Electronic expansion valve

Abstract

The utility model relates to the technical field of expansion valves, in particular to an electronic expansion valve. The electronic expansion valve comprises a valve body assembly, a valve element assembly and an elastic piece, an assembly hole and a valve port are formed in the valve body assembly, the assembly hole comprises a threaded section and a limiting section, internal threads are arranged in the threaded section, and a limiting part is formed in the limiting section. The valve element assembly comprises a screw rod, a valve needle and a rotating piece, and the rotating piece is arranged between the screw rod and the valve needle and used for preventing relative rotation between the screw rod and the valve needle. The screw rod is provided with an external thread, and the external thread is in threaded fit with the internal thread so as to drive the valve element assembly to move in the axial direction of the electronic expansion valve. Wherein a stopping part is arranged on the outer wall of the valve element assembly, and the two ends of the elastic piece are in abutting fit with the stopping part and the limiting part correspondingly so as to apply acting force to the valve element assembly, and the acting force moves in the direction away from the valve port. According to the electronic expansion valve, the problem that an existing electronic expansion valve is prone to generating large mechanical noise and abrasion in the operation process is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of expansion valve, in particular to an electronic expansion valve. BACKGROUND

[0002] The electronic expansion valve is commonly used in air conditioning system, which adjusts flow or throttling pressure by moving the internal valve needle to approach or away from the valve port. The movement of the valve needle is realized by the thread cooperation between the screw rod and the nut.

[0003] In the related art, the electronic expansion valve screw rod rotates circumferentially under the driving of the rotor, and the axial movement of the screw rod is converted through the thread cooperation with the nut. The screw rod and the nut are in hole shaft cooperation, and there is a gap between the threads of the two. Therefore, during the axial and / or circumferential movement of the screw rod, the screw rod is easily shaken in the thread gap between the screw rod and the nut due to the influence of its own gravity, pressure difference force and the unbalanced torque of the rotor on the circumferential direction of the screw rod. The screw rod and the nut collide with each other, thereby generating mechanical noise. Moreover, the rotation of the screw rod will drive the valve needle to rotate, causing the relative rotation between the valve needle and other fixed structures in the electronic expansion valve, which leads to wear between them and affects the use performance. CONTENT OF THE UTILITY MODEL

[0004] Therefore, it is necessary to provide an electronic expansion valve to solve the problem that the existing electronic expansion valve is prone to generate large mechanical noise and wear during operation.

[0005] The present application provides an electronic expansion valve, which comprises a valve body assembly, a valve core assembly and an elastic member. The valve body assembly is provided with an assembly hole and a valve port. The assembly hole comprises a threaded section and a limiting section. The threaded section is located on the side of the limiting section away from the valve port, and the threaded section is provided with an internal thread. The inner wall of the limiting section at the end close to the valve port protrudes towards the axis to form a limiting part. The valve core assembly is at least partially installed in the assembly hole. The valve core assembly comprises a screw rod, a valve needle and a rotating member. The rotating member is arranged between the screw rod and the valve needle to prevent relative rotation between the screw rod and the valve needle. The screw rod is provided with an external thread. The external thread is threadedly connected with the internal thread to drive the valve core assembly to move along the axial direction of the electronic expansion valve. The outer wall of the valve core assembly is provided with a stop part, which is arranged in the limiting section. The elastic member is sleeved on the outer periphery of the valve core assembly and arranged between the stop part and the limiting part. The two ends of the elastic member are respectively in abutting connection with the stop part and the limiting part to apply an action force to the valve core assembly in the direction away from the valve port.

[0006] In one of the embodiments, the rotating member comprises a first rotating part, a second rotating part and a rolling part, the first rotating part is rotationally connected with the second rotating part through the rolling part, and one of the first rotating part and the second rotating part is connected with the screw rod, and the other one is abutted with the valve needle along the axial direction of the electronic expansion valve.

[0007] In one of the embodiments, along the radial direction of the electronic expansion valve, the first rotating part is sleeved with the rolling part and is sleeved with the second rotating part through the rolling part; wherein the screw rod is inserted and connected with the second rotating part.

[0008] In one of the embodiments, the inner wall of the limiting section is clearance-fitted with the outer wall of part of the valve needle to guide the valve needle; and / or the inner wall of the limiting section is clearance-fitted with the outer wall of the first rotating part to guide the rotating member.

[0009] In one of the embodiments, the valve core assembly further comprises a bearing sleeve, the bearing sleeve is sleeved with the outer periphery of the rotating member and can be abutted and fitted along the axial direction with one end of the rotating member, one end of the valve needle is inserted into the bearing sleeve and is fixedly connected with the bearing sleeve, and the valve needle is abutted and fitted with the other end of the rotating member along the axial direction; wherein the inner wall of the limiting section is clearance-fitted with the outer wall of the bearing sleeve to guide the bearing sleeve.

[0010] In one of the embodiments, a balance passage is formed on the valve needle, one end of the balance passage is communicated with the valve port, and the other end is used to communicate with the back pressure chamber of the electronic expansion valve.

[0011] In one of the embodiments, a balance hole is further formed on the valve needle, the balance hole is arranged on the side of the balance passage, and the two ends of the balance hole are communicated with the balance passage and the assembly hole respectively.

[0012] In one of the embodiments, an avoiding hole is formed on one end of the valve needle close to the rotating member, along the axial direction of the electronic expansion valve, the projection of the avoiding hole can cover the screw rod and / or the second rotating part; or a gasket is arranged on one end of the valve needle close to the rotating member, along the axial direction of the electronic expansion valve, the projection of the gasket can cover the screw rod and / or the second rotating part.

[0013] In one of the embodiments, the first rotating part, the rolling part and the second rotating part are sequentially arranged along the axial direction of the electronic expansion valve.

[0014] In one of the embodiments, the assembling hole further comprises a guiding section, which is arranged on the side of the threaded section away from the limiting section, and the inner wall of the guiding section is in clearance fit with the outer wall of part of the valve core assembly to guide the valve core assembly; an upper limiting surface is formed on the end of the limiting section close to the threaded section, and when the valve core assembly moves to the limit in the direction away from the valve port, the valve core assembly can be in axial abutting fit with the upper limiting surface to enable the end of the external thread away from the valve port to be arranged in clearance with the inner wall of the end of the threaded section away from the valve port.

[0015] In one of the embodiments, the valve body assembly comprises a valve seat and a nut sleeve, and the nut sleeve is fixedly connected to one end of the valve seat; the threaded section is arranged in the nut sleeve, the valve port is arranged in the valve seat, and the nut sleeve and the valve seat surround to form the limiting section.

[0016] In one of the embodiments, the valve seat comprises a main body part and a guiding part, the nut sleeve is connected to the main body part, the guiding part is located in the main body part, and one end of the guiding part is inserted into the nut sleeve and connected with the nut sleeve; the nut sleeve and the guiding part surround to form the limiting section.

[0017] Compared with the prior art, the electronic expansion valve provided by the application can exert an action force on the valve core assembly in the direction away from the valve port through the elastic member, so that the upper end surface of the flange of the external thread can abut against the lower end surface of the flange of the internal thread, thereby eliminating the gap between the upper end surface of the flange of the external thread and the lower end surface of the flange of the internal thread and reducing the probability of relative movement of the external thread and the internal thread during thread cooperation. That is, the electronic expansion valve will not shake due to the thread gap during circumferential rotation, thereby avoiding collision and effectively eliminating mechanical noise. In addition, the frictional resistance between the screw rod and the valve needle can be reduced through the arrangement of the rotating member, thereby preventing the valve needle from rotating with the screw rod due to friction, and effectively reducing the probability of wear caused by relative rotation of the valve needle and the valve port or the elastic member and other structures. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0019] Figure 1A cross-sectional view of an electronic expansion valve of an embodiment provided in the present application when fully open;

[0020] Figure 2 A cross-sectional view of an electronic expansion valve of another embodiment provided in the present application when fully closed;

[0021] Figure 3 A cross-sectional view of an electronic expansion valve of yet another embodiment provided in the present application;

[0022] Figure 4 A cross-sectional view of an electronic expansion valve of still another embodiment provided in the present application when fully open;

[0023] Figure 5 A schematic view of a male thread and a female thread threadedly cooperating with each other of an embodiment provided in the present application;

[0024] Figure 6 A cross-sectional view of a rotating member of an embodiment provided in the present application;

[0025] Figure 7 A cross-sectional view of a rotating member of another embodiment provided in the present application;

[0026] Figure 8 A schematic view of a male thread and a female thread threadedly cooperating with each other when no elastic member is provided.

[0027] The meanings of the symbols in the figures are as follows:

[0028] 100, electronic expansion valve; 10, valve body assembly; 101, assembly hole; 1011, threaded section; 1012, limiting section; 1013, guide section; 1014, upper limiting surface; 102, valve port; 11, valve seat; 111, main body portion; 112, guide portion; 1121, limiting portion; 12, nut sleeve; 121, female thread; 13, sealing member; 20, valve core assembly; 201, stop portion; 202, limiting portion; 21, screw rod; 211, male thread; 22, valve needle; 2201, preset gap; 2202, balance passage; 2203, balance hole; 2204, avoidance hole; 23, rotating member; 231, first rotating portion; 232, second rotating portion; 233, rolling portion; 24, bearing sleeve; 25, gasket; 26, spring sleeve; 27, spring seat; 28, supporting spring; 29, pressing sleeve; 30, elastic member; 40, rotor assembly; 50, first connecting pipe; 60, second connecting pipe. DETAILED DESCRIPTION

[0029] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, the detailed description of the specific embodiments of the present application is made below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of different manners according to the description herein, and it is contemplated that some improvement and modifications to the embodiments specifically disclosed can be made without departing from the scope and spirit of the present application. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0030] It is to be noted that when an element as a component is referred to as being "on" or "disposed on" another element, it can be directly on the other element or an intervening element can also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or an intervening element can also be present. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar expressions used in the description of the specification are used for the purpose of illustration only and are not intended to indicate the only orientation of the embodiments.

[0031] In addition, the terms "first", "second", and the like, are used merely as a designation of certain elements, and do not imply or suggest relative importance or a number of the elements indicated. Thus, a feature defined with "first", "second" can include at least one of the feature explicitly or implicitly. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0032] In the present application, unless otherwise explicitly specified and limited, "on", "under", "above", and "over" of a first feature to a second feature can mean that the first feature is in direct contact with the second feature, or the first feature is in indirect contact with the second feature through an intermediate medium. Moreover, "above", "over", and "on" of a first feature to a second feature can mean that the first feature is directly above or obliquely above the second feature, or only means that the first feature is horizontally higher than the second feature. "Below", "under", and "underneath" of a first feature to a second feature can mean that the first feature is directly below or obliquely below the second feature, or only means that the first feature is horizontally lower than the second feature.

[0033] Unless otherwise defined, all technical and scientific terms used in the specification of the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application. The term "and / or" used in the specification of the present application includes any and all combinations of one or more of the associated listed items.

[0034] Please refer to Figures 1-7The application provides an electronic expansion valve 100, which comprises a valve body assembly 10, a valve core assembly 20 and an elastic member 30. The valve body assembly 10 is internally provided with an assembly hole 101 and a valve port 102. The assembly hole 101 comprises a threaded section 1011 and a limiting section 1012. The threaded section 1011 is arranged on the side of the limiting section 1012 away from the valve port 102, and the threaded section 1011 is internally provided with an internal thread 121. The inner wall of the limiting section 1012 on the side close to the valve port 102 protrudes towards the direction close to the axis to form a limiting part 1121. The valve core assembly 20 is at least partially installed in the assembly hole 101, and the outer wall of the valve core assembly 20 is provided with an external thread 211. Specifically, the valve core assembly 20 comprises a screw rod 21 and a valve needle 22. The screw rod 21 is arranged on the threaded section 1011 of the assembly hole 101 and is connected with the valve needle 22. The screw rod 21 is provided with the external thread 211, which is threadedly matched with the internal thread 121 to drive the valve core assembly 20 to move along the axial direction of the electronic expansion valve 100. The outer wall of the valve core assembly 20 is provided with a stop part 201, which is arranged in the limiting section 1012. The elastic member 30 is sleeved on the outer periphery of the valve core assembly 20 and is arranged between the stop part 201 and the limiting part 1121. The two ends of the elastic member 30 are respectively abuttingly matched with the stop part 201 and the limiting part 1121 to apply an action force to the valve core assembly 20 in the direction away from the valve port 102, so that the flange upper end surface of the external thread 211 can abut against the flange lower end surface of the internal thread 121. That is, the elastic member 30 is always in a compressed state during the working process.

[0035] In the conventional technology, the cooperation between the external thread and the internal thread during the movement of the valve core assembly in the direction close to the valve port, i.e. during the valve closing process, will be as shown in the following figure. Figure 8As shown, the outer threaded flange lower end surface and the inner threaded flange upper end surface are in close contact, and during the opening process, the threaded close contact direction is opposite. However, during the operation of the electronic expansion valve, due to the influence of pressure difference, friction and gravity, etc., the threads cannot always maintain close contact, which makes the threads prone to repeated movement, thereby producing mechanical noise due to collision. In the present application, it can be understood that the present application sets an elastic member 30 between the stop portion 201 and the limiting portion 1121. Since the elastic member 30 is in a compressed state, and one end of the elastic member 30 abuts against the stop portion 201 on the valve core assembly 20, the elastic member 30 can exert a force on the valve core assembly 20 in the direction away from the valve port 102, so that the upper end surface of the flange of the outer thread 211 can always abut against the lower end surface of the flange of the inner thread 121, thereby eliminating the gap between the upper end surface of the flange of the outer thread 211 and the lower end surface of the flange of the inner thread 121, and preventing the threads from moving due to the influence of pressure difference, friction and gravity. That is, during the circumferential rotation of the screw rod 21 of the electronic expansion valve 100, the threads will not move due to the influence of the thread gap, pressure difference, friction and gravity, thereby avoiding collision and effectively eliminating mechanical noise.

[0036] The screw rod 21 and the valve needle 22 can be of an integral structure or can be separately arranged.

[0037] It should be noted that the electronic expansion valve 100 of the present application is a bidirectional valve. Specifically, the electronic expansion valve 100 includes a first connecting pipe 50 arranged at the valve port 102 and a second connecting pipe 60 arranged on the side of the valve body assembly 10. Here, the fluid flow path includes forward and reverse directions. In the forward direction, the fluid flows into the valve body assembly 10 from the second connecting pipe 60 and flows out through the valve port 102 and the first connecting pipe 50. In the reverse direction, the fluid flows into the valve body assembly 10 from the first connecting pipe 50 and the valve port 102 and flows out through the second connecting pipe 60.

[0038] In the conventional structure without the elastic member 30, the directions of the pressure difference force acting on the valve core assembly 20 are different during the forward and reverse flow of the fluid, thereby causing the size of the overall force to be different. In addition, under the influence of the gap between the outer thread 211 and the inner thread 121, the amount of movement of the valve core assembly 20 is different, and after each movement, the action of the driving force on the valve core assembly 20 has a certain hysteresis, so that during each flow adjustment process, there is a flow deviation. That is, the conventional structure easily causes the flow of the fluid in the forward and reverse directions to be inconsistent. In the present application, as shown in the drawings, Figure 5As shown, under the action of the elastic member 30, the internal thread 121 and the external thread 211 are always in close abutment, regardless of the forward or reverse flow of the fluid, and no additional active gap is generated. Therefore, during the circumferential rotation of the screw rod 21, no shaking is caused due to the circumferential unbalanced moment of the rotor assembly 40, the spool assembly 20 can respond to the driving force in time without hysteresis, and each flow regulation is relatively stable, thereby solving the problem of large flow deviation of the traditional structure when the fluid flows in the forward or reverse direction.

[0039] In an embodiment, the electronic expansion valve 100 further comprises a rotor assembly 40, which is installed in the valve body assembly 10 and located on the side away from the valve port 102 of the assembly hole 101, and the rotor assembly 40 is connected to the spool assembly 20 for driving the movement of the spool assembly 20. Specifically, the rotor assembly 40 cooperates with an external motor to enable the rotor assembly 40 and the spool assembly 20 to rotate under the driving of the motor. In this way, by providing the rotor assembly 40 and cooperating the rotor assembly 40 with the external motor to provide driving force for the axial movement of the spool assembly 20, the opening and closing of the valve port 102 are facilitated.

[0040] Specifically, the rotor assembly 40 is fixedly connected with the screw rod 21, and the rotor assembly 40 drives the screw rod 21 to rotate, and through the screw thread cooperation between the external thread 211 on the screw rod 21 and the internal thread 121 on the threaded segment 1011, the circumferential rotation of the two is converted into the axial movement of the spool assembly 20.

[0041] In an embodiment, the torque exerted by the rotor assembly 40 on itself and the spool assembly 20 is F1, the total weight of the spool assembly 20 and the rotor assembly 40 is G1, and the load torque coefficient of the spool assembly 20 and the rotor assembly 40 is f, wherein F1>f*G1. In this way, without external force, the torque exerted by the motor on the rotor assembly 40 and the spool assembly 20 can meet the opening valve requirement of the electronic expansion valve 100.

[0042] However, during normal operation of the electronic expansion valve 100, fluids such as refrigerant are introduced into the valve body assembly 10. Therefore, when the valve core assembly 20 is sealing the valve port 102, it is also affected by the fluid pressure difference. Based on this, to meet the opening requirements of the electronic expansion valve 100 during normal operation, in one embodiment, the area of ​​the valve port 102 is S, the pressure difference at the valve port 102 is P, the elastic coefficient of the elastic element 30 is K, the initial length of the elastic element 30 is H0, the length of the elastic element 30 when the electronic expansion valve 100 is fully open is H1, and the length of the elastic element 30 when the electronic expansion valve 100 is fully closed is H2. Since the elastic element 30 is always in a compressed state during operation, H1 and H2 are both less than H0. H1 is also the installation length of the elastic element 30. Furthermore, the maximum pressure difference force experienced by the valve core assembly 20 and the rotor assembly 40 when the electronic expansion valve 100 is fully closed is F. Y The load torque generated by the valve core assembly 20 and rotor assembly 40 when the electronic expansion valve 100 is fully open is F2, and the load torque generated by the valve core assembly 20 and rotor assembly 40 when the electronic expansion valve 100 is fully closed is F3, where F1 > F2, F1 > F3, and F Y =P*S, F2=[K*(H0-H1)-G1+F Y ]*f, F3=[K*(H0-H2)-G1+F Y It is understandable that, since the torque F1 provided by the rotor assembly 40 is greater than the load torque F2 generated by the valve core assembly 20 and the rotor assembly 40 when the electronic expansion valve 100 is fully open, and also greater than the load torque F3 generated by the valve core assembly 20 and the rotor assembly 40 when the electronic expansion valve 100 is fully closed, the driving force provided by the rotor assembly 40 can overcome the external force and drive the valve core assembly 20 to move axially, thereby meeting the opening and closing requirements of the electronic expansion valve 100, regardless of whether the electronic expansion valve 100 is in the fully open or fully closed state.

[0043] It is important to note that the above formulas compare the absolute values ​​of the numerical values, without considering direction. Furthermore, when the fluid flows in the forward direction, throughout the operation of the electronic expansion valve 100, the preload force of the elastic element 30 on the valve core assembly 20 is greater than the differential pressure force on the valve core assembly 20. That is, when the fluid flows in the forward direction, the differential pressure force on the valve core assembly 20 is downward. Simultaneously, since the supporting force of the elastic element 30 is always upward, the two forces are in opposite directions, and the supporting force of the elastic element 30 is greater than the differential pressure force. This avoids abnormal noise caused by the differential pressure separating the mating threads of the internal thread 121 and the external thread 211 when the system differential pressure is large. Thus, the operational stability of the rotor assembly 40 and the valve core assembly 20 is further improved.

[0044] Further, the maximum load force exerted by the elastic member 30 on the valve core assembly 20 is less than the driving force exerted by the rotor assembly 40, that is, the downward force of the rotor assembly 40 is greater than the upward force of the elastic member 30 at full closing, so that the force exerted by the elastic member 30 on the valve core assembly 20 is not too large, and the driving force of the rotor assembly 40 cannot control the valve core assembly 20 to close the valve port 102, thereby eliminating the internal leakage risk of the electronic expansion valve 100 at full closing.

[0045] In the formula, the maximum load force exerted by the elastic member 30 on the valve core assembly 20 is greater than the impact force of the electronic expansion valve 100 when the rotor assembly 40 is deflected due to vibration, so as to prevent the elastic member 30 from being too small, causing the rotor assembly 40 to rotate when vibrating, thereby causing the valve needle 22 to separate from the valve port 102 and causing the internal leakage to exceed the standard, so that the state of the valve core assembly 20 is stable when closing the valve, and has good anti-vibration interference performance.

[0046] In an embodiment, the elastic member 30 is configured as a coil spring, and the coil spring can be formed by winding a steel wire. In the formula, the wire diameter of the coil spring can be set to 0.6mm-1mm, the mean diameter of the coil spring can be set to 3.5mm-5.5mm, the pitch of the coil spring can be set to 1mm-3mm, and the working section of the coil spring can be set to 2mm-5mm. Here, the wire diameter of the coil spring is the cross-sectional diameter of the steel wire, the mean diameter of the coil spring is the average of the outer diameter and the inner diameter of the coil spring, the pitch of the coil spring is the axial distance between the center lines of two adjacent effective sections of the coil spring, and the working section of the coil spring is the part that is elastically deformed and stores energy when the spring is subjected to external force. In this application, the working section length of the coil spring covers the full stroke length of the valve core assembly 20 in the axial direction.

[0047] It can be understood that through the size design of the elastic member 30, the size of the elastic member 30 can be miniaturized, the installation space can be fully utilized, and the overall installation size can be optimized. At the same time, the safe working life of the elastic member 30 can be improved, and the elastic member 30 can be prevented from being broken or deformed due to fatigue.

[0048] Alternatively, the wire diameter of the coil spring can be set to 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm, etc., the mean diameter of the coil spring can be set to 3.5mm, 4mm, 4.5mm, 5mm or 5.5mm, etc., the pitch of the coil spring can be set to 1mm, 1.5mm, 2mm, 2.5mm or 3mm, etc., and the working section of the coil spring can be set to 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc. Here, they are not listed one by one, and the specific values can be reasonably set according to actual needs.

[0049] Since the elastic member 30 is usually formed by winding steel wires, and the steel wires are circular, the elastic member 30 is prone to be deviated when it is matched with the surface of the stop portion 201 and the limiting portion 1121. Therefore, in order to reduce the probability of the movement of the elastic member 30, in an embodiment, the axial both ends of the elastic member 30 can be ground flat, so that the axial both ends of the elastic member 30 are arranged in a plane. In this way, the probability of the inclination of the elastic member 30 is effectively reduced, thereby preventing uneven wear on the valve core assembly 20 or the valve body assembly 10, preventing the elastic member 30 from being deviated relative to the valve core assembly 20 and / or the valve body assembly 10, improving the coaxiality of the valve core assembly 20, the elastic member 30 and the valve port 102, and prolonging the service life of the electronic expansion valve 100.

[0050] In order to further improve the coaxiality between the valve core assembly 20 and the elastic member 30, and prevent the elastic member 30 and the valve core assembly 20 from being deviated relative to each other, in an embodiment, the inner side wall of the elastic member 30 and the outer side wall of the valve core assembly 20 have a gap L, where 0.05mm≤L≤1mm. By reasonably setting the gap size between the elastic member 30 and the valve core assembly 20, stable guidance can be provided for the elastic member 30. If L>1mm, the gap between the elastic member 30 and the valve core assembly 20 is too large, and the elastic member 30 is prone to be deviated relative to the valve core assembly 20, thereby causing uneven wear. If L<0.05mm, the gap between the elastic member 30 and the valve core assembly 20 is too small, and the elastic member 30 and the valve core assembly 20 are prone to be interfered during the movement in the axial direction, thereby being stuck.

[0051] Alternatively, the gap L between the elastic member 30 and the valve core assembly 20 can be set to 0.05mm, 0.1mm, 0.3mm, 0.5mm, 0.7mm, 0.9mm or 1mm, etc., which are not listed one by one here.

[0052] In an embodiment, as shown in FIG. 6, the elastic member 30 is arranged in the valve core assembly 20 in a coaxial manner, and the axial both ends of the elastic member 30 are arranged in a plane. Figure 2As shown, the outer side wall of the valve needle 22 is provided with a limiting portion 202, which is located between the stop portion 201 and the limiting portion 1121. When the valve needle 22 moves to the limit in the direction close to the valve port 102, the end of the valve needle 22 close to the valve port 102 abuts against the valve port 102, and the limiting portion 202 and the limiting portion 1121 are axially spaced. In this embodiment, the valve core assembly 20 and the valve port 102 are axially stopped, that is, the valve needle 22 is closed to the valve port 102 by the abutment of the axial hard fit, so as to cut off the flow of fluid in the valve body assembly 10. Therefore, the valve port 102 and the valve needle 22 may be worn, and when the valve needle 22 and / or the valve port 102 are worn, the sealing position of the valve needle 22 relative to the valve port 102 is changed at full closing, which affects the flow consistency of the electronic expansion valve 100. In this embodiment, the limiting portion 202 is provided on the valve needle 22, and the limiting portion 202 is axially spaced from the limiting portion 1121 in the normal state, so as not to adversely affect the cooperation between the valve needle 22 and the valve port 102 during normal operation. Only when the valve needle 22 and the valve port 102 are relatively worn, the stop between the limiting portion 202 and the limiting portion 1121 prevents the sealing position of the valve needle 22 and the valve port 102 from changing excessively, which greatly affects the flow consistency of the electronic expansion valve 100. In this way, the flow consistency of the valve needle 22 and the valve port 102 before and after wear can be ensured, and the use reliability of the electronic expansion valve 100 is improved.

[0053] Specifically, the gap axially formed between the limiting portion 202 and the limiting portion 1121 when the valve needle 22 moves to the limit in the direction close to the valve port 102 is defined as M, wherein 0.01mm≤M≤1mm. In this way, the gap is reasonably set, which can reduce the flow change caused by wear and further improve the flow consistency.

[0054] Alternatively, the value of M can be 0.01mm, 0.1mm, 0.3mm, 0.5mm, 0.7mm, 0.9mm or 1mm, etc., which is not listed here.

[0055] The limiting portion 202 can be a step structure formed by recessing the outer side wall of the valve needle 22 in the direction close to the axis thereof.

[0056] In an embodiment, as shown in the drawings, Figures 1-4 The valve body assembly 10 includes a valve seat 11 and a nut sleeve 12, and the nut sleeve 12 is fixedly connected to one end of the valve seat 11. The threaded segment 1011 is formed in the nut sleeve 12, the valve port 102 is formed in the valve seat 11, and the nut sleeve 12 and the valve seat 11 form a limiting segment 1012. In this way, the machining of the inner thread 121 and the outer thread 211 is facilitated, and the assembly difficulty of the valve core assembly 20 is greatly reduced, and the overall machining and assembly efficiency is improved.

[0057] Further, in an embodiment, the valve seat 11 comprises a main body part 111 and a guide part 112, the nut sleeve 12 is connected to the main body part 111, the guide part 112 is located in the main body part 111, and one end of the guide part 112 is inserted into and connected with the nut sleeve 12. Wherein, the nut sleeve 12 and the guide part 112 surround to form a limiting section 1012, and the guide part 112 forms a limiting part 1121. Here, the main body part 111 and the guide part 112 can be provided as a split structure to further reduce the processing difficulty of the valve seat 11, at this time, the guide part 112 can be configured as a guide sleeve. Wherein, the guide part 112 can improve the coaxiality of the valve core assembly 20 and the valve port 102.

[0058] Specifically, the valve needle 22 penetrates the guide part 112 away from one end of the screw rod 21 and movably cooperates with the valve port 102. And the limiting part 1121 is specifically formed by the inner wall of the guide part 112 near the end of the valve port 102 protruding towards the direction close to the axis, wherein, when the valve needle 22 moves to the limit in the direction close to the valve port 102, the valve needle 22 abuts and cooperates with the valve port 102 or the limiting part 1121 in the axial direction, to realize the lower stop of the movement of the valve needle 22.

[0059] It should be noted that when the valve needle 22 abuts with the valve port 102, the electronic expansion valve 100 is closed, at this time there is no flow through the valve port 102. And when the valve needle 22 abuts with the limiting part 1121, a gap can be controlled to exist between the valve needle 22 and the valve port 102, so that the electronic expansion valve 100 still has flow through when it is closed, thereby meeting different use requirements.

[0060] Of course, in other embodiments, the main body part 111 and the guide part 112 can also be a one-piece structure, which can be reasonably set according to actual needs.

[0061] In an embodiment, as shown in Figures 1-4 The valve core assembly 20 further comprises a rotating piece 23, the rotating piece 23 comprises a first rotating part 231, a second rotating part 232 and a rolling part 233, the first rotating part 231 is rotationally connected with the second rotating part 232 through the rolling part 233. Wherein, one of the first rotating part 231 and the second rotating part 232 is connected with the screw rod 21, and the other one abuts with the valve needle 22 along the axial direction of the electronic expansion valve 100, and the stop part 201 is arranged on the valve needle 22. By arranging the rotating piece 23, the frictional resistance between the screw rod 21 and the valve needle 22 can be reduced, thereby preventing the valve needle 22 from rotating with the screw rod 21 due to friction, and effectively reducing the probability of wear caused by relative rotation between the valve needle 22 and the valve port 102 or the elastic piece 30.

[0062] Specifically, the rolling part 233 contains a plurality of balls to reduce friction by rolling, and the balls can be spherical or cylindrical.

[0063] Further, in an embodiment, as shown in Figure 6 the radial direction of the electronic expansion valve 100, the first rotating part 231 is sleeved on the rolling part 233 and the second rotating part 232 is sleeved on the rolling part 233. That is, the rotating part 23 in the embodiment can be provided as a common bearing, the first rotating part 231 is located at the outer ring of the rotating part 23, and the second rotating part 232 is located at the inner ring of the rotating part 23, which is simple in structure and can reduce the cost.

[0064] In another embodiment, as shown in Figure 7 the axial direction of the electronic expansion valve 100, the first rotating part 231, the rolling part 233 and the second rotating part 232 are sequentially arranged. That is, the rotating part 23 in the embodiment can also be provided as a thrust bearing, which can better adapt to the axial force applied by the elastic member 30, the valve needle 22 and the like, and effectively reduce the frictional resistance.

[0065] For ease of description, the rotating part 23 in the embodiment is taken as a common bearing structure, and the screw rod 21 is inserted and connected to the second rotating part 232. At this time, the valve needle 22 abuts against the first rotating part 231 in the axial direction. It should be noted that the screw rod 21 can also be connected to the first rotating part 231 according to actual conditions. At this time, the valve needle 22 abuts against the second rotating part 232 in the axial direction. The remaining structures can also change accordingly, and will not be described here.

[0066] Further, in an embodiment, as shown in Figures 2-4 the axial direction of the electronic expansion valve 100, the first rotating part 231, the rolling part 233 and the second rotating part 232 are sequentially arranged. That is, the rotating part 23 in the embodiment can also be provided as a thrust bearing, which can better adapt to the axial force applied by the elastic member 30, the valve needle 22 and the like, and effectively reduce the frictional resistance.

[0067] In another embodiment, as shown in Figure 1 the axial direction of the electronic expansion valve 100, the first rotating part 231, the rolling part 233 and the second rotating part 232 are sequentially arranged. That is, the rotating part 23 in the embodiment can also be provided as a thrust bearing, which can better adapt to the axial force applied by the elastic member 30, the valve needle 22 and the like, and effectively reduce the frictional resistance.

[0068] In an embodiment, as shown in Figure 4 the axial direction of the electronic expansion valve 100, the first rotating part 231, the rolling part 233 and the second rotating part 232 are sequentially arranged. That is, the rotating part 23 in the embodiment can also be provided as a thrust bearing, which can better adapt to the axial force applied by the elastic member 30, the valve needle 22 and the like, and effectively reduce the frictional resistance.

[0069] Here, the balance channel 2202 can extend axially to communicate with the relief hole 2204. Generally, as shown, the inner wall of the assembly hole 101 at the limiting portion 1121 is slotted, and a sealing member 13 is installed in the slot, which is in movable sealing cooperation with the valve needle 22 to form a seal. At this time, the chamber in the assembly hole 101 on the side away from the valve port 102 of the sealing member 13 forms a back pressure chamber. Figure 4

[0070] Further, the valve needle 22 is further provided with a balance hole 2203, which is arranged on the circumferential side of the balance channel 2202 and communicates with the balance channel 2202 and the assembly hole 101 at both ends. In this way, it is beneficial to the communication between the balance channel 2202 and the side of the back pressure chamber of the assembly hole 101, so as to balance the pressure on the side of the valve port 102 and the back pressure chamber, and improve the opening performance.

[0071] In an embodiment, as shown in Figure 1 The valve core assembly 20 further includes a spring sleeve 26, a spring seat 27 and a supporting spring 28, the rotating member 23, the spring seat 27 and the supporting spring 28 are sequentially arranged in the spring sleeve 26 and movably cooperate with the spring sleeve 26. One end of the spring sleeve 26 can be axially stopped at the rotating member 23, and the other end is limitingly connected with the valve needle 22, and the two ends of the supporting spring 28 act on the spring seat 27 and the valve needle 22 respectively, so as to exert an action force on the spring seat 27 to move away from the valve needle 22. Among them, when the electronic expansion valve 100 is in the pre-opening valve, that is, during the movement of the screw rod 21 away from the valve port 102, when the screw rod 21 moves to just drive the valve needle 22 to move, so that the fluid flow at the valve port 102 begins to change, a preset gap 2201 can be formed between the spring seat 27 and the valve needle 22, at this time the screw rod 21 can drive the valve needle 22 to move away from the valve port 102 through the abutment of the rotating member 23 and the spring sleeve 26; when the electronic expansion valve 100 switches from the fully open state to the fully closed state, that is, the screw rod 21 drives the valve needle 22 to move towards the valve port 102, the valve needle 22 first abuts against the valve body assembly 10 (such as the valve port 102), just abuts, the rotating member 23 and the spring sleeve 26 still abut and stop cooperation, and the spring seat 27 and the valve needle 22 have a preset gap 2201, at this time, due to the existence of the preset gap 2201, the screw rod 21 can still continue to move towards the valve port 102, at this time, the axial gap between the spring seat 27 and the valve needle 22 gradually decreases, when the screw rod 21 moves towards the valve port 102 by the same distance as the preset gap 2201, that is, the axial gap between the spring seat 27 and the valve needle 22 is 0, and the two abut, at this time the electronic expansion valve 100 is in the fully closed state, and the valve needle 22 realizes the lower stop limiting.

[0072] ​In the prior art, the electronic expansion valve 100 needs to adopt a fixed pulse process during assembly, and the fixed pulse process is relatively complex, which is easy to cause poor consistency of the flow of the electronic expansion valve 100. In the present application, since the spring seat 27 abuts against the valve needle 22 when the electronic expansion valve 100 is fully closed, and there is a preset gap 2201 between the spring seat 27 and the valve needle 22 when the valve needle 22 just abuts against or before abutting against the valve body assembly 10 (such as the valve port 102), therefore, in order to achieve the opening of the electronic expansion valve 100, it is only necessary to gradually increase the pulse size until a certain pulse is applied, so as to cause the valve needle 22 to move, during which the axial gap between the spring seat 27 and the valve needle 22 gradually increases, and when the gap reaches the size of the preset gap 2201, the valve needle 22 can be driven by the screw rod 21 to move away from the valve port 102, thereby achieving the opening of the valve. In this way, compared with the traditional fixed pulse process, the structure of the present application is simple, and the consistency of the flow can be ensured.

[0073] Here, the spring seat 27 can play the role of the gasket 25 as described above, which not only prevents the support spring 28 from interfering with the rotating member 23 to cause the rotating member 23 to be stuck, and prevents the rotating member 23 from being worn, but also reduces the probability of the valve needle 22 rotating. In addition, under the pre-tightening action of the support spring 28, the spring seat 27 can be stably arranged in the axial direction between the rotating member 23 and the valve needle 22, so as to ensure that the screw rod 21 can drive the valve needle 22 to move axially, and the reliability is higher.

[0074] Further, as shown in Figure 1 , the valve core assembly 20 further comprises a pressing sleeve 29, the pressing sleeve 29 is sleeved on the peripheral side of the valve needle 22, and the valve needle 22 is limitedly connected to the spring sleeve 26 through the pressing sleeve 29. In this way, the valve needle 22 can be prevented from being separated from the spring sleeve 26, and the reliability of the connection between the valve needle 22 and the spring sleeve 26 can be improved. In addition, the pressing sleeve 29 and the spring sleeve 26 can also be provided as an integrated structure.

[0075] Among them, the stop portion 201 can be provided on the step formed on the outer wall of the valve needle 22 as shown in Figures 2-4 , or the stop portion 201 can be directly formed by the structure such as the pressing sleeve 29 as shown in Figure 1 .

[0076] In an embodiment, as shown in Figure 3 , the inner wall of the limiting segment 1012 is in clearance fit with the outer wall of part of the valve needle 22 to guide the valve needle 22. In this way, the coaxiality of the valve needle 22 and the valve port 102 can be improved. Further, the inner wall of the limiting segment 1012 is in clearance fit with the outer wall of the first rotating portion 231 to guide the rotating member 23. In this way, the radial deviation of the rotating member 23 can be prevented, thereby improving the reliability of the rotating member 23 during operation.

[0077] It can be understood that, in Figure 3In the structure shown, the valve needle 22 can stably abut against the rotating member 23 along the axial direction under the action of the elastic member 30, so that the screw 21, the rotating member 23 and the valve needle 22 can move together along the axial direction, resulting in higher stability.

[0078] In one embodiment, such as Figure 2 As shown, the valve core assembly 20 also includes a bearing sleeve 24, which is sleeved on the outer periphery of the rotating member 23 and can abut against one end of the rotating member 23 axially to stop it. One end of the valve needle 22 is inserted into the bearing sleeve 24 and fixedly connected to it. The valve needle 22 abuts against the other end of the rotating member 23 axially, allowing the screw 21, valve needle 22, rotating member 23, and bearing sleeve 24 to move as a unit along the axial direction. The inner wall of the limiting section 1012 is clearance-fitted with the outer wall of the bearing sleeve 24 to guide the bearing sleeve 24. That is, in this embodiment, the bearing sleeve 24 provides a certain degree of protection for the ends of the rotating member 23 and the valve needle 22, reducing the probability of damage to the rotating member 23. At the same time, the bearing sleeve 24 can also improve the coaxiality between the valve needle 22 and the valve port 102.

[0079] In this embodiment, when the valve core assembly 20 moves to its limit in the direction approaching or moving away from the valve port 102, the valve core assembly 20 can abut against the valve body assembly 10 axially. This is mainly because it is under the action of the elastic element 30 and the axial stopping process of the valve core assembly 20. Figure 5 As shown, under the action of the elastic element 30, the external thread 211 and internal thread 121 on the screw 21 and the nut sleeve 12 are in a tight contact relationship. During the axial stop process, when the electronic expansion valve 100 is over-opened or over-closed, the external thread 211 on the screw 21 directly rubs against the internal thread 121 on the nut sleeve 12. If the hardness of the screw 21 and the nut sleeve 12 is small, there is a risk that the screw 21 will wedge into the nut sleeve 12, the thread will deform and increase the friction between the threads and the valve opening resistance, or even jam. Based on this, in one embodiment, the Shore hardness of the part of the valve body assembly 10 at the thread section 1011 and / or the part of the valve core assembly 20 at the external thread 211 is greater than or equal to 80. That is, the Shore hardness of the screw 21 and / or the nut sleeve 12 is set to be greater than or equal to 80. This can effectively improve the hardness of the mating joint between the internal thread 121 and the external thread 211, thereby improving the smoothness of the threaded engagement between the two, reducing the probability of deformation, and avoiding affecting the opening performance of the electronic expansion valve 100.

[0080] Furthermore, the screw 21 and / or the nut sleeve 12 are configured as high-hardness engineering plastic parts or metal parts to increase the hardness of the screw 21 and / or the nut sleeve 12.

[0081] Specifically, the screw 21 can be configured as a stainless steel or brass component, and the nut sleeve 12 can be configured as an engineering plastic component, thereby ensuring the rigidity of the screw 21 and the nut sleeve 12. Here, the stainless steel component can be a structure made entirely of stainless steel, or a structure made with stainless steel as a base and combined with other metal materials. Similarly, the brass component can be a structure made entirely of brass, or a structure made with brass as a base and combined with other metal materials. The nut sleeve 12 can be made of engineering plastic materials such as PEEK (polyetheretherketone).

[0082] Furthermore, the coefficient of friction between the external thread 211 and the internal thread 121 is controlled to be less than or equal to 0.2 to reduce the operating resistance during the threaded transmission process when opening or closing the valve. Since metals typically have a higher coefficient of friction, when the screw 21 and / or the nut sleeve 12 are made of metal, a wear-resistant coating can be applied to the surfaces of the screw 21 and / or the nut sleeve 12. Specifically, a wear-resistant coating can be applied to the surfaces of the external thread 211 and / or the internal thread 121 to reduce friction between them. Of course, when using high-hardness engineering plastic materials, a wear-resistant coating can also be applied to their surfaces.

[0083] In one embodiment, such as Figures 1-4 As shown, the assembly hole 101 also includes a guide section 1013. The guide section 1013 is located on the side of the threaded section 1011 away from the limiting section 1012, and the inner wall of the guide section 1013 is in clearance fit with the outer wall of part of the valve core assembly 20 to guide the valve core assembly 20, thereby improving coaxiality.

[0084] Furthermore, an upper limit surface 1014 is formed at one end of the limiting section 1012 near the threaded section 1011. Specifically, the upper limit surface 1014 is provided on the nut sleeve 12. When the valve core assembly 20 moves to the limit in a direction away from the valve port 102, the valve core assembly 20 can abut against the upper limit surface 1014 in the axial direction.

[0085] That is, the axial contact between the valve core assembly 20 and the upper limit surface 1014 enables the electronic expansion valve 100 to reach its upper stop when fully open, corresponding to the fully open position of the electronic expansion valve 100. Simultaneously, it prevents the external thread 211 on the screw 21 from embedding into the nut sleeve 12, further improving the reliability of the fit between the internal thread 121 and the external thread 211. Here, the upper stop of the valve core assembly 20 when fully open with the upper limit surface 1014 can be achieved by the contact of the end face away from the valve port 102 via a structure such as the rotating member 23, the spring sleeve 26, or the bearing sleeve 24.

[0086] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, it is to be understood that the application embraces all such possible combinations.

[0087] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be pointed out that for ordinary skilled persons in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. An electronic expansion valve characterized by, The valve body assembly (10) is provided with an assembly hole (101) and a valve port (102), the assembly hole (101) comprises a threaded section (1011) and a limiting section (1012), the threaded section (1011) is located on the side of the limiting section (1012) away from the valve port (102), and the threaded section (1011) is provided with an internal thread (121), the inner wall of the limiting section (1012) near one end of the valve port (102) protrudes towards the direction close to the axis to form a limiting part (1121); The valve core assembly (20) is at least partially installed in the assembly hole (101), the valve core assembly (20) comprises a screw rod (21), a valve needle (22) and a rotating part (23), the rotating part (23) is arranged between the screw rod (21) and the valve needle (22) to prevent relative rotation between the screw rod (21) and the valve needle (22); The screw rod (21) is provided with an external thread (211), the external thread (211) is threadedly connected with the internal thread (121) to drive the valve core assembly (20) to move along the axial direction of the electronic expansion valve; Wherein, the outer wall of the valve core assembly (20) is provided with a stop part (201), the stop part (201) is arranged in the limiting section (1012), the elastic member (30) is sleeved on the outer periphery of the valve core assembly (20) and arranged between the stop part (201) and the limiting part (1121), and the two ends of the elastic member (30) are respectively in abutting connection with the stop part (201) and the limiting part (1121) to apply an action force to the valve core assembly (20) in the direction away from the valve port (102).

2. The electronic expansion valve according to claim 1, characterized in that The rotating part (23) comprises a first rotating part (231), a second rotating part (232) and a rolling part (233), the first rotating part (231) is rotationally connected with the second rotating part (232) through the rolling part (233), and one of the first rotating part (231) and the second rotating part (232) is connected with the screw rod (21), and the other is in abutting connection with the valve needle (22) along the axial direction of the electronic expansion valve.

3. The electronic expansion valve according to claim 2, characterized in that Along the radial direction of the electronic expansion valve, the first rotating part (231) is sleeved on the rolling part (233) and the second rotating part (232) through the rolling part (233); Wherein, the screw rod (21) is inserted and connected in the second rotating part (232).

4. The electronic expansion valve according to claim 3, characterized in that The inner wall of the limiting section (1012) is in clearance fit with the outer wall of part of the valve needle (22) to guide the valve needle (22); And / or, the inner wall of the limiting section (1012) is in clearance fit with the outer wall of the first rotating part (231) to guide the rotating part (23).

5. The electronic expansion valve according to claim 3, wherein The valve core assembly (20) further comprises a bearing sleeve (24) sleeved on the outer periphery of the rotating member (23) and capable of abuttingly engaging with one end of the rotating member (23) in the axial direction, one end of the valve needle (22) is inserted into the bearing sleeve (24) and fixedly connected with the bearing sleeve (24), and the other end of the valve needle (22) abuttingly engages with the rotating member (23) in the axial direction; The inner wall of the limiting section (1012) is in clearance fit with the outer wall of the bearing sleeve (24) to guide the bearing sleeve (24).

6. Electronic expansion valve according to any of claims 3-5, characterized in that The valve needle (22) is provided with a balance channel (2202), one end of the balance channel (2202) is in communication with the valve port (102), and the other end is used for communicating the back pressure chamber of the electronic expansion valve.

7. The electronic expansion valve according to claim 6, characterized in that The valve needle (22) is further provided with a balance hole (2203), the balance hole (2203) is arranged on the side of the balance channel (2202), and the two ends of the balance hole (2203) are respectively in communication with the balance channel (2202) and the assembly hole (101).

8. The electronic expansion valve according to claim 3, wherein The valve needle (22) is provided with an avoiding hole (2204) at one end close to the rotating member (23), and the projection of the avoiding hole (2204) can cover the screw rod (21) and / or the second rotating part (232) in the axial direction of the electronic expansion valve. Alternatively, the valve needle (22) is provided with a gasket (25) at one end close to the rotating member (23), and the projection of the gasket (25) can cover the screw rod (21) and / or the second rotating part (232) in the axial direction of the electronic expansion valve.

9. The electronic expansion valve according to claim 2, wherein The first rotating part (231), the rolling part (233) and the second rotating part (232) are arranged in sequence in the axial direction of the electronic expansion valve.

10. The electronic expansion valve according to claim 1, wherein The assembly hole (101) further comprises a guide section (1013), the guide section (1013) is arranged on the side of the threaded section (1011) away from the limiting section (1012), and the inner wall of the guide section (1013) is in clearance fit with part of the outer wall of the valve core assembly (20) to guide the valve core assembly (20); The limiting section (1012) is formed with an upper limiting surface (1014) at one end close to the threaded section (1011), and when the valve core assembly (20) moves to the limit in the direction away from the valve port (102), the valve core assembly (20) can abuttingly engage with the upper limiting surface (1014) in the axial direction.

11. The electronic expansion valve according to claim 1, wherein The valve body assembly (10) comprises a valve seat (11) and a nut sleeve (12), and the nut sleeve (12) is fixedly connected to one end of the valve seat (11). The threaded section (1011) is arranged in the nut sleeve (12), the valve port (102) is arranged in the valve seat (11), and the nut sleeve (12) and the valve seat (11) form the limiting section (1012).

12. The electronic expansion valve according to claim 11, wherein The valve seat (11) comprises a main body part (111) and a guide part (112), the nut sleeve (12) is connected to the main body part (111), the guide part (112) is located in the main body part (111), and one end of the guide part (112) is inserted into the nut sleeve (12) and connected with the nut sleeve (12). Wherein, the nut sleeve (12) and the guide part (112) surround to form the limiting section (1012).

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