阅读说明：本技术 直动式减泄压阀 (Direct-acting pressure reducing and releasing valve ) 是由 欧阳正峰 罗占涛 陶小好 于 2021-09-10 设计创作，主要内容包括：本发明涉及液压阀技术领域,特别是涉及直动式减泄压阀。包括阀座、阀套及阀芯；阀座的外壁开设有第三油口,阀座的外壁上还开设有泄油口,阀套的外壁开设有第一油口以及第二油口,阀套的外壁上还开设有进油口及溢流口,进油口与第二油口连通,溢流口能够与第三油口连通,阀芯能够沿着直动式减泄压阀的轴向运动,以使第二油口与所述第一油口之间能够通过进油口连通或隔断,第三油口与第一油口之间能够通过所述溢流口连通或隔断；直动式减泄压阀还包括缓冲结构,缓冲结构设于阀芯上及/或阀套上,缓冲结构能够缓冲阀芯的震荡。本发明的优点在于：在液压系统压力急剧变化时缓解阀芯的震荡,解决直动式减泄压阀啸叫的问题。(The invention relates to the technical field of hydraulic valves, in particular to a direct-acting pressure reducing and relieving valve. Comprises a valve seat, a valve sleeve and a valve core; the outer wall of the valve seat is provided with a third oil port, the outer wall of the valve seat is also provided with an oil drainage port, the outer wall of the valve sleeve is provided with a first oil port and a second oil port, the outer wall of the valve sleeve is also provided with an oil inlet and an overflow port, the oil inlet is communicated with the second oil port, the overflow port can be communicated with the third oil port, the valve core can move along the axial direction of the direct-acting pressure reducing and releasing valve, so that the second oil port can be communicated or separated with the first oil port through the oil inlet, and the third oil port can be communicated or separated with the first oil port through the overflow port; the direct-acting type pressure reducing and relieving valve further comprises a buffer structure, the buffer structure is arranged on the valve core and/or the valve sleeve, and the buffer structure can buffer the oscillation of the valve core. The invention has the advantages that: when the pressure of the hydraulic system changes sharply, the shock of the valve core is relieved, and the problem of squealing of the direct-acting type pressure reducing and releasing valve is solved.)

1. A direct-acting type pressure reducing and relieving valve comprises a valve seat (20), a valve sleeve (10) and a valve core (30), wherein one end of the valve sleeve (10) extends into the valve seat (20), and the valve core (30) is positioned in the valve sleeve (10);

it is characterized in that the outer wall of the valve seat (20) is provided with a third oil port (14), an oil drainage port (24) is also formed in the outer wall of the valve seat (20), the oil drainage port (24) is communicated with the third oil port (14), the outer wall of the valve sleeve (10) is provided with a first oil port (12) and a second oil port (13), an oil inlet (15) and an overflow port (16) are also arranged on the outer wall of the valve sleeve (10), the oil inlet (15) is communicated with the second oil port (13), the overflow port (16) can be communicated with the third oil port (14), the valve core (30) can move along the axial direction of the direct-acting pressure reducing and relieving valve, so that the second oil port (13) and the first oil port (12) can be communicated or separated through the oil inlet (15), the third oil port (14) and the first oil port (12) can be communicated or separated through the overflow port (16) and the oil drainage port (24);

the direct-acting type pressure reducing and relieving valve further comprises a buffer structure (40), the buffer structure (40) is arranged on the valve core (30) and/or the valve sleeve (10), and the buffer structure (40) can buffer the oscillation of the valve core (30).

2. The direct-acting type pressure reducing and relieving valve according to claim 1, wherein the buffer structure (40) comprises a first buffer portion (41), a first cavity (31) for medium to flow is formed in the valve core (30), a buffer cavity (35) is formed in one end, away from the first oil port (12), of the valve core (30), a damping hole (311) is formed in the inner wall of the first cavity (31), the damping hole (311) is communicated with the buffer cavity (35), and the buffer cavity (35) and the damping hole (311) form the first buffer portion (41).

3. The direct-acting type pressure reducing and relieving valve according to claim 1 or 2, characterized in that the buffer structure (40) comprises a second buffer part (42), the direct-acting type pressure reducing and relieving valve further comprises a buffer sleeve (50), the buffer sleeve (50) is sleeved outside the valve sleeve (10) and can move along the outer side wall of the valve sleeve (10), a first protrusion (19) is arranged on the outer side wall of the valve sleeve (10), the first protrusion (19) and the buffer sleeve (50) form a buffer groove (102), and the buffer groove (102) and the buffer sleeve (50) form the second buffer part (42).

4. The direct-acting pressure relief valve according to claim 3, characterized in that a sealing ring (101) is provided in the buffer groove (102), and one end of the buffer sleeve (50) can abut against the sealing ring (101).

5. The direct-acting type pressure reducing and relieving valve as claimed in claim 3, characterized in that the outer wall of the valve sleeve (10) is provided with a limiting part (103), and the buffer sleeve (50) can be abutted against the limiting part (103) to limit the separation of the buffer sleeve (50) from the valve sleeve (10).

6. The direct-acting type pressure reducing and relieving valve according to claim 1, characterized in that a first cavity (31) is formed in the valve core (30), a pressure reducing control port (33) and an overflow control port (34) which are respectively communicated with the first cavity (31) are formed in the outer wall of the valve core (30), when the valve core (30) is located at a first position, the pressure reducing control port (33) is communicated with the second oil port (13), and when the valve core (30) is located at a second position, the overflow control port (34) is communicated with the third oil port (14).

7. The direct-acting type pressure reducing and relieving valve according to claim 6, characterized in that the pressure reducing control port (33) and the overflow control port (34) are both provided in plural, and the plural pressure reducing control ports (33) and the plural overflow control ports (34) are respectively provided along the circumferential direction of the valve core (30); the oil inlets (15) and the overflow ports (16) are multiple, and the multiple oil inlets (15) and the multiple overflow ports (16) are respectively arranged along the circumferential direction of the valve sleeve (10).

8. The direct-acting pressure-reducing and relieving valve according to claim 1, characterized in that a communication groove (17) is opened on the outer side of the valve sleeve (10), and the communication groove (17) is communicated with the overflow port (16) and can be communicated with the oil drain port (24).

9. The direct-acting type pressure reducing and releasing valve according to claim 1, further comprising an adjusting rod (61) and an elastic member (63), wherein one end of the adjusting rod (61) extends out of the valve seat (20), the other end of the adjusting rod abuts against the elastic member (63), one end of the elastic member (63) far away from the adjusting rod (61) abuts against the valve core (30), and the adjusting rod (61) can adjust the elastic force of the elastic member (63).

10. The direct-acting type pressure reducing and releasing valve according to claim 9, characterized in that a spring cavity (211) is arranged in the valve seat (20), the elastic piece (63) is located in the spring cavity (211), a second oil return opening (23) is formed in the inner wall of the spring cavity (211), and the second oil return opening (23) is communicated with the third oil opening (14).

Technical Field

The invention relates to the technical field of hydraulic valves, in particular to a direct-acting pressure reducing and relieving valve.

Background

The pressure reducing and relieving valve is one of hydraulic control elements of a hydraulic system, and has become a preferred product for fluid control automation due to the characteristics of easy installation, small volume, sensitive action, high control precision, convenience and the like.

When the existing direct-acting type pressure reducing and relieving valve is used, when the pressure of a hydraulic system is changed rapidly, the pressure of the second oil port is changed rapidly, the pressure in the first oil port is changed, the valve core is vibrated, and the direct-acting type pressure reducing and relieving valve is inconvenient to use.

Disclosure of Invention

In order to solve the problems, the invention provides a direct-acting pressure reducing and releasing valve capable of preventing squeal, which has the technical scheme as follows:

a direct-acting type pressure reducing and relieving valve comprises a valve seat, a valve sleeve and a valve core, wherein one end of the valve sleeve extends into the valve seat, and the valve core is positioned in the valve sleeve; the outer wall of the valve seat is provided with a third oil port, the outer wall of the valve seat is also provided with an oil drainage port, the oil drainage port is communicated with the third oil port, the outer wall of the valve sleeve is provided with a first oil port and a second oil port, the outer wall of the valve sleeve is also provided with an oil inlet and an overflow port, the oil inlet is communicated with the second oil port, the overflow port can be communicated with the third oil port, the valve element can move along the axial direction of the direct-acting pressure reducing and releasing valve, so that the second oil port can be communicated or separated from the first oil port through the oil inlet, and the third oil port can be communicated or separated from the first oil port through the overflow port and the oil drainage port;

the direct-acting type pressure reducing and relieving valve further comprises a buffer structure, the buffer structure is arranged on the valve core and/or the valve sleeve, and the buffer structure can buffer the oscillation of the valve core.

By the arrangement, the direct-acting pressure reducing and relieving valve not only has the pressure reducing function, but also has the overflow function, and meanwhile, the direct-acting pressure reducing and relieving valve does not have a pilot valve, can reduce the leakage of a secondary circuit, and can be applied to different hydraulic circuits; when the oil inlet is closed, the pressure in the first oil port is increased instantly, and the medium forms impact force towards the direction far away from the first oil port on the valve core; after the oil inlet is closed, the overflow port is opened, and then the medium instantly rushes to the overflow port, so that the valve core vibrates, the buffer cavity can relieve the vibration of the valve core, and the occurrence of squealing is avoided.

In one embodiment, the buffering structure comprises a first buffering part, a first cavity for medium to flow is formed in the valve core, a buffering cavity is formed in one end, far away from the first oil port, of the valve core, a damping hole is formed in the inner wall of the first cavity and communicated with the buffering cavity, and the buffering cavity and the damping hole form the first buffering part.

So set up, when the oil inlet was closed, pressure in the first oil port can increase in the twinkling of an eye, and the medium can get into the cushion chamber from the damping hole, and the high-frequency vibration of case can be alleviated to the cushion chamber medium, and the cushion chamber medium forms reverse power to the case to reduce the vibration of case.

In one embodiment, the buffer structure includes a second buffer portion, the direct-acting relief valve further includes a buffer sleeve, the buffer sleeve is sleeved outside the valve sleeve and can move along the outer side wall of the valve sleeve, the outer side wall of the valve sleeve is provided with a first protrusion, the first protrusion and the buffer sleeve form a buffer groove, and the buffer groove and the buffer sleeve form the second buffer portion.

So set up, when pressure in first oil port increases in the twinkling of an eye, the cushion collar also can remove, fluid in the dashpot plays the cushioning effect to the removal of cushion collar to play the cushioning effect to the valve barrel, slow down the pressure lift in first oil port.

In one embodiment, a sealing ring is arranged in the buffer groove, and one end of the buffer sleeve can abut against the sealing ring.

So set up, the sealing washer has elasticity, not only plays the cushioning effect, still plays sealed effect.

In one embodiment, the outer wall of the valve sleeve is provided with a limiting part, and the buffer sleeve can be abutted against the limiting part to limit the buffer sleeve to be separated from the valve sleeve.

In one embodiment, the valve core has a first cavity therein, the outer wall of the valve core is provided with a pressure reduction control port and an overflow control port, which are respectively communicated with the first cavity, when the valve core is at a first position, the pressure reduction control port is communicated with the second oil port, and when the valve core is at a second position, the overflow control port is communicated with the third oil port.

In one embodiment, the pressure reduction control port and the relief control port are both provided in plural, and the pressure reduction control port and the relief control port are provided in plural along a circumferential direction of the valve body, respectively; the valve sleeve is characterized in that the valve sleeve is provided with a plurality of valve sleeves, the valve sleeves are arranged in the valve sleeve, and the valve sleeves are arranged in the valve sleeve.

With such an arrangement, the flow rate of the medium can be increased.

In one embodiment, a communicating groove is formed in the outer side of the valve sleeve, and the communicating groove is communicated with the overflow port and can be communicated with the oil drainage port.

So set up, can be according to the length of adjustment intercommunication groove with the position of suitably adjusting overflow mouth and draining port for the position of overflow mouth and draining port is nimble changeable more.

In one embodiment, the direct-acting pressure relief valve further comprises an adjusting rod and an elastic member, one end of the adjusting rod extends out of the valve seat, the other end of the adjusting rod is abutted to the elastic member, one end of the elastic member, far away from the adjusting rod, is abutted to the valve element, and the adjusting rod can adjust the elasticity of the elastic member.

So set up, can adjust the required power of push valve core.

In one embodiment, a spring cavity is formed in the valve seat, the elastic piece is located in the spring cavity, a second oil return opening is formed in the inner wall of the spring cavity, and the second oil return opening is communicated with the third oil opening.

With this arrangement, the oil in the spring chamber can be discharged.

Compared with the prior art, the direct-acting type pressure reducing and relieving valve provided by the invention has the advantages that the valve core relieves the high-frequency movement of the valve core when the pressure of a hydraulic system is changed sharply by arranging the buffer structure on the direct-acting type pressure reducing and relieving valve, so that the problem of squealing of the direct-acting type pressure reducing and relieving valve is solved.

Drawings

FIG. 1 is a cross-sectional view of a direct acting pressure relief valve provided by the present invention;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

FIG. 3 is an enlarged view of a portion of FIG. 1 at B;

FIG. 4 is a perspective view of a direct acting pressure relief valve;

FIG. 5 illustrates the application of the direct acting pressure relief valve of the present invention in a hydraulic circuit;

FIG. 6 is one of the liquid circuits to which the direct acting pressure relief valve of the present invention can be applied;

FIG. 7 is another fluid circuit to which the direct acting pressure relief valve of the present invention can be applied;

FIG. 8 is a pressure relief curve of the direct acting type pressure relief valve;

FIG. 9 is an overflow graph of the direct acting pressure relief valve;

fig. 10 is a functional diagram of a direct-acting pressure relief valve.

The symbols in the drawings represent the following meanings:

100. a direct-acting pressure reducing and releasing valve; 10. a valve housing; 11. a second valve cavity; 12. a first oil port; 13. a second oil port; 14. a third oil port; 15. an oil inlet; 16. an overflow port; 17. a communicating groove; 18. a communicating cavity; 19. a first protrusion; 101. a seal ring; 102. a buffer tank; 103. a limiting part; 104. a retainer ring; 20. a valve seat; 21. a first valve chamber; 211. a spring cavity; 212. a mounting cavity; 22. a buffer seat; 221. mounting holes; 23. a second oil return port; 24. an oil drainage port; 30. a valve core; 31. a first chamber; 311. a damping hole; 321. a first part; 322. a second section; 33. a pressure reduction control port; 34. an overflow control port; 35. a buffer chamber; 40. a buffer structure; 41. a first buffer section; 42. a second buffer section; 50. a buffer sleeve; 60. an adjustment assembly; 61. adjusting a rod; 62. a nut; 63. an elastic member; 64. a first spring seat; 641. a first steel ball; 65. a second spring seat; 651. and the second steel ball.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It will be understood that when an element is referred to as being "mounted on" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. When an element is referred to as being "secured to" another element, it can be directly secured to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, a direct-acting type pressure reducing and relieving valve 100 (hereinafter, referred to as a pressure reducing and relieving valve) provided by the present invention is installed in a hydraulic system circuit for controlling the pressure of oil.

Specifically, referring to fig. 1 and 2, the pressure reducing and relieving valve includes a valve housing 10, a valve seat 20 and a valve core 30, wherein the valve seat 20 has a first valve cavity 21 therein, the valve housing 10 has a second valve cavity 11 therein, one end of the valve housing 10 extends into the first valve cavity 21, and the valve core 30 is located in the second valve cavity 11 and can move in the second valve cavity 11.

The outer side wall of the valve housing 10 is provided with a first oil port 12 and a second oil port 13, the outer wall of the valve seat 20 is provided with a third oil port 14, and the first oil port 12 is arranged at one end of the valve housing 10 far away from the valve seat 20. An oil inlet 15 and an overflow port 16 are formed in the outer wall of the valve housing 10, the oil inlet 15 is communicated with the second oil port 13, the overflow port 16 can be communicated with the third oil port 14, and the valve core 30 can move axially along the direct-acting pressure relief valve 100, so that the second oil port 13 and the first oil port 12 can be communicated or separated through the oil inlet 15, and the first oil port 12 and the third oil port 14 can be communicated or separated through the overflow port 16. When the second oil port 13 is communicated with the first oil port 12, a medium enters the first oil port 12 from the second oil port 13, which is a pressure relief process; at this time, the pressure in the first oil port 12 gradually increases, which pushes the valve core 30 to move in a direction away from the first oil port 12, and gradually closes the oil inlet 15. When the pressure in the first port 12 rises again to about 1bar, the first port 12 communicates with the overflow port 16 to remove the excess medium from the overflow port 16. The number of the oil ports is not limited to three, and the oil ports can be adjusted according to actual requirements. The first position is a state when the first port 12 and the second port 13 are communicated, and the second position is a state when the first port 12 and the third port 14 are communicated.

In this embodiment, the second oil port 13 is formed by the end surface of the valve seat 20 and the outer side wall of the valve housing 10, and in other embodiments, the second oil port 13 may also be directly opened on the outer side wall of the valve housing 10.

The direct-acting relief and pressure reduction valve 100 of the present invention has not only a pressure reduction function but also an overload relief function, and can be applied to, for example, a hydraulic circuit in fig. 5, and can be applied to a circuit without a relief function in fig. 6 or a circuit with a relief function in fig. 7, while simplifying the system by replacing a relief valve and a pressure reduction valve (a dashed line frame on the left side in fig. 5). Further, the direct-acting type pressure reducing and relieving valve 100 has no pilot valve, thereby reducing the leakage of the medium in the secondary circuit, and being suitable for use in a severe environment and a closed-end circuit.

Referring to fig. 1 and 2, the number of the oil inlets 15 and the number of the overflow ports 16 are multiple, and the oil inlets 15 and the overflow ports 16 are respectively arranged along the circumferential direction of the valve housing 10, so that the medium flow rate is increased.

The lateral wall of the valve sleeve 10 is further provided with a communicating groove 17, the communicating groove 17 is matched with the inner wall of the valve seat 20 to form a communicating cavity 18, the outer wall of the valve seat 20 is provided with an oil drainage port 24 communicated with the third oil port 14, the communicating cavity 18 is communicated with the overflow port 16, the communicating cavity 18 can be communicated with the oil drainage port 24 in the movement process of the valve core 30, the length of the communicating groove 17 is designed according to different conditions, and therefore the opening positions of the overflow port 16 and the oil drainage port 24 can be adjusted.

The valve seat 20 is internally provided with a buffer seat 22, and the buffer seat 22 plays a role in abutting and limiting in the movement process of the valve core 30. The buffer seat 22 divides the first valve chamber 21 into a spring chamber 211 and a mounting chamber 212.

And a second oil return port 23 is formed in the outer side wall of the valve seat 20, and the second oil return port 23 is respectively communicated with the spring cavity 211 and the oil drainage port 24. During the movement of the spool 30, a part of oil leaks into the spring chamber 211 and accumulates, and the second oil return port 23 can discharge the oil in the spring chamber 211.

The valve core 30 is internally provided with a first cavity 31, the outer side wall of the valve core 30 is provided with a pressure reduction control port 33 and an overflow control port 34, the pressure reduction control port 33 and the overflow control port 34 are respectively communicated with the first cavity 31, the oil drainage port 24 is arranged on the bottom wall of the third oil port 14, and the oil inlet 15 is arranged on the bottom wall of the second oil port 13. In the movement process of the valve core 30, the second oil port 13 can be communicated with the first oil port 12 through the oil inlet 15, the pressure reduction control port 33 and the first cavity 31, and the third oil port 14 can be communicated with the first oil port 12 through the oil drainage port 24, the overflow port 16, the overflow control port 34 and the first cavity 31.

The pressure reduction control port 33 and the relief control port 34 are provided in plural numbers, and the plural pressure reduction control ports 33 and the plural relief control ports 34 are provided along the circumferential direction of the valve body 30, respectively, so that the medium flow rate is increased.

The direct-acting type pressure reducing and relieving valve 100 further comprises a buffer structure 40, the buffer structure 40 is arranged on the valve core 30 and/or the valve sleeve 10, the oil inlet 15 is closed firstly and then the overflow port 16 is opened in the process that the valve core 30 moves away from the first oil port 12, the valve core 30 overshoots after the oil inlet 15 is closed and the overflow port 16 is opened instantly, so that the valve core 30 vibrates, the buffer structure 40 can play a role in buffering the vibration of the valve core 30, and the problem that the direct-acting type pressure reducing and relieving valve 100 howling is solved.

Table 1 test results of the direct-acting type pressure reducing and releasing valve 100

Referring to fig. 8, in fig. 8, an X axis represents pressure change, a Y axis represents pressure change, both the X axis and the Y axis have a unit of bar, a curve of a lowermost end represents pressure change in the second port 13, and a curve of a middle and an uppermost end represent pressure change in the first port 12. As can be seen from fig. 8, when the set pressure reducing pressure value is not reached (in this case 75bar), the pressure in the first port 12 increases as the pressure in the second port 13 increases. When the reduced pressure is reached, the pressure in the first port 12 remains substantially constant and no longer changes as the pressure in the second port 13 increases. In conjunction with fig. 1, we have: when the pressure in the first oil port 12 increases, the valve core 30 moves toward the direction close to the valve seat 20, which will cause the flow area of the oil inlet 15 and the first oil port 12 to decrease, the valve core 30 continues to move, the oil inlet 15 is isolated from the first oil port 12, the first oil port 12 is communicated with the overflow port 16, and after the pressure in the first oil port 12 reaches a balance, the pressure in the first oil port 12 tends to be stable. Referring to fig. 9, in fig. 9, the X axis represents the flow rate, the Y axis represents the pressure, and the curve represents the flow rate and the pressure change of the medium in the first port 12, and it can be seen from fig. 9 that the flow rate of the medium in the first port 12 is gradually increased first, and the flow rate of the medium in the first port 12 is gradually decreased as the overflow port 16 is communicated with the first port 12. In table 1, P2 indicates the pressure in the second port 13, the relief pressure indicates the pressure that pushes the spool 30 to move when the pressure in the first port 12 increases, and the relief steady-state pressure indicates the change value of the pressure in the first port 12 after the relief pressure is reached. As can be seen from table 1, the pressure reducing and relieving valve of the present invention can implement both the pressure relief function and the overflow function, and when the pressure of the second port 13 suddenly changes, the pressure of the first port 12 can be kept stable, and the valve element 30 does not shake and has no squeal.

The buffer structure 40 includes a first buffer portion 41, one end of the valve core 30, which is far away from the first oil port 12, is provided with a buffer cavity 35, the inner wall of the first cavity 31 is provided with a damping hole 311, the damping hole 311 is communicated with the buffer cavity 35, and the buffer cavity 35 and the damping hole 311 form the first buffer portion 41. In the process of the movement of the valve core 32 away from the first oil port 12, the medium may enter the buffer cavity 35, and the medium in the buffer cavity 35 may exert an opposite acting force on the valve core 30, so as to alleviate the oscillation of the valve core 30.

In this embodiment, the valve core 32 includes a first portion 321 and a second portion 322, the first portion 321 is disposed near the first oil port 12 relative to the second portion 322, an outer diameter of the first portion 321 is greater than an outer diameter of the second portion 322, and an inner wall of the valve sleeve 10, the second portion 322 and the buffer seat 22 cooperate to form the buffer cavity 35.

Referring to fig. 3 and 4, the buffer structure 40 includes a second buffer portion 42, the direct-acting pressure relief valve 100 further includes a buffer sleeve 50, the buffer sleeve 50 is sleeved outside the valve housing 10, the buffer sleeve 50 moves along the outer side wall of the valve housing 10 due to the pressure change in the first oil port 12, a first protrusion 19 is disposed on the outer side wall of the valve housing 10, the first protrusion 19 and the buffer sleeve 50 form a buffer groove 102, and the buffer sleeve 50 and the buffer groove 102 form a second buffer portion 42. When the pressure in the first port 12 increases instantaneously, the cushion sleeve 50 also moves, and the oil in the buffer slot 102 plays a role in buffering the movement of the cushion sleeve 50, so as to slow down the pressure rise and fall in the first port 12.

A seal ring 101 is provided in the buffer groove 102, one end of the buffer sleeve 50 can abut against the seal ring 101, and the seal ring 101 not only performs a sealing function but also performs a buffering function. It can be understood that when the pressure at the second oil port 13 sharply increases or decreases, the pressure in the first oil port 12 also sharply changes, which will cause the spool 30 to oscillate. At this time, the buffer sleeve 50 may move on the valve sleeve 10, and when the pressure in the first port 12 increases, the buffer sleeve 50 moves toward the direction close to the valve seat 20, and the liquid in the buffer groove 102 and the seal ring 101 slow down the movement of the buffer sleeve 50, thereby playing a buffer role, and further alleviating the oscillation of the valve element 30, so that the pressure after pressure reduction is stable, and further alleviating the squeal problem of the direct-acting pressure reducing and relieving valve 100.

A retainer ring 104 is provided between the first protrusion 19 and the seal ring 101, and the retainer ring 104 can enhance sealing.

In the present embodiment, the retainer ring 104 is a plastic retainer ring that can abut against the first projection 19, and can protect the seal ring 101 and enhance sealing performance.

The outer side wall of the valve housing 10 is provided with a limiting portion 103, and the cushion collar 50 can abut against the limiting portion 103 to limit the cushion collar 50 from separating from the valve housing 10. It can be understood that when the pressure in the first port 12 decreases, the cushion sleeve 50 moves in a direction away from the valve seat 20 under the action of the pressure in the seal ring 101 and the cushion groove 102, and is limited by the limiting portion 103, so that the oscillation of the valve element 30 can be alleviated.

In this embodiment, the limiting portion 103 is a steel wire retaining ring, and in other embodiments, the limiting portion 103 may also be a retaining ring made of iron or other materials.

In the present invention, only the first buffer 41 may be provided, only the second buffer 42 may be provided, or both the first buffer 41 and the second buffer 42 may be provided.

The direct-acting type pressure reducing and relieving valve 100 further comprises an adjusting assembly 60, one end of the adjusting assembly 60 extends into the first valve cavity 21 and abuts against the valve core 30, and the adjusting assembly 60 can change the resistance which needs to be overcome when the medium pushes the valve core 30 to move.

The adjusting assembly 60 includes an adjusting rod 61, a nut 62, an elastic member 63, a first spring seat 64 and a second spring seat 65, the first spring seat 64 and the second spring seat 65 are respectively disposed at two ends of the elastic member 63, the first spring seat 64 and the second spring seat 65 are all disposed in the spring cavity 211, and the first spring seat 64 can abut against the buffer seat 22. A mounting hole 221 is formed in the cushion seat 22, and one end of the spool 30 is sealingly inserted into the mounting hole 221 and abuts against the first spring seat 64. The elastic member 63 may be a spring or a bellows.

One end of the adjusting rod 61 extends into the spring cavity 211 and abuts against the second spring seat 65, the nut 62 is arranged outside the valve seat 20 and is in threaded connection with the adjusting rod 61, and the nut 62 is rotated to adjust the depth of the adjusting rod 61 extending into the spring cavity 211, so that the elastic force of the elastic member 63 is adjusted.

The first spring seat 64 is provided with a first steel ball 641 on the side facing the valve element 30, the second spring seat 65 is provided with a second steel ball 651 on the end away from the valve element 30, the valve element 30 can be abutted against the first steel ball 641, the adjusting rod 61 can be abutted against the second steel ball 651, the first steel ball 641 and the second steel ball 651 can roll, sliding friction is changed into rolling friction, and accordingly friction force of the abutting is reduced.

Referring to fig. 10, in the working process, when the second oil port 13 is communicated with the first oil port 12 through the oil inlet 15, the medium enters the first oil port 12, so that the pressure in the second oil port 13 can be reduced; when the pressure of the medium in the first oil port 12 gradually rises, the valve core 30 is pushed to move, the communication area between the oil inlet 15 and the pressure reduction control port 33 is gradually reduced until the oil inlet 15 is separated from the pressure reduction control port 33, and the pressure in the first oil port 12 is balanced with the elastic piece 63; when the pressure in the first port 12 continues to rise, the overflow control port 34 communicates with the overflow port 16, and the medium flows out of the overflow port 16. When the pressure of the hydraulic system changes sharply, the buffer structure 40 can relieve the high-frequency movement of the valve core 30, so that the problem of squealing of the direct-acting type pressure reducing and relieving valve 100 is solved.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.