An overflow valve
The design, which combines a through-hole and a spherical plug, solves the problem of high machining difficulty in the pilot valve seat of the multi-functional relief valve, reduces the defect rate, and improves machining accuracy and sealing performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG SANSHANG ZHIDI TECH CO LTD
- Filing Date
- 2025-08-04
- Publication Date
- 2026-07-21
AI Technical Summary
The high precision and difficulty in machining the pilot valve seat of existing multi-functional relief valves result in a high product defect rate.
The design employs a through-hole design, combined with a spherical plug and a stepped groove, which reduces the machining difficulty of the pilot valve seat. The sealing is achieved through the interference fit between the spherical plug and the stepped groove, avoiding the problem of difficulty in confirming the opening depth caused by the blind hole design.
This reduces the difficulty of machining the pilot valve seat, decreases the product defect rate, and improves machining accuracy and sealing performance.
Smart Images
Figure CN224533111U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of hydraulic components, and in particular to an overflow valve. Background Technology
[0002] The relief valve is a key pressure control component in a hydraulic system, its function being to limit system pressure and ensure safe and stable system operation. A multi-functional relief valve integrates overload protection, limit functions, and one-way functions into the traditional relief valve. Its structure is more complex than that of a traditional relief valve, typically including a pilot valve core, pilot valve seat, main valve core, and main valve seat. The pilot valve core and pilot valve seat employ a piston-buffered structure, and the main bore is a long, narrow blind hole. The machining process is complex, and due to the high precision requirements and difficulty of machining, defects are easily caused.
[0003] Therefore, there is a need to provide an overflow valve to solve the above problems. Utility Model Content
[0004] The purpose of this invention is to provide an overflow valve that can reduce the processing requirements of the pilot valve seat and minimize the probability of product defects caused by the precision and difficulty of pilot valve seat processing.
[0005] To achieve this objective, the present invention adopts the following technical solution:
[0006] An overflow valve, comprising:
[0007] Valve seat, wherein an installation cavity is formed therein;
[0008] A main valve sleeve is connected to the valve seat. A main valve cavity is formed inside the main valve sleeve. The main valve sleeve has a first oil port opened along the axial direction and a second oil port opened along the circumferential direction. Both the first oil port and the second oil port are in communication with the main valve cavity.
[0009] A main valve core assembly is installed in the main valve chamber and is capable of opening or closing the oil passage between the first oil port and the second oil port. The main valve core assembly has a damping orifice communicating with the first oil port.
[0010] A pilot valve seat is fixedly installed between the main valve sleeve and the valve seat. The pilot valve seat has a through hole extending through it along the axial direction and a connecting hole communicating with the main valve cavity along the circumferential direction. A stepped groove communicating with the through hole is provided at one end of the pilot valve seat near the damping hole. A sealing element is provided in the stepped groove.
[0011] A pilot valve core assembly is installed in the mounting cavity and is capable of opening or closing the oil passage between the connecting hole and the mounting cavity.
[0012] By adopting the above technical solution and opening a through hole, the problem of difficulty in confirming the opening depth caused by the blind hole setting of the main hole is avoided. At the same time, the combination of spherical plug and stepped groove and through hole is used to seal the end of the pilot valve seat, reducing the processing difficulty of the pilot valve seat and thus reducing the probability of product defects caused by the processing of the pilot valve seat.
[0013] Preferably, the sealing element is a spherical plug, which is interference-fitted with the stepped groove and abuts against the inner wall of the through hole for sealing.
[0014] Preferably, the stepped groove includes a guide section and a sealing section, the inner diameter of the sealing section is larger than the inner diameter of the through hole, the spherical plug is interference-fitted with the sealing section, the guide section is used to transition between the wall of the through hole and the sealing section, and the spherical plug abuts and seals at the connection between the guide section and the through hole.
[0015] Preferably, the through hole includes a large-diameter section and a small-diameter section, the inner diameter of the large-diameter section is larger than the inner diameter of the small-diameter section, the small-diameter section is connected to the stepped groove, the large-diameter section is connected to the mounting cavity, and the connecting hole is formed in the large-diameter section.
[0016] Preferably, the pilot valve core assembly includes a pilot valve core, a spring seat, and a pressure regulating spring. The pilot valve core is clearance-fitted with the small-diameter section to form an oil passage. An oil passage is formed between the pilot valve core and the large-diameter section. The pilot valve core extends into the mounting cavity and connects to the spring seat. The pressure regulating spring is installed in the mounting cavity and abuts against the spring seat, so that the pilot valve core abuts against the pilot valve seat and closes the oil passage between the connecting hole and the mounting cavity.
[0017] Preferably, a guide groove is provided at the connection between the spring seat and the pilot valve core, and the end of the pilot valve core extending into the mounting cavity is limited and matched with the bottom end of the guide groove.
[0018] Preferably, the main valve core assembly includes a main valve core, a valve sleeve, and a return spring. The main valve sleeve is provided with an abutment platform. The valve sleeve is slidably installed in the main valve cavity and abuts against the abutment platform for limitation. The main valve core is interference-fitted with the valve sleeve. The return spring is installed in the main valve cavity and abuts against the main valve core, so that the main valve core abuts against the first oil port and closes the oil passage between the first oil port and the second oil port.
[0019] Preferably, the main valve sleeve is fitted outside the valve seat, and a limiting groove is formed between the outer peripheral wall of the valve seat and the inner peripheral wall of the main valve sleeve. A retaining ring is installed in the limiting groove to achieve axial limiting of the valve seat and the main valve sleeve. The main valve sleeve has an installation port for the retaining ring to be installed into the limiting groove.
[0020] Preferably, the main valve sleeve has a mounting platform, the valve seat extends into the main valve cavity and abuts against and limits the pilot valve seat on the mounting platform, and a sealing gasket is provided between the mounting platform and the pilot valve seat.
[0021] Preferably, the valve seat end is threadedly connected to a threaded sleeve, the threaded sleeve has an adjustment groove, an adjustment rod is installed in the mounting cavity, the adjustment rod extends into the adjustment groove and is threadedly connected to a limit cap, and the adjustment rod is threadedly engaged with the threaded sleeve.
[0022] The beneficial effects of this utility model are:
[0023] This invention avoids the problem of difficulty in determining the opening depth caused by the blind hole setting of the main hole by opening a through hole. At the same time, the combination of spherical plug, stepped groove and through hole achieves sealing of the end of the pilot valve seat, reducing the processing difficulty of the pilot valve seat, and thus reducing the probability of product defects caused by the processing of the pilot valve seat. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the overall structure of the overflow valve provided by this utility model;
[0025] Figure 2 This is a cross-sectional view of the overflow valve provided by this utility model. Figure 1 ;
[0026] Figure 3 This is a cross-sectional view of the overflow valve provided by this utility model. Figure 2 ;
[0027] Figure 4 This is a schematic diagram of the pilot valve seat of the overflow valve provided by this utility model.
[0028] In the picture:
[0029] 1. Valve seat; 11. Mounting cavity; 12. Oil return port; 2. Main valve sleeve; 21. Main valve cavity; 22. First oil port; 23. Second oil port; 24. Damping orifice; 25. Abutment platform; 26. Mounting platform; 3. Pilot valve seat; 31. Through hole; 311. Large diameter section; 312. Small diameter section; 313. Connecting hole; 32. Stepped groove; 321. Guide section; 322. Sealing section; 33. Ball plug; 4. Pilot valve core assembly; 1. Pilot valve core; 42. Spring seat; 421. Flow guide groove; 422. Limiting platform; 43. Pressure regulating spring; 44. Oil passage gap; 45. Oil passage; 5. Main valve core assembly; 51. Main valve core; 52. Valve sleeve; 53. Return spring; 61. Limiting groove; 62. Retaining ring; 63. Mounting port; 64. Sealing gasket; 71. Screw sleeve; 711. Adjusting groove; 72. Adjusting rod; 721. Mounting groove; 73. Limiting cap. Detailed Implementation
[0030] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.
[0031] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0032] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0033] In the description of this embodiment, the terms "upper," "lower," "left," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and 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. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.
[0034] Traditional relief valves typically consist of a valve body, valve core, spring, and plug. The valve body has an inlet and an outlet. The valve core slides within the valve body and opens or closes the oil passage between the inlet and outlet. The plug is usually fixed at the end of the valve body furthest from the inlet to seal the valve body end. The spring is installed within the valve body and ensures that the valve core initially closes the oil passage between the inlet and outlet. When the oil pressure at the inlet exceeds a set pressure value, the oil pressure acts on the valve core, overcoming the spring force, and thus opening the oil passage between the inlet and outlet, achieving the overflow function and providing overload protection. When this traditional relief valve is applied in engineering machinery, such as in high-pressure pump environments, it cannot meet the pressure limiting requirements of the operating environment. Therefore, a multi-functional relief valve is needed to meet the demands of the application environment.
[0035] Compared to traditional relief valves, multi-functional relief valves add components such as a pilot valve seat, pilot valve core, and pressure regulating spring between the valve seat and the main valve core. Hydraulic oil enters the cavity through the damping orifice of the main valve core and then acts on the end face of the pilot valve core through the side hole on the pilot valve seat. The pilot valve core and pilot valve seat adopt a piston-buffered structure, and the pressure regulating spring plays a role in pressure limiting. Typically, the main hole that mates with the pilot valve seat and pilot valve core is a long and narrow blind hole, which requires high machining precision. Due to the limited machining depth of the main hole, the machining is difficult and prone to producing defective products during the relief valve production process.
[0036] like Figures 1-4As shown, this embodiment provides an overflow valve, including components such as a valve seat 1, a main valve sleeve 2, a main valve core assembly 5, a pilot valve seat 3, and a pilot valve core assembly 4. The valve seat 1 extends axially and forms a mounting cavity 11. One end of the valve seat 1 has an internal thread and is threadedly connected to a threaded sleeve 71. The end of the threaded sleeve 71 away from the mounting cavity 11 has an adjusting groove 711 axially. The adjusting groove 711 has a threaded hole axially. The threaded sleeve 71 is threadedly connected to an adjusting rod 72 through the threaded hole. One end of the adjusting rod 72 passes through the threaded hole and extends into the mounting cavity 11. The other end of the adjusting rod 72 extends into the adjusting groove 711 and is threadedly connected to a limit cap 73. During assembly, the adjusting rod 72 is threadedly connected to the threaded sleeve 71 through the threaded hole, the limit cap 73 is threadedly connected to the adjusting rod 72, and finally the threaded sleeve 71 is threadedly connected to the internal thread of the valve seat 1, thus assembling the components such as the threaded sleeve 71 on the valve seat 1.
[0037] The other end of the valve seat 1 is sleeved with the main valve sleeve 2. The main valve sleeve 2 is sleeved on the outer peripheral wall of the valve seat 1, and the outer peripheral wall of the valve seat 1 and the inner peripheral wall of the main valve sleeve 2 are recessed and fitted to form a limiting groove 61. A retaining ring 62 is engaged in the limiting groove 61, thereby achieving axial limiting between the valve seat 1 and the main valve sleeve 2. Specifically, the end side wall of the main valve sleeve 2 connected to the valve seat 1 is provided with an installation port 63 for the retaining ring 62 to be installed into the limiting groove 61. The end side wall of the valve seat 1 connected to the main valve sleeve 2 is provided with a return oil port 12 connected to the return oil pipeline. The retaining ring 62 can be rotated circumferentially through the installation port 63 into the limiting groove 61 and achieve locking and limiting.
[0038] The pilot valve seat 3 is fixedly installed between the main valve sleeve 2 and the valve seat 1. The end of the main valve sleeve 2 near the valve seat 1 is recessed to form a mounting platform 26. The valve seat 1 extends into the main valve cavity 21 and presses the pilot valve seat 3 against the mounting platform 26. In order to ensure the sealing performance at the connection between the main valve sleeve 2 and the valve seat 1, a sealing gasket 64 is also provided between the pilot valve seat 3 and the mounting platform 26. When the installation is completed, the end face of the valve seat 1 presses the pilot valve seat 3 and the sealing gasket 64 against the mounting platform 26 to achieve a sealed connection between the valve seat 1 and the main valve sleeve 2.
[0039] The main valve sleeve 2 extends axially and forms a main valve chamber 21. A first oil port 22 is axially provided at the end of the main valve chamber 21 away from the valve seat 1. Multiple second oil ports 23 are circumferentially spaced at the end of the main valve chamber 21 away from the valve seat 1. Both the first oil port 22 and the second oil port 23 can communicate with the main valve chamber 21. The number of second oil ports 23 can be 2, 3, 4, etc., and can be increased or decreased according to the flow rate, pressure, and other requirements of the relief valve's operating environment. The main valve core assembly 5 is installed inside the main valve chamber 21 and can open or close the oil passage between the first oil port 22 and the second oil port 23. Normally, the first oil port 22 serves as the oil inlet, and the second oil port 23 serves as the oil return port 12. The main valve core assembly 5 has a damping orifice 24 communicating with the first oil port 22, so that the oil entering the main valve chamber 21 through the main valve core assembly 5 is damped.
[0040] The main valve core assembly 5 includes a main valve core 51, a valve sleeve 52, and a return spring 53. A contact platform 25 protrudes from one end of the main valve sleeve 52 near the first oil port 22. The valve sleeve 52 is axially guided and slidably installed within the main valve cavity 21, initially engaging with the contact platform 25 for a limiting fit, and the valve sleeve 52 is clearance-fitted with the inner wall of the main valve cavity 21. The valve sleeve 52 extends axially through the main valve core 51, which passes through the valve sleeve 52 and is interference-fitted with it. The end of the main valve core 51 passing through the valve sleeve 52 abuts and seals against the peripheral wall of the first oil port 22. A damping hole 24 communicating with the first oil port 22 is axially formed at the end of the main valve core 51 near the first oil port 22. The return spring 53 is installed within the main valve cavity 21, with both ends of the return spring 53 abutting against the main valve core 51 and the pilot valve seat 3 respectively, so that the main valve core 51 closes the oil passage between the first oil port 22 and the second oil port 23.
[0041] To address the issue that the pilot valve seat 3 is difficult to machine and easily leads to product defects.
[0042] See Figure 3 and Figure 4 The pilot valve seat 3 has a through hole 31 extending axially, and a connecting hole 313 extending circumferentially to connect the main valve chamber 21 and the through hole 31. A stepped groove 32 is provided at the end of the pilot valve seat 3 near the damping hole 24, and a sealing element is provided within the stepped groove 32. The sealing element is preferably a spherical plug 33, which is press-fitted with the stepped groove 32 and abuts against the inner wall of the end of the through hole 31 near the stepped groove 32 for sealing. By using a through hole 31, the problem of difficulty in determining the opening depth caused by a blind hole design of the main hole is avoided. Simultaneously, the sealing of the end of the pilot valve seat 3 is achieved by the cooperation of the spherical plug 33, the stepped groove 32, and the through hole 31, reducing the machining difficulty of the pilot valve seat 3 and thus reducing the probability of product defects caused by the machining of the pilot valve seat 3.
[0043] In one embodiment, the stepped groove 32 includes a guide section 321 and a sealing section 322. The inner diameter of the sealing section 322 is larger than the maximum inner diameter of the through hole 31. The sealing section 322 is located closer to the damping hole 24 than the guide section 321. The guide section 321 forms a certain angle with the central axis of the pilot valve seat 3 to guide the inclined surface and to transition between the through hole 31 and the sealing section 322. Compared with the stepped groove 32 which only includes the sealing section 322, the guide section 321 can guide the spherical plug 33 when it is installed into the stepped groove 32 and to a certain extent guide the spherical plug 33 to better abut against and seal the inner wall of the through hole 31. At this time, the spherical plug 33 and the sealing section 322 are in an interference fit, and the spherical surface of the spherical plug 33 passes through the guide section 321 and abuts against and seals the inner wall of the through hole 31.
[0044] The through hole 31 includes a large-diameter section 311 and a small-diameter section 312, with the inner diameter of the large-diameter section 311 being larger than the inner diameter of the small-diameter section 312. In one embodiment, the through hole 31 includes a large-diameter section 311 and two small-diameter sections 312, with the two small-diameter sections 312 located at both ends of the large-diameter section 311. One of the small-diameter sections 312 is connected to the stepped groove 32, and a connecting hole 313 is formed in the large-diameter section 311. The other small-diameter section 312 cooperates with the pilot valve core assembly 4 to open or close the oil passage between the through hole 31 and the mounting cavity 11. When machining the through hole 31 and connecting hole 313 of the pilot valve seat 3, burrs are easily generated during the machining process due to their intersection, leading to product defects. The large-diameter section 311 allows for forming using a boring tool during machining, significantly reducing the occurrence of burrs. Simultaneously, the large-diameter section 311 increases the flow area between the through hole 31 and the pilot valve core assembly 4, thereby increasing the flow rate. Furthermore, the small-diameter section 312, located near the mounting cavity 11, eliminates the need to increase the size of the pilot valve core assembly 4, which abuts and seals with the small-diameter section 312, thus saving raw materials and reducing costs.
[0045] In another embodiment, the through hole 31 includes a large diameter section 311 and a small diameter section 312. The small diameter section 312 is connected to the stepped groove 32. The connecting hole 313 is opened in the large diameter section 311. The large diameter section 311 cooperates with the pilot valve core assembly 4 to open or close the oil passage between the through hole 31 and the mounting cavity 11, which can maximize the flow area between the through hole 31 and the pilot valve core assembly 4.
[0046] Pilot valve core assembly 4 includes pilot valve core 41, spring seat 42, and pressure regulating spring 43. One end of pilot valve core 41 extends into the small-diameter section 312 of pilot valve seat 3. In the initial state, the portion of pilot valve core 41 extending into the small-diameter section 312 has a slightly larger diameter and is clearance-fitted with the small-diameter section 312 to form an oil passage 44. The portion of pilot valve core 41 extending into the large-diameter section 311 has a slightly smaller diameter and forms an oil passage 45 between it and the large-diameter section 311. The end of the pilot valve core 41 near the mounting cavity 11 is tapered. The tapered surface of the portion of the pilot valve core 41 extending into the mounting cavity 11 abuts and seals against the end face of the pilot valve seat 3. The end of the pilot valve core 41 extending into the mounting cavity 11 engages with the spring seat 42 for limiting and positioning. The spring seat 42 has a guide groove 421 facing the pilot valve core 41, so that the hydraulic oil is buffered and guided at the guide groove 421 after passing through the through hole 31 at the junction of the pilot valve core 41 and the pilot valve seat 3. The end face of the spring seat 42 away from the pilot valve seat 3 protrudes to form a limiting platform 422. One end of the pressure regulating spring 43 is sleeved on the outer circumferential surface of the limiting platform 422 and abuts against the spring seat 42. The other end of the pressure regulating spring 43 abuts against the adjusting rod 72. When it is necessary to adjust the opening pressure of the pilot valve core 41, the limit cap 73 can be rotated. The limit cap 73 drives the adjusting rod 72 to move axially to adjust the preload of the pressure adjusting spring 43, thereby realizing the adjustment of the opening pressure of the pilot valve core 41.
[0047] In the initial state, due to the preload of the pressure regulating spring 43 and the return spring 53, the pilot valve core 41 and the main valve core 51 respectively press against the inner wall of the pilot valve seat 3 and the first oil port 22, and the entire valve is in the closed state. When oil is supplied at the first oil port 22, hydraulic oil acts on the end face of the main valve core 51 and enters the main valve chamber 21 through the damping hole 24. The hydraulic oil enters the through hole 31 through the connecting hole 313 on the pilot valve seat 3. The hydraulic oil acts on the end face of the pilot valve core 41 through the oil passage gap 44. When the pressure of the hydraulic oil on the end face of the pilot valve core 41 is greater than the force of the pressure regulating spring 43, the hydraulic oil pushes the pilot valve core 41 to move and open the oil passage between the through hole 31 and the mounting chamber 11, which plays the role of pressure limiting opening. The hydraulic oil entering the mounting chamber 11 is recycled through the return oil port 12. When the oil in the mounting chamber 11 is depressurized, the pressure regulating spring 43 resets and pushes the pilot valve core 41 to move. The pilot valve core 41 discharges the oil in the small diameter section 312 from the oil passage gap 44, which reduces the impact when the pilot valve core 41 closes and plays a buffering role. When the pressure at the first oil port 22 continues to increase, the force exerted by the hydraulic oil on the end face of the main valve core 51 is greater than the force exerted by the return spring 53. The hydraulic oil then pushes the main valve core 51 to move, opening the oil passage between the first oil port 22 and the second oil port 23, thereby achieving the overflow function and playing the role of overload protection.
[0048] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.
Claims
1. An overflow valve, characterized in that, include: Valve seat (1), wherein an mounting cavity (11) is formed in the valve seat (1); The main valve sleeve (2) is connected to the valve seat (1). A main valve cavity (21) is formed inside the main valve sleeve (2). The main valve sleeve (2) has a first oil port (22) opened along the axial direction and a second oil port (23) opened along the circumferential direction. Both the first oil port (22) and the second oil port (23) are connected to the main valve cavity (21). The main valve core assembly (5) is installed in the main valve chamber (21) and can open or close the oil passage between the first oil port (22) and the second oil port (23). The main valve core assembly (5) has a damping hole (24) communicating with the first oil port (22). A pilot valve seat (3) is fixedly installed between the main valve sleeve (2) and the valve seat (1). The pilot valve seat (3) has a through hole (31) through it along the axial direction. The pilot valve seat (3) has a connecting hole (313) that communicates with the main valve cavity (21) along the circumferential direction. The pilot valve seat (3) has a stepped groove (32) that communicates with the through hole (31) at one end near the damping hole (24). A sealing element is sealed in the stepped groove (32). A pilot valve core assembly (4) is installed in the mounting cavity (11) and is capable of opening or closing the oil passage between the connecting hole (313) and the mounting cavity (11).
2. The overflow valve according to claim 1, characterized in that, The sealing component is a spherical plug (33), which is interference-fitted with the stepped groove (32) and abuts against the inner wall of the through hole (31) for sealing.
3. The overflow valve according to claim 2, characterized in that, The stepped groove (32) includes a guide section (321) and a sealing section (322). The inner diameter of the sealing section (322) is larger than the inner diameter of the through hole (31). The spherical plug (33) is interference-fitted with the sealing section (322). The guide section (321) is used to transition between the wall of the through hole (31) and the sealing section (322). The spherical plug (33) abuts and seals at the connection between the guide section (321) and the through hole (31).
4. The overflow valve according to claim 1, characterized in that, The through hole (31) includes a large diameter section (311) and a small diameter section (312). The inner diameter of the large diameter section (311) is larger than the inner diameter of the small diameter section (312). The small diameter section (312) is connected to the stepped groove (32). The large diameter section (311) is connected to the mounting cavity (11). The connecting hole (313) is opened in the large diameter section (311).
5. A relief valve according to claim 4, characterized in that, The pilot valve core assembly (4) includes a pilot valve core (41), a spring seat (42), and a pressure regulating spring (43). The pilot valve core (41) is clearance-fitted with the small diameter section (312) to form an oil passage (44). An oil passage (45) is formed between the pilot valve core (41) and the large diameter section (311). The pilot valve core (41) extends into the mounting cavity (11) and is connected to the spring seat (42). The pressure regulating spring (43) is installed in the mounting cavity (11) and abuts against the spring seat (42) so that the pilot valve core (41) abuts against the pilot valve seat (3) and closes the oil passage between the connecting hole (313) and the mounting cavity (11).
6. A relief valve according to claim 5, characterized in that, A flow guide groove (421) is provided at the connection between the spring seat (42) and the pilot valve core (41), and the end of the pilot valve core (41) extending into the mounting cavity (11) is limited and matched with the bottom end of the flow guide groove (421).
7. A relief valve according to claim 1, characterized in that, The main valve core assembly (5) includes a main valve core (51), a valve sleeve (52), and a return spring (53). The main valve sleeve (2) is provided with an abutment platform (25). The valve sleeve (52) is slidably installed in the main valve cavity (21) and abuts against the abutment platform (25) for limiting. The main valve core (51) and the valve sleeve (52) are interference-fitted. The return spring (53) is installed in the main valve cavity (21) and abuts against the main valve core (51) so that the main valve core (51) abuts against the first oil port (22) and closes the oil passage between the first oil port (22) and the second oil port (23).
8. A relief valve according to claim 1, characterized in that, The main valve sleeve (2) is sleeved outside the valve seat (1), and the outer peripheral wall of the valve seat (1) and the inner peripheral wall of the main valve sleeve (2) are fitted together to form a limiting groove (61). A retaining ring (62) is installed in the limiting groove (61) to achieve axial limiting of the valve seat (1) and the main valve sleeve (2). The main valve sleeve (2) has an installation port (63) for the retaining ring (62) to be installed into the limiting groove (61).
9. A relief valve according to claim 8, characterized in that, The main valve sleeve (2) has a mounting platform (26), the valve seat (1) extends into the main valve cavity (21) and abuts against and limits the pilot valve seat (3) on the mounting platform (26), and a sealing gasket (64) is provided between the mounting platform (26) and the pilot valve seat (3).
10. A relief valve according to claim 1, characterized in that, The valve seat (1) is threaded to the end of a sleeve (71), the sleeve (71) has an adjustment groove (711), an adjustment rod (72) is installed in the mounting cavity (11), the adjustment rod (72) extends into the adjustment groove (711) and is threaded to a limit cap (73), and the adjustment rod (72) is threaded to the sleeve (71).