Overflow valve
By setting up seals and pressure chambers in the relief valve, the secondary pressure instability and processing difficulty caused by oil leakage is solved, effective sealing of oil and stable establishment of secondary pressure is achieved, and processing costs are reduced.
Patent Information
- Application Number
- CN202422551589.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-22
- Publication Date
- 2025-07-22
- Estimated Expiration
- 2034-10-22
AI Technical Summary
The existing relief valve has oil leakage problems during the secondary pressure establishment process, resulting in inconsistent oil force on both sides of the buffer piston, and increased resource waste and processing difficulty.
A seal is provided in the relief valve, located between the piston sleeve and the adjustment sleeve/valve seat or between the piston sleeve and the buffer piston, forming a pressure building cavity and pressure relief channel, sealing the gap between the piston sleeve and the adjustment sleeve/valve seat, reducing oil leakage, and venting excess pressure through the pressure relief channel.
Effectively reduce oil leakage, ensure the stability of secondary pressure establishment, reduce processing difficulty, and save costs.
Smart Images
Figure CN223137063U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of overflow valves, in particular to an overflow valve. Background Art
[0002] During the process of establishing the secondary pressure of the overflow valve, the oil fluid is likely to leak out from the gap between the piston sleeve and the adjusting sleeve, as well as the gap between the piston sleeve and the buffer piston. This external leakage of oil fluid can easily cause the following problems: 1. The oil fluid forces on the first side and the second side of the buffer piston are inconsistent, and it is easy to have a situation where the establishment of the secondary pressure is too low; 2. Due to the leakage of the oil fluid, it leads to waste of resources and high costs; 3. Since the gaps between the piston sleeve and the adjusting sleeve, and between the piston sleeve and the buffer piston rely on clearance seals, and it is necessary to control these gaps very small, therefore, the processing accuracy requirements for the piston sleeve, the adjusting sleeve, and the buffer piston are relatively high, increasing the processing difficulty of the piston sleeve, the adjusting sleeve, and the buffer piston.
[0003] In view of the above problems, there is an urgent need for an overflow valve to solve the above problems. Summary of the Utility Model
[0004] The purpose of the utility model is to provide an overflow valve, which can avoid the situation where the establishment of the secondary pressure is too low, can effectively reduce the leakage amount of the oil fluid, and can reduce the processing difficulty of the buffer piston, the adjusting sleeve, and the piston sleeve.
[0005] To achieve the above object, the utility model adopts the following technical solutions:
[0006] An overflow valve, comprising:
[0007] A pressure relief channel;
[0008] A valve seat, in which a pressure building chamber is formed;
[0009] An adjusting assembly, including an adjusting sleeve, a piston sleeve, and a buffer piston. The pressure relief channel is located in at least two of the valve seat, the adjusting sleeve, and the piston sleeve. The adjusting sleeve is arranged in the valve seat. At least part of the piston sleeve is arranged in the adjusting sleeve. Both the adjusting sleeve and the piston sleeve are slidably connected to the buffer piston, and at least part of the pressure building chamber is located between the adjusting sleeve and the piston sleeve;
[0010] A seal. The seal is arranged between the piston sleeve and the adjusting sleeve / the valve seat, and / or, the seal is arranged between the piston sleeve and the buffer piston. And when the seal is arranged between the piston sleeve and the adjusting sleeve, the seal is located between the pressure relief channel and the pressure building chamber.
[0011] As an optional solution, the adjusting assembly further includes:
[0012] A first wall and a second wall, the first wall being located on the piston sleeve, the second wall being located on the buffer piston and / or the adjusting sleeve. Radially along the valve seat, one side of the seal abuts against the first wall, and the other side of the seal abuts against the second wall.
[0013] As an alternative, the pressure relief passage includes:
[0014] A first passage, a second passage, and a third passage. At least a part of the first passage is located in the piston sleeve, at least a part of the second passage is located in the adjusting sleeve, at least a part of the third passage is located in the valve seat, and the first passage, the second passage, and the third passage are in communication with each other.
[0015] As an alternative, the second passage is inclined axially with respect to the valve seat.
[0016] As an alternative, the buffer piston includes a third wall and a fourth wall disposed opposite to each other. The buffer piston has a first position and a second position. When the buffer piston is in the first position, a first chamber is formed between the third wall and the adjusting sleeve, and the fourth wall abuts against the piston sleeve. When the buffer piston is in the second position, the third wall abuts against the adjusting sleeve, and a second chamber is formed between the fourth wall and the piston sleeve. The area of the oil acting on the third wall in the second chamber is smaller than the area of the oil acting on the fourth wall.
[0017] As an alternative, a first damping hole and a through hole are spaced apart on the buffer piston. A receiving chamber is formed inside the buffer piston. The through hole communicates the receiving chamber with the second chamber, the first damping hole communicates the receiving chamber with the first chamber, and at least a part of the aperture of the first damping hole is smaller than the aperture of the through hole.
[0018] As an alternative, the adjusting sleeve includes a fifth wall, the fifth wall being disposed opposite to the third wall, and with respect to the fifth wall, the first damping hole is disposed close to the third wall.
[0019] As an alternative, the piston sleeve includes a sixth wall, the sixth wall being disposed opposite to the fourth wall, and with respect to the sixth wall, the through hole is disposed close to the fourth wall in the second chamber.
[0020] As an alternative, the pressure relief valve further includes:
[0021] The spool is slidably fitted inside the valve seat. The spool can move in a first direction so that one end of the spool can open or close the valve port inside the valve seat. The other end of the spool communicates with the accommodating cavity so that the spool supplies hydraulic oil to the accommodating cavity. The first direction is the axial direction of the spool and is the direction close to the valve port;
[0022] An elastic member is sleeved on the spool. One end of the elastic member is connected to the limiting platform of the spool;
[0023] A base is slidably sleeved on the spool and is arranged opposite to the limiting platform. The other end of the elastic member is connected to the base, and the buffer piston can push the base to move in the first direction to compress the elastic member.
[0024] The beneficial effects of the present utility model are as follows:
[0025] By forming a pressure - building cavity inside the valve seat, the adjusting sleeve is arranged inside the valve seat, at least part of the piston sleeve is arranged inside the adjusting sleeve, both the adjusting sleeve and the piston sleeve are slidably connected to the buffer piston, and at least part of the pressure - building cavity is located between the adjusting sleeve and the piston sleeve; meanwhile, a seal is arranged between the piston sleeve and the adjusting sleeve / valve seat, and / or, the seal is arranged between the piston sleeve and the buffer piston, and when the seal is arranged between the piston sleeve and the adjusting sleeve, the seal is located between the pressure - relief channel and the pressure - building cavity, so as to be able to build pressure on the buffer piston through the pressure - building cavity and discharge the hydraulic oil through the pressure - relief channel to avoid excessive pressure inside the overflow valve; the above - mentioned arrangement of the seal between the piston sleeve and the adjusting sleeve / valve seat, and / or, the seal between the piston sleeve and the buffer piston can seal the gap between the piston sleeve and the adjusting sleeve / valve seat, and / or, the gap between the piston sleeve and the buffer piston, to avoid the leakage of hydraulic oil through the gap between the piston sleeve and the adjusting sleeve / valve seat, and / or, the gap between the piston sleeve and the buffer piston. On the one hand, it can ensure that the hydraulic oil acting forces on the opposite two walls of the buffer piston are equal, so as to avoid the situation of low secondary pressure establishment; on the other hand, it can effectively reduce the leakage amount of hydraulic oil, avoid waste of resources, save costs; at the same time, it can reduce the processing precision requirements for the piston sleeve, the adjusting sleeve and the buffer piston, so as to reduce the processing difficulty of the buffer piston, the adjusting sleeve and the piston sleeve. Description of the Drawings
[0026] Figure 1 is a cross - sectional view of the overflow valve provided by the present utility model (when the buffer piston is in the first position);
[0027] Figure 2 is Figure 1 the partial enlarged structural schematic diagram at position C in
[0028] Figure 3It is a partial enlarged structural schematic diagram of the first wall and the second wall (with gaps between the piston sleeve and the buffer piston, and between the piston sleeve and the adjusting sleeve) provided by the present utility model.
[0029] Explanation of reference numerals:
[0030] 1 - valve seat; 11 - valve port; 12 - pressure - building cavity;
[0031] 21 - adjusting sleeve; 211 - fifth wall; 22 - piston sleeve; 221 - sixth wall; 222 - first wall; 23 - buffer piston; 231 - third wall; 232 - fourth wall; 233 - first damping hole; 234 - through - hole; 235 - accommodating cavity; 24 - first cavity; 25 - second wall;
[0032] 3 - seal; 4 - valve core; 41 - limiting platform; 42 - second damping hole; 43 - flow cavity; 5 - elastic member; 6 - base;
[0033] 7 - pressure - relief channel; 71 - first channel; 72 - second channel; 73 - third channel. Detailed implementation manners
[0034] All features disclosed in this specification, or all steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any manner.
[0035] Any feature disclosed in this specification, unless specifically stated, can be replaced by other equivalent or similar - purpose alternative features. That is, unless specifically stated, each feature is only an example of a series of equivalent or similar features. Throughout the specification, the same reference numerals indicate the same elements.
[0036] To make the technical problems solved by the present utility model, the technical solutions adopted, and the achieved technical effects clearer, the technical solutions of the present utility model will be further described below with reference to the accompanying drawings and through specific implementation manners.
[0037] In this embodiment, a pressure - relief valve is proposed. The pressure - relief valve has a good sealing effect, can ensure the establishment time of the secondary pressure and the stable establishment of the secondary pressure, can achieve a good buffer and pressure - relief effect, can avoid the leakage and waste of oil, save resources, and at the same time can reduce the processing difficulty of the pressure - relief valve.
[0038] Specifically, as Figures 1 to 3As shown in the figure, the overflow valve includes a pressure relief passage 7, a valve seat 1, an adjustment assembly, and a seal 3. Among them, a pressure building chamber 12 is formed in the valve seat 1. The adjustment assembly includes an adjustment sleeve 21, a piston sleeve 22, and a buffer piston 23. The pressure relief passage 7 is located in at least two of the valve seat 1, the adjustment sleeve 21, and the piston sleeve 22. The adjustment sleeve 21 is arranged in the valve seat 1. At least part of the piston sleeve 22 is arranged in the adjustment sleeve 21. Both the adjustment sleeve 21 and the piston sleeve 22 are slidably connected to the buffer piston 23, and at least part of the pressure building chamber 12 is located between the adjustment sleeve 21 and the piston sleeve 22. The seal 3 is arranged between the piston sleeve 22 and the adjustment sleeve 21 / valve seat 1, and / or the seal 3 is arranged between the piston sleeve 22 and the buffer piston 23. And when the seal 3 is arranged between the piston sleeve 22 and the adjustment sleeve 21, the seal 3 is located between the pressure relief passage 7 and the pressure building chamber 12.
[0039] By forming the pressure building chamber 12 in the valve seat 1, the adjustment sleeve 21 is arranged in the valve seat 1, at least part of the piston sleeve 22 is arranged in the adjustment sleeve 21, both the adjustment sleeve 21 and the piston sleeve 22 are slidably connected to the buffer piston 23, and at least part of the pressure building chamber 12 is located between the adjustment sleeve 21 and the piston sleeve 22. At the same time, the seal 3 is arranged between the piston sleeve 22 and the adjustment sleeve 21 / valve seat 1, and / or the seal 3 is arranged between the piston sleeve 22 and the buffer piston 23. And when the seal 3 is arranged between the piston sleeve 22 and the adjustment sleeve 21, the seal 3 is located between the pressure relief passage 7 and the pressure building chamber 12, so as to be able to build pressure on the buffer piston 23 through the pressure building chamber 12 and discharge the oil through the pressure relief passage 7 to avoid excessive pressure in the overflow valve.
[0040] Compared with the prior art, the overflow valve in this embodiment adds a seal 3. By arranging the seal 3 between the piston sleeve 22 and the adjustment sleeve 21 / valve seat 1, and / or the seal 3 is arranged between the piston sleeve 22 and the buffer piston 23, it is possible to seal the gap between the piston sleeve 22 and the adjustment sleeve 21 / valve seat 1, and / or the gap between the piston sleeve 22 and the buffer piston 23, and avoid oil leakage through the gap between the piston sleeve 22 and the adjustment sleeve 21 / valve seat 1, and / or the gap between the piston sleeve 22 and the buffer piston 23. On the one hand, it can ensure that the oil pressure forces on the opposite two walls of the buffer piston 23 are equal, so as to avoid the situation of low secondary pressure establishment. On the other hand, it can effectively reduce the oil leakage amount, avoid resource waste, and save costs. At the same time, it can reduce the processing precision requirements for the piston sleeve 22, the adjustment sleeve 21, and the buffer piston 23, so as to reduce the processing difficulty of the buffer piston 23, the adjustment sleeve 21, and the piston sleeve 22.
[0041] It should be noted that in other embodiments, the piston sleeve 22 can be partially disposed outside the adjusting sleeve 21. Even more, when the pressure relief passage 7 described above is provided on the valve seat 1, the seal 3 can be provided between the valve seat 1 and the piston sleeve 22 to seal the gap between the valve seat 1 and the piston sleeve 22.
[0042] Furthermore, as Figure 3 shown, the adjusting assembly further includes a first wall 222 and a second wall 25. The first wall 222 is located on the piston sleeve 22, that is, the first wall 222 is specifically the inner peripheral wall and the outer peripheral wall of the piston sleeve 22; the second wall 25 is located on the buffer piston 23 and / or the adjusting sleeve 21, that is, the second wall 25 is specifically the outer peripheral wall of the buffer piston 23 and the inner peripheral wall of the adjusting sleeve 21; along the radial direction of the valve seat 1, one side of the seal 3 abuts against the first wall 222, and the other side of the seal 3 abuts against the second wall 25 to seal the gap between the piston sleeve 22 and the adjusting sleeve 21 or the gap between the piston sleeve 22 and the buffer piston 23 through the seal 3.
[0043] Specifically, as Figure 1 and Figure 2 shown, the pressure relief passage 7 includes a first passage 71, a second passage 72 and a third passage 73. At least part of the first passage 71 is located in the piston sleeve 22, at least part of the second passage 72 is located in the adjusting sleeve 21, and at least part of the third passage 73 is located in the valve seat 1. The first passage 71, the second passage 72 and the third passage 73 are connected to each other so that the hydraulic oil can be discharged to the oil tank outside the valve seat 1 through the first passage 71, the second passage 72 and the third passage 73 in sequence, ensuring that the pressure inside the entire relief valve is more appropriate.
[0044] Furthermore, as Figure 1 and Figure 2 shown, the second passage 72 is inclined axially with respect to the valve seat 1. On the one hand, it can better guide the hydraulic oil in the first passage 71 to flow into the second passage 72, ensuring the smoothness and reliability of the oil discharge; on the other hand, it can reduce the axial and radial layout dimensions of the second passage 72, making the layout of the entire pressure relief passage more reasonable and compact.
[0045] In this embodiment, as Figures 1 to 3 shown, in order to ensure better sealing effect, the seal 3 is provided between the piston sleeve 22 and the adjusting sleeve 21. At the same time, the seal 3 is provided between the piston sleeve 22 and the buffer piston 23. In other embodiments, the seal 3 can be provided only between the piston sleeve 22 and the adjusting sleeve 21 or only between the piston sleeve 22 and the buffer piston 23, and no specific limitation is made here. Among them, the seal 3 can specifically be an O-ring. Here, no specific limitation is made on the specific structure of the seal 3 as long as it can provide a sealing effect.
[0046] Further, as Figure 2 shown, the buffer piston 23 includes a third wall 231 and a fourth wall 232 arranged back to back. The buffer piston 23 has a first position and a second position. When the buffer piston 23 is in the first position, a first chamber 24 is formed between the third wall 231 and the adjusting sleeve 21, and the fourth wall 232 abuts against the piston sleeve 22. When the buffer piston 23 is in the second position, the third wall 231 abuts against the adjusting sleeve 21, and a second chamber is formed between the fourth wall 232 and the piston sleeve 22. The first chamber 24 and the second chamber together constitute the above-mentioned pressure building chamber 12, and the area of the oil acting on the third wall 231 is smaller than the area of the oil acting on the fourth wall 232. Specifically, as Figure 2 shown, a first damping hole 233 and a through hole 234 are arranged at intervals on the buffer piston 23, and a receiving chamber 235 is formed in the buffer piston 23. The through hole 234 communicates the receiving chamber 235 with the second chamber, and the first damping hole 233 communicates the receiving chamber 235 with the first chamber 24, so that the oil in the receiving chamber 235 can flow into the first chamber 24 through the first damping hole 233, and the oil in the first chamber 24 acts on the third wall 231 of the buffer piston 23. At the same time, the oil in the receiving chamber 235 can flow into the second chamber through the through hole 234, so that the oil in the second chamber acts on the fourth wall 232 of the buffer piston 23.
[0047] Specifically, at least part of the aperture of the first damping hole 233 is smaller than the aperture of the through hole 234, so that the first damping hole 233 can play a role in throttling and pressure reduction.
[0048] Further, as Figure 1 and Figure 2 shown, the adjusting sleeve 21 includes a fifth wall 211. The fifth wall 211 is arranged opposite to the third wall 231, so that the space between the fifth wall 211 and the third wall 231 forms the above-mentioned first chamber 24, and the third wall 231 can move in the first direction to abut against the fifth wall 211, so as to provide a limiting effect on the movement of the buffer piston 23 in the first direction through the fifth wall 211. Wherein, the first direction is the axial direction of the valve seat 1 and away from the piston sleeve 22, and the first direction is specifically as Figure 1 shown by the arrow A in
[0049] Specifically, the first damping hole 233 is arranged close to the third wall 231 relative to the fifth wall 211. On the one hand, it can make the oil in the first damping hole 233 act on the third wall 231 more quickly, so that the action of the oil on the third wall 231 is relatively fast and timely. On the other hand, when the buffer piston 23 moves in the first direction and the first chamber 24 is gradually reduced, the first damping hole 233 can still supply oil into the first chamber 24, so that the action time of the first chamber 24 is longer, thereby ensuring that the action time of the oil on the third wall 231 is longer.
[0050] Specifically, as Figure 1 and Figure 2 shown, the piston sleeve 22 includes a sixth wall 221, and the sixth wall 221 is disposed opposite to the fourth wall 232, so that the space between the sixth wall 221 and the fourth wall 232 forms the above-mentioned second chamber, and the fourth wall 232 can move in the second direction to abut against the sixth wall 221, so as to provide a limiting effect on the movement of the buffer piston 23 in the second direction through the sixth wall 221. Wherein, the second direction is opposite to the first direction, and the second direction is specifically as Figure 1 shown by the arrow B in
[0051] Specifically, relative to the sixth wall 221, the through hole 234 is disposed close to the fourth wall 232; on the one hand, it can make the oil in the fourth wall 232 act on the fourth wall 232 more quickly, so that the action of the oil on the fourth wall 232 is relatively fast and timely; on the other hand, when the buffer piston 23 moves in the second direction and the second chamber is gradually reduced, the through hole 234 can still supply oil into the second chamber, so that the action time of the second chamber is longer, thereby ensuring that the action time of the oil on the fourth wall 232 is longer.
[0052] Furthermore, as Figure 1 and Figure 2 shown, the overflow valve further includes a valve core 4, an elastic member 5 and a base 6; wherein, the valve core 4 is slidably fitted in the valve seat 1, and the valve core 4 can move in the first direction, so that one end of the valve core 4 can open or close the valve port 11 in the valve seat 1, and the other end of the valve core 4 is communicated with the accommodating cavity 235 in the buffer piston 23, so that the valve core 4 supplies oil into the accommodating cavity 235; the elastic member 5 is sleeved on the valve core 4, and one end of the elastic member 5 is connected to the limiting platform 41 of the valve core 4; the base 6 is slidably sleeved on the valve core 4 and is disposed opposite to the limiting platform 41, and the other end of the elastic member 5 is connected to the base 6, that is, both ends of the elastic member 5 are limited between the limiting platform 41 and the base 6, and the buffer piston 23 can push the base 6 to move in the first direction to compress the elastic member 5, thereby being able to push the valve core 4 to move close to the valve port 11 in the first direction, so that the valve core 4 can move to close the valve port 11. In this embodiment, the elastic member 5 may specifically be a spring.
[0053] It should be noted that the first position of the above-mentioned buffer piston 23 specifically refers to the position when the valve port 11 is at the maximum opening, and at this time, the overflow function is performed; the second position of the above-mentioned buffer piston 23 specifically refers to the position when the secondary pressure in the overflow valve is stably established. At this time, the valve port 11 is in the closed state, and in the closed state, the valve core 4 abuts against the valve seat 1, and the oil can flow into the accommodating cavity 235 through the second damping hole 42.
[0054] Specifically, as Figure 1 and Figure 2As shown, the buffer piston 23 is sleeved on the outer periphery of the valve core 4, so that the valve core 4 communicates with the accommodation cavity 235 in the buffer piston 23, so that the buffer piston 23 can push against the base 6 in the first direction under the action of the oil in the valve core 4 to compress the elastic member 5, and the third wall 231 of the buffer piston 23 can move in the first direction to abut against the fifth wall 211 of the adjusting sleeve 21, so that the buffer piston 23 can no longer continue to move in the first direction to push against the valve core 4. At this time, the secondary pressure in the overflow valve is fully established.
[0055] Specifically, as Figure 1 and Figure 2 shown, a second damping hole 42 and a flow cavity 43 are respectively arranged in the valve core 4 and are communicated with each other. The flow cavity 43 is communicated with the accommodation cavity 235. The oil flowing into the second damping hole 42 can sequentially pass through the flow cavity 43, the accommodation cavity 235, and the first damping hole 233 in the second direction and flow into the first chamber 24, so that the oil can act on the third wall 231 of the buffer piston 23. At the same time, the oil flowing into the second damping hole 42 can sequentially pass through the flow cavity 43, the accommodation cavity 235, and the through hole 234 in the second direction and flow into the second chamber, so that the oil can act on the fourth wall 232 of the buffer piston 23.
[0056] The specific working process of the overflow valve in this embodiment is as follows:
[0057] First of all, the oil at the valve port 11 has not had time to act on the buffer piston 23 through the second damping hole 42 and the flow cavity 43. Therefore, the pressure of the oil at the valve port 11 acts on the right side surface of the valve core 4, so that the pressure of the oil acting on the right side surface of the valve core 4 overcomes the elastic force of the elastic member 5 to push the valve core 4 to move in the second direction, so that the valve core 4 is separated from the valve port 11, and the valve port 11 is instantaneously opened.
[0058] While the valve port 11 is instantaneously opened, the oil at the valve port 11 can flow into the flow cavity 43 through the second damping hole 42, then flow into the accommodation cavity 235 through the flow cavity 43, and then flow into the first chamber 24 through the accommodation cavity 235 and the first damping hole 233, so that the oil in the first chamber 24 acts on the third wall 231 of the buffer piston 23. At the same time, the oil in the accommodation cavity 235 flows into the second chamber through the through hole 234 on the buffer piston 23, so that the oil in the second chamber acts on the fourth wall 232 of the buffer piston 23.
[0059] Due to the provision of the above-mentioned seal 3, the pressures acting on both sides of the third wall 231 and the fourth wall 232 of the buffer piston 23 are the same. However, the area where the hydraulic fluid acts on the third wall 231 of the buffer piston 23 is smaller than the area where the hydraulic fluid acts on the fourth wall 232 of the buffer piston 23. Therefore, at this time, the buffer piston 23 can move closer to the valve port 11 in the second direction under the action of the hydraulic fluid, so that the buffer piston 23 can push the base 6 to compress the elastic member 5, thereby being able to push the valve core 4 to reseal the valve port 11 again.
[0060] Then, as the hydraulic fluid pressure at the valve port 11 increases, at the same time, when the buffer piston 23 moves in the first direction until it abuts against the fifth wall 211 of the adjusting sleeve 21, the buffer piston 23 cannot continue to move closer to the valve port 11 in the first direction. At this time, the secondary pressure of this relief valve has been fully established, and at this time, the buffer piston 23 is located at the second position.
[0061] Finally, when the pressure of the hydraulic fluid at the valve port 11 continues to increase until it can overcome the elastic force of the elastic member 5, the valve core 4 can move in the second direction under the action of the hydraulic fluid pressure at the valve port 11 to disengage from the valve port 11, causing the valve port 11 to open for overflow; at this time, the valve core 4 pushes the elastic member 5 and the base 6 to move in the second direction to push the buffer piston 23 to move in the second direction until the fourth wall 232 of the buffer piston 23 abuts against the sixth wall 221 of the piston sleeve 22. At this time, the opening degree of the valve port 11 reaches the maximum, and the buffer piston 23 cannot continue to move in the second direction. The buffer piston 23 is located at the first position.
[0062] It should be noted that if the above-mentioned seal 3 is not provided, when the hydraulic fluid flows into the second chamber through the through hole 234, due to the leakage existing in the gap between the piston sleeve 22 and the adjusting sleeve 21, and the leakage existing in the gap between the buffer piston 23 and the piston sleeve 22, therefore, part of the hydraulic fluid in the second chamber will leak through the gap between the piston sleeve 22 and the adjusting sleeve 21, and the gap between the buffer piston 23 and the piston sleeve 22, resulting in a pressure difference ΔP being formed between the hydraulic fluid pressure P1 at the valve port 11 and the hydraulic fluid pressure P2 in the second chamber. ΔP will cause the secondary pressure establishment time to be prolonged, and will cause the secondary pressure establishment to be low or the secondary pressure cannot be established, and it cannot play a buffering role.
[0063] Therefore, as Figure 1 and Figure 2As shown, after adding the seal 3, the area A1 of the hydraulic fluid acting on the spool 4 = S1 - S2; the area A2 of the hydraulic fluid acting on the buffer piston 23 = (S4 - S5) - (S4 - (S3 - S2)) = S4 - S5 - (S4 - S3 + S2) = S4 - S5 - S4 + S3 - S2 = S3 - S5 - S2; where S1 is the cross-sectional area of the valve port 11, S2 is the cross-sectional area of the spool 4, S3 is the cross-sectional area of the part of the buffer piston 23 located outside the spool 4, S4 is the cross-sectional area of the adjusting sleeve 21, and S5 is the cross-sectional area of the part of the buffer piston 23 located inside the piston sleeve 22.
[0064] Since A1 < A2, P1 > P2, and P1 - P2 = ΔP, therefore, when the buffer piston 23 moves in the first direction to a certain position and this position has not reached the contact and abutment of the third wall 231 of the buffer piston 23 with the fifth wall 211 of the adjusting sleeve 21, when ΔP is large enough, it may cause P1×A1 > P2×A2. At this time, the secondary pressure will be established too low, resulting in the buffer effect not reaching the expected design effect.
[0065] Therefore, in the relief valve of this embodiment, by setting the seal 3 in the gap between the adjusting sleeve 21 and the piston sleeve 22 and the gap between the piston sleeve 22 and the buffer piston 23, the sealing effect is ensured to be good. That is, after adding the seal 3, it can always be ensured that P1 = P2. Correspondingly, it can always be ensured that P1×A1 < P2×A2; therefore, it can be ensured that the third wall 231 of the buffer piston 23 moves in the first direction to abut against the fifth wall 211 of the adjusting sleeve 21, so as to ensure that the secondary buffer pressure in the relief valve is fully established.
[0066] The above content is only the preferred embodiment of the present invention. For those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. The content of this specification should not be construed as a limitation to the present invention.
Claims
1. Overflow valve, characterized in that, Comprising: A pressure relief passage (7); A valve seat (1) in which a pressure - building cavity (12) is formed; An adjusting assembly, including an adjusting sleeve (21), a piston sleeve (22) and a buffer piston (23), the pressure relief passage (7) is located in at least two of the valve seat (1), the adjusting sleeve (21) and the piston sleeve (22), the adjusting sleeve (21) is arranged in the valve seat (1), at least part of the piston sleeve (22) is arranged in the adjusting sleeve (21), both the adjusting sleeve (21) and the piston sleeve (22) are slidably connected to the buffer piston (23), and at least part of the pressure - building cavity (12) is located between the adjusting sleeve (21) and the piston sleeve (22); A seal (3), the seal (3) is arranged between the piston sleeve (22) and the adjusting sleeve (21) / the valve seat (1), and / or the seal (3) is arranged between the piston sleeve (22) and the buffer piston (23), and when the seal (3) is arranged between the piston sleeve (22) and the adjusting sleeve (21), the seal (3) is located between the pressure relief passage (7) and the pressure - building cavity (12).
2. The overflow valve according to claim 1, characterized in that, The adjusting assembly further includes: A first wall (222) and a second wall (25), the first wall (222) is located on the piston sleeve (22), the second wall (25) is located on the buffer piston (23) and / or the adjusting sleeve (21), along the radial direction of the valve seat (1), one side of the seal (3) abuts against the first wall (222), and the other side of the seal (3) abuts against the second wall (25).
3. The overflow valve according to claim 1, characterized in that, The pressure relief passage (7) includes: A first passage (71), a second passage (72) and a third passage (73), at least part of the first passage (71) is located in the piston sleeve (22), at least part of the second passage (72) is located in the adjusting sleeve (21), at least part of the third passage (73) is located in the valve seat (1), and the first passage (71), the second passage (72) and the third passage (73) are connected.
4. The overflow valve according to claim 3, characterized in that, The second passage (72) is inclined axially with respect to the valve seat (1).
5. The overflow valve according to any one of claims 1-4, characterized in that, The buffer piston (23) includes a third wall (231) and a fourth wall (232) arranged opposite to each other, the buffer piston (23) has a first position and a second position, when the buffer piston (23) is in the first position, a first cavity (24) is formed between the third wall (231) and the adjusting sleeve (21), and the fourth wall (232) abuts against the piston sleeve (22); when the buffer piston (23) is in the second position, the third wall (231) abuts against the adjusting sleeve (21), and a second cavity is formed between the fourth wall (232) and the piston sleeve (22), and the area of the oil acting on the third wall (231) in the second cavity is smaller than the area of the oil acting on the fourth wall (232).
6. The overflow valve according to claim 5, characterized in that, The buffer piston (23) is provided with a first damping hole (233) and a through hole (234) at intervals. An accommodation cavity (235) is formed in the buffer piston (23). The through hole (234) communicates the accommodation cavity (235) with the second cavity. The first damping hole (233) communicates the accommodation cavity (235) with the first cavity (24). At least part of the aperture of the first damping hole (233) is smaller than the aperture of the through hole (234).
7. The overflow valve according to claim 6, characterized in that, The adjusting sleeve (21) includes a fifth wall (211). The fifth wall (211) is disposed opposite to the third wall (231). With respect to the fifth wall (211), the first damping hole (233) is disposed close to the third wall (231).
8. The overflow valve according to claim 6, characterized in that, The piston sleeve (22) includes a sixth wall (221). The sixth wall (221) is disposed opposite to the fourth wall (232). With respect to the sixth wall (221), the through hole (234) is disposed close to the fourth wall (232).
9. The overflow valve according to any one of claims 6-8, characterized in that, The overflow valve further includes: a valve core (4), slidably fitted in the valve seat (1). The valve core (4) can move in a first direction so that one end of the valve core (4) can open or close the valve port (11) in the valve seat (1). The other end of the valve core (4) communicates with the accommodation cavity (235) so that the valve core (4) supplies hydraulic fluid to the accommodation cavity (235). The first direction is the axial direction of the valve core (4) and is the direction close to the valve port (11); an elastic member (5), sleeved on the valve core (4). One end of the elastic member (5) is connected to the limiting platform (41) of the valve core (4); a base (6), slidably sleeved on the valve core (4) and disposed opposite to the limiting platform (41). The other end of the elastic member (5) is connected to the base (6). And the buffer piston (23) can push the base (6) to move in the first direction to compress the elastic member (5).