Pilot-operated overflow valve

Abstract

The utility model belongs to the technical field of hydraulic elements, and discloses a pilot-operated overflow valve. The pilot valve comprises a valve sleeve, a first threaded sleeve, a pilot valve element assembly and a main valve element assembly. Part of the first threaded sleeve is located in the valve sleeve, the valve sleeve is provided with an oil inlet and an oil return hole, the first threaded sleeve is provided with an oil inlet channel and an oil outlet hole, and the oil outlet hole is communicated with the oil return hole; the pilot valve element assembly is slidably arranged in the first threaded sleeve along the X axis, a first cavity is formed between the main valve element assembly and the pilot valve element assembly, the main valve element assembly comprises a main valve element and a sliding valve element, the main valve element is slidably arranged in the valve sleeve along the X axis, the sliding valve element is provided with a damping hole, and the sliding valve element is slidably arranged in the main valve element along the X axis. An oil passing gap is formed between the sliding valve element and the main valve element, the first cavity and the oil inlet are communicated through the oil passing gap, and damping generated when hydraulic oil flows through the oil passing gap is larger than damping generated when the hydraulic oil flows through the damping hole. And by decreasing the variable damping, it is guaranteed that the pilot valve element assembly and the main valve element assembly are opened stably, and the pressure adjusting deviation is reduced.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic component technology, and in particular to a pilot-operated relief valve. Background Technology

[0002] Pressure regulation deviation refers to the difference between the set pressure and the actual pressure of pressure control components in a hydraulic system, such as relief valves or pressure reducing valves, during actual operation. Excessive pressure regulation deviation can lead to unstable system pressure, affect the working performance of actuators, cause energy waste, or prevent the hydraulic system from working properly, and may even damage hydraulic components or pipelines.

[0003] To reduce pressure regulation deviation, taking the relief valve as an example, a pilot-operated relief valve is usually used instead of a direct-acting relief valve in order to reduce pressure regulation deviation. However, since the opening of the pilot valve core of the pilot-operated relief valve in the existing technology is still unstable, it leads to the unstable opening of the main valve core, thus causing pressure regulation deviation.

[0004] Therefore, a pilot-operated relief valve is needed to solve the above problems. Utility Model Content

[0005] The purpose of this invention is to provide a pilot-operated relief valve with small pressure regulation deviation, more stable working performance, and higher precision.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A pilot-operated relief valve, comprising:

[0008] A valve sleeve and a first threaded sleeve, at least part of the first threaded sleeve is located inside the valve sleeve, the valve sleeve is provided with an oil inlet and an oil return hole, the first threaded sleeve is provided with an oil inlet channel and an oil outlet hole, and the oil outlet hole and the oil return hole are connected.

[0009] The pilot valve core assembly is slidably disposed in the first threaded sleeve along the X-axis so as to close or open the oil passage between the oil inlet channel and the oil outlet hole;

[0010] A main valve core assembly is provided, with a first chamber between the main valve core assembly and the pilot valve core assembly. The main valve core assembly includes a main valve core and a spool valve core. The main valve core is slidably disposed within the valve sleeve along the X-axis to close or open the oil passage between the oil inlet and the oil return port. The spool valve core has a damping orifice and is slidably disposed within the main valve core along the X-axis so that the damping orifice can close or open the first chamber and the oil inlet. An oil passage gap is formed between the spool valve core and the main valve core, which connects the first chamber and the oil inlet. The damping generated by the hydraulic oil flowing through the oil passage gap is less than the damping generated by the hydraulic oil flowing through the damping orifice.

[0011] Preferably, the main valve core includes a first section and a second section. The first section is capable of opening or closing the oil inlet. The second section is located at the end of the first section away from the oil inlet. The side of the second section facing the oil inlet has a concave guide surface, which guides the hydraulic oil flowing into the oil inlet to the return oil hole.

[0012] Preferably, the first section has a sealing surface and a buffer surface. The sealing surface can abut against the inner wall of the oil inlet to close the oil inlet. The buffer surface is located between the sealing surface and the concave guide surface. The angle between the buffer surface and the axis of the main valve core is smaller than the angle between the sealing surface and the axis of the main valve core.

[0013] Preferably, the first section also has an arc-shaped guide surface, which is located on the side of the sealing surface away from the buffer surface, and the arc-shaped guide surface guides the hydraulic oil from the oil inlet to the sealing surface.

[0014] Preferably, the pilot valve core assembly includes:

[0015] The pilot valve core is slidably disposed within the first threaded sleeve;

[0016] The first elastic element is housed within the first threaded sleeve and is located on the side of the pilot valve core away from the main valve core assembly. One end of the first elastic element is connected to or abuts against the pilot valve core.

[0017] Preferably, the pilot-operated relief valve further includes:

[0018] The second elastic element is housed in the first chamber, and its two ends are connected to or abut against the first threaded sleeve and the main valve core assembly, respectively.

[0019] Preferably, the pilot-operated relief valve further includes:

[0020] A first oil passage is provided at least in the first threaded sleeve and / or the valve sleeve and / or the main valve core, and the first oil passage connects the oil outlet and the oil return hole.

[0021] Preferably, the pilot-operated relief valve further includes:

[0022] A threaded sleeve assembly is disposed at the end of the first threaded sleeve away from the valve sleeve, and the threaded sleeve assembly has a hydraulic control port;

[0023] A pressure regulating valve core assembly is slidably disposed within the threaded sleeve assembly along the X-axis. The other end of the second elastic element is connected to or abuts against the pressure regulating valve core assembly. The first end of the pressure regulating valve core assembly away from the second elastic element forms a second chamber with the threaded sleeve assembly. The second end of the pressure regulating valve core assembly close to the second elastic element forms a third chamber with the threaded sleeve assembly. The end face area of ​​the first end is smaller than that of the second end. The pressure regulating valve core assembly has a second oil passage. The hydraulic control port, the second chamber, the second oil passage, and the third chamber are connected.

[0024] Preferably, the pressure regulating valve core assembly includes:

[0025] The pressure regulating valve core is slidably disposed within the screw sleeve assembly along the X-axis, and the other end of the second elastic element is connected to or abuts against the pressure regulating valve core;

[0026] The third elastic element is housed within the threaded sleeve assembly, and its two ends are connected to or abut against the threaded sleeve assembly and the pressure regulating valve core, respectively.

[0027] Preferably, the second oil passage includes:

[0028] The third channel is provided along the axial direction of the pressure regulating valve core, and the third channel is connected to the second chamber;

[0029] The fourth channel is provided radially on the pressure regulating valve core, and the fourth channel is connected to the third channel and the third chamber.

[0030] The beneficial effects of this utility model are:

[0031] This pilot-operated relief valve includes a valve sleeve, a first threaded sleeve, a pilot valve core assembly, and a main valve core assembly. At least a portion of the first threaded sleeve is located within the valve sleeve, which is provided with an oil inlet and an oil return hole. The first threaded sleeve is provided with an oil inlet channel and an oil outlet hole, which are connected. The pilot valve core assembly is slidably disposed within the first threaded sleeve along the X-axis to close or open the oil passage between the oil inlet channel and the oil outlet hole. A first chamber is provided between the main valve core assembly and the pilot valve core assembly. The main valve core assembly includes a main valve core and a spool valve core. The main valve core is slidably disposed within the valve sleeve along the X-axis to close or open the oil passage between the oil inlet and the oil return hole. The spool valve core has a damping orifice and is slidably disposed within the main valve core along the X-axis so that the damping orifice can close or open the first chamber and the oil inlet. An oil passage gap is formed between the spool valve core and the main valve core. The oil passage gap connects the first chamber and the oil inlet, and the damping generated by the hydraulic oil flowing through the oil passage gap is less than the damping generated by the hydraulic oil flowing through the damping orifice.

[0032] Initially, both the pilot valve assembly and the main valve assembly are closed; that is, the oil passages between the inlet and outlet are closed, and the oil passages between the inlet and return ports are closed. Hydraulic oil flows from the inlet into the valve sleeve, enters the first chamber through the damping orifice, and acts on the pilot valve assembly. When the hydraulic oil pressure rises to the set pressure, the hydraulic oil in the first chamber pushes the pilot valve assembly to the left, opening the oil passage between the inlet and outlet. The hydraulic oil in the first chamber flows from the inlet to the outlet, then from the outlet to the return port, and finally back to the oil tank through the return port. At this point, the pilot valve assembly is in the open state. Because the hydraulic oil is flowing, it is damped by the damping orifice of the spool valve, pushing the spool valve to the left until it contacts the pilot valve assembly. At this point, the pilot valve assembly... The component can block the damping orifice, so that the damping orifice closes the first chamber and the oil inlet, that is, the hydraulic oil no longer flows from the damping orifice; at this time, the hydraulic oil flowing in from the oil inlet flows into the first chamber through the oil gap. Since the damping generated by the hydraulic oil flowing through the oil gap is less than the damping generated by the hydraulic oil flowing through the damping orifice, the impact of the hydraulic oil on the pilot valve core assembly is smaller, which makes the opening state of the pilot valve core assembly more stable, and the hydraulic oil pressure in the first chamber is stable; at this time, the damping generated by the hydraulic oil flowing through the oil gap pushes the main valve core to move to the left, so that the oil passage between the oil inlet and the return oil hole is connected, and the hydraulic oil flows from the oil inlet to the return oil hole and flows back to the oil tank through the return oil hole.

[0033] Compared with existing technologies, the main valve core assembly of the pilot-operated relief valve in this invention includes a main valve core and a spool valve core. A damping orifice is provided on the spool valve core, and an oil passage gap is formed between the spool valve core and the main valve core. The damping generated by the hydraulic oil flowing through the oil passage gap is less than the damping generated by the flow through the damping orifice. The damping orifice ensures that the pilot valve core assembly responds quickly to system pressure, with rapid and precise action, ensuring rapid relief when the system pressure exceeds the set pressure. The oil passage gap ensures smooth opening of the pilot valve core assembly when handling large-flow relief, stabilizing the hydraulic oil pressure in the first chamber and reducing pressure fluctuations. This, in turn, ensures that the main valve core can stably open for relief under the damping effect of the hydraulic oil flowing through the oil passage gap, resulting in smaller pressure regulation deviations. By using progressively decreasing damping, while ensuring the pilot-operated relief valve can respond quickly to changes in system pressure, the opening stability of both the pilot valve core assembly and the main valve core assembly is guaranteed, reducing pressure regulation deviations and making the pilot-operated relief valve more stable and accurate. Attached Figure Description

[0034] Figure 1 This is a cross-sectional view of the pilot-operated relief valve provided by this utility model;

[0035] Figure 2 This is a cross-sectional view of the main valve core provided by this utility model;

[0036] Figure 3 This is a cross-sectional view of the slide valve core provided by this utility model;

[0037] Figure 4 This is a cross-sectional view of the pressure regulating valve core provided by this utility model.

[0038] In the picture:

[0039] 1. Valve sleeve; 11. Oil inlet; 121. First oil return hole; 122. Second oil return hole;

[0040] 2. First threaded sleeve; 21. Oil inlet channel; 22. Oil outlet hole;

[0041] 3. Pilot valve core assembly; 31. Pilot valve core; 32. First elastic element;

[0042] 4. Main valve core assembly; 41. Main valve core; 4111. First section; 41111. Sealing surface; 41112. Buffer surface; 41113. Arc-shaped guide surface; 4112. Second section; 41121. Concave guide surface; 412. Guide hole; 413. Receiving groove; 42. Spool valve core; 421. Damping hole; 422. Sliding part; 423. Limiting part; 43. Oil passage gap;

[0043] 51. First chamber; 52. Second chamber; 53. Third chamber;

[0044] 6. Second elastic element;

[0045] 71. First Channel; 72. Second Channel;

[0046] 8. Screw sleeve assembly; 81. Second screw sleeve; 82. Adjusting component; 83. Locking component;

[0047] 9. Pressure regulating valve core assembly; 91. Pressure regulating valve core; 911. First part; 9111. First end; 912. Second part; 9121. Second end; 913. Third part; 914. Third channel; 915. Fourth channel; 92. Third elastic element. Detailed Implementation

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] Pressure regulation deviation refers to the difference between the set pressure and the actual pressure of pressure control components in a hydraulic system, such as relief valves or pressure reducing valves, during actual operation. Excessive pressure regulation deviation can lead to unstable system pressure, affect the performance of actuators, cause energy waste, or even damage to hydraulic components or pipelines. To reduce pressure regulation deviation, pilot-operated relief valves are often used instead of direct-acting relief valves, aiming to reduce this deviation. However, the opening of the pilot valve core in existing pilot-operated relief valves is still unstable, leading to unstable opening of the main valve core and thus causing pressure regulation deviation.

[0053] like Figures 1-4As shown, this embodiment provides a pilot-operated relief valve, including a valve sleeve 1, a first threaded sleeve 2, a pilot valve core assembly 3, and a main valve core assembly 4. At least a portion of the first threaded sleeve 2 is located within the valve sleeve 1. The valve sleeve 1 is provided with an oil inlet 11 and an oil return hole. The first threaded sleeve 2 is provided with an oil inlet channel 21 and an oil outlet 22, and the oil outlet 22 and the oil return hole are connected. The pilot valve core assembly 3 is slidably disposed within the first threaded sleeve 2 along the X-axis to close or open the oil passage between the oil inlet channel 21 and the oil outlet 22. A first chamber 51 is provided between the main valve core assembly 4 and the pilot valve core assembly 3. The main valve core assembly 4 includes a main valve core 41 and a spool valve core 42. The main valve core 41 is slidably disposed along the X-axis. The valve core 42 is slidably disposed within the valve sleeve 1 to close or open the oil passage between the oil inlet 11 and the oil return hole. The valve core 42 has a damping hole 421. The valve core 42 is slidably disposed within the main valve core 41 along the X-axis so that the damping hole 421 can connect the first chamber 51 and the oil inlet 11. An oil passage gap 43 is formed between the valve core 42 and the main valve core 41. The oil passage gap 43 connects the first chamber 51 and the oil inlet 11, and the damping generated by the hydraulic oil flowing through the oil passage gap 43 is greater than the damping generated by the hydraulic oil flowing through the damping hole 421.

[0054] In the initial state, both the pilot valve core assembly 3 and the main valve core assembly 4 are in the closed state, that is, the oil passage between the oil inlet channel 21 and the oil outlet 22 is closed, and the oil passage between the oil inlet 11 and the oil return hole is closed. Hydraulic oil flows from inlet 11 into valve sleeve 1, and enters first chamber 51 through damping hole 421. The hydraulic oil in first chamber 51 acts on pilot valve core assembly 3. When the hydraulic oil pressure rises to the set pressure, the hydraulic oil in first chamber 51 pushes pilot valve core assembly 3 to the left, so that the oil passage between inlet channel 21 and outlet hole 22 is connected. The hydraulic oil in first chamber 51 flows from inlet channel 21 to outlet hole 22, and from outlet hole 22 to return hole, and finally flows back to oil tank through return hole. At this time, pilot valve core assembly 3 is in the open state. Since the hydraulic oil is in a flowing state, the hydraulic oil generates liquid resistance through damping hole 421 of spool valve core 42, pushing spool valve core 42 to the left until spool valve core 42 abuts against pilot valve core assembly 3. At this time, pilot valve core assembly 3 can block damping hole. 421, so that the oil passage between the first chamber 51 and the oil inlet 11 is closed, that is, the hydraulic oil no longer flows from the damping hole 421; at this time, the hydraulic oil flowing in from the oil inlet 11 flows into the first chamber 51 through the oil gap 43. Since the damping generated by the hydraulic oil flowing through the oil gap 43 is greater than the damping generated by the hydraulic oil flowing through the damping hole 421, the flow rate of hydraulic oil to the first chamber 51 is smaller, which in turn makes the impact of hydraulic oil on the pilot valve core assembly 3 smaller, so that the opening state of the pilot valve core assembly 3 is more stable and the hydraulic oil pressure in the first chamber 51 is stable; at this time, the damping generated by the hydraulic oil flowing through the oil gap 43 pushes the main valve core 41 to the left, so that the oil passage between the oil inlet 11 and the return oil hole is connected, and the hydraulic oil flows from the oil inlet 11 to the return oil hole and flows back to the oil tank through the return oil hole.

[0055] Compared with the prior art, the main valve core assembly 4 of the pilot-operated relief valve in this embodiment includes a main valve core 41 and a spool valve core 42. The spool valve core 42 is provided with a damping orifice 421. An oil passage gap 43 is formed between the spool valve core 42 and the main valve core 41, and the damping generated by the hydraulic oil flowing through the oil passage gap 43 is greater than the damping generated by the hydraulic oil flowing through the damping orifice 421. The setting of the damping orifice 421 can ensure that the pilot valve core assembly 3 can respond quickly to the system pressure and act quickly and accurately, ensuring that the system pressure is greater than the set pressure and that the relief can be quickly achieved. The setting of the oil passage gap 43 makes the opening of the pilot valve core assembly 3 smooth when a large flow relief needs to be handled, so that the hydraulic oil pressure in the first chamber 51 is stable, reducing pressure fluctuations. This ensures that the main valve core 41 can stably open for relief under the damping generated by the hydraulic oil flowing through the oil passage gap 43, resulting in a smaller pressure adjustment deviation. By gradually decreasing the damping, the pilot-operated relief valve can respond quickly to changes in system pressure, while ensuring stable opening of the pilot valve core assembly 3 and the main valve core assembly 4, reducing pressure regulation deviation, and making the pilot-operated relief valve more stable and accurate.

[0056] Specifically, such as Figure 1 , Figure 2 As shown, the main valve core 41 includes a first section 4111 and a second section 4112. The first section 4111 can open or close the oil inlet 11. The second section 4112 is located at the end of the first section 4111 away from the oil inlet 11. The side of the second section 4112 facing the oil inlet 11 has a concave guide surface 41121, which guides the hydraulic oil flowing into the oil inlet 11 to the return oil hole. By setting the concave guide surface 41121, when the main valve core 41 is open, the hydraulic oil in the oil inlet 11 can flow smoothly to the return oil hole under the guidance of the concave guide surface 41121, reducing the impact of hydraulic oil on the main valve core 41, making the opening state of the main valve core 41 more stable, thereby reducing pressure regulation deviation.

[0057] Preferably, the first section 4111 has a sealing surface 41111 and a buffer surface 41112. The sealing surface 41111 can abut against the inner wall of the oil inlet 11 to close the oil inlet 11. The buffer surface 41112 is located between the sealing surface 41111 and the concave guide surface 41121. The angle between the buffer surface 41112 and the axis of the main valve core 41 is smaller than the angle between the sealing surface 41111 and the axis of the main valve core 41. By abutting the inner wall of the oil inlet 11 with the sealing surface 41111, the oil inlet 11 is closed, thus forming a hard seal. When closed, there is no elastic deformation, resulting in a more stable system pressure setting value and smaller pressure adjustment deviation. By setting the included angle between the buffer surface 41112 and the axis of the main valve core 41 to be smaller than the included angle between the sealing surface 41111 and the axis of the main valve core 41, when the main valve core 41 is open, the hydraulic oil is sprayed and overflowed from the gap between the sealing surface 41111 and the inner wall of the oil inlet 11. It can then smoothly diffuse along the buffer surface 41112. The buffer surface 41112 guides the hydraulic oil to flow gently to the concave guide surface 41121, reducing the violent impact of the hydraulic oil on the main valve core 41. This makes the opening state of the main valve core 41 more stable, thereby reducing pressure adjustment deviation.

[0058] Furthermore, the first section 4111 also has an arc-shaped guide surface 41113, which is located on the side of the sealing surface 41111 away from the buffer surface 41112. The arc-shaped guide surface 41113 guides the hydraulic oil from the inlet 11 to the sealing surface 41111. The arc-shaped guide surface 41113 optimizes the flow path of the hydraulic oil, allowing it to flow smoothly from the inlet 11 to the sealing surface 41111. Its smooth arc-shaped contour helps guide the hydraulic oil to flow stably, thereby making the opening state of the main valve core 41 more stable and reducing pressure regulation deviation.

[0059] Specifically, such as Figure 1 As shown, the pilot valve core assembly 3 includes a pilot valve core 31 and a first elastic element 32. The pilot valve core 31 is slidably disposed within the first threaded sleeve 2, and the first elastic element 32 is housed within the first threaded sleeve 2 and located on the side of the pilot valve core 31 away from the main valve core assembly 4. One end of the first elastic element 32 is connected to or abuts against the pilot valve core 31. It can be understood that the preload of the first elastic element 32 is the set pressure of this pilot-operated relief valve. When the system pressure drops below the set pressure, the first elastic element 32 pushes the pilot valve core 31 to slide to the right, thereby closing the oil passage between the oil inlet channel 21 and the oil outlet 22, and the pilot valve core 31 switches to the closed state.

[0060] In this embodiment, the first elastic element 32 is a spring.

[0061] Specifically, such as Figure 1As shown, this pilot-operated relief valve also includes a second elastic element 6, which is housed in the first chamber 51. The two ends of the second elastic element 6 are connected to or abut against the first threaded sleeve 2 and the main valve core assembly 4, respectively. When the system pressure drops below the set pressure, the pilot valve core 31 slides to the right, closing the oil passage between the oil inlet channel 21 and the oil outlet 22. At this time, the hydraulic oil at the oil inlet 11 flows into the first chamber 51 through the oil passage gap 43, gradually balancing the oil pressure in the first chamber 51 with the oil pressure at the oil inlet 11. The preload of the second elastic element 6 pushes the main valve core assembly 4 to the right, closing the oil passage between the oil inlet 11 and the return oil hole, and the main valve core assembly 4 switches to the closed state.

[0062] In this embodiment, as Figures 1-3 As shown, the main valve core 41 has a guide hole 412, and the slide valve core 42 includes a sliding part 422 and a limiting part 423. The sliding part 422 is slidably disposed in the guide hole 412, and the limiting part 423 is located in the first chamber 51 and can abut against the main valve core 41. The two ends of the second elastic member 6 are connected to or abut against the first screw sleeve 2 and the limiting part 423, respectively. When the second elastic member 6 pushes the main valve core assembly 4 to reset, it first pushes the slide valve core 42 to slide to the right until the limiting part 423 abuts against the main valve core 41. Then, the main valve core 41 slides to the right together under the drive of the slide valve core 42 until the conical guide surface of the main valve core 41 abuts against the oil inlet 11 of the valve sleeve 1, and the main valve core assembly 4 switches to the closed state.

[0063] In this embodiment, the second elastic element 6 is a spring.

[0064] Specifically, this pilot-operated relief valve also includes a first oil passage, at least a portion of which is disposed in the first threaded sleeve 2 and / or valve sleeve 1 and / or main valve core 41. The first oil passage connects the oil outlet 22 and the oil return hole. The hydraulic oil flowing out of the oil outlet 22 is guided to the oil return hole through the first oil passage and then flows back to the oil tank through the oil return hole.

[0065] In this embodiment, as Figure 1 , Figure 2 As shown, the main valve core 41 has a receiving groove 413, and at least a portion of the first threaded sleeve 2 is located in the receiving groove 413. This arrangement allows the axial length of the pilot-operated relief valve to be shorter and the overall structure to be more compact. At this time, there is a space between one end of the first threaded sleeve 2 and the inner wall of the receiving groove 413, which forms the first chamber 51 mentioned above. The first oil passage includes a first channel 71 and a second channel 72. Along the Y-axis direction, the gap between the first threaded sleeve 2 and the valve sleeve 1 forms the first channel 71, which is connected to the oil outlet 22. Along the Y-axis direction, the gap between the main valve core 41 and the valve sleeve 1 forms the second channel 72, which is connected to the first channel 71 and the oil return hole.

[0066] Furthermore, such as Figure 1 As shown, the return oil holes in this embodiment include a first return oil hole 121 and a second return oil hole 122. The first return oil hole 121 and the second return oil hole 122 are spaced apart on the valve sleeve 1 along the X-axis, and the first return oil hole 121 and the second return oil hole 122 are not connected when the main valve core assembly 4 is in the closed state. The first return oil hole 121 is connected to the oil outlet hole 22 through the first oil passage, so that when the pilot valve core 31 is open and the main valve core assembly 4 is closed, the hydraulic oil can only flow back to the oil tank through the first return oil hole 121. When the main valve core assembly 4 is open, the oil passage between the oil inlet 11 and the second return oil hole 122 is connected, and the hydraulic oil flows back to the oil tank through both the first return oil hole 121 and the second return oil hole 122.

[0067] In the operating environment of construction machinery, changes in workload are a common operating condition for various valves. For example, when an excavator switches from rock breaking to earth excavation, the excavator's workload is significantly reduced. At this time, the set pressure of the relief valve in the excavator's hydraulic system remains unchanged, which will lead to energy consumption.

[0068] To solve the above problems, such as Figure 1 , Figure 4 As shown, this pilot-operated relief valve also includes a screw sleeve assembly 8 and a pressure regulating valve core assembly 9. The screw sleeve assembly 8 is located at the end of the first screw sleeve 2 away from the valve sleeve 1, and the screw sleeve assembly 8 has a hydraulic control port. The pressure regulating valve core assembly 9 is slidably disposed within the screw sleeve assembly 8 along the X-axis. The other end of the second elastic member 6 is connected to or abuts against the pressure regulating valve core assembly 9. The first end 9111 of the pressure regulating valve core assembly 9 away from the second elastic member 6 forms a second chamber 52 with the screw sleeve assembly 8. The second end 9121 of the pressure regulating valve core assembly 9 close to the second elastic member 6 forms a third chamber 53 with the screw sleeve assembly 8. The end face area of ​​the first end 9111 is smaller than the end face area of ​​the second end 9121. The pressure regulating valve core assembly 9 has a second oil passage, and the hydraulic control port, the second chamber 52, the second oil passage, and the third chamber 53 are connected.

[0069] When the workload decreases, hydraulic oil is supplied through the hydraulic control port. The hydraulic oil flows sequentially to the second chamber 52, the second oil passage, and the third chamber 53. It can be understood that when the hydraulic oil fills the second chamber 52 and the third chamber 53, the pressure of the hydraulic oil in the second chamber 52 and the third chamber 53 is the same. Since the end face area of ​​the first end 9111 is smaller than the end face area of ​​the second end 9121, the pressure exerted by the hydraulic oil in the third chamber 53 on the end face of the second end 9121 is greater than the pressure exerted by the hydraulic oil in the second chamber 52 on the end face of the first end 9111. The pressure regulating valve core assembly 9 moves to the left, that is, the pressure regulating valve core assembly 9 moves away from the pilot valve core assembly 3, which reduces the pre-compression of the second elastic element 6, that is, reduces the pre-tightening force of the second elastic element 6, thereby reducing the set pressure of this pilot-operated relief valve.

[0070] Specifically, such as Figure 1 As shown, the pressure regulating valve core assembly 9 includes a pressure regulating valve core 91 and a third elastic element 92. The pressure regulating valve core 91 is slidably disposed within the threaded sleeve assembly 8 along the X-axis. The other end of the second elastic element 6 is connected to or abuts against the pressure regulating valve core 91. The third elastic element 92 is housed within the threaded sleeve assembly 8, and its two ends are connected to or abut against the threaded sleeve assembly 8 and the pressure regulating valve core 91, respectively. When the working load is restored, the hydraulic oil flow at the hydraulic control port is stopped. The third elastic element 92 pushes the pressure regulating valve core 91 to reset, and the pressure regulating valve core 91 moves to the right, that is, it moves towards the pilot valve core assembly 3, so that the pre-compression of the second elastic element 6 is restored, thereby restoring the set pressure of this pilot-operated relief valve to its initial value.

[0071] In this embodiment, as Figure 4 As shown, the pressure regulating valve core 91 includes a first part 911, a second part 912, and a third part 913. The first part 911 and the third part 913 are disposed at both ends of the second part 912. The diameter of the second part 912 is larger than the diameter of the first part 911 and the diameter of the third part 913. The end face of the first part 911 facing away from the second part 912 is the end face of the first end 9111, and the end face of the second part 912 facing away from the first part 911 is the end face of the second end 9121. It can be understood that the end face of the second end 9121 is annular. The third part 913 is connected to or abuts against the first elastic member 32.

[0072] Specifically, such as Figure 1 , Figure 4As shown, the second oil passage includes a third passage 914 and a fourth passage 915. The pressure regulating valve core 91 has the third passage 914 axially, which communicates with the second chamber 52. The pressure regulating valve core 91 has the fourth passage 915 radially, which communicates with the third passage 914 and the third chamber 53. Hydraulic oil can flow through the third passage 914 and the fourth passage 915 into the third chamber 53 and act on the end face of the second end 9121.

[0073] Specifically, such as Figure 1 As shown, the screw sleeve assembly 8 includes a second screw sleeve 81 and an adjusting member 82. The second screw sleeve 81 is located at the end of the first screw sleeve 2 away from the valve sleeve 1. At least part of the adjusting member 82 is threadedly connected to the end of the second screw sleeve 81 away from the first screw sleeve 2. The third elastic member 92 is connected to or abuts against the adjusting member 82. By turning the adjusting member 82 to change its screwing depth into the second screw sleeve 81, the preload of the third elastic member 92 is adjusted, thereby adjusting the hydraulic oil pressure supplied at the hydraulic control port to adjust the precompression of the second elastic member 6 when the working load needs to be changed.

[0074] In this embodiment, the adjusting member 82 has a sliding groove, at least a portion of the first part 911 is slidably disposed in the sliding groove, and the third elastic member 92 is sleeved on the outer periphery of the second part 912. The two ends of the third elastic member 92 are connected to or abut against the adjusting member 82 and the second part 912 respectively. By sleeved on the outer periphery of the second part 912, the internal space of the pilot-operated relief valve is effectively utilized, and the axial length of the pilot-operated relief valve is reduced.

[0075] Specifically, such as Figure 1 As shown, the screw sleeve assembly 8 also includes a locking member 83, which is threadedly connected to the portion of the adjusting member 82 located outside the second screw sleeve 81. The locking member 83 can abut against the second screw sleeve 81. By threading the locking member 83 onto the portion of the adjusting member 82 located outside the second screw sleeve 81 and by abutting the locking member 83 against the second screw sleeve 81, the adjusting member 82 can be locked by the torque of the locking member 83, preventing the adjusting member 82 from shifting.

[0076] In this embodiment, the locking element 83 is a locking nut.

[0077] 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. A pilot operated spill valve characterized by, The valve sleeve (1) and the first screw sleeve (2) are located at least partially in the valve sleeve (1), the valve sleeve (1) is provided with an oil inlet (11) and an oil return hole, the first screw sleeve (2) is provided with an oil inlet channel (21) and an oil outlet hole (22), and the oil outlet hole (22) and the oil return hole are communicated; The pilot valve core assembly (3) is slidably arranged in the first screw sleeve (2) along the X axis to close or open the oil path between the oil inlet channel (21) and the oil outlet hole (22); The main valve core assembly (4) and the pilot valve core assembly (3) have a first cavity (51), the main valve core assembly (4) includes a main valve core (41) and a spool valve core (42), the main valve core (41) is slidably arranged in the valve sleeve (1) along the X axis to close or open the oil path between the oil inlet (11) and the oil return hole, the spool valve core (42) has a damping hole (421), the spool valve core (42) is slidably arranged in the main valve core (41) along the X axis, the damping hole (421) is communicated with the first cavity (51) and the oil inlet (11), and an oil passing gap (43) is formed between the spool valve core (42) and the main valve core (41), the oil passing gap (43) is communicated with the first cavity (51) and the oil inlet (11), and the damping generated by the oil flowing through the oil passing gap (43) is greater than the damping generated by the oil flowing through the damping hole (421). The main valve core (41) includes a first section (4111) and a second section (4112), the first section (4111) can open or close the oil inlet (11), the second section (4112) is arranged at one end of the first section (4111) away from the oil inlet (11), one side of the second section (4112) towards the oil inlet (11) has a concave flow guide surface (41121), and the concave flow guide surface (41121) guides the hydraulic oil flowing into the oil inlet (11) to the oil return hole.

2. The pilot operated spill valve of claim 1 wherein, The first section (4111) has a sealing surface (41111) and a buffer surface (41112), the sealing surface (41111) can abut the inner wall of the oil inlet (11) to close the oil inlet (11), and the buffer surface (41112) is located between the sealing surface (41111) and the concave flow guide surface (41121), and the angle between the buffer surface (41112) and the axis of the main valve core (41) is smaller than the angle between the sealing surface (41111) and the axis of the main valve core (41).

3. The pilot operated spill valve of claim 2 wherein, The first section (4111) further has an arc-shaped flow guide surface (41113) located on the side of the sealing surface (41111) away from the buffer surface (41112), and the arc-shaped flow guide surface (41113) guides the hydraulic oil of the oil inlet (11) to the sealing surface (41111).

4. The pilot operated spill valve of claim 3 wherein, The pilot valve core assembly (3) includes:

5. The pilot operated spill valve of claim 1 wherein, ​ A pilot spool (31) is slidably arranged in the first screw sleeve (2); A first elastic member (32) is accommodated in the first screw sleeve (2) and located on a side of the pilot spool (31) away from the main spool assembly (4), one end of the first elastic member (32) is connected to or abuts against the pilot spool (31).

6. The pilot operated pressure relief valve of claim 1, wherein, The pilot overflow valve further comprises: A second elastic member (6) is accommodated in the first chamber (51), and two ends of the second elastic member (6) are connected to or abut against the first screw sleeve (2) and the main spool assembly (4) respectively.

7. The pilot operated spill valve of claim 1 wherein, The pilot overflow valve further comprises: A first oil passage, at least a part of the first oil passage is arranged in the first screw sleeve (2) and / or the valve sleeve (1) and / or the main spool (41), the first oil passage communicates the oil outlet hole (22) and the oil return hole.

8. The pilot operated spill valve of claim 6 wherein, The pilot overflow valve further comprises: A screw sleeve assembly (8) is arranged at an end of the first screw sleeve (2) away from the valve sleeve (1), the screw sleeve assembly (8) has a hydraulic control port; A pressure regulating spool assembly (9) is slidably arranged in the screw sleeve assembly (8) along the X-axis, the other end of the second elastic member (6) is connected to or abuts against the pressure regulating spool assembly (9), a first end (9111) of the pressure regulating spool assembly (9) away from the second elastic member (6) forms a second chamber (52) with the screw sleeve assembly (8), a second end (9121) of the pressure regulating spool assembly (9) close to the second elastic member (6) forms a third chamber (53) with the screw sleeve assembly (8), the end face area of the first end (9111) is smaller than that of the second end (9121), the pressure regulating spool assembly (9) has a second oil passage, the hydraulic control port, the second chamber (52), the second oil passage and the third chamber (53) are communicated.

9. The pilot operated spill valve of claim 8 wherein, The pressure regulating spool assembly (9) comprises: A pressure regulating spool (91) is slidably arranged in the screw sleeve assembly (8) along the X-axis, the other end of the second elastic member (6) is connected to or abuts against the pressure regulating spool (91); A third elastic member (92) is accommodated in the screw sleeve assembly (8), two ends of the third elastic member (92) are connected to or abut against the screw sleeve assembly (8) and the pressure regulating spool (91) respectively.

10. The pilot operated spill valve of claim 9, wherein, The second oil passage comprises: A third passage (914) is axially arranged in the pressure regulating spool (91), the third passage (914) is communicated with the second chamber (52); A fourth passage (915) is radially arranged in the pressure regulating spool (91), the fourth passage (915) is communicated with the third passage (914) and the third chamber (53).

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