CN105715285A - Spool Assembly of Relief Safety Valve - Google Patents

Abstract

The invention discloses a valve core assembly of an overflow safety valve, which comprises a nut and a valve pad arranged in the nut and used for being matched with a liquid inlet connector of the overflow safety valve. The valve core assembly is applied to an overflow safety valve and can be used for controlling the on-off of an oil path from a liquid inlet hole to a liquid outlet hole, large-flow overflow can be realized after the valve core assembly is far away from a liquid inlet joint, the flow of the safety valve is greatly improved, the axial displacement of the valve core assembly can be reduced through short-time quick overflow, the axial displacement of the valve core assembly can be reduced, the axial deformation of a reset spring can be reduced, and finally pressure fluctuation can be reduced.

Description

Spool Assembly of Relief Safety Valve

technical field

The invention belongs to coal mine fully mechanized mining hydraulic support, in particular, the invention relates to a valve core assembly of an overflow safety valve.

Background technique

With the large-scale implementation and development of coal mine fully mechanized mining hydraulic supports, fully mechanized mining work has more and more stringent requirements for hydraulic supports, so there are further requirements for the safety valve of the hydraulic cylinder of the protection support, especially for the safety valve There are further requirements for the service life and reliability of the hydraulic support. When the pressure from the top of the hydraulic support causes passive force, whether the safety valve can unload in a short time, fully and stably under the condition of high pressure directly affects the service life of the support. and support security. It will not only damage seals, pipes and hydraulic components, but also cause vibration and noise; sometimes cause errors in certain pressure-controlled hydraulic components.

The safety valve currently used mainly includes a valve housing, a liquid inlet joint, a valve core, a valve sleeve, a return spring, a spring seat and a pressure regulating screw. In the inner spring chamber of the valve casing, one end of the return spring abuts on the pressure regulating screw which is threadedly connected with the valve casing, and the other end abuts on the movable spring seat. The valve body is inserted into the other end of the valve casing and is threadedly connected with the valve casing. There is a cavity inside the valve body for accommodating the valve sleeve. The valve core is located in the valve sleeve. The end of the valve core is in contact with the spring seat for pushing the spring seat. The movement realizes the opening of the safety valve.

The overflow channel of the existing safety valve adopts the liquid passage hole arranged around the side wall of the valve core. The diameter of the liquid passage hole is small, resulting in small discharge flow and large flow loss. The seat bears the axial force exerted by the return spring, which leads to poor stress on the valve core and large pressure fluctuations during the working process, which leads to generally unsatisfactory closing pressure of the safety valve, and eventually leads to failure of the hydraulic components connected to the safety valve. Such as the excessive loss of oil in the high-pressure cylinder causes waste. The sealing effect between the valve core and the valve sleeve is not ideal, and the processing accuracy of the grooves provided on the surface of the valve core for installing the seal is not easy to control. In addition, the spring cavity inside the valve housing is in an open state, and the dustproof, waterproof and rustproof effects are poor, which reduces the service life of the safety valve.

Contents of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, the present invention provides a valve core assembly of an overflow safety valve, the purpose of which is to reduce pressure fluctuations.

In order to achieve the above object, the technical solution adopted by the present invention is: the valve core assembly of the overflow safety valve, which is characterized in that it includes a nut and a valve pad arranged in the nut, and the valve pad has a The matching sealing surface of the liquid inlet joint, and the sealing surface is a spherical surface.

The liquid inlet joint includes a joint body connected to the valve housing of the overflow safety valve and a sealing part that is fixedly connected with the joint body and matches the nut and the valve pad. The liquid inlet joint has a liquid inlet hole, and the valve housing has a drain hole.

The valve core assembly also includes a screw plug that cooperates with the nut to axially limit the valve pad.

The nut has a first accommodating cavity, a second accommodating cavity for accommodating the valve pad and a third accommodating cavity for accommodating the screw plug, the first accommodating cavity, the second accommodating cavity and the third accommodating cavity The cavities are arranged sequentially, and the screw plug is used to close the second accommodating cavity.

The end surface of the nut is provided with an oil passage for guiding the oil to the drain hole. When the valve pad is separated from the sealing part, the oil in the liquid inlet hole flows to the oil passage through the oil passage. at the drain hole.

The oil passage and the drain hole are located on the same radial line of the valve housing.

The liquid inlet joint has a sealing portion, which is a stepped structure that can be embedded in the first accommodation cavity of the nut and contacts the valve pad, and the diameter of the second accommodation cavity is larger than that of the first accommodation cavity. The diameter of the cavity.

The liquid inlet joint has a sealing part, and the sealing part has a first shaft section, a second shaft section and a third shaft section arranged in sequence with gradually increasing outer diameters, the third shaft section is fixedly connected to the joint body, and the second shaft section A shaft section matches with the valve pad, and the outer diameter of the second shaft section is not larger than the diameter of the accommodating cavity.

The length of the second shaft section is not less than the depth of the first accommodating cavity.

The spool assembly of the present invention is applied to the overflow safety valve and can be used to control the on-off of the oil passage from the inlet hole to the discharge hole. When the spool assembly is far away from the inlet joint, a large flow overflow can be realized, and the flow rate of the safety valve Greatly improved, the short-term rapid overflow can reduce the axial displacement of the valve core assembly, and the reduction of the axial displacement of the valve core assembly can reduce the axial deformation of the return spring, and finally reduce the pressure fluctuation.

Description of drawings

This manual includes the following drawings, the contents shown are:

Fig. 1 is a cross-sectional view of an overflow safety valve with a spool assembly of the present invention;

Fig. 2 is a cross-sectional view of the overflow safety valve when it is in an open state;

Fig. 3 is a sectional view of the valve core assembly of the present invention;

Fig. 4 is a sectional view of the liquid inlet joint;

Fig. 5 is an enlarged view at I place among Fig. 4;

Fig. 6 is the sectional view of nut;

Fig. 7 is a sectional view of the spring seat;

Fig. 8 is a schematic diagram of cooperation between the valve pad and the sealing part of the first structure;

Fig. 9 is a schematic diagram of cooperation between the valve pad and the sealing part of the first structure when it is in the open state;

Fig. 10 is the sectional view of the valve pad of the second structure;

Fig. 11 is a schematic diagram of the force of the valve pad of the second structure when it is in the closed state;

Fig. 12 is a schematic diagram of cooperation between the valve pad and the sealing part of the second structure when it is in the closed state;

Fig. 13 is a schematic diagram of cooperation between the valve pad and the sealing part of the second structure when it is in the open state;

Labeled in the figure:

1. Pressure regulating screw; 2. Return spring;

3. Valve housing; 31. Drain hole; 32. Spring cavity;

4. Spring seat; 41. The first boss; 42. The guide section; 43. The second boss;

5. Nut; 51. Large diameter chamber; 52. Second accommodation chamber; 53. Third accommodation chamber; 54. Small diameter chamber; 55. Oil passage; 6. Screw plug; 61. Positioning hole; 62. Hexagon hole;

7. Valve pad; 71. Sealing surface; 72. Torus; 8. Inlet joint; 81. Joint body; 82. First shaft section; 83. Second shaft section; 84. Third shaft section; 9. The first sealing ring; 10, the second sealing ring.

detailed description

The specific embodiment of the present invention will be described in further detail by describing the embodiments below with reference to the accompanying drawings, the purpose is to help those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solutions of the present invention, and contribute to its implementation.

As shown in Figures 1 to 7, it is a kind of overflow safety valve using the spool assembly of the present invention, which includes a valve housing 3 with a liquid discharge hole 31, a liquid inlet joint 8 with a liquid inlet hole and The reset mechanism, the liquid inlet hole communicates with the liquid discharge hole 31 through the unloading chamber inside the valve housing 3 and the three form an overflow channel of the safety valve. The overflow safety valve also includes the spool assembly of the present invention, the spool assembly of the present invention is movably arranged in the valve housing 3 and is used to control the on-off of the overflow passage, the spool assembly is located at the liquid inlet joint 8 and reset Among the mechanisms, the spool assembly is used to control the opening and closing of the liquid inlet hole, that is, the spool assembly controls the opening and closing of the liquid inlet hole by moving to realize the control of the on-off of the overflow channel.

The safety valves in the prior art are generally connected to the fully mechanized coal mining hydraulic support and the hydraulic elements such as hydraulic cylinders equipped with pressure medium. Under the action of pre-tightening force, it is in the closed state; when the internal pressure of the hydraulic cylinder is higher than the set pressure of the safety valve under the action of external force, the pressure of the hydraulic medium exceeds the pre-tightening force of the spring to open the valve core to overflow, and the moment of opening is called the safety valve. Working opening pressure; through the overflow of the safety valve for a period of time, the medium will flow out to release the pressure to the balance between the internal pressure of the hydraulic cylinder and the spring preload. At this time, the safety valve is closed, and the stable pressure maintained after the safety valve stops overflowing is called turn off the pressure,

Specifically, as shown in FIG. 1 and FIG. 2 , the valve housing 3 is a cylindrical member with two ends open and a hollow interior, and the valve housing 3 has a spring chamber 32 for accommodating a reset mechanism. The reset mechanism is used to apply an axial force to the spool assembly to move toward the liquid inlet joint 8 to close the liquid inlet hole. The reset mechanism includes a spring seat 4, a return spring 2 and a pressure regulating screw 1. The pressure regulating screw 1 is screwed into the spring cavity 32 at one end of the valve housing 3 and threaded with the valve housing 3, the return spring 2 is clamped between the pressure regulating screw 1 and the spring seat 4, and the spring seat 4 is held in the valve housing 3 by the return spring 2 The valve core assembly can move along the axial direction of the valve casing 3, the valve core assembly pushes the spring seat 4 to move toward the pressure regulating screw 1 to open the safety valve, and the return spring 2 pushes the spring seat 4 and the valve core assembly to move. The safety valve is closed.

As shown in Figure 1 and Figure 2, the liquid inlet joint 8 is used to plug and connect with the hydraulic components such as hydraulic cylinders of the fully mechanized mining hydraulic support in coal mines, and the pressure regulating screw 1 of the reset mechanism is connected to the valve housing 3 at one end of the valve housing 3 Threaded connection, the liquid inlet joint 8 is screwed into the valve housing 3 at the other end of the valve housing 3 and is threadedly connected with the valve housing 3 . As shown in Figure 4, the liquid inlet joint 8 includes a joint body 81 that is threadedly connected with the valve casing 3 and a sealing part that is coaxially fixedly connected with the joint body 81 and is matched with the valve core assembly. The outer surface of the joint body 81 is provided with There are external threads, and internal threads are correspondingly provided on the inner surface of the valve housing 3 . The liquid inlet hole is a through hole starting from the center of the end face of the joint body 81 and penetrating axially to the end face of the sealing part. The sealing part is located inside the valve housing 3 and is used to cooperate with the valve core assembly to control the overflow channel on and off.

As shown in Figures 1 and 2, the part of the cavity inside the valve housing 3 between the joint body 81 and the valve core assembly is used as an unloading cavity. Since the valve core assembly is movable relative to the liquid inlet joint 8, the unloading The volume of the cavity is adjustable. The sealing part closes the liquid inlet hole through contact with the valve core assembly. At this time, the volume of the unloading chamber is the smallest, and the liquid inlet hole and the liquid discharge hole 31 are not connected, so that the overflow channel is disconnected, and the safety valve is closed. When the spool assembly moves axially away from the liquid inlet joint 8, the volume of the unloading chamber gradually increases, and the liquid inlet hole can communicate with the discharge hole 31 through the unloading chamber, the overflow channel is connected, and the safety valve Realize on. Therefore, the overflow safety valve of the present invention realizes the on-off control of the overflow channel through the axial movement of the valve core assembly, and communicates with the liquid inlet hole and the liquid discharge hole 31 through the unloading chamber. The volume of the unloading chamber is large, and when the overflow When the flow channel is turned on, a large flow overflow can be realized, and the resistance loss in the process of the oil in the inlet hole flowing to the drain hole 31 is small, so that a fast unloading can be realized in a short time, and correspondingly, a short time fast The overflow can reduce the axial displacement of the valve core assembly, and the valve core assembly can move a small distance s in the axial direction in the valve housing 3 to complete the opening action. However, the axial displacement of the spool assembly is reduced. When the overflow safety valve of the present invention adopts the return spring with the same elastic coefficient as the safety valve of the prior art, the stroke of the return spring 2 in the overflow safety valve of the present invention is short. The axial deformation of the return spring 2 is small, and finally the pressure fluctuation of the overflow safety valve is small.

As shown in FIG. 1 and FIG. 2 , the drain hole 31 is disposed on the side wall of the valve housing 3 , and the drain hole 31 is a through hole arranged radially. A plurality of drain holes 31 are evenly distributed circumferentially on the side wall of the valve housing 3, and all the drain holes 31 are distributed around the sealing portion of the unloading chamber and the liquid inlet joint 8, so that when the safety valve is opened, the liquid inlet The oil in the hole can pass between the sealing portion and the valve core assembly and flow to the drain hole 31 . This unloading method has a large liquid flow area, larger and more direct flow, and less resistance loss.

As shown in Figures 1 to 3, the valve core assembly of the present invention includes a nut 5, a valve gasket 7 arranged in the nut 5 and matched with the sealing part to realize sealing, and a valve gasket 7 arranged in the nut 5 and connected with the nut 5 Cooperate with the screw plug 6 for axially limiting the valve pad 7 . The nut 5 is a cylindrical structure with openings at both ends and a hollow inside. The cavity at the center of the nut 5 is a first accommodating cavity for accommodating the sealing part, a second accommodating cavity 52 for accommodating the valve pad 7 and a In the third accommodation chamber 53 for accommodating the screw plug 6 , the first accommodation chamber, the second accommodation chamber 52 and the third accommodation chamber 53 are sequentially arranged along the axial direction of the nut 5 , and the diameter thereof gradually increases. One end of the valve pad 7 faces the sealing part, and the end face of the valve pad 7 is a plane perpendicular to the axis of the liquid inlet joint 8, and the valve pad 7 controls the closing of the liquid inlet hole through plane contact with the sealing part. It adopts flat sealing form, and the sealing effect is good.

As shown in FIGS. 1 and 2 , the outer surface of the nut 5 is in contact with the inner surface of the valve casing 3 , and the nut 5 is located between the spring seat 4 and the liquid inlet joint 8 . As shown in FIGS. 3 and 6 , the first accommodating chamber, the second accommodating chamber 52 and the third accommodating chamber 53 are coaxial and communicated. The sealing part of the liquid joint 8 is inserted into the opening in the first accommodating chamber. The valve pad 7 is a circular block structure made of polyurethane, and the diameter of the valve pad 7 is not smaller than the diameter of the second accommodating cavity 52. Since the diameter of the first accommodating cavity is smaller than the diameter of the second accommodating cavity 52, the second accommodating cavity A limit step is formed in the first accommodation chamber and the second accommodation chamber 52, and the valve pad 7 is inserted into the second accommodation chamber 52 after passing through the third accommodation chamber 53 during installation, and the valve pad 7 is connected with the nut 5 The interference fit, and the screw plug 6 is installed in the second accommodation cavity 52, the screw plug 6 is used to close the end opening of the second accommodation cavity 52, and the screw plug 6 cooperates with the limit step to clamp the valve pad 7. Realize the axial fixation of the valve pad 7.

As shown in Figure 3, preferably, the screw plug 6 is threadedly connected to the nut 5, and the outer surface of the screw plug 6 is provided with external threads, and the inner surface of the third accommodation cavity 53 of the nut 5 is provided with an inner thread. thread. The screw plug 6 and the nut 5 are threadedly connected, so that the screw plug 6 can be disassembled conveniently, so that the valve pad 7 can be replaced.

As shown in Fig. 3 and Fig. 6, as a preference, the end face of the nut 5 facing the liquid inlet joint 8 is provided with an oil passage 55 that allows oil to pass through and guides the oil to the drain hole 31, the oil passage 55 is a groove extending from the first accommodating cavity along the radial direction of the nut 5 to the outer surface of the nut 5 . By setting the oil passage 55 on the end surface of the nut 5, when the valve pad 7 is separated from the sealing part, the oil passage 55 will guide the oil flowing from the liquid inlet hole to the unloading chamber to the liquid discharge hole 31, which is beneficial The safety valve realizes rapid relief in a short time.

As shown in FIG. 1 and FIG. 2 , preferably, the number of oil passages 55 and the drain holes 31 are equal and their positions are aligned, and the oil passages 55 are uniformly distributed along the circumferential direction on the end surface of the nut 5 . In the axial direction of the valve casing 3, the drain hole 31 is located between the spring seat 4 and the joint body 81, and each oil passage 55 is respectively aligned with a drain hole 31 on the outside and located on the same radial line of the valve casing 3 .

Preferably, the sealing part is a multi-stage stepped structure that can be embedded in the first accommodation cavity of the nut 5 and is in contact with the valve pad 7, so that the sealing part can have multiple plane contacts with the valve core assembly, improving the reliability of the seal sex.

As shown in Fig. 4 and Fig. 5, in this embodiment, the sealing part has a three-stage stepped structure, and the sealing part has a first shaft segment 82, a second shaft segment 83 and a third shaft segment which are arranged in sequence and whose outer diameter gradually increases. The shaft segment 84, the first shaft segment 82, the second shaft segment 83 and the third shaft segment 84 are coaxial. The third shaft section 84 is coaxially fixedly connected to the end of the joint body 81 , and the outer diameter of the third shaft section 84 is smaller than the outer diameter of the joint body 81 . The first shaft section 82 and the second shaft section 83 are used to be embedded in the first accommodating cavity of the nut 5, the first shaft section 82 is matched with the valve pad 7 and can be in planar contact, the second shaft section 83 The outer diameter is not greater than the diameter of an accommodating cavity.

As shown in FIG. 4 and FIG. 5 , the length of the second shaft section 83 is not less than the depth of the first accommodating cavity, so as to ensure that the end surface of the first shaft section 82 can contact the end surface of the valve pad 7 to achieve sealing. The liquid inlet hole forms an opening on the end surface of the first shaft section 82 for the oil to flow to, and the end surface of the first shaft section 82 is also the end surface of the insertion end of the liquid inlet joint 8 . The outer diameter of the first shaft section 82 is smaller than the diameter of the end surface of the valve pad 7 , so as to ensure that the end surface of the valve pad 7 can completely seal the opening on the end surface of the first shaft section 82 . Moreover, when the sealing part is in contact with the valve core assembly, the safety valve is closed. At this time, the end faces of the first shaft segment 82 and the second shaft segment 83 are in contact with the valve pad 7, and the end face of the third shaft segment 84 is in contact with the nut 5. The end faces of the second shaft section 83 and the third shaft section 84 are both planes parallel to the end face of the first shaft section 82, that is, the sealing part has multiple planes in contact with the valve core assembly to achieve sealing, and the sealing effect Well, high reliability. In addition, due to the surface structure of the liquid passing method, the valve pad 7 is only subjected to the contact effect of the end surface of the liquid inlet joint 8, the impact of the valve pad 7 is small, and the service life is long.

As preferably, as shown in Figure 6, the first accommodating cavity in the nut 5 is divided into a cylindrical small-diameter cavity 54 and a conical large-diameter cavity 51, the large-diameter cavity 51 has a large-diameter end and a small-diameter end, and the large-diameter cavity 51 has a large-diameter end and a small-diameter end. The diameter of the small-diameter end of the diameter cavity 51 is equal to the diameter of the small-diameter cavity 54 , and the small-diameter end of the large-diameter cavity 51 is connected with the small-diameter cavity 54 . The large-diameter cavity 51 is coaxial with the small-diameter cavity 54, and the small-diameter cavity 54 is located between the large-diameter cavity 51 and the second accommodating cavity 52. The diameter of the large-diameter end of the large-diameter cavity 51 is greater than the outer diameter of the second shaft section 83. Oil The channel 55 is provided from the large-diameter cavity 51 and forms an opening on the inner surface of the large-diameter cavity 51 . The nut with this structure has an opening facing the sealing part, which is convenient for the sealing part to embed, and the conical inner surface has a better flow guiding effect on the oil.

Preferably, as shown in Figure 1 and Figure 2, the valve core assembly of the present invention also includes a second sealing ring 10 sleeved on the nut 5, and the second sealing ring 10 is sandwiched between the valve housing 3 and the nut 5 Between, the second sealing ring 10 is located between the spring seat 4 and the drain hole 31, used to realize the sealing between the unloading cavity and the spring cavity 32, and prevent the oil from leaking from the gap between the nut 5 and the valve housing 3 The medium flows into the spring chamber 32, so that corrosion of the return spring 2 can be avoided.

As shown in Figure 7, the spring seat 4 of reset mechanism is made of guide section 42, first boss 41 and second boss 43, and guide section 42 is circular block structure, and first boss 41 and second boss The platforms 43 are respectively connected to the guide section 42 on one side of the guide section 42 to form the spring seat 4 of an integral structure. The first boss 41 and the second boss 43 are coaxial with the guide section 42 , the first boss 41 is cylindrical, and the diameter of the guide section 42 is larger than the diameter of the first boss 41 and the second boss 43 . The return spring 2 is a coil spring, and the first boss 41 is used for inserting into the return spring 2 to position one end of the return spring 2 . The second boss 43 is spherical. As shown in FIG. 3 , the center of the end face of the screw plug 6 facing the spring seat 4 has a conical positioning hole 61 for the second boss 43 to embed, and the cone in the positioning hole 61 The inner surface of the shape serves as a positioning surface that fits with the spherical surface of the second boss 43 . Since the spring seat 4 is clamped between the return spring 2 and the valve core assembly, and there is a gap between the spring seat 4 and the inner wall of the valve housing 3 in the radial direction (that is, the spring seat 4 lacks support in the radial direction), the valve core assembly and the return spring 2 apply an axial force to the spring seat 4, and a conical positioning hole 61 is provided in the screw plug 6 to cooperate with the second boss 43 of the spring seat 4 to form a spherical contact, which can ensure that the spring seat 4 is The force is uniform, so that the spring seat 4 is only subjected to axial force and is not subject to radial interference, preventing the return spring 2 from being stuck or bent due to radial force, thereby improving reliability.

As shown in Fig. 8 and Fig. 9, for the valve pad 7 whose both end faces are flat, one end of the valve pad 7 faces the sealing part, and the end face of the valve pad 7 is a plane perpendicular to the axis of the liquid inlet joint 8 , when the safety valve is opened to overflow, shear flow will be generated when the liquid flows out during the overflow, and a vacuum negative pressure tension will be formed at the center of the valve pad 7, which will cause the valve pad 7 to pull out and fail, affecting the reliability of the safety valve.

Therefore, as a modified embodiment, as shown in Figures 10 to 13, the valve pad 7 is a circular block structure made of polyurethane, one end of the valve pad 7 faces the sealing part, and the end surface of the valve pad 7 is made of A sealing surface 71 and an annular surface 72 are formed. The torus 72 is a circular plane with a central hole, and the torus 72 is used to contact the inner wall of the second accommodating cavity 52 . The sealing surface 71 is located in the central hole of the annular surface 72 , both are coaxial, and the outer edge of the sealing surface 71 is connected with the inner edge of the annular surface 72 to form a complete end surface. Preferably, the sealing surface 71 is a spherical surface, and a spherical groove concave toward the inside is formed at the center of the end of the valve pad 7 . The sealing surface 71 is used to cooperate with the liquid inlet joint to achieve sealing. The outer diameter of the annular surface 72 is not smaller than the diameter of the second accommodating chamber 52, and the inner diameter of the annular surface 72 is greater than the outer diameter of the second shaft section 83. Ensure that the area of the sealing surface 71 is large enough to keep in contact with the end surface of the first shaft section 82 when the safety valve is closed, and close the liquid inlet hole.

For the valve pad 7 with concave sealing surface 71, as shown in Figure 11, because the valve pad 7 has a concave arc surface, the high-pressure liquid from the liquid inlet joint will be divided into axial force Fr and radial force on the curved surface. Force Fn, compared with the valve pad without concave arc surface (as shown in Figure 8), can withstand higher pressure. As shown in Figure 12, since the valve pad 7 has a concave arc surface, a gap is left after the end surface of the liquid inlet joint contacts the sealing surface 71, and at this gap, the high-pressure liquid flows in from the large arc surface and acts on the inlet liquid in reverse. joint, which can reduce the pressure on the end face of the liquid inlet joint. As shown in Figure 13, when the safety valve is opened to overflow, under the action of the concave sealing surface 71, the high-pressure liquid flows disorderly and disorderly, and the force formed by the liquid contact surface generates continuous pressure, so that the valve pad is stably pressed against the screw Plug it to prevent the valve pad from being pulled out and failing.

The present invention has been exemplarily described above with reference to the accompanying drawings. Apparently, the specific implementation of the present invention is not limited by the above methods. As long as various insubstantial improvements are made using the method concept and technical solution of the present invention; or without improvement, the above-mentioned concept and technical solution of the present invention are directly applied to other occasions, all within the protection scope of the present invention within.

Claims (9)

1. The spool assembly of the overflow safety valve is characterized in that it includes a nut and a valve pad arranged in the nut, the valve pad has a sealing surface for matching with the liquid inlet joint of the overflow safety valve, and is sealed The surface is spherical. 2. The spool assembly of the overflow safety valve according to claim 1, characterized in that: the liquid inlet joint includes a joint body connected to the valve casing of the overflow safety valve and is fixedly connected with the joint body and connected to the The sealing part where the nut and the valve pad cooperate, the liquid inlet joint has a liquid inlet hole, and the valve housing has a liquid discharge hole. 3 . The valve core assembly of the overflow safety valve according to claim 1 , wherein the valve core assembly further comprises a screw plug cooperating with the nut to axially limit the valve pad. 4 . 4. The spool assembly of the overflow safety valve according to claim 3, wherein the nut has a first accommodating cavity, a second accommodating cavity for accommodating the valve pad and a screw cap for accommodating The third accommodating cavity, the first accommodating cavity, the second accommodating cavity and the third accommodating cavity are arranged in sequence, and the screw plug is used to close the second accommodating cavity. 5. The spool assembly of the overflow safety valve according to claim 3, characterized in that: the end surface of the nut is provided with an oil channel for guiding the oil to the drain hole, when the valve pad and After the sealing part is separated, the oil in the liquid inlet hole flows to the liquid discharge hole through the oil passage. 6 . The spool assembly of the overflow safety valve according to claim 5 , wherein the oil passage and the drain hole are located on the same radial line of the valve housing. 7 . 7. The spool assembly of the overflow safety valve according to claim 5, wherein the liquid inlet joint has a sealing portion which can be inserted into the first accommodating cavity of the nut and is compatible with The valve pad is in contact with a stepped structure, and the diameter of the second accommodating cavity is larger than that of the first accommodating cavity. 8. The spool assembly of the overflow safety valve according to claim 5, characterized in that: the liquid inlet joint has a sealing part, and the sealing part has a first shaft section, a second shaft section, and a second shaft section, which are arranged in sequence and whose outer diameter gradually increases. Two shaft sections and a third shaft section, the third shaft section is fixedly connected with the joint body, the first shaft section matches with the valve pad, and the outer diameter of the second shaft section is not larger than the diameter of the accommodating cavity . 9. The spool assembly of the overflow safety valve according to claim 8, wherein the length of the second shaft section is not less than the depth of the first accommodating cavity.