Control valve group, hydraulic pump displacement adjusting mechanism, hydraulic system and walking machine

Abstract

The utility model relates to the technical field of work fixtures, and particularly discloses a control valve bank, a hydraulic pump displacement adjusting mechanism, a hydraulic system and a walking machine, the control valve bank comprises a control valve and a shell, the shell is provided with a throttling path, the control valve is located in the shell, the throttling path is connected to the input side of the control valve, and the shell is provided with a hydraulic pump displacement adjusting mechanism. The throttling path comprises a fixed throttling path and an adjustable flow path, the adjustable flow path is connected with the fixed throttling path in parallel, the shell is connected with an adjusting part, at least part of the adjusting part is located in the adjustable flow path, and the adjusting part can change the flow of the pressure medium in the adjustable flow path. An adjustable flow path is arranged to be connected with a fixed throttling path in parallel, pressure media flow through the fixed throttling path and the adjustable flow path to be throttled and then converge, and in the process, the flow of the pressure media in the adjustable flow path is changed through an adjusting piece, so that the throttling capacity of the adjustable flow path is changed; the throttling capacity of the control valve group can be changed within a certain range through the adjustable flow path, and parts do not need to be replaced after shutdown.

Description

Technical Field

[0001] The utility model relates to the technical field of traveling machinery, in particular to a control valve group, a hydraulic pump displacement regulating mechanism and a traveling machinery. Background Art

[0002] In the field of walking machinery, such as loaders, the displacement change of the hydraulic pump of its hydraulic system is controlled by the change of engine speed. A control loop is set up, and the oil replenishment pump of the control loop is connected to the engine in a coaxial manner with the hydraulic pump of the hydraulic system. The oil replenishment pump changes its displacement according to the change of engine speed, thereby controlling the displacement change of the hydraulic pump and changing the walking speed of the walking machinery. The oil replenishment pump is connected to a control valve group, and a throttle orifice plate is arranged on the control valve group. A pressure difference is formed before and after the throttle orifice plate. The flow of the oil replenishment pump is controlled by the engine speed to change the pressure difference before and after the throttle orifice plate. When the speed is low, the flow of the oil replenishment pump is small, the pressure difference before and after the throttle orifice plate is small, the control pressure is small, the displacement of the hydraulic pump is small, and the vehicle speed is slow; when the speed is high, the flow of the oil replenishment pump is large, the pressure difference before and after the throttle orifice plate is large, the control pressure becomes large, and the pump displacement is large, and the vehicle speed increases. In this way, each engine speed can correspond to the displacement of a hydraulic pump.

[0003] The throttling capacity of the throttling orifice of the control valve group in the prior art cannot be adjusted. When the throttling capacity needs to be changed, it can only be achieved by replacing the throttling orifice with a different specification, which requires shutdown and the operation process is cumbersome. Utility Model Content

[0004] The utility model aims to provide a control valve group, a hydraulic pump displacement adjustment mechanism, a hydraulic system and a walking machine, so as to solve the problem that the throttling capacity cannot be adjusted in the prior art.

[0005] The utility model provides a control valve group, including a control valve, and also includes:

[0006] A housing, wherein a throttling path is provided on the housing, the control valve is located inside the housing, and the throttling path is connected to an input side of the control valve;

[0007] The throttling path includes a fixed throttling path and an adjustable path. The adjustable path is connected in parallel with the fixed throttling path. The pressure medium flows in the fixed throttling path and the adjustable path. The fixed throttling path is used to throttle the pressure medium. The shell is also connected to an adjusting member. At least part of the adjusting member is located in the adjustable path and the adjusting member can change the flow rate of the pressure medium in the adjustable path.

[0008] As a preferred technical solution for the control valve group, a throttling orifice plate is connected to the fixed throttling circuit, and the throttling orifice plate is used to throttle the pressure medium. The adjustable flow path includes a first branch and a second branch that are interconnected, and the first branch and the second branch are arranged at an angle, and the first branch and the second branch are respectively connected upstream and downstream of the throttling orifice plate.

[0009] As a preferred technical solution for the control valve group, the shell is also provided with a threaded hole communicating with the adjustable flow path, and the adjusting member is threadedly connected to the threaded hole.

[0010] As a preferred technical solution for the control valve group, the threaded hole is coaxial with one of the first branch and the second branch, the adjusting member is threadedly connected to the threaded hole, at least part of the adjusting member is located at the junction of the first branch and the second branch, and at least part of the adjusting member can cooperate with one of the first branch and the second branch that is coaxial with the threaded hole.

[0011] As a preferred technical solution for the control valve group, a filter is also installed on the shell, and the outlet of the filter is connected to the fixed throttling path.

[0012] The utility model provides a hydraulic pump displacement regulating mechanism, comprising an oil replenishing pump, a reversing valve, a servo variable mechanism and a control valve group of any of the above schemes, the control valve comprising a valve body, a valve core and a spring, the valve body of the control valve is provided with an input side and an output side, the input side comprises an oil inlet end, a high pressure control end and a low pressure control end, the output side comprises an oil outlet end, the spring is located between the valve core and the valve body, the valve core can move in the valve body and is used to change the pressure of a pressure medium at the oil outlet end, the high pressure control end is connected to the inlet of a throttling path, the oil replenishing pump is used to supply pressure medium to the throttling path, and the oil inlet end is connected to the outlet of the throttling path; the housing is also provided with an overflow path, the overflow path is communicated with the outlet of the throttling path, the low pressure control end is connected to the overflow path, the overflow path is used to return the pressure medium to the oil tank, the oil outlet end is used to deliver the pressure medium to the servo variable mechanism, the output end of the servo variable mechanism is connected to the hydraulic pump and can change the displacement of the hydraulic pump, the reversing valve is arranged on the flow path between the control valve group and the servo variable mechanism, and the reversing valve is used to change the movement direction of the output end of the servo variable mechanism.

[0013] As a preferred technical solution of the hydraulic pump displacement regulating mechanism, it also includes an oil replenishment overflow valve, which is arranged on the overflow path.

[0014] As a preferred technical solution for the hydraulic pump displacement adjustment mechanism, it also includes a pressure cut-off valve, which is arranged on the flow path between the control valve group and the reversing valve, and is used to disconnect the flow path between the control valve group and the reversing valve.

[0015] The utility model provides a hydraulic system, comprising a hydraulic pump and a hydraulic pump displacement regulating mechanism of the above scheme. The servo variable mechanism is connected with the hydraulic pump and is used for changing the displacement of the hydraulic pump.

[0016] The utility model provides a walking machine, comprising a transmission system and also comprising the hydraulic system of the above-mentioned solution, wherein the hydraulic pump is connected with the transmission system and drives the transmission system to operate.

[0017] The beneficial effects of the utility model are:

[0018] The utility model provides a control valve group, in which an adjustable flow path and a fixed throttling path are arranged in parallel, and pressure medium flows through the fixed throttling path and the adjustable flow path respectively, and then merges after being throttled. In this process, the flow rate of the pressure medium in the adjustable flow path is changed by the adjusting member, thereby changing the throttling capacity of the adjustable flow path, and realizing changing the throttling capacity of the control valve group through the adjustable flow path within a certain range, without replacing parts after shutdown. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of a hydraulic pump displacement adjustment mechanism in an embodiment of the utility model;

[0020] Figure 2 This is a schematic diagram of the control valve group in the embodiment of the utility model;

[0021] Figure 3 It is a structural schematic diagram of the control valve group in the embodiment of the utility model.

[0022] In the figure:

[0023] 1. Hydraulic pump; 2. Servo variable mechanism; 3. Reversing valve; 4. Oil replenishment relief valve; 5. Pressure cut-off valve; 6. Control valve group; 61. Fixed throttling path; 611. Throttle orifice; 62. Adjustable flow path; 621. First branch; 622. Second branch; 63. Adjusting part; 64. Oil replenishment path; 7. Oil replenishment pump. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solution of the utility model in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0027] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0028] Due to the complexity of the use scenarios of walking machinery, mechanical transmission cannot meet the use requirements, so hydraulic drive is often used to drive walking machinery to move or walk. Walking machinery includes but is not limited to construction machinery, agricultural machinery, mining machinery and special vehicles, such as bulldozers, excavators, rollers, pavers, cranes, tractors, forklifts, combine harvesters and mining trucks. By changing the displacement of the hydraulic pump in the hydraulic system, the transmission ratio of the hydraulic system can be infinitely changed. The displacement of the hydraulic pump 1 is controlled by the hydraulic pump displacement adjustment mechanism.

[0029] like Figure 1-Figure 3As shown, the utility model provides a hydraulic pump displacement adjustment mechanism, which is applied to the hydraulic system of a walking machine and is used to change the displacement of a hydraulic pump 1 of the hydraulic system of the walking machine. The hydraulic pump displacement adjustment mechanism includes an oil replenishment pump 7, a reversing valve 3, a servo variable mechanism 2 and a control valve group 6. The control valve group includes a control valve and a housing, and a throttling path and an overflow path are provided on the housing. The overflow path is connected to the outlet of the throttling path, and the overflow path is used to return the pressure medium to the oil tank. The control valve is located inside the housing, and the throttling path is connected to the input side of the control valve. As a structure in the prior art, the control valve includes a valve body, a valve core and a spring. The valve body is provided with an input side and an output side. The input side includes an oil inlet end, a low-pressure control end and a high-pressure control end. The output side includes an oil outlet end. The spring is located between the valve core and the valve body. The valve core can move in the valve body and is used to change the pressure of the pressure medium at the oil outlet end. The high-pressure control end is connected to the inlet of the throttling path, and the oil replenishment pump 7 is used to supply the pressure medium to the throttling path. The oil inlet is connected to the outlet of the oil-throttling circuit, and the pressure medium enters the valve body from the oil inlet after throttling. The low-pressure control end is connected to the overflow circuit, that is, the pressure at the low-pressure control end is the pressure at the outlet of the throttling circuit. Since there is a pressure difference between the inlet and outlet of the throttling circuit, the valve core moves under the action of the pressure difference and compresses the spring, and changes the pressure of the pressure medium at the oil outlet. The oil outlet is connected to the servo variable mechanism 2. The output end of the servo variable mechanism 2 is connected to the hydraulic pump 1 and can change the displacement of the hydraulic pump 1. The reversing valve 3 is arranged on the flow path between the control valve group 6 and the servo variable mechanism 2. The reversing valve 3 is used to change the movement direction of the output end of the servo variable mechanism 2. The servo variable mechanism 2 can be set as a two-way cylinder, and a piston is arranged inside the cylinder body. Springs are arranged at both ends of the piston. When the pressure of the hydraulic pump displacement adjustment mechanism is a specific value, the position of the piston inside the cylinder body is determined, thereby determining the displacement of the hydraulic pump 1. The reversing valve 3 is arranged on the flow path between the control valve group 6 and the servo variable mechanism 2. The reversing valve 3 is used to change the movement direction of the output end of the servo variable mechanism 2. The reversing valve 3 can be set as a three-position four-way solenoid valve. The throttling path on the housing includes a fixed throttling path 61 and an adjustable path 62. The fixed throttling path 61 and the adjustable path 62 are arranged in parallel. Both ends of the adjustable path 62 are connected to the fixed throttling path 61. The pressure medium flows in the fixed throttling path 61 and the adjustable path 62. The pressure medium can be hydraulic oil, but is not limited to this. The fixed throttling path 61 can throttle the pressure medium. For example, the fixed throttling path 61 is set as a necking structure, or a venturi nozzle or a throttling orifice plate is connected inside. In this embodiment, the fixed throttling path 61 is preferably connected with a throttling orifice plate 611. The throttling orifice plate 611 is connected to the fixed throttling path 61 by a threaded connection, thereby improving the disassembly convenience of the throttling orifice plate 611 and facilitating replacement. The throttling orifice plate 611 is provided with a throttling hole for throttling the pressure medium. The two ends of the adjustable flow path 62 are respectively connected to the upstream and downstream of the throttling orifice plate 611.The valve body is also connected to an adjusting member 63, at least part of which is located in the adjustable flow path 62 and the adjusting member 63 can change the flow rate of the pressure medium in the adjustable flow path 62, thereby changing the throttling effect of the adjustable flow path 62 on the pressure medium. The pressure medium pumped by the oil replenishment pump 7 is divided at the position where the fixed throttling path 61 and the adjustable flow path 62 are connected, that is, at the inlet, and merges at the outlets of the two after passing through the fixed throttling path 61 and the adjustable flow path 62 respectively. The merged pressure medium enters the valve body from the oil inlet end. Due to the throttling effect of the fixed throttling path 61 and the adjustable flow path 62 on the pressure medium, the pressure at the high-pressure control end is greater than the pressure at the low-pressure control end, thereby pushing the valve core to move in the valve body and compressing the spring until the valve core is balanced. In this process, the area of ​​the oil outlet end changes due to the movement of the valve core, that is, under this working condition, a certain pressure at the oil outlet end corresponds. Therefore, under the premise that the displacement of the replenishing pump 7 remains unchanged and the position of the adjusting member 63 of the control valve group 6 remains unchanged, a certain displacement of the hydraulic pump 1 can be corresponded. Among them, the structure of the valve core, the connection mode of the valve core and the spring, the distribution position of the oil inlet end, the high pressure control end, the low pressure control end and the oil outlet end on the valve body, and the relative position relationship between each and the valve core are all existing technologies in the field, and are not repeated here. In this embodiment, the housing of the control valve group and the valve body of the control valve can be set as an integrated structure to improve the compactness. Under the premise that the displacement of the replenishing pump 7 remains unchanged, the flow rate of the pressure medium in the adjustable flow path 62 is changed by the adjusting member 63, and the pressure difference between the diversion position and the confluence position of the fixed throttling path 61 and the adjustable flow path 62 changes, so that the pressure of the pressure medium entering the servo variable mechanism 2 changes, and then the displacement of the hydraulic pump 1 is changed. Therefore, within a certain range, the throttling capacity of the control valve group 6 can be changed through the adjustable flow path 62, and finally the displacement of the hydraulic pump 1 is changed, without stopping the machine to replace the throttling orifice plate 611.

[0030] Specifically, Figure 3As shown, the adjustable flow path 62 includes a first branch 621 and a second branch 622 that are interconnected, the first branch 621 and the second branch 622 are arranged at an angle, and the first branch 621 and the second branch 622 are respectively connected to the upstream and downstream of the throttling orifice 611. The first branch 621 and the second branch 622 are arranged at an angle and are connected to each other, without the need to additionally set a connecting branch or connecting hole, which is more convenient for processing. The valve body is also provided with a threaded hole that is connected to the adjustable flow path 62, and the adjusting member 63 is threadedly connected to the threaded hole, so that when the adjusting member 63 rotates in the threaded hole, the part of the adjusting member 63 located in the adjustable flow path 62 can change the flow cross-section of the adjustable flow path 62 to change the flow rate of the pressure medium. Further, for the convenience of adjustment, a threaded hole is provided to be coaxial with one of the first branch 621 and the second branch 622, at least a portion of the adjusting member 63 is located at the junction of the first branch 621 and the second branch 622, and at least a portion of the adjusting member 63 can cooperate with one of the first branch 621 and the second branch 622 that is coaxial with the threaded hole. In this way, the amount of screwing in or out of the adjusting member 63 is positively correlated with the amount of reduction or increase in the flow cross section of the adjustable flow path 62, which is more convenient for adjustment. In this embodiment, the first branch 621 is connected to the upstream of the throttling orifice plate 611, the second branch 622 is connected to the downstream of the second orifice plate, the threaded hole is coaxial with the second branch 622, the adjusting member 63 is provided as an adjusting bolt, the lower end of the adjusting bolt cooperates with the second branch 622, and the flow cross section at the connection position of the first branch 621 and the second branch 622 is reduced or increased by screwing in or out the adjusting bolt, thereby changing the flow of the pressure medium passing through the adjustable flow path 62.

[0031] Optionally, the valve body may be integrated on the housing of the oil replenishment pump 7, and a filter (not shown in the figure) is also installed on the valve body, and the outlet of the filter is connected to the fixed throttle path 61. The pressure medium enters the filter from the oil replenishment path 64 provided in the housing of the oil replenishment pump 7, and enters the fixed throttle path 61 and the adjustable flow path 62 after being filtered and impurities are removed by the filter, so as to prevent the fixed throttle path 61 and / or the adjustable flow path 62 from being blocked by impurities.

[0032] The pressure medium is divided at the diversion position of the fixed throttle path 61 and the adjustable flow path 62, and flows along the path S1 and the path S2 in the fixed throttle path 61 and the adjustable flow path 62 respectively, and merges at the confluence position of the fixed throttle path 61 and the adjustable flow path 62, wherein the path S1 and the path S2 are as shown in FIG. Figure 2 and Figure 3 As shown in . Assume that the flow rate of the pressure medium after confluence is Q, the flow rate in the fixed throttling path 61 is Q1, and the flow rate in the adjustable flow path 62 is Q2, then Q=Q1+Q2. According to the small hole flow formula Available Where C is the flow coefficient, A1 is the area of ​​the throttle hole, and Δp is the pressure difference. Where C is the flow coefficient, A2 is the flow cross-sectional area of ​​the adjustable flow path 62, and Δp is the pressure difference. The flow coefficient C is determined by the pressure medium and can be regarded as a constant. The area A1 of the throttle hole remains unchanged, and the pressure difference Δp of the fixed throttle path 61 and the adjustable flow path 62 is equal. When the displacement of the charge pump 7 remains unchanged, Q remains constant. Therefore That is, when the flow cross section of the adjustable flow path 62 is changed by the adjusting member 63, for example, the flow cross section of the adjustable flow path 62 is reduced, the flow after the confluence remains constant, so the pressure difference increases, the pressure of the pressure medium at the oil outlet end of the control valve group 6 increases, the stroke of the output end of the servo variable mechanism 2 increases, and the displacement of the hydraulic pump 1 increases. By connecting the adjustable flow path 62 in parallel to the fixed throttling path 61 of the control valve group 6, the displacement of the hydraulic pump 1 can be changed under the premise that the displacement of the supplementary oil pump 7 remains unchanged, thereby changing the speed of the walking machine. The displacement of the supplementary oil pump 7 is controlled by the speed of the engine. Therefore, by setting the control valve group 6, a wider speed regulation range can be obtained to a certain extent, and there is no need to stop the machine to replace the throttling orifice plate 611, thereby shortening the debugging cycle of the walking machine.

[0033] Furthermore, if Figure 1 As shown, the hydraulic pump displacement regulating mechanism also includes an oil replenishing overflow valve 4 and a pressure cut-off valve 5. The oil replenishing overflow valve 4 is arranged on the overflow path. The extra pressure medium in the hydraulic pump displacement regulating mechanism is returned to the oil tank through the oil replenishing overflow valve 4. The pressure cut-off valve 5 is arranged on the flow path between the control valve group 6 and the reversing valve 3. The pressure cut-off valve 5 is used to disconnect the flow path between the control valve group 6 and the reversing valve 3. By setting the pressure cut-off valve 5, when the hydraulic pump displacement regulating mechanism fails, the flow path can be cut off in time to avoid more serious consequences. The oil replenishing overflow valve 4 and the pressure cut-off valve 5 can both adopt the structures in the prior art, so their structures are not described in detail here.

[0034] The utility model also provides a hydraulic system, including a hydraulic pump 1, a hydraulic pump displacement adjustment mechanism in this embodiment, a servo variable mechanism 2 of the hydraulic pump displacement adjustment mechanism connected to the hydraulic pump 1, and the servo variable mechanism 2 is used to change the displacement of the hydraulic pump 1. By setting the hydraulic pump displacement adjustment mechanism in this embodiment, the corresponding relationship between the engine speed and the displacement of the hydraulic pump 1 can be changed within a certain range without stopping the machine.

[0035] The utility model also provides a walking machine, comprising a transmission system and a hydraulic system in this embodiment, wherein a hydraulic pump 1 of the hydraulic system is connected to the transmission system and drives the transmission system to operate. By setting the hydraulic system in this embodiment, the debugging period of the walking machine is shortened.

[0036] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A control valve group, comprising a control valve, characterized in that: Also includes: A housing, wherein a throttling path is provided on the housing, the control valve is located inside the housing, and the throttling path is connected to an input side of the control valve; The throttling path comprises a fixed throttling path (61) and an adjustable path (62), the adjustable path (62) being connected in parallel with the fixed throttling path (61), the pressure medium flowing in the fixed throttling path (61) and the adjustable path (62), and the fixed throttling path (61) being used to throttle the pressure medium; The housing is also connected to an adjusting member (63), at least a portion of which is located in the adjustable flow path (62), and the adjusting member (63) is capable of changing the flow rate of the pressure medium in the adjustable flow path (62).

2. The control valve assembly according to claim 1, characterized in that: A throttling orifice plate (611) is connected to the fixed throttling path (61), and the throttling orifice plate (611) is used to throttle the pressure medium. The adjustable flow path (62) includes a first branch (621) and a second branch (622) that are interconnected, and the first branch (621) and the second branch (622) are arranged at an angle, and the first branch (621) and the second branch (622) are respectively connected to the upstream and downstream of the throttling orifice plate (611).

3. The control valve assembly according to claim 2, characterized in that: The housing is also provided with a threaded hole communicating with the adjustable flow path (62), and the adjusting member (63) is threadedly connected to the threaded hole.

4. The control valve assembly according to claim 3, characterized in that: The threaded hole is coaxial with one of the first branch (621) and the second branch (622); the adjusting member (63) is threadedly connected to the threaded hole; at least a portion of the adjusting member (63) is located at the junction of the first branch (621) and the second branch (622); and at least a portion of the adjusting member (63) is capable of cooperating with one of the first branch (621) and the second branch (622) that is coaxial with the threaded hole.

5. The control valve assembly according to any one of claims 1 to 4, characterized in that: A filter is also installed on the housing, and an outlet of the filter is communicated with the fixed throttling path (61).

6. Hydraulic pump displacement adjustment mechanism, characterized in that: The invention comprises an oil replenishment pump (7), a reversing valve (3), a servo variable mechanism (2) and a control valve group (6) as claimed in any one of claims 1 to 5, wherein the control valve comprises a valve body, a valve core and a spring, the valve body of the control valve is provided with an input side and an output side, the input side comprises an oil inlet end, a high pressure control end and a low pressure control end, the output side comprises an oil outlet end, the spring is located between the valve core and the valve body, the valve core can move within the valve body and is used to change the pressure of the pressure medium at the oil outlet end, the high pressure control end is connected to the inlet of the throttling path, the oil replenishment pump (7) is used to supply pressure medium to the throttling path, the oil inlet end is connected to the The outlet of the throttling circuit is connected; the housing is also provided with an overflow circuit, the overflow circuit is communicated with the outlet of the throttling circuit, the low-pressure control end is connected with the overflow circuit, the overflow circuit is used to return the pressure medium to the oil tank, the oil outlet end is used to deliver the pressure medium to the servo variable mechanism (2), the output end of the servo variable mechanism (2) is connected to the hydraulic pump (1) and can change the displacement of the hydraulic pump (1), the reversing valve (3) is arranged on the flow path between the control valve group (6) and the servo variable mechanism (2), and the reversing valve (3) is used to change the movement direction of the output end of the servo variable mechanism (2).

7. The hydraulic pump displacement adjustment mechanism according to claim 6, characterized in that: It also includes an oil replenishment overflow valve (4), which is arranged on the overflow path.

8. The hydraulic pump displacement adjustment mechanism according to claim 6, characterized in that: It also includes a pressure cut-off valve (5), which is arranged on the flow path between the control valve group (6) and the reversing valve (3), and is used to disconnect the flow path between the control valve group (6) and the reversing valve (3).

9. A hydraulic system comprising a hydraulic pump (1), characterized in that: It also comprises the hydraulic pump displacement adjustment mechanism according to any one of claims 6 to 8, wherein the servo variable mechanism (2) is connected to the hydraulic pump (1), and the servo variable mechanism (2) is used to change the displacement of the hydraulic pump (1).

10. A walking machine, including a transmission system, characterized in that: It also includes the hydraulic system according to claim 9, wherein the hydraulic pump (1) is connected to the transmission system and drives the transmission system to operate.

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