Overflow unloading combination valve

Abstract

The invention discloses an overflow unloading combination valve which comprises a pump body and a valve body which are communicated through a high-pressure oil inlet channel. A first chamber and a second chamber are arranged in the valve body; the valve body is provided with a first-stage overflow port, a second-stage overflow port and a pressure relief port; valve cores are arranged in the first chamber and the second chamber; the moving direction of the valve element is perpendicular to the axis direction of the first-stage overflow opening. The valve core comprises a first valve core section and a second valve core section; in the initial state, the side wall of the first valve element section seals the first-stage overflow opening and the second-stage overflow opening. In an overflow state, the first valve element section and the second valve element section open the first-stage overflow opening and the second-stage overflow opening; and in an unloading state, the first-stage overflow port and the second-stage overflow port are completely opened by the second valve core section. The moving direction of the valve element is perpendicular to the axis direction of the overflow port, the overflow port is closed or opened through the side wall of the valve element, the valve element is effectively prevented from repeatedly colliding with the oil port, and abrasion of the valve element and / or the overflow port is reduced; damage to parts in the valve body is avoided, and the service life of the valve body is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of valve body manufacturing, and in particular relates to an overflow unloading combined valve. Background Art

[0002] A valve is a device used to control the direction, pressure, and flow of a fluid in a fluid system. It is a device that allows the medium (liquid, gas, powder) in pipes and equipment to flow or stop and control its flow. A valve is a control component in a pipeline fluid delivery system. It is used to change the passage section and the flow direction of the medium. It has the functions of diversion, cutoff, throttling, non-return, diversion, or overflow pressure relief.

[0003] The existing overflow valve structure can refer to patent CN220016202U, "A New Overflow Valve"; the unloading valve structure can refer to patent CN103089740B, "Unloading Valve and Unloading Valve Cylinder". In the prior art including the above patents, a steel ball structure is set in the overflow valve and the unloading valve, and the opening and closing of the oil port are controlled by the movement of the steel ball to achieve the function of overflow pressure relief or unloading. In actual operation, since the steel ball or other structure is coaxially arranged with the oil port, other known structures including the steel ball structure will be affected by the oil pressure fluctuation and repeatedly collide with the oil port (i.e., the overflow port of this application), thereby causing different degrees of wear on the surface of the steel ball and the oil port; and in this process, the movement of the steel ball will cause pressure and friction, thereby converting mechanical energy into heat energy, causing the internal heating of the valve body. Due to the internal heating of the valve body, the sealing ring and other structural parts may wear due to the high temperature, which not only affects the stability of the structure, but also shortens the service life of the valve body.

[0004] In addition, in practical applications, the equipment needs to satisfy both overflow and unloading functions. At this time, overflow valves and unloading valves are usually configured in the equipment pipeline respectively, which not only increases the volume of the overall structure, but also increases the complexity and cost of the system.

[0005] In order to solve the above problems, designing a relief unloading combination valve is an important technical problem that the technicians in this field need to solve. Summary of the invention

[0006] The purpose of the present invention is to solve the above problems existing in the prior art and to provide a relief unloading combined valve.

[0007] The purpose of the present invention is achieved through the following technical solutions: A relief unloading combined valve comprises a pump body and a valve body, the two are connected through a high-pressure oil inlet passage, and the pump body controls the amount of oil and the oil pressure input to the valve body; at least a first chamber and a second chamber are arranged in the valve body; the valve body is provided with two primary overflow ports and a secondary overflow port respectively connected to the first chamber and the second chamber, and a pressure relief port connected to the main body of the first chamber and the second chamber; The first chamber and the second chamber are both provided with a valve core, a sealing gasket and a compression spring; the movement direction of the valve core is perpendicular to the axial direction of the primary overflow port and / or the secondary overflow port; the valve core is formed by a first valve core section and a second valve core section being integrally arranged; In an initial state, the first valve core section is located at the primary overflow port and the secondary overflow port, and closes the primary overflow port and the secondary overflow port; In the overflow state, the first valve core section and the second valve core section are located at the primary overflow port and the secondary overflow port, and the primary overflow port and the secondary overflow port are partially opened to communicate with the pressure relief port; In the unloading state, the second valve core section is located at the primary overflow port and the secondary overflow port, and fully opens the primary overflow port and the secondary overflow port to communicate with the pressure relief port.

[0008] Preferably, the first chamber and the second chamber are T-shaped; a first overflow unloading group is arranged in the first chamber, which at least includes a first valve core, a first sealing gasket fixed to the output end of the first valve core, and a first compression spring; the first valve core is located in the small diameter section of the first chamber, and the input end of the first valve core is located at the output end of the high-pressure oil inlet channel; the first compression spring is located in the large diameter section of the first chamber, and is always in contact with the first sealing gasket.

[0009] Preferably, a second overflow unloading group is arranged in the second chamber, which at least includes a second valve core, a second sealing gasket fixed to the output end of the second valve core, and a second compression spring; the second valve core is located in the small diameter section of the second chamber, and the input end of the second valve core is located at the output end of the high-pressure oil inlet channel, and the second compression spring is located in the large diameter section of the second chamber and is always in contact with the second sealing gasket.

[0010] Preferably, the spring force of the second compression spring is greater than the spring force of the first compression spring; the second compression spring is composed of an inner compression spring and an outer compression spring nested together, wherein the model of the inner compression spring is the same as that of the first compression spring, and the spring force of the outer compression spring is greater than the spring force of the inner compression spring.

[0011] Preferably, the first compression spring and the second compression spring are respectively mounted on a first spring seat and a second spring seat having a T-shaped cross-section; and both ends of the first compression spring are fixed to the first spring seat and the first sealing gasket, and both ends of the second compression spring are fixed to the second spring seat and the second sealing gasket.

[0012] Preferably, in an initial state, ends of the first spring seat and the second spring seat are spaced apart from the first sealing gasket and the second sealing gasket, and the shortest distance between the two is equivalent to the diameter of the primary overflow port and the secondary overflow port; in an unloading state, the first spring seat abuts against the first sealing gasket, and / or the second spring seat abuts against the second sealing gasket.

[0013] Preferably, the valve body is composed of a first shell and a second shell, which are connected by bolts to form the first chamber and the second chamber.

[0014] Preferably, two adjusting screws are passed through the end of the first shell, the bottoms of the adjusting screws are respectively abutted against the ends of the first spring seat and the second spring seat, and the spring forces of the first compression spring and the second compression spring are adjusted by the adjusting screws.

[0015] Preferably, a fixing bolt is provided at the end of the second shell; in an initial state, the input ends of the first valve core and the second valve core abut against the end of the fixing bolt; in an overflow state and an unloading state, the input ends of the first valve core and the second valve core are spaced apart from the end of the fixing bolt.

[0016] The utility model relates to an overflow unloading combined valve, which is applied to the control oil circuit of a hydraulic wrench.

[0017] The advantages of the technical solution of the present invention are mainly reflected in: Compared with the prior art in which the valve core is coaxially arranged with the oil port and moves along the axial direction of the oil port, the present application sets the moving direction of the valve core perpendicular to the axial direction of the overflow port, and only uses the side wall of the valve core to close or open the overflow port, which can effectively avoid the valve core from repeatedly colliding with the oil port, reducing the wear of the valve core and / or the overflow port; at the same time, it avoids damage to the components in the valve body due to heat, and prolongs the service life of the valve body; At least two overflow unloading groups are arranged in the valve body, and the two overflow unloading groups can work independently or simultaneously to meet the overflow or unloading requirements under different levels of oil pressure; and the overflow unloading groups are arranged in parallel in the valve body, simplifying the complexity of the pipeline valve body structure while reducing the volume of the valve body; The second compression spring is composed of two springs of different types nested together, which increases the spring force without increasing the overall length of the compression spring, thereby enhancing the feasibility and compatibility with the valve body; and the second compression spring cooperates with the first compression spring to control the overflow and pressure relief of oil in a graded manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 : A cross-sectional view of a preferred embodiment of the present invention; Figure 2 : A cross-sectional view of the valve body structure of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0019] The purpose, advantages and features of the present invention will be illustrated and explained by the non-limiting description of the following preferred embodiments. These embodiments are only typical examples of the application of the technical solution of the present invention, and any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection claimed by the present invention.

[0020] In the description of the scheme, it should be noted that the terms "center", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience and simplification of description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance. Moreover, in the description of the scheme, with the operator as a reference, the direction close to the operator is the proximal end, and the direction away from the operator is the distal end.

[0021] The present invention discloses a relief unloading combination valve which can be applied to the control oil circuit of a hydraulic wrench. The relief unloading combination valve specifically includes: Figure 1 The pump body 1 and the valve body 2 are connected through the high-pressure oil inlet passage 102, and the pump body 1 controls the oil volume and oil pressure input to the valve body 2. Figure 2 As shown, the valve body 2 is composed of a first shell 210 and a second shell 220 , which are connected by bolts to form a first chamber 201 and a second chamber 202 .

[0022] like Figure 2 As shown, at least the first chamber 201 and the second chamber 202 are arranged in the valve body 2, and the first chamber 201 can work independently of the second chamber 202, or the two can work simultaneously. The present application includes but is not limited to two chambers, and the specific number of chambers can be adjusted according to the use requirements, and the specific number is not limited here.

[0023] Furthermore, the valve body 2 is provided with two primary overflow ports 2011 and secondary overflow ports 2021 respectively communicating with the first chamber 201 and the second chamber 202, and a pressure relief port 203 communicating with the main bodies of the first chamber 201 and the second chamber 202. The pressure relief port 203 can be selectively communicated with the primary overflow port 2011 and / or the secondary overflow port 2021 to achieve the function of overflowing or unloading oil.

[0024] Furthermore, a valve core, a sealing gasket and a compression spring are arranged in the first chamber 201 and the second chamber 202. The moving direction of the valve core is perpendicular to the axial direction of the primary overflow port 2011 and / or the secondary overflow port 2021. Compared with the prior art in which the valve core is coaxially arranged with the oil port and moves along the axial direction of the oil port, the design of the present application can effectively prevent the valve core from repeatedly colliding with the oil port, reduce the wear of the valve core and / or the overflow port; at the same time, avoid damage to the components in the valve body due to heat.

[0025] like Figure 2 As shown, the valve core is formed by a first valve core section 2121 and a second valve core section 2122. Further, the diameter of the first valve core section 2121 is greater than the diameter of the second valve core section 2122; and the outer diameter of the first valve core section 2121 is equivalent to the inner diameter of the small diameter section of the first chamber 201 and / or the second chamber 202. Therefore, in the initial state, the first valve core section 2121 is located at the primary overflow port 2011 and the secondary overflow port 2021, and closes the primary overflow port 2011 and the secondary overflow port 2021. In the overflow state, the valve core moves along the axial direction of the first chamber 201 and / or the second chamber 202 under the action of oil pressure, so that the first valve core section 2121 and the second valve core section 2122 are located at the primary overflow port 2011 and the secondary overflow port 2021, and the primary overflow port 2011 and the secondary overflow port 2021 are partially opened to communicate with the pressure relief port 203. In the unloading state, the second valve core section 2122 is located at the primary overflow port 2011 and the secondary overflow port 2021, and the primary overflow port 2011 and the secondary overflow port 2021 are fully opened to communicate with the pressure relief port 203.

[0026] Furthermore, the first chamber 201 and the second chamber 202 are both T-shaped. A first overflow unloading group 21 is provided in the first chamber 201, which at least includes a first valve core 211, a first sealing gasket 212 fixed to the output end of the first valve core 211, and a first compression spring 213. The first valve core 211 is located in the small diameter section of the first chamber 201, and the input end of the first valve core 211 is located at the output end of the high-pressure oil inlet passage 102, and is driven by oil pressure during use. The first compression spring 213 is located in the large diameter section of the first chamber 201, and is always in contact with the first sealing gasket 212.

[0027] Specifically, the pump body 1 controls the low-pressure oil to flow from the high-pressure oil inlet passage 102 into the first chamber 201 and the second chamber 202, and the oil surges at the input port of the first chamber 201 until the oil pressure is greater than the first compression spring 213 and less than the spring force of the second compression spring 223, so the oil pressure can drive the first valve core 211 to move toward the first sealing gasket 212, and the first valve core 211 compresses the first compression spring 213 during the movement. At the same time, due to the movement of the first valve core 211, the second valve core section 2122 gradually reaches the first overflow port 2011. At this time, since the diameter of the second valve core section 2122 is smaller than the inner diameter of the first chamber 201, the first overflow port 2011 will be gradually opened during the movement of the first valve core 211, and the oil of the excess output pressure will be discharged from the first overflow port 2011 and the pressure relief port 203, so as to achieve low-pressure overflow. When the output pressure reaches zero, the primary overflow port 2011 will be fully opened, and at this time all the oil will be discharged from the primary overflow port 2011 and the pressure relief port 203 to achieve low-pressure unloading.

[0028] like Figure 2 As shown, a second overflow unloading group 22 is provided in the second chamber 202, which at least includes a second valve core 221, a second sealing gasket 222 fixed to the output end of the second valve core 221, and a second compression spring 223. The second valve core 221 is located in the small diameter section of the second chamber 202, and the input end of the second valve core 221 is located at the output end of the high-pressure oil inlet passage 102, and is driven by oil pressure during use. The second compression spring 223 is located in the large diameter section of the second chamber 202, and is always in contact with the second sealing gasket 222.

[0029] Specifically, the pump body 1 controls the high-pressure oil to flow from the high-pressure oil inlet channel 102 into the first chamber 201 and the second chamber 202, and the oil increases at the input ports of the first chamber 201 and the second chamber 202. At the same time, since the oil pressure at this time is greater than the spring force of the first compression spring 213 and the second compression spring 223, the oil pressure will drive the first valve core 211 and the second valve core 221 to move toward the first sealing gasket 212 and the second sealing gasket 222, thereby compressing the first compression spring 213 and the second compression spring 223. At the same time, due to the movement of the first valve core 211 and the second valve core 221, the second valve core 2122 gradually reaches the first overflow port 2011 and the second overflow port 2021, and because the diameter of the second valve core section 2122 is smaller than the inner diameter of the first cavity 201 and the second cavity 202, the first overflow port 2011 and the second overflow port 2021 will be gradually opened during the movement of the valve core, and the oil with excess output pressure will be discharged from the first overflow port 2011, the second overflow port 2021 and the pressure relief port 203 to achieve high-pressure overflow. After the output pressure is zero, all the oil is discharged from the first overflow port 2011, the second overflow port 2021 and the pressure relief port 203 to achieve high-pressure unloading.

[0030] Furthermore, the spring force of the second compression spring 223 is greater than the spring force of the first compression spring 213. Specifically, since the spring forces of the two compression springs are different and the lengths of the two compression springs are equal, it is preferred in the present application that the second compression spring 223 is composed of an inner compression spring 2232 and an outer compression spring 2233, wherein the model of the inner compression spring 2232 is the same as the model of the first compression spring 213, and the spring force of the outer compression spring 2233 is greater than the spring force of the inner compression spring 2232. The second compression spring is composed of two springs of different models, which are nested to enhance the spring force without increasing the overall length of the compression spring, thereby enhancing the feasibility and the adaptability to the valve body; and the second compression spring cooperates with the first compression spring to play a role in graded control of oil overflow pressure relief.

[0031] like Figure 2As shown, the first compression spring 213 and the second compression spring 223 are respectively sleeved on the first spring seat 2131 and the second spring seat 2231 with a T-shaped cross section; and the two ends of the first compression spring 213 are fixed on the first spring seat 2131 and the first sealing gasket 212, and the two ends of the second compression spring 223 are fixed on the second spring seat 2231 and the second sealing gasket 222. The installation position and deformation amount of the first compression spring 213 and the second compression spring 223 are limited by the first spring seat 2131 and the second spring seat 2231, which effectively prevents the first compression spring 213 and the second compression spring 223 from excessive deformation, and at the same time ensures that the inner compression spring and the outer compression spring in the second compression spring 223 do not interfere with each other during use, thereby ensuring the smoothness of the application process and improving the service life of the first compression spring 213 and the second compression spring 223.

[0032] Further, in the initial state, the ends of the first spring seat 2131 and the second spring seat 2231 are spaced from the first sealing gasket 212 and the second sealing gasket 222, and the shortest distance between the two is equivalent to the diameter of the first overflow port 2011 and the second overflow port 2021. In the unloading state, the first spring seat 2131 abuts against the first sealing gasket 212, and / or the second spring seat 2231 abuts against the second sealing gasket 222. Specifically, when the valve body 2 is in low-pressure unloading, the first sealing gasket 212 abuts against the first spring seat 2131; when the valve body 2 is in high-pressure unloading, the first sealing gasket 212 abuts against the first spring seat 2131, and the second sealing gasket 222 abuts against the second spring seat 2231. The moving stroke of the valve body 2 is made equal to the diameter of the primary overflow port 2011 and the secondary overflow port 2021 to ensure that the valve body is in an unloading state when the first compression spring 213 and the second compression spring 223 are at the limit position of movement, thereby improving the structure and unloading accuracy.

[0033] Furthermore, a partition is provided between the first spring seat 2131 and the second spring seat 2231 , and sealing rings are provided on the first spring seat 2131 and the second spring seat 2231 .

[0034] like Figure 1 to Figure 2 As shown, the valve body 2 is composed of a first shell 210 and a second shell 220, which are connected by bolts to form the first chamber 201 and the second chamber 202. Figure 2As shown, two adjusting screws 23 are passed through the end of the first housing 210, and the bottom of the adjusting screw 23 is respectively in contact with the end of the first spring seat 2131 and the second spring seat 2231, and the spring force of the first compression spring 213 and the second compression spring 223 is adjusted by the adjusting screw 23. Specifically, in the present application, it is preferred to design the spring force of the first compression spring 213 to be 75±5KG, which can withstand a pressure not exceeding 8MPa; so when the first valve core 211 moves, it indicates that the oil pressure at the input end of the first valve core 211 is greater than 8MPa. The spring force of the second compression spring 223 is designed to be 300KG, which can withstand a pressure not exceeding 30 MPa; so when the second valve core 221 moves, it indicates that the oil pressure at the input end of the second valve core 211 is greater than 30 MPa. The inner compression spring 2232 can withstand a pressure not exceeding 8MPa, and the outer compression spring 2233 can withstand a pressure not exceeding 22 MPa. Of course, in other embodiments, the spring forces of the first compression spring and the second compression spring may also be designed to be other values, which may be adjusted according to usage requirements. The number of compression springs and the values ​​of their spring forces are not specifically limited here.

[0035] like Figure 2 As shown, a fixing bolt 24 is provided at the end of the second housing 220. In the initial state, the input ends of the first valve core 211 and the second valve core 221 abut against the end of the fixing bolt 24. In the overflow state and the unloading state, the input ends of the first valve core 211 and the second valve core 221 are spaced from the end of the fixing bolt 24.

[0036] The following briefly describes the use of the present invention: S1, the pump body 1 does not output oil into the valve body 2, and the input ends of the first valve core 211 and the second valve core 221 are located at the output ends of the high-pressure oil inlet channel 102, and abut against the fixing bolt 24; at this time, the first valve core section 2121 of the first valve core 211 and the second valve core 221 are located at the primary overflow port 2011 and the secondary overflow port 2021, and the side wall of the first valve core section 2121 completely closes the primary overflow port 2011 and the secondary overflow port 2021.

[0037] S2, the pump body 1 outputs low-pressure oil to the valve body 2. At this time, the oil flows to the first cavity 201 and the second cavity 202 through the high-pressure oil inlet channel 102. Since the oil pressure is relatively low, the second overflow unloading group will remain stationary, and the oil will surge in the first cavity 201 to drive the first valve core 211 and the first sealing gasket 212 to move in the direction of the first compression spring 213.

[0038] S2.1, when the first valve core section 2121 and the second valve core section 2122 in the first valve core 211 are located at the primary overflow port 2011, that is, the primary overflow port 2011 is partially opened; and at the same time, the first sealing gasket 212 and the first spring seat 213 are spaced apart, the oil of the excess output pressure will be discharged from the primary overflow port 2011 and the pressure relief port 203, and at this time, the valve body 2 is in a low-pressure overflow state.

[0039] S2.2, when the first valve core section 2121 in the first valve core 211 is away from and the second valve core section 2122 is located at the primary overflow port 2011, that is, the primary overflow port 2011 is fully opened; and at the same time, the first sealing gasket 212 abuts against the first spring seat 213, the oil will be discharged from the primary overflow port and the pressure relief port 203, and the valve body 2 is in a low-pressure unloading state.

[0040] S3, the pump body 1 outputs high-pressure oil to the valve body 2, and the oil now flows to the first cavity 201 and the second cavity 202 through the high-pressure oil inlet channel 102. Since the oil pressure is relatively high, the first overflow unloading group 21 and the second overflow unloading group 22 will work simultaneously, and the oil increases in the first cavity 201 and the second cavity 202 to drive the first valve core 211, the first sealing gasket 212, the second valve core 221 and the second sealing gasket 222 to move toward the direction of the first compression spring 213 and the second compression spring 223 respectively.

[0041] S3.1, when the first valve core section 2121 and the second valve core section 2122 in the first valve core 211 and the second valve core 212 are located at the primary overflow port 2011 and the secondary overflow port 2021, that is, the primary overflow port 2011 and the secondary overflow port 2021 are partially opened; and at the same time, the first sealing gasket 212 and the first spring seat 213, and the second sealing gasket 222 and the second spring seat 223 are spaced apart, the oil of the excess output pressure will be discharged from the primary overflow port 2011, the secondary overflow port 2021 and the pressure relief port 203, and at this time, the valve body 2 is in a high-pressure overflow state.

[0042] S3.2, when the first valve core section 2121 of the first valve core 211 and the second valve core 212 are far away and the second valve core section 2122 is located at the primary overflow port 2011 and the secondary overflow port 2021, that is, the primary overflow port 2011 and the secondary overflow port 2021 are fully opened; at the same time, the first sealing gasket 212 is in contact with the first spring seat 213, and the second sealing gasket 222 is in contact with the second spring seat 223, the oil will be discharged from the primary overflow port 2011, the secondary overflow port 2021 and the pressure relief port 203, and the valve body 2 is in a high-pressure unloading state.

[0043] In addition, in step S3 to step S3.2, since the spring force of the first compression spring 213 is smaller than the spring force of the second compression spring 223, the movement speed of the first valve core 211 is greater than the movement speed of the second valve core 221, thereby making the opening time of the primary overflow port 2011 shorter than the opening time of the secondary overflow port 2021. In step S3.2 and step S3.2, the primary overflow port 2011 may be fully opened while the secondary overflow port is partially opened, and at this time, high-pressure overflow and high-pressure unloading coexist.

[0044] There are many implementation methods of the present invention, and all technical solutions formed by equivalent transformation or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A relief unloading combined valve, comprising a pump body (1) and a valve body (2), the two being connected via a high-pressure oil inlet passage (102), and the pump body (1) controlling the amount and pressure of oil input to the valve body (2); characterized in that: At least a first chamber (201) and a second chamber (202) are arranged in the valve body (2); the valve body (2) is provided with two primary overflow ports (2011) and a secondary overflow port (2021) respectively communicating with the first chamber (201) and the second chamber (202), and a pressure relief port (203) communicating with the main bodies of the first chamber (201) and the second chamber (202); A valve core, a sealing gasket and a compression spring are provided in the first chamber (201) and the second chamber (202); the movement direction of the valve core is perpendicular to the axial direction of the primary overflow port (2011) and / or the secondary overflow port (2021); the valve core is formed by a first valve core section (2121) and a second valve core section (2122) being integrally arranged; In an initial state, the first valve core section (2121) is located at the primary overflow port (2011) and the secondary overflow port (2021), and the side wall of the first valve core section (2121) closes the primary overflow port (2011) and the secondary overflow port (2021); In the overflow state, the first valve core section (2121) and the second valve core section (2122) are located at the primary overflow port (2011) and the secondary overflow port (2021), and the primary overflow port (2011) and the secondary overflow port (2021) are partially opened to communicate with the pressure relief port (203); In the unloading state, the second valve core section (2122) is located at the primary overflow port (2011) and the secondary overflow port (2021), and fully opens the primary overflow port (2011) and the secondary overflow port (2021) so as to communicate with the pressure relief port (203).

2. The overflow unloading combination valve according to claim 1, characterized in that: The first chamber (201) and the second chamber (202) are in a T shape; a first overflow unloading group (21) is arranged in the first chamber (201), which comprises at least a first valve core (211), a first sealing gasket (212) fixed to an output end of the first valve core (211), and a first compression spring (213); the first valve core (211) is located in a small diameter section of the first chamber (201), and the input end of the first valve core (211) is located at the output end of the high-pressure oil inlet passage (102); the first compression spring (213) is located in a large diameter section of the first chamber (201), and is always in contact with the first sealing gasket (212).

3. The overflow unloading combination valve according to claim 2, characterized in that: A second overflow unloading group (22) is arranged in the second chamber (202), and comprises at least a second valve core (221), a second sealing gasket (222) fixed to the output end of the second valve core (221), and a second compression spring (223); the second valve core (221) is located in the small diameter section of the second chamber (202), and the input end of the second valve core (221) is located at the output end of the high-pressure oil inlet passage (102); the second compression spring (223) is located in the large diameter section of the second chamber (202), and is always in contact with the second sealing gasket (222).

4. The overflow unloading combination valve according to claim 3, characterized in that: The spring force of the second compression spring (223) is greater than the spring force of the first compression spring (213); the second compression spring (223) is composed of an inner compression spring (2232) and an outer compression spring (2233) which are nested, wherein the model of the inner compression spring (2232) is the same as that of the first compression spring (213), and the spring force of the outer compression spring (2233) is greater than the spring force of the inner compression spring (2232).

5. The overflow unloading combination valve according to claim 4, characterized in that: The first compression spring (213) and the second compression spring (223) are respectively sleeved on a first spring seat (2131) and a second spring seat (2231) having a T-shaped cross-section; and the two ends of the first compression spring (213) are fixed on the first spring seat (2131) and the first sealing gasket (212), and the two ends of the second compression spring (223) are fixed on the second spring seat (2231) and the second sealing gasket (222).

6. The overflow unloading combination valve according to claim 5, characterized in that: In an initial state, the ends of the first spring seat (2131) and the second spring seat (2231) are spaced apart from the first sealing gasket (212) and the second sealing gasket (222), and the shortest distance between the two is equivalent to the diameter of the first overflow port (2011) and the second overflow port (2021); in an unloaded state, the first spring seat (2131) abuts against the first sealing gasket (212), and / or the second spring seat (2231) abuts against the second sealing gasket (222).

7. The overflow unloading combination valve according to claim 6, characterized in that: The valve body (2) is composed of a first shell (210) and a second shell (220), which are connected by bolts, and the first chamber (201) and the second chamber (202) are formed after the two are connected.

8. The overflow unloading combination valve according to claim 7, characterized in that: Two adjusting screws (23) are passed through the end of the first shell (210), and the bottoms of the adjusting screws (23) are respectively in contact with the ends of the first spring seat (2131) and the second spring seat (2231), and the spring forces of the first compression spring (213) and the second compression spring (223) are adjusted by the adjusting screws (23).

9. The overflow unloading combination valve according to claim 7, characterized in that: A fixing bolt (24) is provided at the end of the second housing (220); in an initial state, the input ends of the first valve core (211) and the second valve core (221) are in contact with the end of the fixing bolt (24); in an overflow state and a load-unloading state, the input ends of the first valve core (211) and the second valve core (221) are spaced from the end of the fixing bolt (24).

10. A relief unloading combination valve according to any one of claims 1 to 9, characterized in that: Used in the control oil circuit of hydraulic wrench.

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