Pressure reducing and releasing valve

Abstract

A pressure reducing and releasing valve comprises a shell, a sleeve, a pressed pushing unit and an elastic piece. The housing defines a chamber and includes a discharge hole fluidly connected to the chamber. The sleeve includes a peripheral wall, and a plurality of inlet apertures. The peripheral wall defines a relief aperture fluidly connected to the inlet aperture. The pressed push unit comprises a pressed push rod arranged in the sleeve in a penetrating mode, a flow guide channel penetrating through the pressed push rod and a valve deck abutting against the pressed push rod. The elastic piece constantly pushes and abuts against the valve deck to move in the direction of the pressed push rod. When the fluid pressure of the pressure relief hole is too high, the fluid in the flow guide channel can push the valve deck to be away from the pressed push rod so as to open the flow guide channel, the fluid can flow to the cavity and then is discharged through the discharge hole, and pressure relief of the pressure relief hole can be completed.

Description

Technical Field

[0001] The invention relates to a valve, and in particular to a pressure reducing and relief valve. Background Art

[0002] See also Figure 1 and Figure 2 , a conventional pressure reducing valve comprises a housing 91, a sleeve 92 connected to one end of the housing 91, an end plug 93 connected to the other end of the housing 91, a pressure push rod 94 movably disposed in the sleeve 92 and the housing 91 along an axis X, an abutment member 95 connected to the pressure push rod 94, an adjustment rod 96 movably disposed in the end plug 93 along the axis X, and an elastic member 97 disposed in the housing 91 and elastically abutting against between the abutment member 95 and the adjustment rod 96. The housing 91 defines a first chamber 911 and a second chamber 912 spaced apart from each other, and a connecting passage 913 connecting the first chamber 911 and the second chamber 912. The sleeve 92 is partially screwed to the housing 91 and is located in the first chamber 911, and has a peripheral wall 921 surrounding the axis X, a plurality of transverse holes 922 formed in the peripheral wall 921, and a flow blocking shoulder 923 extending inward from the peripheral wall 921 and surrounding the axis X. The peripheral wall 921 defines a pressure relief hole 924 around the axis X that is fluidically connected to the transverse hole 922. The flow blocking shoulder 923 is located between the transverse hole 922 and the pressure relief hole 924. The pressure push rod 94 can be pushed by the fluid to move relative to the sleeve 92 along the axis X, and the pressure push rod 94 has a flow blocking inclined surface 941 that can be movably clamped against the flow blocking shoulder 923 to prevent the fluid from being connected between the transverse hole 922 and the pressure relief hole 924. The abutting member 95 is linked to the pressure push rod 94 and can be movably disposed along the axis X through the connecting passage 913, and has a first abutting end 951 located in the first chamber 911, and a second abutting end 952 located in the second chamber 912 and abutting against one end of the elastic member 97. The end plug 93 is screwed to the end of the housing 91 opposite to the sleeve 92. The adjusting rod 96 is screwed to the end plug 93, and the adjusting rod 96 partially extends into the second chamber 912 and abuts against one end of the elastic member 97 opposite to the abutting member 95. The elastic thrust provided by the elastic member 97 to the abutting member 95 can be adjusted by rotating the adjusting rod 96.

[0003] The pressure push rod 94 and the abutment member 95 can move relative to the sleeve 92 between a connecting position and a closing position. Figure 1In the communication position, the second abutting end 952 of the abutting member 95 is pushed by the elastic member 97, so that the first abutting end 951 abuts against the sleeve 92, and the flow blocking inclined surface 941 of the pressure push rod 94 is away from the flow blocking shoulder 923, so that the transverse hole 922 and the pressure relief hole 924 can maintain fluid communication. Figure 2 When in the closed position, the fluid applies a fluid thrust to the pressurized push rod 94, thereby causing the abutment member 95 to overcome the elastic thrust of the elastic member 97. The first abutment end 951 is away from the sleeve 92, and the flow-blocking slope 941 is stuck on the flow-blocking shoulder 923, preventing the fluid from being connected between the transverse hole 922 and the pressure-reducing hole 924.

[0004] When the existing pressure reducing valve is used, the transverse hole 922 is connected to the first oil groove (not shown), and the pressure reducing hole 924 is connected to the second oil groove (not shown). When the pressure push rod 94 and the abutment 95 are in the communication position, the fluid in the first oil groove can flow to the pressure reducing hole 924 through the transverse hole 922, and then flow to the second oil groove. When the fluid thrust provided by the fluid in the second oil groove and the pressure reducing hole 924 to the pressure push rod 94 overcomes the elastic thrust provided by the elastic member 97 to the abutment 95, the abutment 95 compresses the elastic member 97, and the first abutment end 951 moves away from the sleeve 92. At this time, the flow blocking slope 941 stops at the flow blocking shoulder 923 to prevent the fluid communication between the transverse hole 922 and the pressure reducing hole 924, and the pressure push rod 94 and the abutment 95 are in the closed position. Therefore, the existing pressure reducing valve can reduce the pressure in the first oil groove and achieve the purpose of pressure reduction.

[0005] However, if the second oil groove adopts a closed space, when the ambient temperature rises, the fluid in the second oil groove will expand, causing the pressure in the second oil groove to increase, and the second oil groove may be damaged due to excessive pressure, causing fluid leakage; or after long-term use, the baffle slope 941 and the baffle shoulder 923 may produce a gap due to wear, resulting in that when in the closed position, some fluid can still flow from the transverse hole 922 to the pressure reducing hole 924, causing the pressure in the second oil groove to continue to rise and gradually become consistent with the pressure in the first oil groove, causing the fluid in the second oil groove to provide the pressurized push rod 94 with a fluid thrust that is much greater than the elastic thrust provided by the elastic member 97 to the abutment member 95, causing the second oil groove to be damaged due to excessive pressure, causing fluid leakage. Summary of the invention

[0006] The object of the present invention is to provide a pressure reducing and relief valve which can relieve pressure and has zero leakage.

[0007] Therefore, the pressure relief valve of the present invention comprises a shell, a sleeve, a pressure push unit, and an elastic member. The shell defines a chamber around an axis and includes at least one discharge hole connected to the chamber by fluid. The sleeve is connected to one end of the shell and includes a peripheral wall around the axis and a plurality of inlet holes formed on the peripheral wall. The peripheral wall defines a pressure relief hole connected to the inlet hole by fluid. The pressure push unit comprises a pressure push rod movably inserted into the sleeve, a guide channel penetrating the pressure push rod, and a valve cover arranged in the chamber and capable of resisting the pressure push rod. The pressure push rod can be pushed by the fluid in the pressure relief hole to move relative to the sleeve and can prevent the fluid from flowing from the inlet hole to the pressure relief hole. The guide channel is fluidly connected to the pressure relief hole. The elastic member is arranged in the chamber and constantly pushes the valve cover to move in the direction of the pressure push rod. The valve cover can move between a normally closed position and a pressure relief position relative to the pressure push rod. In the normally closed position, the valve cover is pressed against the pressure push rod by the elastic thrust of the elastic member to close the flow guide channel. In the pressure relief position, the pressure relief thrust of the fluid in the pressure relief channel against the valve cover overcomes the elastic thrust of the elastic member, so that the valve cover moves away from the pressure push rod to open the flow guide channel, and the fluid in the flow guide channel flows to the chamber and is discharged through the at least one discharge hole.

[0008] In the pressure reducing and relief valve of the present invention, the sleeve also includes a first shoulder extending inward from the peripheral wall and surrounding the axis, the first shoulder is located between the inlet hole and the pressure reducing hole, the pressure-bearing push rod has an inclined surface that can correspond to the first shoulder, the pressure-bearing push rod is pushed by the fluid in the pressure reducing hole to move relative to the sleeve, and when the inclined surface is stuck to the first shoulder, the fluid is prevented from flowing from the inlet hole to the pressure reducing hole.

[0009] The pressure reducing and relief valve of the present invention, the pressurized push unit also includes a pressure relief channel formed between the pressurized push rod and the valve cover, the pressure relief channel fluid is connected to the end of the guide channel opposite to the pressure reducing hole, the pressurized push rod also has a second shoulder adjacent to the valve cover and surrounding the axis, the valve cover has an arc surface that can correspond to the second shoulder, in the normally closed position, the arc surface is stuck to the second shoulder to close the pressure relief channel, in the pressure relief position, the arc surface is away from the second shoulder to open the pressure relief channel.

[0010] In the pressure reducing and relief valve of the present invention, the cross-sectional area of ​​the first shoulder surrounding the axis is larger than the cross-sectional area of ​​the second shoulder surrounding the axis.

[0011] The pressure reducing and relief valve of the present invention, the pressure push rod has a straight rod member that can be movably arranged along the axis and penetrated in the sleeve, and a stopper connected to the straight rod member and located in the chamber, the straight rod member has a head located in the pressure reducing hole, a body connected to the head and extending through the peripheral wall, and the inclined surface formed on the head, the guide channel passes through the head and the body along the axis, one end of the stopper can abut against the sleeve, and the other end of the stopper can abut against the valve cover, and the stopper has the second shoulder.

[0012] The pressure relief valve of the present invention has a valve cover having an annular plate portion abutting against the elastic member, and a convex column portion extending from the annular plate portion along the axis and capable of abutting against the stopper, wherein the convex column portion has an arc surface capable of abutting against the second shoulder.

[0013] The pressure reducing valve of the present invention further comprises a pressure setting unit connected to an end of the shell opposite to the sleeve, the pressure setting unit comprises an adjusting rod which can move along the axis and is partially disposed in the chamber, and a sliding cover connected between the adjusting rod and the elastic member, the movement of the adjusting rod along the axis can adjust the compression degree of the elastic member, and accordingly can adjust the elastic thrust provided by the elastic member to the valve cover.

[0014] The beneficial effect of the present invention is that the guide channel passes through the pressure-bearing push rod and is connected to the pressure-reducing hole. When the fluid pressure of the pressure-reducing hole is too high, the fluid in the guide channel can push against the valve cover, so that the valve cover moves in a direction away from the pressure-bearing push rod to open the guide channel. The fluid in the guide channel can flow to the chamber and then be discharged through the at least one discharge hole, thereby completing the pressure relief of the pressure-reducing hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other features and effects of the present invention will be clearly presented in the embodiments with reference to the accompanying drawings, in which:

[0016] Figure 1 It is a cross-sectional schematic diagram of an existing pressure reducing valve;

[0017] Figure 2 is another cross-sectional schematic diagram of the existing pressure reducing valve;

[0018] Figure 3 It is a cross-sectional schematic diagram of an embodiment of a pressure relief valve of the present invention inserted into a valve block;

[0019] Figure 4 is similar Figure 3 A cross-sectional schematic diagram illustrating that the inclined surface of the embodiment is clamped against the first shoulder;

[0020] Figure 5 yes Figure 4 A partial enlarged schematic diagram of

[0021] Figure 6 is a cross-sectional schematic diagram of the embodiment performing pressure relief;

[0022] Figure 7 yes Figure 6 A partial enlarged schematic diagram of . DETAILED DESCRIPTION

[0023] See also Figure 3 The embodiment of the pressure reducing and relief valve 1 of the present invention is applicable to a valve block 10, and the valve block 10 includes a slot 11 for inserting the pressure reducing and relief valve 1, a first oil inlet 12 connected to the slot 11, a second oil inlet 13 connected to the slot 11, and a third oil inlet 14 connected to the slot 11. The first oil inlet 12 is fluidically connected to a first oil tank (not shown), the second oil inlet 13 is fluidically connected to a second oil tank (not shown), and the third oil inlet 14 is connected to a recovery oil tank (not shown). The pressure reducing and relief valve 1 includes a housing 2, a sleeve 3, a pressure pushing unit 4, a pressure setting unit 5, and an elastic member 6.

[0024] The housing 2 includes a shell 21 defining a chamber 211 around an axis L, and a plurality of discharge holes 22 formed in the shell 21 around the axis L. The discharge holes 22 fluidically connect the chamber 211 and the third oil inlet 14 .

[0025] The sleeve 3 includes a peripheral wall 31 partially connected to one end of the housing 21, a plurality of inlet holes 32 formed on the peripheral wall 31 around the axis L, and a first shoulder 33 extending inward from the peripheral wall 31 and surrounding the axis L. The peripheral wall 31 defines a pressure relief hole 311 around the axis L that is fluidically connected to the inlet hole 32 at one end opposite to the housing 21. The inlet hole 32 is fluidically connected to the first oil inlet port 12. The first shoulder 33 is located between the inlet hole 32 and the pressure relief hole 311. The pressure relief hole 311 is fluidically connected to the second oil inlet port 13. The first shoulder 33 is a structure that protrudes inward from the peripheral wall 31 toward the axis L, and the diameter of the circular hole formed by the first shoulder 33 around the axis L is smaller than the diameter of the pressure relief hole 311.

[0026] The pressurized push unit 4 includes a pressurized push rod 41 that can be movably arranged along the axis L and is inserted into the sleeve 3, a guide channel 42 that passes through the pressurized push rod 41 along the axis L, a valve cover 43 that is arranged in the chamber 211 and can abut against the pressurized push rod 41, and a pressure relief channel 44 formed between the pressurized push rod 41 and the valve cover 43.

[0027] See also Figure 3 and Figure 4The pressure push rod 41 has a straight rod 411 that can be movably disposed in the sleeve 3 along the axis L, and a stopper 412 that is screwed to the straight rod 411 and located in the chamber 211. The straight rod 411 has a head 413 located in the pressure reducing hole 311, a body 414 connected to the head 413 and extending in the peripheral wall 31, and an inclined surface 415 formed on the head 413 and capable of abutting against the first shoulder 33. The stopper 412 is screwed to an end of the body 414 opposite to the head 413, and can move along the axis L with the straight rod 411. The stopper 412 has a first stopper end 416 that can abut against the sleeve 3, a second stopper end 417 opposite to the first stopper end 416, and a second shoulder 418 formed on the second stopper end 417. The second shoulder 418 is a structure protruding from the second stop end 417 toward the axis L. It is worth noting that the inclined surface 415 is not limited to the flat inclined surface drawn in the drawings, and can also be an arc surface.

[0028] The cross-sectional area of ​​the first shoulder 33 around the axis L is greater than the cross-sectional area of ​​the second shoulder 418 around the axis L.

[0029] The guide channel 42 passes through the head portion 413 and the body portion 414 along the axis L, and is fluidically connected to the pressure reducing hole 311 and the second oil inlet 13 .

[0030] See also Figure 4 and Figure 5 The valve cover 43 has an annular plate portion 431 that abuts against the elastic member 6, and a convex column portion 432 that extends from the annular plate portion 431 along the axis L and can abut against the stopper 412. The convex column portion 432 has an arc surface 433 that can abut against the second shoulder 418. It is worth noting that the arc surface 433 is not limited to the arc surface drawn in the drawings, and can also be a flat inclined surface.

[0031] The pressure relief passage 44 is defined by the body 414 of the straight rod 411 , the second shoulder 418 of the stopper 412 , and the arc surface 433 of the valve cover 43 . The pressure relief passage 44 is fluidically connected to the flow guide passage 42 .

[0032] It is worth noting that, in this embodiment, the pressure push rod 41 is composed of the straight rod 411 and the stopper 412 screwed together, but in other embodiments, the straight rod 411 and the stopper 412 can also be made in one piece, which is not limited to this embodiment.

[0033] See also Figure 3The pressure setting unit 5 is screwed to the end of the housing 2 opposite to the sleeve 3, and includes an adjusting rod 51 that can move along the axis L and is partially located in the chamber 211, and a sliding cover 52 that is located in the chamber 211 and connected to the adjusting rod 51.

[0034] The elastic member 6 is disposed in the chamber 211 and abuts between the valve cover 43 and the push cover 52. The elastic member 6 constantly pushes the valve cover 43 to move toward the stopper 412.

[0035] When the adjusting rod 51 is rotated, the adjusting rod 51 can be moved along the axis L, and the elastic member 6 can be pushed against by the push cover 52 to adjust the compression degree of the elastic member 6, thereby adjusting the elastic thrust provided by the elastic member 6 to the valve cover 43.

[0036] See also Figures 3 to 7 The valve cover 43 can move between the normally closed position and the pressure relief position relative to the pressure push rod 41. Figures 3 to 5 As shown, in the normally closed position, the valve cover 43 is pushed against the pressure push rod 41 by the elastic thrust of the elastic member 6, and the arc surface 433 is pushed against the second shoulder 418 to close the pressure relief channel 44. Figure 6 and Figure 7 As shown, when in the pressure relief position, the pressure relief thrust of the fluid in the pressure relief channel 44 pushes against the valve cover 43 to overcome the elastic thrust of the elastic member 6, so that the valve cover 43 moves away from the pressurized push rod 41, and a gap is generated between the second shoulder 418 and the arc surface 433 to open the pressure relief channel 44. The fluid in the pressure relief channel 44 flows into the chamber 211 and is then discharged through the discharge hole 22.

[0037] See also Figure 3 When the pressure reducing and relief valve 1 is in use, when the pressure of the fluid (such as hydraulic oil) in the first oil groove is too high, the fluid in the first oil groove is transported to the inlet hole 32 through the first oil inlet 12, and the fluid then flows to the pressure reducing hole 311, and then flows into the second oil groove through the second oil inlet 13 to reduce the pressure of the first oil groove. At this time, the fluid also flows to the pressure relief channel 44 through the guide channel 42, but the fluid thrust applied to the pressure push rod 41 by the fluid in the second oil groove, the second oil inlet 13 and the pressure reducing hole 311 cannot overcome the elastic thrust provided by the elastic member 6 to the valve cover 43, so the pressure push rod 41 does not move along the axis L, the valve cover 43 still abuts against the stopper 412, and closes the pressure relief channel 44, and the valve cover 43 is in the normally closed position.

[0038] See also Figure 4 and Figure 5 When the fluid pressure in the second oil groove, the second oil inlet 13 and the pressure reducing hole 311 gradually increases, the fluid thrust applied by the fluid in the second oil groove, the second oil inlet 13 and the pressure reducing hole 311 to the pressurized push rod 41 overcomes the elastic thrust provided by the elastic member 6 to the valve cover 43, so that the pressurized push rod 41 moves along the axis L and pushes against the valve cover 43 and compresses the elastic member 6 and the first stop end 416 of the stop member 412 moves away from the sleeve 3 until the inclined surface 415 is stuck on the first shoulder 33, and the pressurized push rod 41 no longer moves. At this time, because the flow guide channel 42, the pressure relief channel 44, the pressure reducing hole 311, the second oil inlet 13, and the second oil groove are connected and thus have the same fluid pressure, and the pressure relief thrust exerted by the fluid in the pressure relief channel 44 on the valve cover 43 is the same as the elastic thrust exerted by the elastic member 6 on the valve cover 43, the valve cover 43 still abuts against the stopper 412, the arc surface 433 abuts against the second shoulder 418, and closes the pressure relief channel 44. The valve cover 43 is still in the normally closed position.

[0039] See also Figure 6 and Figure 7, when the inclined surface 415 is stuck on the first shoulder 33, and the valve cover 43 is still against the stopper 412 to close the pressure relief channel 44, if the fluid in the second oil groove, the second oil inlet 13 and the pressure reducing hole 311 expands due to the increase in ambient temperature, causing the fluid pressure to increase again, or because there is a slight gap between the inclined surface 415 and the first shoulder 33, causing the fluid in the first oil groove to continue to flow into the pressure reducing hole 311 through the first oil inlet 12 and the inlet hole 32, causing the fluid pressure in the second oil groove, the second oil inlet 13, the pressure reducing hole 311, the guide channel 42 and the pressure relief channel 44 to increase again, because the pressurized push rod 41 can no longer move, it is impossible to compress the elastic member 6 by pushing against the valve cover 43 through the stopper 412. At this time, according to the pressure formula P=F / A, when the force area (A) applied by the fluid in the pressure relief channel 44 to the valve cover 43 is fixed, the pressure (P) is proportional to the positive force (F). If the fluid pressure (P) in the pressure relief channel 44 increases, the pressure relief thrust (F) applied by the fluid in the pressure relief channel 44 to the valve cover 43 also increases. The pressure relief thrust is greater than the elastic thrust provided by the elastic member 6 to the valve cover 43, so that the fluid in the pressure relief channel 44 pushes the valve cover 43 away from the stopper 412, and a gap is generated between the second shoulder 418 and the arc surface 433, thereby opening the pressure relief channel 44 and placing the valve cover 43 in the pressure relief position. The fluid in the pressure relief channel 44 flows to the chamber 211, and flows to the third oil inlet 14 through the discharge hole 22, and then flows into the recovery oil tank, thereby completing the pressure relief of the second oil tank, and preventing the second oil tank from being damaged due to excessive pressure, causing fluid leakage.

[0040] It is worth mentioning that the cross-sectional area of ​​the first shoulder 33 around the axis L is larger than the cross-sectional area of ​​the second shoulder 418 around the axis L, which brings about the effect that: it can ensure that the pressure push rod 41 moves first so that the inclined surface 415 is stuck on the first shoulder 33, and the excess fluid pushes against the valve cover 43 to open the pressure relief channel 44. The principle is as follows: when the inclined surface 415 has not yet been stuck on the first shoulder 33, the inlet hole 32 and the pressure relief hole 311 are still in fluid communication, the pressure relief hole 311, the flow guide channel 42, and the pressure relief channel 44 maintain the same pressure. According to the pressure formula P=F / A, at this time, the thrust provided by the fluid to the pressure push rod 41 and the thrust provided by the fluid to the valve cover 43 are the product of pressure (P) and cross-sectional area (A), and the thrust (F1) provided by the fluid to the pressure push rod 41 is the product of the pressure (P) in the pressure relief hole 311 and the cross-sectional area (A) around the first shoulder 33. The thrust (F2) provided by the fluid to the valve cover 43 is the product of the pressure (P) in the pressure relief passage 44 and the cross-sectional area (A2) of the second shoulder 418 around the axis L, that is, F2 = P × A2. Under the same pressure condition, because the cross-sectional area (A1) of the first shoulder 33 around the axis L is larger than the cross-sectional area (A2) of the second shoulder 418 around the axis L, the thrust (F1) provided by the fluid to the pressure-receiving push rod 41 is larger than the thrust (F2) provided by the fluid to the valve cover 43. In this way, it can be ensured that the pressure-receiving push rod 41 first drives the valve cover 43 to move to compress the elastic member 6, so that the inclined surface 415 is first stuck on the first shoulder 33, and it is prevented that the valve cover 43 moves first to compress the elastic member 6, and the pressure relief passage 44 is opened before the inclined surface 415 is stuck on the first shoulder 33.

[0041] In other words, when the cross-sectional area of ​​the first shoulder 33 around the axis L is smaller than the cross-sectional area of ​​the second shoulder 418 around the axis L, the pressure relief passage 44 will open first, causing the fluid to continue to flow into the chamber 211 and flow through the discharge hole 22 to the third oil inlet 14, causing the fluid pressure in the first oil groove to drop excessively, exceeding the expected pressure reduction value.

[0042] In summary, the pressure reducing and relief valve 1 of the present invention, by providing the guide channel 42 on the pressure-bearing push rod 41, and the pressure relief channel 44 defined by the pressure-bearing push rod 41 and the valve cover 43, when the inclined surface 415 abuts against the first shoulder 33 to prevent the fluid from flowing to the pressure reducing hole 311 through the inlet hole 32, if the pressure in the second oil groove continues to increase, the pressure relief thrust applied by the fluid in the pressure relief channel 44 to the valve cover 43 is greater than the elastic thrust applied by the elastic member 6 to the valve cover 43, so that the valve cover 43 is away from the stop member 412 and the pressure relief channel 44 is opened, and the fluid in the pressure relief channel 44 can flow to the chamber 211 and flow out through the discharge hole 22, thereby completing the pressure relief of the second oil groove, so that the purpose of the present invention can be achieved.

[0043] The above descriptions are merely embodiments of the present invention and should not be used to limit the scope of the present invention. That is, any simple equivalent changes and modifications made according to the claims and description of the present invention still fall within the scope of the present invention.

Claims

1. A pressure relief valve, characterized in that: Include a housing defining a chamber about an axis and including at least one exhaust port fluidly connected to the chamber; a sleeve connected to one end of the housing and comprising a peripheral wall surrounding the axis and a plurality of inlet holes formed in the peripheral wall, wherein the peripheral wall defines a pressure relief hole fluidly connected to the inlet holes; A pressure push unit, comprising a pressure push rod movably inserted into the sleeve, a flow guide channel penetrating the pressure push rod, and a valve cover disposed in the chamber and capable of abutting against the pressure push rod, wherein the pressure push rod can be pushed by the fluid in the pressure reducing hole to move relative to the sleeve and can prevent the fluid from flowing from the inlet hole to the pressure reducing hole, and the flow guide channel is fluidically connected to the pressure reducing hole; and An elastic member is disposed in the chamber and constantly pushes the valve cover to move toward the pressurized push rod; The valve cover can move between a normally closed position and a pressure relief position relative to the pressure push rod. In the normally closed position, the valve cover is pressed against the pressure push rod by the elastic thrust of the elastic member to close the flow guide channel. In the pressure relief position, the pressure relief thrust of the fluid in the flow guide channel pushes against the valve cover to overcome the elastic thrust of the elastic member, so that the valve cover moves in a direction away from the pressure push rod to open the flow guide channel. The fluid in the flow guide channel flows into the chamber and is then discharged through the at least one discharge hole.

2. The pressure relief valve according to claim 1, characterized in that: The sleeve also includes a first shoulder extending inward from the peripheral wall and surrounding the axis, the first shoulder being located between the inlet hole and the pressure reducing hole, the pressure-bearing push rod having an inclined surface that can correspond to and abut against the first shoulder, the pressure-bearing push rod is pushed by the fluid in the pressure reducing hole to move relative to the sleeve, and when the inclined surface abuts against the first shoulder, the fluid is prevented from flowing from the inlet hole to the pressure reducing hole.

3. The pressure relief valve according to claim 2, characterized in that: The pressure push unit also includes a pressure relief channel formed between the pressure push rod and the valve cover, the pressure relief channel fluidly connected to the end of the guide channel opposite to the pressure relief hole, the pressure push rod The push rod also has a second shoulder adjacent to the valve cover and surrounding the axis, and the valve cover has an arc surface that can correspond to the second shoulder. In the normally closed position, the arc surface is stuck to the second shoulder to close the pressure relief channel. In the pressure relief position, the arc surface is away from the second shoulder to open the pressure relief channel.

4. The pressure relief valve according to claim 3, characterized in that: A cross-sectional area of ​​the first shoulder around the axis is greater than a cross-sectional area of ​​the second shoulder around the axis.

5. The pressure relief valve according to claim 3, characterized in that: The pressure push rod has a straight rod member that can be movably arranged along the axis and is inserted into the sleeve, and a stopper connected to the straight rod member and located in the chamber. The straight rod member has a head located in the pressure reducing hole, a body connected to the head and extending into the peripheral wall, and the inclined surface formed on the head. The guide channel passes through the head and the body along the axis. One end of the stopper can abut against the sleeve, and the other end of the stopper can abut against the valve cover. The stopper has the second shoulder.

6. The pressure relief valve according to claim 5, characterized in that: The valve cover has an annular plate portion abutting against the elastic member, and a convex column portion extending from the annular plate portion along the axis and capable of abutting against the stopper, wherein the convex column portion has the arc surface capable of abutting against the second shoulder portion.

7. The pressure reducing and relief valve according to claim 1, characterized in that: The pressure reducing valve also includes a pressure setting unit connected to an end of the housing opposite to the sleeve, the pressure setting unit includes an adjusting rod that can move along the axis and is partially disposed in the chamber, and a sliding cover connected between the adjusting rod and the elastic member, and the movement of the adjusting rod along the axis can adjust the compression degree of the elastic member, and the elastic thrust provided by the elastic member to the valve cover can be adjusted accordingly.

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