Overflow valve

Abstract

The utility model belongs to the technical field of hydraulic valves, and discloses an overflow valve. Comprising a valve seat, a valve sleeve assembly, a piston, a valve element and an elastic assembly. The valve seat is provided with an oil inlet hole and an oil return hole; the valve sleeve assembly is arranged in the valve seat and provided with a limiting space in the axial direction of the valve seat. The piston is movably arranged in the limiting space in the axial direction of the valve seat, the piston is movably arranged in the limiting space in the axial direction of the valve sleeve assembly, a first gap is formed between one side of the piston and the inner wall of the limiting space, a first cavity is formed in the other side of the piston, and the first gap is communicated with the first cavity through a flow channel; the valve element is movably arranged in the valve seat in the axial direction of the valve seat so as to open or close a channel between the oil inlet hole and the oil return hole, the end, away from the oil inlet hole, of the valve element extends into the first cavity and is in sliding fit with the inner wall of the first cavity, a through oil passing channel is formed in the valve element in the axial direction of the valve element, and the oil passing channel comprises at least two first damping holes communicating in the axial direction.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic valves, in particular to a relief valve. Background Art

[0002] A relief valve is a hydraulic pressure control valve that primarily functions as a constant-pressure relief valve in hydraulic equipment. Due to this function, relief valves are widely used in various fields, particularly in the hydraulic motors of large excavators. A hydraulic motor is an actuator in a hydraulic system, converting the fluid pressure provided by the hydraulic pump into mechanical energy on the output shaft. As a component of a hydraulic motor, the relief valve primarily ensures smooth operation. When a hydraulic motor is heavily loaded, the relief valve is prone to significant pressure overshoot, resulting in unstable operation. This condition not only compromises the hydraulic motor's smooth operation but also damages it, shortening its service life.

[0003] Therefore, a relief valve is urgently needed to solve the above problems. Utility Model Content

[0004] The purpose of the utility model is to provide a relief valve, so as to make the system respond more smoothly to pressure changes and reduce pressure fluctuations and pressure shocks.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] A relief valve, comprising:

[0007] The valve seat is provided with an oil inlet hole and an oil return hole;

[0008] A valve sleeve assembly is arranged in the valve seat, and the valve sleeve assembly is provided with a limited space along the axial direction of the valve seat;

[0009] a piston movably disposed in the confined space along the axial direction of the valve seat, a first gap being formed between one side of the piston and an inner wall of the confined space, a first chamber being disposed on the other side of the piston, and the first gap and the first chamber being connected via a flow channel;

[0010] A valve core is movably arranged in the valve seat along the axial direction of the valve seat to open or close the passage between the oil inlet hole and the oil return hole. One end of the valve core away from the oil inlet hole extends into the first chamber and slides with the inner wall of the first chamber. The valve core is provided with a through oil passage along its axial direction, and the oil passage includes at least two damping holes connected along the axial direction.

[0011] Preferably, the valve core comprises:

[0012] A valve core body is movably arranged in the valve seat along the axial direction of the valve seat, and a passage is provided in the valve core body along the axial direction thereof;

[0013] At least two damping sleeves are arranged in the channel at intervals along the axial direction of the valve core body, the first damping holes are correspondingly arranged in the damping sleeves, and the channel and the plurality of the first damping holes are sequentially connected to form the oil passage.

[0014] Preferably, there are two damping sleeves, which are respectively located at two ends of the valve core body along its axial direction.

[0015] Preferably, the valve core body and at least two of the damping sleeves are detachably matched.

[0016] Preferably, the valve core body and at least one damping sleeve are an integrated structure.

[0017] Preferably, the valve sleeve assembly includes a piston sleeve and an adjusting sleeve, the adjusting sleeve is arranged on the inner circumference of the valve seat, and the adjusting sleeve includes a first section and a second section, the inner diameter of the first section is larger than the inner diameter of the second section, and the connection position of the first section and the second section forms a limiting step, the piston sleeve is arranged on the inner circumference of the first section, and has a second gap between it and the limiting step, and the second gap and the inner cavity of the piston sleeve and the inner cavity of the second section form the limiting space.

[0018] Preferably, the piston includes a connected top and a skirt, the diameter of the top is larger than the diameter of the skirt, the top is movably arranged in the second gap, the skirt is movably arranged in the second section, the first chamber is located in the skirt, the first section, the second section, the skirt and the top together form a second chamber, the skirt is provided with a second damping hole, and the second damping hole is connected to both the first chamber and the second chamber.

[0019] Preferably, the relief valve further includes a plug, which is arranged at an end of the piston sleeve away from the oil inlet hole, and the plug abuts against the piston sleeve.

[0020] Preferably, the diameter of the valve core at one end close to the oil inlet hole gradually decreases in the direction close to the oil inlet hole and forms a push slope, and the push slope can abut against the edge of the oil inlet hole to form a cone seal.

[0021] Preferably, the overflow valve also includes an elastic component, which includes an elastic member and a fixed seat. The elastic member is sleeved on the outside of the valve core, and one end of the elastic member is in contact with the end of the valve core close to the oil inlet hole; the fixed seat is sleeved on the outer periphery of the valve core and is connected to or in contact with the end of the elastic member away from the oil inlet hole, and the side of the fixed seat facing away from the elastic member is in contact with the valve sleeve assembly and the piston.

[0022] Beneficial effects of the utility model:

[0023] The utility model discloses a relief valve. It includes a valve seat, a valve sleeve assembly, a piston, a valve core and an elastic assembly. The valve seat is provided with an oil inlet hole and an oil return hole; the valve sleeve assembly is provided in the valve seat, and the valve sleeve assembly is provided with a limited space along the axial direction of the valve seat; the piston is provided in the limited space along the axial movement of the valve seat, and the piston is provided in the limited space along the axial movement of the valve sleeve assembly. One side of the piston forms a first gap with the inner wall of the limited space, and the other side of the piston is provided with a first chamber, and the first gap and the first chamber are connected through a flow channel; the valve core is provided in the valve seat along the axial movement of the valve seat to open or close the passage between the oil inlet hole and the oil return hole, and one end of the valve core away from the oil inlet hole extends into the first chamber and slides with the inner wall of the first chamber. The valve core is provided with a through oil passage along its axial direction, and the oil passage includes at least two first damping holes connected along the axial direction.

[0024] The hydraulic oil pushes the valve core to the left through the oil inlet hole to open the valve core. Part of the hydraulic oil can flow out from the oil return hole, and the other part of the hydraulic oil can pass through at least two first damping holes in sequence to reach the first chamber, thereby forming multiple pressure drops, and then the flow channel enters the first gap and pushes the buffer piston and then pushes the valve core to move to the right together, thereby more flexibly adjusting the pressure difference at both ends of the valve core, providing more stable and more precise pressure control, and ensuring smoother operation of the hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a cross-sectional view of the relief valve provided by the utility model;

[0026] Figure 2 yes Figure 1 A partial enlarged view of part A;

[0027] Figure 3 This is a schematic structural diagram of the valve core body and the damping sleeve provided by the utility model as an integrated unit.

[0028] In the picture:

[0029] 10. Valve seat; 11. Oil inlet hole; 12. Oil return hole;

[0030] 20. Valve sleeve assembly; 21. Piston sleeve; 22. Adjustment sleeve; 221. First section; 222. Second section;

[0031] 30. Valve core; 31. Valve core body; 311. Through hole; 312. Pushing inclined surface; 32. Damping sleeve; 321. First damping hole; 33. Oil passage;

[0032] 41. First chamber; 42. Second chamber; 43. First gap;

[0033] 50. Piston; 51. Flow channel; 511. First oil hole; 512. Second oil hole; 52. Second damping hole; 53. Top; 54. Skirt;

[0034] 60. Seals;

[0035] 70. Plug;

[0036] 80. Elastic component; 81. Elastic member; 82. Fixed seat. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all of its components.

[0038] In the description of this utility model, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0039] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0040] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0041] In a hydraulic system, the hydraulic motor is a crucial actuator, converting the pressure provided by the hydraulic pump into mechanical energy for the output shaft. The relief valve is a crucial component of the hydraulic motor, ensuring smooth operation. When the hydraulic motor is heavily loaded, the relief valve often experiences significant pressure overshoot, leading to unstable operation, damage to the motor, and shortening its service life.

[0042] In order to solve the above problems, a relief valve is provided in this embodiment. Figure 1-Figure 2 As shown, the relief valve includes a valve seat 10 , a valve sleeve assembly 20 , a piston 50 , a valve core 30 and an elastic assembly 80 . The valve seat 10 is provided with an oil inlet hole 11 and an oil return hole 12; the valve sleeve assembly 20 is provided in the valve seat 10, and the valve sleeve assembly 20 is provided with a limited space along the axial direction of the valve seat 10; the piston 50 is provided in the limited space for axial movement along the valve seat 10, and the piston 50 is provided in the limited space for axial movement along the valve sleeve assembly 20. One side of the piston 50 forms a first gap 43 with the inner wall of the limited space, and the other side of the piston 50 is provided with a first chamber 41. The first gap 43 and the first chamber 41 are connected by a flow channel 51; the valve core 30 is provided in the valve seat 10 for axial movement along the valve seat 10 to open or close the passage between the oil inlet hole 11 and the oil return hole 12. The end of the valve core 30 away from the oil inlet hole 11 extends into the first chamber 41 and slides with the inner wall of the first chamber 41. The valve core 30 is provided with a through oil passage 33 along its axial direction, and the oil passage 33 includes at least two first damping holes 321 connected in the axial direction.

[0043] In the above structure, hydraulic oil can enter the valve seat 10 through the oil inlet hole 11, pushing the valve core 30 to the left, allowing the hydraulic oil to flow back through the oil return hole 12, slowing the pushing speed. Furthermore, the hydraulic oil enters the first chamber 41 through the oil passage 33. During this process, the hydraulic oil passes through at least two first damping holes 321, which creates multiple pressure drops, preventing the hydraulic oil from entering the first chamber 41 from overly high pressure and ensuring stability. Finally, the hydraulic oil in the first chamber 41 enters the first gap 43 through the flow passage 51. The hydraulic oil in the first gap 43 pushes the piston 50 to the right, thereby driving the valve core 30 to the right. During this process, the first damping holes 321 create multiple damping effects on the hydraulic oil, creating pressure drops, allowing for more flexible adjustment of the pressure difference across the valve core 30. Therefore, when dealing with a changing hydraulic system, this relief valve can provide more stable and precise pressure and flow control, thereby resolving the problem of unstable operation.

[0044] Specifically, if Figure 1 As shown, the flow channel 51 includes a first oil hole 511 and a second oil hole 512 that communicate with each other. The first oil hole 511 is arranged radially of the piston 50, and the second oil hole 512 is arranged axially of the piston 50. The first oil hole 511 communicates with the first gap 43, and the second oil hole 512 communicates with the first chamber 41. This arrangement enables the radially opening first oil hole 511 and the axially opening second oil hole 512 to cooperate with each other, not only simplifying the overall structure but also ensuring smooth flow of hydraulic oil within the flow channel 51, ensuring good communication.

[0045] In addition, it is worth noting that in this embodiment, the relief valve also includes an elastic assembly 80, which includes an elastic member 81 and a fixed seat 82. The elastic member 81 is sleeved on the outer side of the valve core 30, and the space between the valve core 30 and the inner wall of the valve seat 10 can accommodate the elastic member 81. One end of the elastic member 81 abuts against the end of the valve core 30 near the oil inlet hole 11. The fixed seat 82 is sleeved on the outer periphery of the valve core 30 and is connected to or abuts against the end of the elastic member 81 away from the oil inlet hole 11. The side of the fixed seat 82 facing away from the elastic member 81 abuts against the valve sleeve assembly 20 and the piston 50. When the piston 50 moves to the right, it can push the fixed seat 82 to move to the right together, thereby compressing the elastic member 81. The elastic force generated by the compression of the elastic member 81 can push the valve core 30 to the right through the other end, thereby re-blocking the oil inlet hole 11, simplifying the overall structure and reducing the difficulty of installation. In addition, the elastic member 81 is a spring, which has a simple structure, low price, and is easy to produce and install.

[0046] Furthermore, the valve core 30 includes a valve core body 31 and at least two damping sleeves 32. The valve core body 31 is movably disposed within the valve seat 10 along the axial direction of the valve seat 10. The valve core body 31 has a through hole 311 extending therethrough along its axial direction. At least two damping sleeves 32 are spaced apart within the through hole 311 along the axial direction of the valve core body 31. First damping holes 321 are correspondingly disposed within the damping sleeves 32. The through hole 311 and the plurality of first damping holes 321 are sequentially connected to form an oil passage 33. This structure simplifies the overall structure of the valve core 30, not only facilitating the provision of the through hole 311 in the valve core body 31, but also ensuring smooth flow of hydraulic oil into the first chamber 41.

[0047] It is worth noting that if Figure 1 As shown, there are two damping sleeves 32, which are respectively located at the two ends of the valve core body 31 along its axial direction. This structure facilitates the installation of the damping sleeve 32. At the same time, if the damping sleeve 32 is blocked, it is convenient to dredge the first damping hole 321, thereby ensuring a good oil flow effect. It should be noted here that in this embodiment, two damping sleeves 32 are provided. In other embodiments, the number of damping sleeves 32 provided can be adjusted according to actual needs. In addition, the valve core body 31 and at least two damping sleeves 32 are all detachable. This arrangement facilitates the maintenance and replacement of the damping sleeve 32, thereby improving the disassembly and assembly effect.

[0048] In other embodiments, the valve core body 31 and at least one damping sleeve 32 are integrally formed. Specifically, the first damping hole 321 is integrally formed with the valve core body 31 and can be formed through machining or other methods. This arrangement improves processing efficiency and facilitates processing and installation, eliminating the need for separate processing to allow the damping sleeve 32 to be used in conjunction with the valve core body 31. Either method can be selected based on actual needs. In other embodiments, one damping sleeve 32 can be integrally formed with the valve core body 31, while multiple damping sleeves 32 are separately installed within the through-hole 311 of the valve core body 31.

[0049] Specifically, if Figure 1As shown, the valve sleeve assembly 20 includes a piston sleeve 21 and an adjustment sleeve 22. The adjustment sleeve 22 is disposed on the outer periphery of the valve seat 10 and includes a first section 221 and a second section 222. The inner diameter of the first section 221 is larger than the inner diameter of the second section 222. The connection between the first section 221 and the second section 222 forms a limiting step. The piston sleeve 21 is disposed on the inner periphery of the first section 221 and has a second gap between it and the limiting step. The second gap, together with the inner cavity of the piston sleeve 21 and the inner cavity of the second section 222, forms a limiting space. In this structure, the adjustment sleeve 22 has a simple structure, and the limiting step can limit the rightward movement distance of the piston 50 (movement within the second gap), while the piston sleeve 21 can limit the leftward movement distance of the piston 50, preventing the piston 50 from moving too much to one side, thereby producing a good hydraulic effect.

[0050] Considering that the hydraulic oil in the first gap 43 will enter the gap between the piston sleeve 21 and the adjustment sleeve 22. To solve this problem, Figure 1 As shown, a seal 60 is provided between the outer periphery of the piston sleeve 21 and the inner periphery of the adjustment sleeve 22. The seal 60 prevents hydraulic oil from entering the gap between the piston sleeve 21 and the adjustment sleeve 22, thereby preventing hydraulic oil leakage. It should be noted that in this embodiment, the seal 60 is an O-ring. O-rings have a simple structure, are inexpensive, and are easy to install, effectively reducing manufacturing and post-use costs.

[0051] What needs to be explained here is that Figure 1 As shown, the relief valve further includes a plug 70, which is disposed at the end of the piston sleeve 21 away from the oil inlet hole 11 and abuts against the side of the piston sleeve 21 facing away from the piston 50. The provision of the plug 70 secures the piston sleeve 21, preventing the pressure from pushing the piston sleeve 21 to the left after the hydraulic oil enters the first gap 43, thereby reducing the cushioning effect. By securing the piston sleeve 21, a good operating effect can be ensured.

[0052] Specifically, if Figure 1 As shown, the piston 50 includes a connected top portion 53 and a skirt portion 54. The diameter of the top portion 53 is larger than that of the skirt portion 54. The top portion 53 is movably disposed within the second gap, and the skirt portion 54 is movably disposed within the second section 222. The first chamber 41 is located within the skirt portion 54. The first section 221, the second section 222, the skirt portion 54, and the top portion 53 collectively form the second chamber 42. This structure eliminates the need for a separate second chamber 42 within the adjustment sleeve 22. Instead, the first section 221, the second section 222, the top portion 53, and the skirt portion 54 cooperate to form the second chamber 42, simplifying the overall structure and reducing manufacturing costs. Furthermore, the inner wall of the skirt portion 54, the top portion 53, and the end of the valve core 30 away from the oil inlet hole 11 collectively form the first chamber 41, further simplifying the overall structure.

[0053] In addition, if Figure 1 As shown, the top portion 53 and the first section 221 are slidably guided, and the skirt portion 54 and the second section 222 are slidably guided. This arrangement ensures the smoothness of the piston 50 during its left and right reciprocating motion, and can be guided by the axial direction of the adjustment sleeve 22, preventing up and down shaking. This ensures the stability of the reciprocating motion of the piston 50, thereby ensuring a good hydraulic effect.

[0054] In addition, if Figure 1 As shown, the skirt 54 is provided with a second damping orifice 52, which communicates with both the first chamber 41 and the second chamber 42. The second chamber 42 is located to the right of the piston 50, and the first gap 43 is located to the left of the piston 50. The hydraulic oil in the first chamber 41 enters the second chamber 42 through the second damping orifice 52, which reduces the pressure entering the second chamber 42 and, in turn, reduces the speed at which the hydraulic oil pushes the piston 50 to the left, thereby ensuring smooth operation. Furthermore, after the hydraulic oil enters the second chamber 42, it partially offsets the pressure generated in the first gap 43 on the left side of the piston 50, thereby reducing the speed at which the valve core 30 moves to the right, thereby ensuring smooth operation.

[0055] In addition, if Figure 1 As shown, the diameter of the valve core 30 at one end near the oil inlet hole 11 gradually decreases as it approaches the oil inlet hole 11 and forms a push slope 312. The push slope 312 can abut against the edge of the oil inlet hole 11 and form a cone seal. This structure enables the valve core 30 to enter and block the oil inlet hole 11 more smoothly. Since the diameter gradually decreases as it approaches the oil inlet hole 11, a push gap can be formed with the inner wall of the oil inlet hole 11. When hydraulic oil enters the oil inlet hole 11, it can push the valve core 30 through the push gap, causing the valve core 30 to move to the left and compress the elastic member 81, thereby allowing a portion of the hydraulic oil to flow out through the oil return hole 12, and the other portion of the hydraulic oil passes through the two first damping holes 321, passes through the oil channel 33, and finally enters the first gap 43, completing the working cycle. Furthermore, the push slope 312 not only forms a push notch with the inner wall of the oil inlet hole 11, but also forms a highly airtight conical seal with the oil inlet hole 11 when the push slope 312 abuts the edge of the oil inlet hole 11, thereby increasing the pressure outside the oil inlet hole 11, allowing the pressure of the external hydraulic oil to push the valve core 30 leftward again, thus completing the working cycle. The push slope 312 not only has a simple structure but also has a good sealing effect, which facilitates the cyclic driving of the valve core 30.

[0056] Obviously, the above-described embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the manner in which the present invention is to be implemented. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A relief valve, characterized in that: include: The valve seat (10) is provided with an oil inlet hole (11) and an oil return hole (12); A valve sleeve assembly (20) is arranged in the valve seat (10), and a limited space is provided on the valve sleeve assembly (20) along the axial direction of the valve seat (10); A piston (50) is arranged in the limiting space so as to be movable along the axial direction of the valve seat (10), a first gap (43) is formed between one side of the piston (50) and the inner wall of the limiting space, a first chamber (41) is provided on the other side of the piston (50), and the first gap (43) and the first chamber (41) are connected through a flow channel (51); A valve core (30) is movably arranged in the valve seat (10) along the axial direction of the valve seat (10) to open or close the passage between the oil inlet hole (11) and the oil return hole (12); one end of the valve core (30) away from the oil inlet hole (11) extends into the first chamber (41) and slides with the inner wall of the first chamber (41); the valve core (30) is provided with a through oil passage (33) along its axial direction, and the oil passage (33) includes at least two first damping holes (321) connected in the axial direction.

2. The relief valve according to claim 1, characterized in that The valve core (30) comprises: A valve core body (31) is movably arranged in the valve seat (10) along the axial direction of the valve seat (10), and a through hole (311) is provided in the valve core body (31) and is penetrated along the axial direction thereof; At least two damping sleeves (32) are arranged in the through hole (311) at intervals along the axial direction of the valve core body (31), the first damping holes (321) are correspondingly arranged in the damping sleeve (32), and the through hole (311) and the plurality of the first damping holes (321) are sequentially connected to form the oil passage (33).

3. The relief valve according to claim 2, characterized in that: There are two damping sleeves (32), and the two damping sleeves (32) are respectively located at two ends of the valve core body (31) along its axial direction.

4. The relief valve according to claim 2, characterized in that The valve core body (31) and at least two damping sleeves (32) are detachably matched.

5. The relief valve according to claim 2, characterized in that: The valve core body (31) and at least one damping sleeve (32) are an integrated structure.

6. The relief valve according to any one of claims 1 to 5, characterized in that: The valve sleeve assembly (20) includes a piston sleeve (21) and an adjusting sleeve (22), wherein the adjusting sleeve (22) is arranged on the inner periphery of the valve seat (10), and the adjusting sleeve (22) includes a first section (221) and a second section (222), wherein the inner diameter of the first section (221) is larger than the inner diameter of the second section (222), and a connecting position of the first section (221) and the second section (222) forms a limiting step, and the piston sleeve (21) is arranged on the inner periphery of the first section (221) and has a second gap with the limiting step, and the second gap, the inner cavity of the piston sleeve (21) and the inner cavity of the second section (222) enclose the limiting space.

7. The relief valve according to claim 6, characterized in that The piston (50) includes a top (53) and a skirt (54) connected to each other. The diameter of the top (53) is larger than the diameter of the skirt (54). The top (53) is movably arranged in the second gap, and the skirt (54) is movably arranged in the second section (222). The first chamber (41) is located in the skirt (54). The first section (221), the second section (222), the skirt (54) and the top (53) together form a second chamber (42). The skirt (54) is provided with a second damping hole (52). The second damping hole (52) is communicated with both the first chamber (41) and the second chamber (42).

8. The relief valve according to claim 6, characterized in that The overflow valve further comprises a plug (70), which is arranged at one end of the piston sleeve (21) away from the oil inlet hole (11), and the plug (70) abuts against the piston sleeve (21).

9. The overflow valve according to any one of claims 1 to 5, characterized in that: The diameter of the valve core (30) at one end close to the oil inlet hole (11) gradually decreases in a direction close to the oil inlet hole (11) and is formed with a push inclined surface (312). The push inclined surface (312) can abut against the edge of the oil inlet hole (11) and form a cone seal.

10. The overflow valve according to any one of claims 1 to 5, characterized in that: The overflow valve further comprises an elastic component (80), the elastic component (80) comprising an elastic member (81) and a fixed seat (82), the elastic member (81) being sleeved on the outer side of the valve core (30), one end of the elastic member (81) being in contact with an end of the valve core (30) close to the oil inlet hole (11); the fixed seat (82) being sleeved on the outer periphery of the valve core (30), and being connected to or in contact with an end of the elastic member (81) away from the oil inlet hole (11), and the side of the fixed seat (82) facing away from the elastic member (81) being in contact with the valve sleeve component (20) and the piston (50).

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