A valve group, intended for an actuator, characterized in that It comprises: An oil inlet oil path (1) for introducing pressure oil to a pressure oil port p of a reversing valve (2); The reversing valve (2) controls the oil inlet and outlet of an actuator, and is located on the oil inlet oil path (1) to control the opening and closing and flow of the oil inlet oil path (1); The compensation valve (3) is located on the oil inlet oil path (1) and downstream of the reversing valve (2), one end of the compensation valve (3) introduces pressure to the inlet p3, and the other end forms a control chamber, and the compensation valve (3) slides under the pressure of both ends to control the opening area of the oil inlet oil path (1); The switching valve (4) controls the control chamber to communicate with the load sensing oil port P0 or the drain port Dr.

2. A valve group according to claim 1, characterised in that In the initial state, the switching valve (4) controls the control chamber to communicate with the load sensing oil port P0; after reversing under the action of the first pilot pressure, the switching valve (4) controls the control chamber to communicate with the drain port Dr.

3. A valve group according to claim 1, characterised in that The inlet p3 and the outlet p4 of the compensation valve (3) are both communicated with the oil inlet oil path (1), and the compensation valve (3) further has a sensing outlet c, which is one-way communicated with the load sensing oil port P0.

4. A valve group according to claim 3, characterised in that The compensation valve (3) has a disconnection position, an intermediate position and a communication position set in sequence, when the compensation valve (3) is in the disconnection position, the oil ports of the compensation valve (3) are not communicated; when the compensation valve (3) is in the intermediate position, the inlet p3 and the outlet p4 of the compensation valve (3) are small-area communicated; when the compensation valve (3) is in the communication position, the inlet p3 and the outlet p4 are large-area communicated, the inlet p3 is communicated with the sensing outlet c, and the inlet p3 pressure drives the compensation valve (3) to shift towards the communication position.

5. A valve group according to claim 1, characterised in that It further comprises a logic valve (5), which is located on the oil inlet oil path (1) and downstream of the compensation valve (3), and controls the opening area of the oil inlet oil path (1).

6. A valve group according to claim 5, characterised in that Under the action of the second pilot pressure, the logic valve (5) switches from large-area communication to small-area communication.

7. A valve group according to claim 5, wherein A one-way valve is provided on the oil inlet oil path (1); or a one-way valve is integrated in the logic valve (5).

8. A valve group according to claim 5, wherein It further comprises a valve body, and the reversing valve (2), the compensation valve (3), the switching valve (4) and the logic valve (5) are integrally arranged in the valve body.

9. A hydraulic system characterized by, It comprises: An oil source P for providing pressure oil; The valve group of any one of claims 1-8, at least one oil inlet oil path (1) is communicated with the oil source P; An actuator is arranged corresponding to the valve group, and the valve group controls the oil inlet and outlet of the actuator.

10. A hydraulic system according to claim 9, wherein, The reversing valve (2) further comprises two working oil ports and a return oil port t, the two working oil ports are communicated with the actuator, when the reversing valve (2) is in the neutral position, the reversing valve (2) controls the oil inlet oil path (1) to be disconnected, and each oil port is not communicated; when the reversing valve (2) is in the working position, the reversing valve (2) controls the oil inlet oil path (1) to be connected, one working oil port is for oil inlet, and the other working oil port is for oil return.

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