A bidirectional overflow valve
By using a dual-valve-core design within the same valve body and a hydraulic differential principle, the problems of large size and complex adjustment of existing bidirectional relief valves have been solved, achieving reduced size, simplified adjustment, and consistent pressure, thereby improving the efficiency and sealing performance of the bidirectional relief valve.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU HENGLI HYDRAULIC TECH CO LTD
- Filing Date
- 2025-09-19
- Publication Date
- 2026-07-21
Smart Images
Figure CN224533116U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of hydraulic technology, and in particular to a bidirectional relief valve. Background Technology
[0002] Existing bidirectional relief valves often employ two relief valves connected together via a valve body. For example, application number CN201820164355.8 discloses a bidirectional relief valve for motor protection, including a valve body with an oil chamber 1 and an oil chamber 2 within it. The oil chamber 1 and oil chamber 2 are respectively connected to process holes 1 and 2. The valve body has a mounting hole 1 connecting to oil chamber 1 and a mounting hole 2 connecting to oil chamber 2. Process holes 1 and 2 are respectively connected to mounting holes 1 and 2. An overflow safety valve 1 and an overflow safety valve 2 are respectively installed in mounting hole 1 and mounting hole 2. Both overflow safety valve 1 and overflow safety valve 2 include a safety valve body. A pressure regulating screw is installed in the center hole at the outer end of the safety valve body. A pressure regulating piston is installed at the inner end of the pressure regulating screw. A spring is installed at the inner end of the pressure regulating piston. A safety valve core is installed at the inner end of the spring. A safety valve seat is installed at the inner end of the safety valve core. A sealing ring is provided between the safety valve body and the valve body. The valve body is also provided with a first oil inlet, a second oil inlet, a first oil outlet, and a second oil outlet.
[0003] The above application can achieve bidirectional overflow protection, but it is too large and takes up a lot of space, which greatly interferes with the replacement operation; the internal structure of the two independent overflow valves is also independent, and the two overflow valves need to be adjusted separately during the adjustment process, which greatly prolongs the adjustment time. Utility Model Content
[0004] To address the problems of large size and space occupation of existing bidirectional relief valves, and the long adjustment time caused by using two independent relief valves, this invention provides a brake and hydraulic motor that solves the aforementioned technical problems.
[0005] The technical solution of this utility model is as follows: This utility model provides a bidirectional overflow valve, comprising: A valve body, wherein a first oil port is formed at a first end of the valve body, and a second oil port is formed on the outer periphery of the valve body; A valve core assembly is slidably mounted in a valve body, the valve core assembly including a first valve core and a second valve core; An elastic element acts on the valve core assembly, causing the second valve core to abut against the first valve core to form a seal. The first valve core abuts against the inner wall of the valve body to seal and block the communication between the first oil port and the second oil port. The abutment point between the second valve core and the first valve core is connected to the second oil port. The cross-sectional area of the abutment between the first valve core and the valve body is larger than the cross-sectional area of the sliding fit between the second valve core and the valve body, and the cross-sectional area of the sliding fit between the second valve core and the valve body is larger than the cross-sectional area of the abutment between the second valve core and the first valve core.
[0006] According to one embodiment of the present invention, the cross-sectional area of the abutment between the first valve core and the valve body is S1, the cross-sectional area of the abutment between the second valve core and the first valve core is S3, and the cross-sectional area of the sliding fit between the second valve core and the valve body is S2, where S1-S2=S2-S3.
[0007] According to one embodiment of the present invention, there are multiple second oil ports, which are arranged circumferentially at two axial positions.
[0008] According to one embodiment of the present invention, the first valve core abuts against the inner wall of the valve body to block the communication between the first oil port and the second oil port at the adjacent first axial position, and the second valve core abuts against the first valve core to block the communication between the first oil port and the second oil port at the second axial position.
[0009] According to one embodiment of the present invention, a through hole is formed on the first valve core, the through hole is kept in communication with the first oil port, and the second valve core abuts against the first valve core to seal and block the communication between the through hole and the second oil port; a through central flow channel is formed on the second valve core.
[0010] According to one embodiment of the present invention, the valve body includes an outer valve seat, a valve sleeve, and an inner valve seat. The valve sleeve is fitted onto one end of the outer valve seat. The first oil port and the second oil port are both disposed on the valve sleeve. The inner valve seat is fitted inside the valve sleeve and the outer valve seat. The first valve core slides within the valve sleeve. The second valve core slides within the inner valve seat. Under the action of an elastic element, there is an axial gap between the first valve core and the inner valve seat. The axial gap communicates with the second oil port.
[0011] According to one embodiment of the present invention, a sliding seal is provided between the second valve core and the inner valve seat, and the roughness Ra of the inner hole of the inner valve seat is not greater than 0.1 μm.
[0012] According to one embodiment of the present invention, an adjusting screw is installed inside the second end of the valve body, and an elastic element is located between the adjusting screw and the valve core assembly.
[0013] According to one embodiment of the present invention, the adjusting screw is threadedly engaged with the valve body. After the adjusting screw is assembled in place, a limiting structure is formed at the threaded part of the valve body to prevent the adjusting screw from being unscrewed.
[0014] According to one embodiment of the present invention, a plug is provided at the second end of the valve body.
[0015] Based on the above technical solution, the technical effects that this utility model can achieve are as follows: This utility model's bidirectional relief valve uses two independent valve cores set in the same mounting hole. Only one elastic element is needed to act on both valve cores simultaneously. The hydraulic differential principle allows for unloading in both directions, concentrating the functions of two relief valves into one valve, greatly reducing the size of the valve body. When adjusting the pressure, only one adjusting screw is needed to adjust the pre-compression of the elastic element to simultaneously adjust the relief pressure unloaded in both directions. By comparing the cross-sectional areas of the contact points between the first valve core and the valve body, the sliding contact points between the second valve core and the valve body, and the contact points between the second valve core and the first valve core, and ensuring a difference in area, when pressurized oil enters from the first port, if the oil pressure exceeds the overflow pressure, the pressurized oil can push the entire valve core assembly to slide against the elastic element, releasing the sealing effect of the first valve core against the inner wall of the valve body, and the pressurized oil flows out from the second port; when pressurized oil enters from the second port, if the oil pressure exceeds the overflow pressure, the pressurized oil can push the second valve core to slide against the elastic element, releasing the sealing effect of the second valve core against the first valve core, and the pressurized oil can flow out through the first port, thus achieving bidirectional unloading. The bidirectional overflow valve of this utility model further sets the cross-sectional area of the abutment of the first valve core and the valve body, the cross-sectional area of the sliding fit between the second valve core and the valve body, and the cross-sectional area of the abutment of the second valve core and the first valve core to have an equal area difference. This makes the area of oil pressure action when oil enters the first oil port equal to the area of oil pressure action when oil enters the second oil port, thereby ensuring that the overflow pressure of the bidirectional overflow valve is equal in both directions when the elastic element is under the same compression state. The bidirectional overflow valve of this utility model has a second oil port arranged in two axial positions. Overflow can be achieved as long as either the abutment between the valve core assembly and the valve body or the abutment between the first valve core and the second valve core is released under the action of pressure oil. This utility model discloses a bidirectional relief valve where the second valve core moves regardless of which port the oil enters from. A sliding seal between the second valve core and the inner valve seat ensures a tight seal during relative sliding motion. Since the friction of the sliding seal significantly affects the opening pressure of the relief valve, the surface roughness of the contact surface between the inner valve seat and the sliding seal is crucial for smoother opening of the second valve core. If the roughness of the inner bore of the inner valve seat is too high, the coefficient of friction between the sliding seal and the inner valve seat will be too large. Changes in oil temperature and sealing ring compression will affect the timing of the valve core's transition from a static to a dynamic state, and from static friction to dynamic friction, thus impacting the repeatability of the relief pressure and potentially causing significant pressure overshoot. This application limits the inner bore roughness Ra of the inner valve seat to no more than 0.1 μm to reduce friction at the sliding seal, thereby optimizing the repeatability of the relief valve's opening pressure and ensuring that the opening pressure remains stable at the same value each time. The bidirectional overflow valve of this utility model has an adjusting screw at the second end of the valve body. After the adjusting screw is assembled, the threads on the outside of the adjusting screw can be disabled by breaking the threads inside the valve body or by sealing the threads with glue or adhesive particles. The adjusting screw can no longer be unscrewed through the threads, thus playing a role in preventing adjustment. A plug is also provided at the second end of the valve body, which can also seal the inside of the valve body, further playing a role in sealing and preventing adjustment. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the structure of the bidirectional overflow valve of this utility model; Figure 2 for Figure 1 A magnified view of a portion of the image; Figure 3 This is a hydraulic schematic diagram of a two-way relief valve. Figure 4 This is a diagram showing the state of pressurized oil flowing from the first port to the second port; Figure 5 This is a diagram showing the state of pressurized oil flowing from the second port to the first port; In the diagram: 1-Valve body; 11-Outer valve seat; 12-Valve sleeve; 121-First oil port; 122-Second oil port; 13-Inner valve seat; 2-Valve core assembly; 21-First valve core; 211-Through hole; 212-First outer conical surface; 22-Second valve core; 221-Central flow channel; 222-Second outer conical surface; 3-Elastic element; 4-Sliding seal; 5-Adjusting screw; 6-Plug. Detailed Implementation
[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.
[0018] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0019] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.
[0020] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.
[0021] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.
[0022] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.
[0023] like Figure 1-5 As shown, this embodiment proposes a bidirectional relief valve, including a valve body 1, a valve core assembly 2, and an elastic element 3. The valve body 1 has a first oil port 121 and a second oil port 122. The valve core assembly 2 and the elastic element 3 are assembled inside the valve body 1. The elastic element 3 acts on the valve core assembly 2, forming a sealing seal between the valve core assembly 2 and the valve body 1, and inside the valve core assembly 2, blocking the communication between the first oil port 121 and the second oil port 122. When the pressure oil entering through the first oil port 121 or the second oil port 122 reaches the relief pressure, the pressure oil will correspondingly release the sealing seal, achieving bidirectional relief.
[0024] like Figure 1 , 4 As shown in Figure 5, a through mounting hole is formed inside the valve body 1 to facilitate the assembly of the valve core assembly 2 and the elastic element 3; a first oil port 121 is formed at the first end of the valve body 1, and a second oil port 122 is formed on the outer peripheral surface of the valve body 1; the valve core assembly 2 can abut against the inner wall of the valve body 1 to form a seal.
[0025] Specifically, the valve body 1 can be configured as a split structure, including an outer valve seat 11, a valve sleeve 12, and an inner valve seat 13. The outer valve seat 11, valve sleeve 12, and inner valve seat 13 are all hollow structures. The valve sleeve 12 is assembled on the first end of the outer valve seat 11. The first oil port 121 and the second oil port 122 are both formed on the valve sleeve 12. The first oil port 121 can be the end port of the valve sleeve 12 away from the outer valve seat 11. The second oil port 122 is disposed on the outer peripheral surface of the valve sleeve 12. The inner valve seat 13 is assembled inside the valve sleeve 12.
[0026] As a preferred embodiment, the valve sleeve 12 can be threadedly connected to the outer valve seat 11. Specifically, the end of the valve sleeve 12 is screwed into the first end port of the outer valve seat 11 to form a threaded connection; the inner valve seat 13 is threadedly connected to the valve sleeve 12, and the inner valve seat 13 is screwed into the port of the valve sleeve 12 located inside the outer valve seat 11 to form a threaded connection. Preferably, an outer protrusion is formed on the inner valve seat 13. When the inner valve seat 13 is screwed into the port of the valve sleeve 12, the outer protrusion can abut against the end face of the valve sleeve 12 to form a limit.
[0027] As a preferred embodiment, multiple second oil ports 122 can be provided, and the multiple second oil ports 122 are arranged circumferentially at two axial positions. The two axial positions specifically include a first axial position and a second axial position, with the first axial position being closer to the first oil port 121 than the second axial position. Preferably, the second oil ports 122 are evenly arranged circumferentially at both axial positions.
[0028] like Figure 1-2 As shown in Figures 4-5, the valve core assembly 2 is assembled inside the valve body 1. The valve core assembly 2 includes a first valve core 21 and a second valve core 22. Both the first valve core 21 and the second valve core 22 are slidably assembled inside the valve body 1. Under the action of the elastic member 3, the first valve core 21 can abut against the inner wall of the valve body 1 to form abutment seal; the second valve core 22 can abut against the first valve core 21 to form abutment seal.
[0029] As a preferred embodiment, the first valve core 21 has a through hole 211, which communicates with the first oil port 121. The first valve core 21 abuts against the inner wall of the valve body 1, blocking the communication between the first oil port 121 and the second oil port 122 at the first axial position. The second valve core 22 abuts against the end of the first valve core 21, blocking the communication between the through hole 211 and the second oil port 122 at the second axial position. Specifically, the first valve core 21 abuts against the inner wall of the valve sleeve 12.
[0030] As a preferred technical solution in this embodiment, the end of the first valve core 21 near the first oil port 121 is formed with a first outer conical surface 212. Under the action of the elastic member 3, the first outer conical surface 212 of the first valve core 21 abuts against the inner wall of the valve body 1, forming a conical surface fit with the valve body 1.
[0031] As a preferred technical solution in this embodiment, the end of the second valve core 22 near the first valve core 21 is formed with a second outer conical surface 222. Under the action of the elastic member 3, the second outer conical surface 222 of the second valve core 22 abuts against the port of the first valve core 21, forming a conical surface fit with the first valve core 21.
[0032] As a preferred technical solution in this embodiment, a through-flow central flow channel 221 is formed on the second valve core 22.
[0033] As a preferred embodiment, the first valve core 21 is slidably assembled inside the valve sleeve 12, and the first valve core 21 slides within the valve sleeve 12; the second valve core 22 is slidably assembled inside the inner valve seat 13, and the second valve core 22 slides within the inner valve seat 13. When the valve core assembly 2 forms abutment under the action of the elastic member 3, there is an axial gap between the first valve core 21 and the inner valve seat 13. This axial gap communicates with the second oil port 122 located at the second axial position, and the second oil port 122 communicates with the abutment of the first valve core 21 and the second valve core 22 through this axial gap.
[0034] As a preferred technical solution in this embodiment, such as Figure 2 As shown, the cross-sectional area of the abutment between the first valve core 21 and the valve body 1 is S1, specifically the cross-sectional area of the abutment between the first valve core 21 and the valve sleeve 12 is S1; the cross-sectional area of the sliding fit between the second valve core 22 and the valve body 1 is S2, specifically the cross-sectional area of the sliding fit between the second valve core 22 and the inner valve seat 13 is S2; the cross-sectional area of the abutment between the second valve core 22 and the first valve core 21 is S3, where S1 is greater than S2, and S2 is greater than S3. Preferably, S1-S2=S2-S3.
[0035] As a preferred embodiment, a sliding seal 4 is provided between the second valve core 22 and the inner valve seat 13. The sliding seal 4 may be, but is not limited to, a sliding sealing ring.
[0036] As a preferred technical solution in this embodiment, the roughness Ra of the inner hole of the inner valve seat 13 is not greater than 0.1 μm.
[0037] As a preferred technical solution in this embodiment, the outer valve seat 11, valve sleeve 12, inner valve seat 13, first valve core 21 and second valve core 22 are coaxially arranged.
[0038] like Figure 1 , 4 As shown in Figure -5, the elastic element 3 is located inside the valve body 1 and acts on the valve core assembly 2. Specifically, the elastic element 3 is located inside the outer valve seat 11, and the end of the elastic element 3 abuts against the end of the second valve core 22 that is away from the first valve core 21. Preferably, the end of the second valve core 22 that is away from the first valve core 21 has an outer stepped surface, and the end of the elastic element 3 is limited by the outer stepped surface.
[0039] As a preferred technical solution in this embodiment, the elastic element 3 may be, but is not limited to, a spring. The elastic cavity where the elastic element 3 is located is connected to the central flow channel 221 of the second valve core 22.
[0040] like Figure 1 , 4As shown in Figure 5, the bidirectional overflow valve in this embodiment also includes an adjusting screw 5, which is assembled inside the outer valve seat 11. The overflow pressure of the bidirectional overflow valve is adjusted by adjusting the compression of the elastic element 3.
[0041] As a preferred technical solution in this embodiment, the adjusting screw 5 can be screwed in from the second end of the outer valve seat 11, and the elastic element 3 is located between the adjusting screw 5 and the second valve core 22. The two ends of the elastic element 3 act on the adjusting screw 5 and the second valve core 22 respectively.
[0042] As a preferred technical solution in this embodiment, after the adjusting screw 5 is installed in place, a limiting structure is formed at the thread inside the outer valve seat 11 to prevent the adjusting screw 5 from being unscrewed, thereby preventing adjustment. For example, the threads on the outside of the adjusting screw 5 can be damaged to prevent it from being unscrewed; a curable adhesive can be added to the threads on the outside of the adjusting screw 5 to seal them, preventing the adjusting screw from being unscrewed; or an adhesive fixing particle can be added to the threads on the outside of the adjusting screw 5 to seal them, preventing the adjusting screw 5 from being unscrewed. Other methods can also be used to prevent the installed adjusting screw 5 from being unscrewed.
[0043] like Figure 1 , 4 As shown in Figure -5, the bidirectional overflow valve of this embodiment also includes a plug 6, which is installed at the second end of the valve body 1, specifically at the second end of the outer valve seat 11. The plug 6 serves to seal the interior of the outer valve seat 11, further providing sealing and preventing adjustment. Preferably, the plug 6 can be a plug without external hexagonal, internal hexagonal, or knurled structures. This prevents disassembly and assembly using ordinary tools such as wrenches or pipe wrenches, requiring the use of special clamps and similar special fixtures. Furthermore, tightening the plug 6 can be done by increasing the torque or applying thread-locking adhesive to increase the difficulty of disassembly, thus preventing adjustments by users other than the manufacturer.
[0044] To ensure the structure's airtightness, such as Figure 1 , 4 As shown in Figure 5, sealing elements are provided between the outer valve seat 11 and the valve sleeve 12, between the valve sleeve 12 and the inner valve seat 13, and between the outer valve seat 11 and the plug 6. The sealing elements can be selected from, but are not limited to, O-ring seals.
[0045] Based on the above technical solution, the working principle of the bidirectional overflow valve in this embodiment is as follows: like Figure 4As shown, when the pressure oil enters from the first oil port 121, the pressure oil pushes the valve core assembly 2 to move as a whole against the force of the elastic element 3. The effective area of the pressure oil is S1-S2. The abutment seal between the first valve core 21 and the valve body 1 is released, and the first oil port 121 and the second oil port 122 located in the first axial position are connected. The pressure oil overflows from the second oil port 122 located in the first axial position.
[0046] like Figure 5 As shown, when the pressurized oil enters from the second oil port 122, the pressurized oil entering from the second oil port 122 in the second axial position reaches the abutment of the first valve core 21 and the second valve core 22. The pressurized oil pushes the second valve core 22 to move against the force of the elastic element 3. The effective area of the pressurized oil is S2-S3. The abutment seal between the first valve core 21 and the second valve core 22 is released. The second oil port 122 in the second axial position communicates with the first oil port 121 through the through hole 211 of the first valve core 21. The pressurized oil overflows from the first oil port 121.
[0047] In summary, the bidirectional overflow valve of this embodiment can achieve overflow in two directions: from the first oil port 121 to the second oil port 122 and from the second oil port 122 to the first oil port 121. Moreover, the overflow pressure of the bidirectional overflow valve of this embodiment is equal in both directions.
[0048] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.
Claims
1. A bidirectional relief valve, characterized in that, include: A valve body (1) has a first oil port (121) formed at its first end and a second oil port (122) formed on its outer periphery. The valve core assembly (2) is slidably assembled inside the valve body (1), and the valve core assembly (2) includes a first valve core (21) and a second valve core (22). The elastic element (3) acts on the valve core assembly (2) to make the second valve core (22) abut against the first valve core (21) to form a seal. The first valve core (21) abuts against the inner wall of the valve body (1) to seal and block the communication between the first oil port (121) and the second oil port (122). The abutment of the second valve core (22) and the first valve core (21) is connected to the second oil port (122). The cross-sectional area of the abutment of the first valve core (21) and the valve body (1) is greater than the cross-sectional area of the sliding fit of the second valve core (22) and the valve body (1), and the cross-sectional area of the sliding fit of the second valve core (22) and the valve body (1) is greater than the cross-sectional area of the abutment of the second valve core (22) and the first valve core (21).
2. The bidirectional overflow valve according to claim 1, characterized in that, The cross-sectional area of the abutment of the first valve core (21) and the valve body (1) is S1, the cross-sectional area of the abutment of the second valve core (22) and the first valve core (21) is S3, the cross-sectional area of the sliding fit between the second valve core (22) and the valve body (1) is S2, and S1-S2=S2-S3.
3. A bidirectional overflow valve according to claim 1, characterized in that, There are multiple second oil ports (122), which are arranged circumferentially at two axial positions.
4. A bidirectional overflow valve according to claim 3, characterized in that, The first valve core (21) abuts against the inner wall of the valve body (1) to block the communication between the first oil port (121) and the second oil port (122) at the adjacent first axial position, and the second valve core (22) abuts against the first valve core (21) to block the communication between the first oil port (121) and the second oil port (122) at the second axial position.
5. A bidirectional relief valve according to any one of claims 1-4, characterized in that, The first valve core (21) has a through hole (211) that is connected to the first oil port (121). The second valve core (22) abuts against the first valve core (21) to seal and block the connection between the through hole (211) and the second oil port (122). The second valve core (22) has a through central flow channel (221).
6. A bidirectional relief valve according to claim 1, characterized in that, The valve body (1) includes an outer valve seat (11), a valve sleeve (12), and an inner valve seat (13). The valve sleeve (12) is mounted on one end of the outer valve seat (11). The first oil port (121) and the second oil port (122) are both located on the valve sleeve (12). The inner valve seat (13) is mounted inside the valve sleeve (12) and the outer valve seat (11). The first valve core (21) slides inside the valve sleeve (12). The second valve core (22) slides inside the inner valve seat (13). Under the action of the elastic element (3), there is an axial gap between the first valve core (21) and the inner valve seat (13). The axial gap is connected to the second oil port (122).
7. A bidirectional overflow valve according to claim 6, characterized in that, A sliding seal (4) is provided between the second valve core (22) and the inner valve seat (13), and the inner hole roughness Ra of the inner valve seat (13) is not greater than 0.1μm.
8. A bidirectional relief valve according to claim 1, characterized in that, An adjusting screw (5) is fitted inside the second end of the valve body (1), and an elastic element (3) is located between the adjusting screw (5) and the valve core assembly (2).
9. A bidirectional overflow valve according to claim 8, characterized in that, The adjusting screw (5) is threadedly engaged with the valve body (1). After the adjusting screw (5) is assembled in place, a limiting structure is formed at the thread inside the valve body (1) so that the adjusting screw (5) cannot be unscrewed.
10. A bidirectional relief valve according to any one of claims 8-9, characterized in that, A plug (6) is provided at the second end of the valve body (1).