Two-stage pressure overflow valve

Abstract

The two-stage pressure overflow valve comprises a sleeve, a valve seat is arranged in the sleeve, the valve seat is supported in the sleeve, and the valve seat is provided with an abutting port for hydraulic oil to pass through; a first elastic member; one end of the valve element abuts against the first elastic piece, and the other end of the valve element abuts against the abutting port through the first elastic piece so as to close the abutting port; in the sleeve, the valve element is driven by first pressure to compress the first elastic piece, so that the valve element is separated from the abutting port, the valve element continuously compresses the first elastic piece by second pressure to open the abutting port, and the second pressure is smaller than the first pressure. Two-stage pressure fit is designed through abutting of the valve element and the valve seat, the lower cavity of the oil cylinder of the bending machine in the whole feeding stage works under the low-pressure condition, feeding power is reduced, bending power is improved, energy loss is reduced, and the system heating requirement is met.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic valves, and in particular to a two-stage pressure relief valve. Background Art

[0002] The bending machine is a machine that can bend thin plates. Its structure mainly includes a bracket, a workbench and a clamping plate. The workbench is placed on the bracket. The workbench consists of a base and a slider. The base is connected to the clamping plate through a hinge. The base consists of a base shell, a coil and a cover plate. The coil is placed in the depression of the base shell, and the top of the depression is covered with a cover plate. When in use, the coil is energized by a wire, and after energization, gravity is generated on the slider, thereby clamping the thin plate between the pressure plate and the base.

[0003] In current bending machine applications, the slider on the bending machine requires a relief valve to keep the lower chamber of the cylinder always maintained at a certain pressure to ensure that the weight of the slider is balanced. However, during the working action (the cylinder drives the slider downward), after the slider contacts the workpiece, the pressure will be lost in the upper chamber of the cylinder to resist the pressure set by the lower chamber relief valve. This will lead to power loss, reduced folding power of the machine, high heat generation of the hydraulic system and other problems. In other existing technical solutions, the above problems are solved by adding a reversing valve to completely release the pressure in the lower chamber of the cylinder during the working stage, but this will undoubtedly increase costs and make the hydraulic system more complicated. Summary of the invention

[0004] The two-stage pressure relief valve of the present invention can effectively solve the problem that the relief valve of the bending machine maintains pressure and loses a large power during the working stage.

[0005] According to one aspect of the present invention, there is provided a two-stage pressure relief valve, comprising a sleeve, wherein the sleeve is provided with:

[0006] A valve seat, the valve seat is supported in the sleeve, and the valve seat is provided with an abutment port for hydraulic oil to pass through;

[0007] a first elastic member;

[0008] A valve core, one end of which abuts against the first elastic member, and the other end of which abuts against the abutting port to close the abutting port;

[0009] The first pressure in the sleeve drives the valve core to compress the first elastic member so that the valve core is disengaged from the abutment port, and the second pressure drives the valve core to continuously compress the first elastic member to open the abutment port, and the second pressure is less than the first pressure.

[0010] In some embodiments, the valve core is provided with a primary pressure surface and a secondary pressure surface, the primary pressure surface is in contact with the abutment interface, and the secondary pressure surface is located inside the abutment interface; the first pressure in the sleeve drives the primary pressure surface to disengage from the abutment interface, and fills the secondary pressure surface to form the second pressure. Thus, two opening pressures with very large differences are formed in the sleeve through the primary pressure surface and the secondary pressure surface.

[0011] In some embodiments, the pressure action area of ​​the secondary pressure surface is greater than the pressure action area of ​​the primary pressure surface. Thus, the pressure to maintain the opening of the abutment port is reduced by the different pressure action areas, and the pressure action area is the action area of ​​the primary pressure surface and the secondary pressure surface covered by the hydraulic oil under pressure.

[0012] In some embodiments, the abutment interface is provided with a stepped platform, the primary pressure surface abuts against the stepped platform, and there is a gap between the stepped platform and the secondary pressure surface. Thus, a preset pressure of the first-level seal is formed by the abutment of the stepped platform and the primary pressure surface, and the first pressure is used to open the preset pressure.

[0013] In some embodiments, the step is provided with an abutment surface, and the abutment surface abuts against the primary pressure surface. Thus, the abutment surface is used to improve the abutment fit with the primary pressure surface, and further prevent penetration before the primary pressure surface is released from abutment.

[0014] In some embodiments, the diameter of the primary pressure surface is larger than the diameter of the secondary pressure surface, so that the hydraulic oil first fills the primary pressure surface and then fills the secondary pressure surface.

[0015] In some embodiments, the sleeve is provided with an oil cavity for hydraulic oil to flow, and the valve seat is provided with a first communicating hole, which is connected with the oil cavity and the abutment port. Thus, the first communicating hole is used to provide a path for the hydraulic oil to flow to the abutment port.

[0016] In some embodiments, in the axial direction of the first connecting hole, the first connecting hole coincides or partially coincides with the projection of the primary pressure surface.

[0017] In some embodiments, the valve seat is provided with a receiving cavity communicated with the abutment port, and the valve core and the first elastic member are arranged in the receiving cavity. Thus, the receiving cavity is used to provide a space for the valve core and the first elastic member to cooperate with each other, so that the valve core and the first elastic member act in the valve seat.

[0018] In some embodiments, the valve seat is provided with a communication cavity, and the communication cavity is communicated with the accommodating cavity through the abutment port. Thus, the communication cavity is used to maintain the second pressure for the sleeve so that the hydraulic oil can be directly or indirectly output from the communication cavity to the external oil tank.

[0019] Compared with the prior art, the two-stage pressure relief valve of the present invention has the following beneficial effects:

[0020] The present application adopts a two-stage pressure coordination design through the abutment between the valve core and the valve seat. Under the action of the first pressure, the abutment interface between the valve core and the valve seat is disengaged, and the first pressure is staged into the second pressure to continuously compress the first elastic member to maintain the state of the abutment interface open, and the second pressure is less than the first pressure, so that the lower chamber of the cylinder of the bending machine works under low pressure during the entire working stage, thereby reducing the working power, improving the bending power, and reducing energy loss and system heating requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a cross-sectional view of a two-stage pressure relief valve of the present invention;

[0022] Figure 2 for Figure 1 A magnified view of part A;

[0023] Figure 3 is a cross-sectional view of the valve seat in the present invention;

[0024] Figure 4 for Figure 2 Enlarged view of part C;

[0025] Figure 5 for Figure 4 Schematic diagram of the working state of the valve core;

[0026] Figure 6 for Figure 1 Enlarged view of part B.

[0027] In the figure: 1-sleeve, 11-oil chamber, 2-valve seat, 3-first elastic member, 4-valve core, 5-stopper, 6-support cylinder, 7-spring seat, 8-retaining ring, 9-sealing ring, 21-accommodating chamber, 22-butt interface, 23-connecting chamber, 221-step platform, 24-first connecting hole, 25-second connecting hole, 41-primary pressure surface, 42-secondary pressure surface, 43-oil drain hole, 10-valve stem, 31-second elastic member. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0030] The present invention relates to a two-stage pressure relief valve, which is particularly suitable for a pump-controlled bending machine. The relief valve mainly acts on the working action and can make the lower chamber of the oil cylinder work in a low-pressure state during the entire working stage, so as to improve the bending power and reduce energy loss and system heating requirements.

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0032] Figure 1 A secondary pressure relief valve according to an embodiment of the present invention is schematically shown. Figure 1 As shown, the secondary pressure relief valve is used in conjunction with hydraulic oil, and the secondary pressure relief valve includes a sleeve 1, a valve seat 2, a first elastic member 3, and a valve core 4.

[0033] The sleeve 1 is a metal cylindrical structure, and a hollow oil chamber 11 is provided inside the sleeve 1 for the flow of hydraulic oil. A stopper 5 is provided at one end of the sleeve 1. This embodiment uses a sealed system as an illustration. In other embodiments, the sleeve 1 may be provided with holes for the flow of hydraulic oil. After the hydraulic oil enters the sleeve 1, it passes through the oil chamber 11 and is then output to the external oil tank for circulation.

[0034] like Figure 2 , Figure 3 As shown, the valve seat 2 adopts a cylindrical structure, the interior of which is connected along the axial direction, and the valve seat 2 is supported in the sleeve 1. Specifically, the valve seat 2 is located in the oil chamber 11 and there is a gap between the valve seat 2 and the inner wall of the sleeve 1, that is, the valve seat 2 does not completely cover the oil chamber 11. When hydraulic oil is used for operation, the hydraulic oil can pass through the gap. A support cylinder 6 is also provided in the oil chamber 11. The support cylinder 6 is directly or indirectly connected to the bottom of the sleeve 1. One end of the valve seat 2 is connected to the support cylinder 6, so that the valve seat 2 can be supported in the oil chamber 11.

[0035] The valve seat 2 is also provided with a receiving chamber 21, an abutting port 22 and a connecting chamber 23 in sequence. The receiving chamber 21, the abutting port 22 and the connecting chamber 23 are connected in sequence and can allow hydraulic oil to pass through. The receiving chamber 21 is used to install the first elastic member 3 and the valve core 4. The abutting port 22 adopts a frustum-shaped structure. The abutting port 22 is provided with a stepped platform 221. The stepped platform 221 protrudes along the radial direction of the abutting port 22 to reduce the diameter of the part inside the abutting port 22. The connecting chamber 23 is used to connect the end of the valve seat 2. When the abutting port 22 is opened, the hydraulic oil can pass through the connecting chamber 23 and then flow back to the oil tank directly or indirectly. The valve seat 2 is also provided with a first connecting hole 24 and a second connecting hole 25. The first connecting hole 24 is connected to the abutting port 22 and the oil chamber 11, and the second connecting hole 25 is connected to the connecting chamber 23, so that the hydraulic oil can pass through the first connecting hole 24 and fill the abutting port 22 and then be output from the second connecting hole 25. In addition, the valve seat 2 is further provided with a retaining ring 8 and a sealing ring 9 , which are located between the first communicating hole 24 and the second communicating hole 25 , to ensure that the hydraulic oil flows from the first communicating hole 24 to the abutting port 22 and the communicating chamber 23 .

[0036] The first elastic member 3 is specifically a spring, one end of which abuts against a spring seat 7, which is connected to the end of the valve seat 2 to close the accommodating cavity 21, and the spring seat 7 can directly abut against the end of the sleeve 1. The first elastic member 3 is used to provide elastic potential energy for the valve core 4 to abut against the valve seat 2.

[0037] like Figure 4 As shown, the valve core 4 is arranged in the valve seat 2. Specifically, the valve core 4 abuts against the abutting interface 22. One end of the valve core 4 abuts against the first elastic member 3, and the other end is set to a frustum-shaped structure so as to abut against the abutting interface 22. The valve core 4 has a primary pressure surface 41 and a secondary pressure surface 42. Both the primary pressure surface 41 and the secondary pressure surface 42 are inclined surface structures on the valve core 4. The diameter surrounded by the primary pressure surface 41 is larger than the diameter surrounded by the secondary pressure surface 42, so that the primary pressure surface 41 and the secondary pressure surface 42 form a stepped structure. The valve core 4 makes the primary pressure surface 41 abut against the abutting interface 22 through the first elastic member 3. Specifically, the primary pressure surface 41 abuts against the stepped platform 221, and the secondary pressure surface 42 is located in the abutting interface 22, that is, compared with the primary pressure surface 41, the secondary pressure surface 42 is closer to the connecting cavity 23, thereby closing the abutting interface 22, so that the hydraulic oil has an open and closed state when passing through. The projections of the primary pressure surface 41 and the secondary pressure surface 42 in the axial and radial directions of the valve core 4 do not overlap with each other, and there is a gap between the secondary pressure surface 42 and the abutment port 22, that is, the secondary pressure surface 42 does not contact the abutment port 22. In the axial direction of the first connecting hole 24, the projection of the first connecting hole 24 overlaps or partially overlaps with the projection of the primary pressure surface 41, so that after the hydraulic oil in the oil chamber 11 passes through the first connecting hole 24, the hydraulic oil can be directly filled on the primary pressure surface 41 to make the valve core 4 compress the first elastic member 3 and disengage from the abutment port 22, thereby opening the abutment port 22.

[0038] In addition, the valve core 4 is also provided with an oil drain hole 43, which penetrates the valve core 4 axially so that the oil drain hole 43 is connected with the accommodating chamber 21 and the connecting chamber 23. When some hydraulic oil seeps into the accommodating chamber 21, it can be discharged from the oil drain hole 43 to the connecting chamber 23 and finally output to the oil tank.

[0039] In other embodiments, the step platform 221 is provided with an abutment surface, and the abutment surface adopts a sloped structure to adapt to the primary pressure surface 41. The abutment surface abuts against the primary pressure surface 41, that is, the step platform 221 abuts against the primary pressure surface 41 through surface-to-surface contact, thereby improving the sealing performance of the valve core 4 and the abutment interface 22 after abutment.

[0040] Working principle: Figure 4 and Figure 5 As shown, the first pressure in the sleeve 1 drives the hydraulic oil in the oil chamber 11 to enter the first connecting hole 24 from the gap between the valve seat 2 and the inner wall of the sleeve 1. The hydraulic oil first covers the primary pressure surface 41. Under the action of the first pressure, the valve core 4 compresses the first elastic member 3 so that the primary pressure surface 41 is out of contact with the step platform 221, and gradually fills the secondary pressure surface 42 to form a second pressure. Finally, the valve core 4 continues to compress the first elastic member 3 to maintain the open state of the abutment port 22. The hydraulic oil is directly or indirectly delivered to the oil tank through the connecting chamber 23 and the second connecting hole 25.

[0041] In the above process, since the primary pressure surface 41 and the secondary pressure surface 42 are designed on the valve core 4 to cooperate with the valve seat 2, the opening and sealing relationship of the first pressure and the second pressure is realized. The first pressure resists the hydraulic pressure action area of ​​the first elastic member 3 is significantly smaller than the pressure action area of ​​the second pressure, that is, the pressure action area S1 of the primary pressure surface 41 is equal to the area of ​​the primary pressure surface 41 covered by the hydraulic oil, and the pressure action area S2 of the secondary pressure surface 42 is equal to S1 plus the area of ​​the secondary pressure surface 42 covered by the hydraulic oil, so S2 is greater than S1. When the hydraulic oil fills the secondary pressure surface 42, the first pressure resists the hydraulic pressure action area of ​​the first elastic member 3 becomes larger.

[0042] According to this scheme, the valve core 4 loaded with the same spring force will form two opening pressures with very different hydraulic pressure action areas. Based on this principle, in the working stage of the bending machine, when the slider just starts to move, the pressure in the upper chamber of the oil cylinder increases, and the pressure in the lower chamber connects to the secondary pressure relief valve and instantly opens the first-stage set pressure of the relief valve with the first pressure, that is, the first-stage seal is opened, and the second-stage seal has not yet been opened. Then the action area suddenly changes (increases), causing the set pressure to instantly drop to the secondary pressure and continue to work under the second pressure, that is, the second pressure is less than the first pressure, so that only after the high pressure is established in the lower chamber of the oil cylinder at the starting point of the working stage, the lower chamber of the oil cylinder is in a low-pressure state throughout the working stage. According to the formula P=F*S, P is power, F is pressure, and S is area. When the hydraulic oil fills the secondary pressure surface 42, compared with opening the first-stage seal, the hydraulic oil coverage area is increased, the work done in the sleeve 1 is increased, and the loss of the oil cylinder during the working stage of the bending machine is reduced. In this way, the working power is reduced, the bending power is increased, and the energy loss and system heating requirements are reduced.

[0043] In summary, in this field, any occasion where the system pressure needs to be quickly reduced after overpressure to ensure the safe operation of the system. For example, the pump port safety valve of a hydraulic pump station, once the working pressure is overpressured, the conventional technical solution will always work at the set safety pressure, which brings many uncertain risks. The use of this two-stage pressure relief valve can ensure that once the pressure is overpressured, the system safety pressure is instantly switched to the low-pressure safety pressure, thereby ensuring that potential dangers such as overheating and burning of the motor will not occur, and no external safety monitoring is required.

[0044] In other embodiments, Figure 1 and Figure 6 As shown, the secondary pressure two-stage matching group includes a valve seat 2, a first elastic member 3 and a valve core 4. In this embodiment, there are two groups, one of which is further provided with a valve stem 10 and a second elastic member 31 in the oil chamber 11. One end of the valve stem 10 is connected to one end of the sleeve 1, and the other end of the valve stem 10 is connected to the spring seat 7. The second elastic member 31 is specifically a spring. The second elastic member 31 is sleeved on the end of the valve stem 10. One end of the second elastic member 31 abuts against the protruding structure of the valve stem 10, and the other end abuts against the spring seat 7. The difference between the other secondary pressure two-stage matching group in the oil chamber 11 is that the installation direction is opposite, that is, two groups of secondary pressure two-stage matching mechanisms are symmetrically arranged in the sleeve 1. The valve seat 2 of this group is also connected to the spring seat 7, and the spring seat 7 directly abuts against the end of the sleeve 1. It can be seen that in this embodiment, since one of the secondary pressure two-stage matching groups has a valve stem 10 and a second elastic member 31, the required opening pressure is different, so two different action states can be satisfied.

[0045] The above description is only a preferred embodiment of the present invention. In order to make the description concise, not all possible combinations of the various technical features in the above embodiment are described, and the present invention is not limited in any form. Therefore, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A two-stage pressure relief valve, characterized in that: It comprises a sleeve, in which is provided: A valve seat, the valve seat is supported in the sleeve, and the valve seat is provided with an abutment port for hydraulic oil to pass through; a first elastic member; A valve core, one end of which abuts against the first elastic member, and the other end of which abuts against the abutting port to close the abutting port; The first pressure in the sleeve drives the valve core to compress the first elastic member so that the valve core is disengaged from the abutment port, and the second pressure drives the valve core to continuously compress the first elastic member to open the abutment port, and the second pressure is less than the first pressure.

2. The two-stage pressure relief valve according to claim 1, characterized in that: The valve core is provided with a primary pressure surface and a secondary pressure surface, the primary pressure surface is in contact with the abutment interface, and the secondary pressure surface is located inside the abutment interface; the first pressure in the sleeve drives the primary pressure surface to disengage from the abutment interface and fills the secondary pressure surface to form the second pressure.

3. The two-stage pressure relief valve according to claim 2, characterized in that: The pressure action area of ​​the secondary pressure surface is greater than the pressure action area of ​​the primary pressure surface.

4. The two-stage pressure relief valve according to claim 2, characterized in that: The abutting interface is provided with a stepped platform, the primary pressure surface abuts against the stepped platform, and there is a gap between the stepped platform and the secondary pressure surface.

5. The two-stage pressure relief valve according to claim 4, characterized in that: The stepped platform is provided with a contact surface, and the contact surface contacts the primary pressure surface.

6. The two-stage pressure relief valve according to claim 2, characterized in that: The diameter surrounded by the primary pressure surface is greater than the diameter surrounded by the secondary pressure surface.

7. The two-stage pressure relief valve according to claim 1, characterized in that: An oil chamber for hydraulic oil to flow is provided inside the sleeve, and a first communicating hole is provided on the valve seat, wherein the first communicating hole is communicated with the oil chamber and the abutting port.

8. The two-stage pressure relief valve according to claim 7, characterized in that: In the axial direction of the first communicating hole, the first communicating hole coincides with or partially coincides with a projection of the primary pressure surface.

9. The two-stage pressure relief valve according to claim 1, characterized in that: The valve seat is provided with an accommodating cavity communicated with the abutting port, and the valve core and the first elastic member are arranged in the accommodating cavity.

10. The two-stage pressure relief valve according to claim 1, characterized in that: The valve seat is provided with a communication cavity, and the communication cavity is communicated with the accommodating cavity through the abutment port.

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