CN105626105A - Safety valve - Google Patents

Abstract

The invention discloses a safety valve, which comprises a valve pocket, a spring seat, a liquid inlet joint, and also comprises a valve core assembly and a push rod, wherein the liquid inlet joint is provided with a liquid inlet hole; the valve core assembly is movably arranged in the valve pocket and is further used for controlling the opening and the closing of the liquid inlet hole; the push rod is located between the valve core assembly and the spring seat; the valve pocket is provided with a liquid discharge hole. According to the safety valve provided by the invention, by arranging the movable valve core assembly inside a valve body, the valve core assembly can be used for controlling the on/off of an oil way from the liquid inlet hole to the liquid discharge hole; the mass-flow overflow can be realized after the valve core assembly is far away from the liquid inlet joint; the flow of the safety valve is greatly improved; the axial displacement of the valve core assembly can be shortened by short-time quick overflow; the axial deformation of a reset spring can be reduced when the axial displacement of the valve core assembly is shortened; finally, the pressure fluctuation can be decreased.

Description

Relief valve

Technical field

The invention belongs to coal mine fully-mechanized mining hydraulic support, specifically, the present invention relates to a kind of relief valve.

Background technology

Large-scale along with coal mine fully-mechanized mining hydraulic support is implemented and development; working face is also more and more stricter to the requirement of hydraulic support; thus the relief valve of protective cradle hydraulic jack there is further requirement; especially the service life of relief valve and reliability there is further requirement; when causing by power from the pressure at hydraulic support top; can relief valve when bearing high pressure, and short time substantially stabilized in time off-load directly affects service life and the supporting safety of support. It not only can damage sealing member, pipeline and Hydraulic Elements, but also can cause vibrations and noise; Sometimes some pressure controlled Hydraulic Elements is made to produce error.

Currently used relief valve, mainly includes valve casing, liquid inlet joint, spool, valve pocket, back-moving spring, spring base and voltage regulation screw. In valve casing contained spring chamber, it is on the voltage regulation screw threadeded that back-moving spring one end is against with valve casing, and the other end is against on moveable spring base. Valve pocket inserts the valve casing other end and with valve casing for threadeding, and is provided with the cavity for holding valve pocket inside valve pocket, and spool is positioned at valve pocket, and the end of spool contacts with spring base, realizes the unlatching of relief valve for promoting spring base to move.

The overflow ducts of existing relief valve is to adopt the liquid pass hole around being arranged on spool sidewall, liquid pass hole aperture is little, cause that draining flow is little, flow loss is big, and owing to spool matches with spring base, spring base bears the axial force that back-moving spring applies, cause that spool force-bearing situation is bad, in work process, pressure oscillation is bigger, and then cause that the closing presure of relief valve is general all undesirable, eventually result in the fluid of the Hydraulic Elements such as high-voltage oil cylinder being connected with relief valve and too much run off and cause waste. Sealing effectiveness between spool and valve pocket is undesirable, and the groove processing precision for installing sealing member that spool face is arranged is wayward. It addition, the spring cavity within valve casing is in open state, dust-proof, waterproof and rust-proof effect are poor, reduce the service life of relief valve.

Summary of the invention

It is contemplated that at least solve one of technical problem of existence in prior art. For this, the present invention provides a kind of relief valve, it is therefore an objective to reduce pressure oscillation.

To achieve these goals, the technical scheme that the present invention takes is: relief valve, including valve pocket, spring base, there is the liquid inlet joint of inlet opening, also include for being movably arranged in described valve pocket and for controlling the core assembly of described inlet opening opening and closing and the push rod between core assembly and spring base, valve pocket has outage.

Described liquid inlet joint includes the joint body that is connected with valve pocket and fixes the sealing being connected and matching with described core assembly with joint body, and described outage is distributed in around sealing.

Described core assembly includes nut and the spool being arranged in nut, and described push rod is clipped between nut and described spring base.

Described spool has the plug that can be inserted in described inlet opening and is fixed on the core bar within described nut.

Described core bar with described nut for threadeding.

Described core assembly also includes for contacting realization sealing and the valve pad for being sheathed on described spool with described liquid inlet joint.

Described spool also includes the connecting portion being arranged between described plug with described core bar and being connected with plug and core bar, and described valve pad is sheathed on connecting portion.

Described nut have for the first containing cavity holding described liquid inlet joint with hold described spool and the second containing cavity of connecting with the first containing cavity.

The end face of described nut is provided with for fluid is guided the oil duct to outage, and after described core assembly separates with described liquid inlet joint, the fluid in described inlet opening flow to described outage place through oil duct.

Described oil duct and described outage are positioned on the same RADIAL of described valve pocket.

The relief valve of the present invention, by arranging moveable core assembly at valve inner, core assembly can be used for the break-make controlling inlet opening to the oil circuit of outage, big flow overflow can be realized after core assembly is away from liquid inlet joint, relief valve flow is greatly improved, the quick overflow of short time can reduce the axial displacement of core assembly, and core assembly axial displacement is reduced and the axial deformation of back-moving spring can be made to reduce, and may finally reduce pressure oscillation.

Accompanying drawing explanation

This specification includes the following drawings, it is shown that content respectively:

Fig. 1 is the sectional view of relief valve of the present invention;

Fig. 2 is the sectional view of core assembly;

Fig. 3 is the sectional view of liquid inlet joint;

Fig. 4 is the sectional view of nut;

Fig. 5 is the sectional view of valve pocket;

Fig. 6 is the sectional view of spool;

Fig. 7 is the sectional view of spring base;

Fig. 8 is the sectional view of push rod;

Figure is labeled as:

1, voltage regulation screw; 2, back-moving spring;

3, valve pocket; 31, outage; 32, unloading cavity;

4, spring base; 41, the first boss; 42, guide section; 43, hole, location;

5, nut; 51, chamber, big footpath; 52, path chamber; 53, the second containing cavity; 54, oil duct; 6, spool; 61, plug; 62, connecting portion; 63, core bar;

7, valve pad; 8, liquid inlet joint; 81, joint body; 82, the first shaft part; 83, the second shaft part; 84, inlet opening; 9, push rod; 91, the second boss; 92, sliding bar; 10, valve casing; 11, the first sealing ring; 12, the second sealing ring.

Detailed description of the invention

Below against accompanying drawing, by the description to embodiment, the specific embodiment of the present invention is described in further detail, it is therefore an objective to help those skilled in the art that the design of the present invention, technical scheme are had more complete, accurate and deep understanding, and contribute to its enforcement.

As shown in Figures 1 to 8, the invention provides a kind of relief valve, including having the valve pocket 3 of outage 31, having valve casing 10 that the liquid inlet joint 8 of inlet opening 84 is connected with valve pocket 3 and be arranged at the resetting-mechanism within valve casing 10, inlet opening 84 is connected with outage 31 by the unloading cavity 32 within valve pocket 3 and three forms the overflow ducts of relief valve. In order to solve problem existing in prior art, the relief valve of the present invention also includes for being movably arranged in valve pocket 3 and for controlling the core assembly of overflow ducts break-make and the push rod 9 between core assembly and resetting-mechanism, core assembly is between liquid inlet joint 8 and push rod 9, core assembly and for controlling the opening and closing of inlet opening 84, namely core assembly realizes the control of overflow ducts break-make by the opening and closing of mobile control inlet opening 84.

The relief valve of prior art is generally connected on coal mine fully-mechanized mining hydraulic support and equipped with on the Hydraulic Elements such as hydraulic cylinder of pressure medium, when hydraulic cylinder internal liquid is in the work set pressure of relief valve, overflow relief valve, under initial tension of spring effect, is closed; When hydraulic cylinder is higher than minimum setting pressure of relief valve by External Force Acting internal pressure, hydraulic medium pressure exceedes initial tension of spring and opens spool overflow, and the moment of unlatching is referred to as the work of relief valve and opens pressure; Making medium flow out release pressure to hydraulic cylinder internal pressure and spring pre-tightening dynamic balance by the overflow of a period of time of relief valve, now relief valve cuts out, and the steady pressure that relief valve keeps after stopping overflow being referred to as closing presure.

Specifically, as shown in Fig. 1, Fig. 3 and Fig. 5, liquid inlet joint 8, valve pocket 3 and valve casing 10 are the cylindrical member of both ends open, inner hollow, liquid inlet joint 8 is inserted in the one end of valve pocket 3 and with valve pocket 3 as threadeding, the other end of valve pocket 3 insert the one end of valve casing 10 interior and with valve casing 10 for threadeding. valve casing 10 is internal has the spring cavity holding resetting-mechanism, resetting-mechanism is for applying core assembly to make it move towards liquid inlet joint 8 place to realize the axial force that inlet opening 84 is closed, resetting-mechanism includes spring base 4, back-moving spring 2 and voltage regulation screw 1, voltage regulation screw 1 is to screw in spring cavity at the other end of valve casing 10 and threaded with valve casing 10, back-moving spring 2 is to be clipped between voltage regulation screw 1 and spring base 4, spring base 4 can moving axially along valve casing 10 by the promotion of back-moving spring 2 and core assembly in valve casing 10, push rod 9 is between core assembly and spring base 4, core assembly promotes spring base 4 to move towards voltage regulation screw 1 place relief valve can be made to open by push rod 9, back-moving spring 2 promotes spring base 4 and core assembly to move relief valve can be made to close.

As shown in figures 1 and 3, liquid inlet joint 8 is for the such as hydraulic cylinder socket connection of the Hydraulic Elements with coal mine fully-mechanized mining hydraulic support, as shown in figures 1 and 3, liquid inlet joint 8 includes with valve pocket 3 to be threaded liquid inlet joint 81 and is the sealing being fixedly and coaxially connected and matching with core assembly with liquid inlet joint 81, the outer surface of liquid inlet joint 81 is provided with external screw thread, is provided with female thread at the terminal interior surface of valve pocket 3 accordingly. Inlet opening 84 is that the end face center from liquid inlet joint 81 starts and axially through the through hole to the end face of sealing, and sealing is in valve pocket 3 inside and for matching with core assembly, to control the break-make of overflow ducts.

As shown in Figure 1 and Figure 5, it is positioned at the part cavity inside liquid inlet joint 81 as the unloading cavity 32 allowing fluid pass through within valve pocket 3, outage 31 connects with unloading cavity 32, owing to the relative liquid inlet joint 8 of core assembly is moveable, then and the adjustable volume of unloading cavity 32. Sealing is by realizing the closedown of inlet opening 84 with contacting of core assembly, and now unloading cavity 32 volume is minimum, and inlet opening 84 does not connect with outage 31, and then makes overflow ducts disconnect, and relief valve realizes cutting out. When core assembly is axially towards when moving away from liquid inlet joint 8 direction, the volume of unloading cavity 32 is gradually increased, and inlet opening 84 can pass through unloading cavity 32 and connect with outage 31, and overflow ducts turns on, and relief valve realizes opening. Therefore, the relief valve of the present invention is moved axially by core assembly, realize the control of overflow ducts break-make, and connect inlet opening 84 and outage 31 by unloading cavity 32, unloading cavity 32 volume is big, big flow overflow can be realized when overflow ducts turns on, it is little that fluid in inlet opening 84 flow in outage 31 process drag losses, such that it is able to realize quick relief in the short time, corresponding, the quick overflow of short time can reduce the axial displacement of core assembly, and core assembly is axially moveable only small distance in valve pocket 3 can complete breakdown action. And the axial displacement of core assembly is reduced, when the relief valve of the present invention adopts the back-moving spring 2 with identical coefficient of elasticity with the relief valve of prior art, the stroke of the back-moving spring 2 in relief valve of the present invention is short, and the axial deformation of back-moving spring 2 is little, and the pressure oscillation finally making overflow relief valve is little.

As shown in Figure 1 and Figure 5, outage 31 is arranged on the sidewall of valve pocket 3, outage 31 and for extending radially through the through hole of setting. Outage 31 is also evenly distributed multiple on the sidewall of valve pocket 3, and all outages 31 is distributed in around the sealing of unloading cavity 32 and liquid inlet joint 8, so when relief valve is opened, the fluid in inlet opening 84 from passing through between sealing and core assembly and can flow to outage 31. This unloading way liquid stream area is big, and flow is bigger more direct, and drag losses is little.

As depicted in figs. 1 and 2, core assembly includes the nut 5 that is movably arranged in valve pocket 3 inner chamber and be arranged in nut 5 and match with the sealing valve pad 7 and spool 6 that realize sealing, valve pad 7 and being fixedly clamped by spool 6 and nut 5.

As shown in Figure 2 and Figure 4, nut 5 is the cylindrical structural of both ends open and inner hollow, the cavity at nut 5 inside center place is for holding the first containing cavity of sealing and holding spool 6 and valve pad 7 and the second containing cavity 53 connected with the first containing cavity, first containing cavity and the second containing cavity 53 are for axially to set gradually along nut 5, and diameter is for being gradually increased. One end of valve pad 7 is towards sealing, and the annular plane that this end end face is the axis perpendicular with liquid inlet joint 8 of valve pad 7, valve pad 7 is by carrying out, with sealing, the control that plane contact realizes inlet opening 84 is closed, adopting flat seal form, good sealing effect.

As shown in Figure 2 and Figure 4, both first containing cavity and the second containing cavity 53 are coaxial and connect, first containing cavity forms the opening allowing the sealing of liquid inlet joint 8 insert on the end face of nut 5, and the second containing cavity 53 forms the opening allowing spool 6 insert on the other end of nut 5. Valve pad 7 is the annular block structure adopting polyurethane to make, valve pad 7 is sheathed on spool 6, spool 6 and with nut 5 for threadeding, the outer surface of spool 6 is provided with external screw thread, the inner surface of the second containing cavity 53 is provided with female thread, threaded form facilitates spool 6 and the dismounting of valve pad 7, it is simple to change valve pad 7. The overall diameter of valve pad 7 is not less than the diameter of the second containing cavity 53, owing to the diameter of the first containing cavity is less than the diameter of the second containing cavity 53, first containing cavity and the second containing cavity 53 are formed a limited step, valve pad 7 is fill in the second containing cavity 53 together with spool 6 when installing, valve pad 7 and with nut 5 interference fit, it is matched for clamping tightly valve pad 7, it is achieved the axial restraint of valve pad 7 finally by limited step and spool 6.

As it is shown in figure 1, nut 5 is the cylindrical structural coaxial with valve pocket 3 and spool 6, the periphery of nut 5 contacts with the inner headed face of valve pocket 3, and nut 5 is between push rod 9 and liquid inlet joint 8, and nut 5 can move axially and can be inserted into along valve pocket 3 in unloading cavity 32.

As shown in Figure 2 and Figure 4, as preferably, the end face facing liquid inlet joint 8 of nut 5 is provided with and allows fluid pass through and fluid is guided the oil duct 54 to outage 31, and this oil duct 54 is for start the groove along the periphery extending radially to nut 5 of nut 5 from the first containing cavity. By arranging oil duct 54 on the end face of nut 5, when valve pad 7 and hermetic unit from after, the fluid flowing to from inlet opening 84 in unloading cavity 32 is guided to outage 31 by these oil ducts 54, is conducive to relief valve to realize the quick overflow of short time.

As depicted in figs. 1 and 2, as preferably, oil duct 54 is equal with the quantity of outage 31 and aligned in position, oil duct 54 on the end face of nut 5 for being uniformly distributed circumferentially. At valve pocket 3 axially, outage 31 is between push rod 9 and liquid inlet joint 81, each oil duct 54 respectively with outside outage 31 aligned in position and be positioned on the same RADIAL of valve pocket 3, when valve pad 7 and hermetic unit from after, the fluid in inlet opening 84 flow to outage 31 place through oil duct 54.

As preferably, sealing is to embed the multi-stage stairs shape structure contacted in the first containing cavity of nut 5 and with valve pad 7, and such sealing can have multiple plane contact with core assembly, improves the reliability sealed.

As shown in figures 1 and 3, in the present embodiment, the sealing of liquid inlet joint 8 is two-stage step-like structure, and sealing has and sets gradually and the first shaft part 82 and the second shaft part 83 that overall diameter is gradually increased, and both the first shaft part 82 and the second shaft part 83 are coaxial. The end of the second shaft part 83 and liquid inlet joint 81 for being fixedly and coaxially connected, the overall diameter of the second shaft part 83 less than the overall diameter of liquid inlet joint 81, the periphery of the second shaft part 83 and contacting with the inner headed face of valve pocket 3. First shaft part 82 is for embedding in the first containing cavity of nut 5, the first shaft part 82 for matching with valve pad 7 and both can carry out plane contact, and the overall diameter of the first shaft part 82 is not more than the diameter of a containing cavity.

As shown in figures 1 and 3, the length of the first shaft part 82 is not less than the degree of depth of the first containing cavity, and the end face to guarantee the first shaft part 82 can with the end contact of valve pad 7, it is achieved seal. Inlet opening 84 forms the opening allowing fluid flow out on the end face of the first shaft part 82, the end face of this end face of the first shaft part 82 namely the insertion end of liquid inlet joint 8. The overall diameter of the first shaft part 82 is less than the end face diameter of valve pad 7, so that it is guaranteed that the opening on the end face of the first shaft part 82 can be fully sealed by the end face of valve pad 7. And, when sealing contacts with core assembly, relief valve cuts out, now the end face of the first shaft part 82 contacts with valve pad 7, the end face of the second shaft part 83 and the end contact of nut 5, the end face of the first shaft part 82 and the second shaft part 83 is the plane that the end face with nut 5 and valve pad 7 is paralleled, and namely sealing has multiple plane to contact with core assembly realization sealing, good sealing effect, reliability is high. Further, since the face of employing structure crosses liquid mode, valve pad 7 is only limited by the end contact effect of liquid inlet joint 8, and the impact that valve pad 7 bears is little, long service life.

As preferably, as shown in Figure 4, the first containing cavity in nut 5 is divided into the path chamber 52 of cylinder and the chamber, big footpath 51 of cone, chamber, big footpath 51 has bigger diameter end and miner diameter end, the diameter of the miner diameter end in chamber, big footpath 51 is equal with the diameter in path chamber 52, and the miner diameter end in big chamber, footpath 51 is connected with path chamber 52. Chamber, big footpath 51 is coaxial with path chamber 52, path chamber 52 between chamber, big footpath 51 and the second containing cavity 53, the diameter of the bigger diameter end in chamber, big footpath 51 is more than the overall diameter of the first shaft part 82, the overall diameter of the first shaft part 82 is not more than the diameter in path chamber 52, and oil duct 54 is to start setting up from chamber, big footpath 51 and inner surface in chamber, big footpath 51 forms opening. It is uncovered that the nut 5 of this structure has towards sealing, it is simple to sealing embeds, and fluid is had good water conservancy diversion effect by the inner surface of cone.

As shown in Figure 6, spool 6 is the integrative-structure being made up of the plug 61 being sequentially connected with, connecting portion 62 and core bar 63. Plug 61 is for insertion in inlet opening 84, is blocked by inlet opening 84. Core bar 63 is for threadeding with nut 5, spool 6 is integrally fastened to nut 5 internal, and core bar 63 outer surface has external screw thread. Core bar 63 is entirely located in the second containing cavity 53 of nut 5, and the diameter of core bar 63 and the diameter of the second containing cavity 53 are suitable. Connecting portion 62 is between plug 61 and core bar 63, and connecting portion 62 is used for installing valve pad 7, and valve pad 7 is sheathed on connecting portion 62, and valve pad 7 center has a through hole allowing connecting portion 62 insert, valve pad 7 and clamp by core bar 63 and limited step that to realize axis spacing.

As preferably, as shown in Figure 6, the connecting portion 62 of spool 6 and core bar 63 are cylindrical structural, and the diameter of connecting portion 62 is less than the diameter of core bar 63, the diameter in the diameter of connecting portion 62 and the path chamber 52 less than nut 5. Plug 61 is truncated cone structure, has a bigger diameter end and a miner diameter end, and the bigger diameter end of plug 61 is connected with connecting portion 62, plug 61, connecting portion 62 and core bar 63 three be coaxial. The diameter of the bigger diameter end of plug 61 is more than the diameter of connecting portion 62, the diameter of the bigger diameter end of plug 61 is also equal with the interior diameter of the first shaft part 82, namely face, in liquid inlet joint 8, the equal diameters of opening formed on the end face of core assembly with inlet opening 84, the diameter of the miner diameter end of plug 61, less than the interior diameter of the first shaft part 82, realizes sealing so that it is guaranteed that plug 61 is inserted in inlet opening 84. The diameter of the bigger diameter end of plug 61 is less than the diameter of the first containing cavity of nut 5, thus forming the gap allowing the first shaft part 82 insert between plug 61 and nut 5, it is ensured that the first shaft part 82 can contact with valve pad 7. After valve pad 7 is installed on spool 6, valve pad 7 is clipped between plug 61 and core bar 63, one end of valve pad 7 and plug 61 end contact, the other end and core bar 63 ends contact. It addition, spool 6 adopts hard material to make, when overflow opened by relief valve, spool 6 contacts fluid prior to valve pad 7, and valve pad 7 is little with fluid contact area, such that it is able to reduce the impact that valve pad 7 bears, improves service life.

As preferably, as shown in Figure 1, core assembly also includes the second sealing ring 12 being sheathed on nut 5, second sealing ring 12 is clipped between valve pocket 3 and nut 5, second sealing ring 12 and between push rod 9 and outage 31, for realizing the sealing between unloading cavity 32 and spring cavity, it is to avoid fluid flow in spring cavity from the gap between nut 5 and valve pocket 3, such that it is able to avoid corrosion back-moving spring 2.

As shown in Figure 7, the spring base 4 of resetting-mechanism is to be made up of guide section 42 and the first boss 41, guide section 42 is circular block shape structure, and the first boss 41 is connected to form one at the center, side of guide section 42 and guide section 42 spring base 4 of structure, and the first boss 41 protrudes towards voltage regulation screw 1. First boss 41 is coaxial with guide section 42, and the first boss 41 is cylindrical, and the diameter of guide section 42 is more than the diameter of the first boss 41. Back-moving spring 2 is helical spring, and the first boss 41 is for insertion in back-moving spring 2 one end of back-moving spring 2 is positioned, and voltage regulation screw 1 has for inserting the boss in back-moving spring 2, the other end of back-moving spring 2 positioned.

Such as Fig. 1, Fig. 7 with shown in 8, push rod 9 includes sliding bar 92 and the second boss 91 being arranged on sliding bar 92 and protruding towards spring base 4. sliding bar 92 is the cylindrical structural coaxial with valve pocket 3 and core assembly, the periphery of sliding bar 92 and contacting with the inner headed face of valve pocket 3. one end end face of sliding bar 92 is and the plane of swivel nut end contact, and the second boss 91 is arranged at the other end end face center of sliding bar 92. as preferably, the second boss 91 is spherical, and the second boss 91 is coaxial with sliding bar 92. the end face center facing push rod 9 of spring base 4 has allows the second boss 91 embed and for the hole, location 43 of cone, the locating surface fitted as the sphere with the second boss 91 of conical inner surface in hole 43, location. spring base 4 is owing to being clipped between back-moving spring 2 and push rod 9, and spring base 4 diametrically and leaves gap (namely spring base 4 radially lacks support) between valve casing 10 inwall, spring base 4 is all applied active force vertically by push rod 9 and back-moving spring 2, match with the second boss 91 on push rod 9 by arranging the hole 43, location of cone in spring base 4, form sphere-contact, may insure that spring base 4 uniform force, spring base 4 is made to be only limited by axial force, not by diametral interference, prevent from being caused back-moving spring 2 stuck or flexural deformation by radial force, improve reliability.

Above in association with accompanying drawing, the present invention is exemplarily described. Obviously, the present invention implements and is not subject to the restrictions described above. As long as have employed the improvement of the various unsubstantialities that the design of the method for the present invention carries out with technical scheme; Or not improved, the above-mentioned design of the present invention and technical scheme are directly applied to other occasion, all within protection scope of the present invention.

Claims (10)

1. relief valve, including valve pocket, spring base, there is the liquid inlet joint of inlet opening, it is characterized in that: also include for being movably arranged in described valve pocket and for controlling the core assembly of described inlet opening opening and closing and the push rod between core assembly and spring base, valve pocket has outage.

2. relief valve according to claim 1, it is characterised in that: described liquid inlet joint includes the joint body that is connected with valve pocket and fixes the sealing being connected and matching with described core assembly with joint body, and described outage is distributed in around sealing.

3. relief valve according to claim 1, it is characterised in that: described core assembly includes nut and the spool being arranged in nut, and described push rod is clipped between nut and described spring base.

4. relief valve according to claim 3, it is characterised in that: described spool has the plug that can be inserted in described inlet opening and is fixed on the core bar within described nut.

5. relief valve according to claim 4, it is characterised in that: described core bar with described nut for threadeding.

6. relief valve according to claim 4, it is characterised in that: described core assembly also includes for contacting realization sealing and the valve pad for being sheathed on described spool with described liquid inlet joint.

7. relief valve according to claim 6, it is characterised in that: described spool also has the connecting portion being arranged between described plug with described core bar and being connected with plug and core bar, and described valve pad is sheathed on connecting portion.

8. relief valve according to claim 3, it is characterised in that: described nut have for the first containing cavity holding described liquid inlet joint with hold described spool and the second containing cavity of connecting with the first containing cavity.

9. the relief valve according to claim 1 to 8, it is characterized in that: the end face of described nut is provided with for fluid is guided the oil duct to outage, after described core assembly separates with described liquid inlet joint, the fluid in described inlet opening flow to described outage place through oil duct.

10. relief valve according to claim 9, it is characterised in that: described oil duct and described outage are positioned on the same RADIAL of described valve pocket.