Electronic expansion valve

Abstract

The electronic expansion valve comprises a valve seat assembly, a screw assembly and a valve needle assembly, a valve port is formed in the valve seat assembly, the valve seat assembly is connected and communicated with a first connecting pipe, and the first connecting pipe is communicated with the valve port; the screw assembly comprises a threaded sleeve, and the threaded sleeve is fixedly installed on the valve seat assembly. The valve needle assembly can be driven by the screw assembly to be used for controlling opening / closing of the valve port. Wherein the threaded sleeve is provided with a first part, and the first part is in guide fit with the valve needle assembly; in the axis direction of the threaded sleeve, the end face of the end, facing the valve port, of the first part is not lower than the inner circumferential wall of the first connecting pipe. In this way, it can be guaranteed that when refrigerants enter and exit from the first connecting pipe, the refrigerants are not prone to forming vortexes between the first connecting pipe and the first portion on the threaded sleeve, so that the communication capacity of the electronic expansion valve in the working process is improved, and meanwhile the situation that the threaded sleeve is burnt by heat generated when a client side welds a follow-up pipeline can be avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field related to control valves, and particularly relates to an electronic expansion valve. Background Art

[0002] The electronic expansion valve is a throttling element that can control the flow of refrigerant entering the refrigeration cycle system according to a preset program. It is usually installed between the outdoor heat exchanger and the indoor heat exchanger of the refrigeration cycle system. When the refrigeration cycle system is in cooling mode, the electronic expansion valve throttles and reduces the pressure of the refrigerant from the outdoor heat exchanger and then directs it to the indoor heat exchanger; when the refrigeration cycle system is in heating mode, the electronic expansion valve throttles and reduces the pressure of the refrigerant from the indoor heat exchanger and then directs it to the outdoor heat exchanger.

[0003] At present, the existing electronic expansion valve usually uses a threaded sleeve to guide the movement of the valve needle assembly. However, since the lower end surface of the portion of the threaded sleeve used to guide the valve needle assembly exceeds the inner wall of the connecting pipe connected to the valve seat assembly in the electronic expansion valve, this will affect the flow capacity of the electronic expansion valve when it is working. Utility Model Content

[0004] In view of this, it is necessary to provide an electronic expansion valve for solving the above technical problems.

[0005] An electronic expansion valve, the electronic expansion valve comprising:

[0006] A valve seat assembly, wherein a valve port is formed on the valve seat assembly, and a first connecting pipe is connected to the valve seat assembly, wherein the first connecting pipe is in communication with the valve port;

[0007] A screw assembly, the screw assembly comprising a threaded sleeve, the threaded sleeve being fixedly mounted on the valve seat assembly;

[0008] A valve needle assembly, wherein the valve needle assembly can control the on / off of the valve port;

[0009] The threaded sleeve has a first portion, the first portion is guided and matched with the valve needle assembly, and along the axial direction of the threaded sleeve, the end surface of the first portion facing one end of the valve port is not lower than the inner circumferential wall of the first connecting pipe.

[0010] It can be understood that, by setting the position between the above-mentioned first part and the first connecting pipe, the setting of the first part will not cause obstruction to the refrigerant introduced by the first connecting pipe. In this way, it can be ensured that when the refrigerant enters and exits the first connecting pipe, the refrigerant is not easy to form a vortex between the pipe mouth of the first connecting pipe and the first part, thereby improving the connectivity of the electronic expansion valve when it is working.

[0011] In one embodiment, a preset gap A is formed between an end surface of an open end where the first connecting pipe and the valve seat assembly are connected and an outer side wall of the first portion of the threaded sleeve opposite thereto, wherein 0.5 mm ≤ A ≤ 2.5 mm.

[0012] It can be understood that, by utilizing the preset gap A formed between the first part and the first connecting tube in the axial direction of the first connecting tube, the heat of the client during welding of subsequent pipelines will not be directly transferred to the threaded sleeve through the first connecting tube, thereby avoiding burns to the threaded sleeve and increasing the service life of the threaded sleeve.

[0013] In one embodiment, the threaded sleeve further has a second portion, the valve seat assembly has a connecting portion, and the second portion is connected to the connecting portion in an interference fit manner.

[0014] It can be understood that the assembly connection of the threaded sleeve on the valve seat assembly is achieved by utilizing the interference fit between the second portion of the threaded sleeve and the connecting portion, which can ensure the assembly accuracy of the threaded sleeve when assembling it on the valve seat assembly.

[0015] In one embodiment, a step surface is formed on the valve seat assembly, and the step surface can abut against the second part pressed into the connecting part, so as to limit the press-fitting depth of the second part on the connecting part;

[0016] In the axial direction of the threaded sleeve, the axial height of the second portion is set to B, wherein 5 mm ≥ B ≥ 1.5 mm.

[0017] It can be understood that the abutment between the step surface on the valve seat assembly and the second part is used to achieve the assembly limit of the second part on the connecting part, which not only ensures the concentricity of the assembly between the second part and the connecting part, but also makes it easy to assemble the threaded sleeve onto the connecting part of the valve seat assembly.

[0018] In one embodiment, the electronic expansion valve further comprises a connecting plate, which is sleeved on the threaded sleeve and abuts against the second part;

[0019] Wherein, the connecting plate is connected to the connecting portion by welding.

[0020] It is understandable that the connection plate is used to realize the assembly limit of the second part on the connection part, so that the electronic expansion valve can realize the disassembly of the threaded sleeve without damaging the threaded sleeve, so that the threaded sleeve can be recycled and reused, which has the effect of reducing costs.

[0021] In one embodiment, the connecting plate is connected to the connecting portion by laser welding;

[0022] In the axial direction of the threaded sleeve, the connecting plate partially protrudes outward relative to the connecting portion, and the thickness of the portion of the connecting plate protruding from the connecting portion is set to E, wherein 0.8 mm>E≥0.1 mm.

[0023] It can be understood that the height difference between the connecting plate and the connecting portion can be used to facilitate focusing during laser welding between the connecting plate and the connecting portion, thereby facilitating welding of the connecting plate to the connecting portion.

[0024] In one of the embodiments, an anti-foolproofing portion is formed on the threaded sleeve, and an anti-foolproofing matching portion is formed on the connecting plate, and the anti-foolproofing matching portion can be limitedly matched with the anti-foolproofing portion.

[0025] It can be understood that by utilizing the limiting cooperation between the fool-proof cooperation parts, it is possible to achieve fool-proofing of the connecting plate pre-installed on the threaded sleeve and to achieve circumferential limiting during assembly between the connecting plate and the threaded sleeve.

[0026] In one embodiment, the threaded sleeve further comprises a second portion and a connecting portion, the threaded sleeve can be fixedly connected to the valve seat assembly through the second portion, and the connecting portion is arranged between the second portion and the first portion;

[0027] The first part, the second part and the connecting part can be enclosed together to form a cavity, and the cavity is communicated with the first connecting pipe.

[0028] It can be understood that by forming a cavity between the first part, the second part and the connecting part, the amount of material required for the preparation of the threaded sleeve can be reduced, which has the effect of reducing costs. The thickness of the threaded sleeve at the first part, the second part and the connecting part is relatively uniform, which reduces the poor injection molding of the nut and does not form pores, whitening of the material and other injection molding problems in the thicker part; on the other hand, the internal space formed between the valve seat assembly and the threaded sleeve can be further increased, which is beneficial to the noise under specific working conditions, has the effect of reducing noise, and can also improve the refrigerant flow capacity when the whole valve is fully opened.

[0029] In one embodiment, the thickness of the first portion, the thickness of the second portion and the thickness of the connecting portion are uniform, and the thickness difference between any two walls is less than or equal to 1 mm.

[0030] It can be understood that, through the above-mentioned structural setting, the threaded sleeve can be integrally injection molded, thereby facilitating the production and preparation of the threaded sleeve.

[0031] In one embodiment, the screw assembly further comprises a screw, a portion of the screw extends into the valve needle assembly, a bearing is sleeved on the portion of the screw extending into the valve needle assembly, and the screw is interference fit with an inner ring of the bearing;

[0032] Wherein, the axis of the threaded sleeve is consistent with the axis of the valve port.

[0033] It can be understood that the screw is driven and connected to the valve needle assembly through the bearing, so that when the screw drives the valve needle assembly to open or close the electronic expansion valve, the friction resistance between the valve needle assembly and the corresponding position on the valve port can be reduced.

[0034] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art:

[0035] The electronic expansion valve for which protection is sought in the present application is arranged so that the arrangement of the first part does not hinder the refrigerant introduced into the first connecting pipe by arranging the position between the first part and the first connecting pipe. This ensures that when the refrigerant enters and exits the first connecting pipe, it is not easy for the refrigerant to form a vortex between the first connecting pipe and the first part on the threaded sleeve, thereby improving the connectivity of the electronic expansion valve during operation and preventing the threaded sleeve from being burned by the heat generated when the client welds subsequent pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 A schematic diagram of the structure of an electronic expansion valve provided in one embodiment of the present application;

[0038] Figure 2 A schematic structural diagram of an electronic expansion valve provided in an embodiment of the present application from another perspective;

[0039] Figure 3 for Figure 2 Cross-sectional view of the middle TT;

[0040] Figure 4 for Figure 3 Enlarged view of the middle P part;

[0041] Figure 5 A schematic diagram of the structure of a threaded sleeve provided in one embodiment of the present application;

[0042] Figure 6 A schematic diagram of the structure of a connecting plate provided in one embodiment of the present application.

[0043] : Illustrations: 100, electronic expansion valve; 10, valve seat assembly; 101, valve port; 110, first connecting pipe; 111, inner wall; 120, second connecting pipe; 11, connecting part; 12, step surface; 20, screw assembly; 21, threaded sleeve; 210, cavity; 211, first part; 2111, end face; 212, second part; 213, fool-proof part; 2131, first boss; 2132, second boss; 2133, third boss; 214, connecting part; 22, screw; 221, bearing; 23, connecting plate; 231, fool-proof fitting part; 2311, first groove; 2312, second groove; 2313, third groove; 30, valve needle assembly. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0045] It should be noted that when an element is referred to as being "provided on" another element, it may be directly provided on the other element or there may be a central element. When an element is considered to be "provided on" another element, it may be directly provided on the other element or there may be a central element at the same time. When an element is considered to be "fixed to" another element, it may be directly fixed to the other element or there may be a central element at the same time.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0047] like Figure 3 , Figure 4As shown, an electronic expansion valve 100 provided in an embodiment of the present application includes a valve seat assembly 10, a screw assembly 20 and a valve needle assembly 30, a valve seat assembly 10 is formed with a valve port 101, a first connecting pipe 110 is connected to the valve seat assembly 10, and the first connecting pipe 110 is communicated with the valve port 101; the screw assembly 20 includes a threaded sleeve 21, and the threaded sleeve 21 is fixedly mounted on the valve seat assembly 10; the valve needle assembly 30 can control the on / off of the valve port 101; wherein, the threaded sleeve 21 has a first portion 211, and the first portion 211 cooperates with the guide of the valve needle assembly 30 to guide the movement of the valve needle assembly 30; and, along the axial direction of the threaded sleeve 21, an end surface 2111 of the first portion 211 facing one end of the valve port 101 is not lower than the inner circumferential wall 111 of the first connecting pipe 110. Here, the first connecting pipe 110 has an inner peripheral wall 111 for the circulation of refrigerant, and the side of the inner peripheral wall 111 away from the valve port 101 along the axial direction of the threaded sleeve 21 is defined as the top wall, and the side close to the valve port 101 is defined as the bottom wall, that is, the end surface 2111 of the first portion 211 facing the valve port 101 is not lower than the top wall of the inner peripheral wall 111 of the first connecting pipe 110. In other words, the electronic expansion valve 100 uses the threaded sleeve 21 to directly guide the movement of the valve needle assembly 30 to control the on / off of the valve port 101, and realizes the design of the electronic expansion valve 100 without a guide sleeve.

[0048] It can be understood that since the electronic expansion valve 100 omits the structure of the guide sleeve, this not only reduces costs, but also increases the internal space of the valve seat assembly 10, thereby improving the flow capacity of the electronic expansion valve 100 and reducing the turbulent kinetic energy of the refrigerant when flowing in the valve seat assembly 10, which has the effect of reducing noise; in addition, through the setting of the position between the above-mentioned first part 211 and the first connecting pipe 110, the setting of the first part 211 will not cause obstruction to the refrigerant introduced by the first connecting pipe 110, which can ensure that the refrigerant is not easy to form a vortex at the first part 211 and the pipe mouth of the first connecting pipe 110 when entering and exiting the first connecting pipe 110, thereby improving the flow capacity of the electronic expansion valve 100 when it is working, which has the effect of reducing the noise of the electronic expansion valve 100.

[0049] like Figure 1 , Figure 2As shown, the electronic expansion valve 100 of the present application is connected and communicated with a second connecting pipe 120 at the position of the valve port 101, and the second connecting pipe 120 can be either a refrigerant inlet or an outlet; when the refrigerant flows in from the second connecting pipe 120, the refrigerant can flow into the valve seat assembly 10 through the valve port 101 and flow out from the first connecting pipe 110; and when the refrigerant flows out from the second connecting pipe 120, the refrigerant flows in from the first connecting pipe 110, passes through the valve seat assembly 10 and the valve port 101 in sequence, and finally flows out from the second connecting pipe 120. The screw assembly 20 also includes a screw 22. In this process, the screw 22 can drive the valve needle assembly 30 to move under the guidance of the threaded sleeve 21, so as to realize the control of the on / off of the valve port 101 and achieve the purpose of controlling the operation of the electronic expansion valve 100. The structure of the valve needle assembly 30 and the working principle of how the screw rod 22 drives the valve needle assembly 30 to move under the guidance of the first portion 211 on the threaded sleeve 21 can all adopt existing conventional methods, which will not be elaborated here.

[0050] like Figure 3 As shown, a preset gap A is formed between the end surface of the open end of the first connecting pipe 110 and the valve seat assembly 10 and the outer side wall of the first part 211 of the threaded sleeve 21 opposite thereto, wherein 0.5mm≤A≤2.5mm. In other words, the first part 211 of the threaded sleeve 21 does not contact the part of the first connecting pipe 110 inserted into the valve seat assembly 10, so that when welding with the client pipeline later, the heat generated will not be directly transferred to the threaded sleeve 21 through the first connecting pipe 110, so that the threaded sleeve 21 can be prevented from being burned, thereby increasing the service life of the threaded sleeve 21. Here, the threaded sleeve 21 is a non-metallic part, which can be prepared by injection molding.

[0051] Preferably, the value of the preset gap A can be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, etc. Of course, within the value range of the preset gap A, the value of the preset gap A is not limited thereto, and can be set according to actual needs.

[0052] like Figure 3 , Figure 4As shown, the threaded sleeve 21 also has a second portion 212, and the valve seat assembly 10 has a connecting portion 11, and the second portion 212 is connected to the connecting portion 11 in an interference fit manner. In other words, the threaded sleeve 21 can be assembled to the connecting portion 11 by press-fitting, and the threaded sleeve 21 can be assembled and connected to the valve seat assembly 10, so that the assembly accuracy of the threaded sleeve 21 when assembled on the valve seat assembly 10 can be ensured. It should be noted that since the threaded sleeve 21 is directly assembled to the connecting portion 11 of the valve seat assembly 10 by the second portion 212, direct contact between the second portion 212 on the threaded sleeve 21 and the first connecting pipe 110 can be avoided, so that the processing accuracy of the first connecting pipe 110 and the insertion depth of the first connecting pipe 110 when inserted into the valve seat assembly 10 will not affect the assembly of the threaded sleeve 21 on the valve seat assembly 10, and the threaded sleeve 21 prepared in one piece is used to assemble and connect with the valve seat assembly 10, so that the assembly accuracy of the threaded sleeve 21 when assembled on the valve seat assembly 10 can be ensured.

[0053] Furthermore, if Figure 4 As shown, a step surface 12 is formed on the valve seat assembly 10, and the step surface 12 can abut against the second part 212 pressed into the connecting part 11, and is used to limit the pressing depth of the second part 212 on the connecting part 11, so that the assembly limit of the second part 212 on the threaded sleeve 21 on the connecting part 11 can be achieved, and it is convenient to assemble the threaded sleeve 21 on the valve seat assembly 10.

[0054] like Figure 3 As shown, in the axial direction of the threaded sleeve 21, the axial height of the second portion 212 pressed into the connecting portion 11 is set to B, where 5mm≥B≥1.5mm. This ensures the concentricity of the second portion 212 and the connecting portion 11, thereby ensuring the assembly accuracy of the threaded sleeve 21 when assembled on the valve seat assembly 10.

[0055] Preferably, the value of B can be 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc. Of course, within the value range of B, the value of B is not limited thereto, and can be set according to actual needs.

[0056] Please continue to refer to Figure 3 and Figure 4The electronic expansion valve 100 further includes a connecting plate 23, which is mounted on the threaded sleeve 21 and abuts against the second portion 212; wherein the connecting plate 23 is fixed to the connecting portion 11 by welding. In other words, the electronic expansion valve 100 can use the connecting plate 23 to realize the assembly limit of the threaded sleeve 21 on the connecting portion 11 of the valve seat assembly 10, so that the electronic expansion valve 100 can realize the disassembly of the threaded sleeve 21 without damaging the threaded sleeve 21, so that the threaded sleeve 21 can be recycled and reused, which has the effect of reducing costs. Here, the connecting plate 23 is connected to the connecting portion 11 by laser welding.

[0057] like Figure 3 As shown, in the axial direction of the threaded sleeve 21, after the connecting plate 23 is sleeved on the threaded sleeve 21, the connecting plate 23 partially protrudes outward relative to the connecting portion 11, and the thickness of the portion of the connecting plate 23 protruding from the connecting portion 11 is set to E, where 0.8mm>E≥0.1mm. In other words, when the connecting plate 23 is limited by the second portion 212 pressed onto the connecting portion 11, a height difference is formed between the connecting plate 23 and the connecting portion 11, which facilitates the focusing of the connecting plate 23 and the connecting portion 11 during laser welding, thereby facilitating the welding of the connecting plate 23 to the connecting portion 11.

[0058] Preferably, the value of E can be 0.1 mm, 0.3 mm, 0.5 mm, 0.6 mm, 0.8 mm, etc. Of course, within the value range of B, the value of B is not limited thereto, and can be set according to actual needs.

[0059] like Figure 5 , Figure 6 As shown, an anti-foolproofing portion 213 is formed on the threaded sleeve 21, and an anti-foolproofing fitting portion 231 is formed on the connecting plate 23. The anti-foolproofing fitting portion 231 is limitedly fitted with the anti-foolproofing portion 213. This can, on the one hand, achieve anti-foolproofing of the connecting plate 23 pre-installed on the threaded sleeve 21, so as to facilitate the assembly of the connecting plate 23 on the threaded sleeve 21; on the other hand, it can also achieve circumferential limitation during assembly between the connecting plate 23 and the threaded sleeve 21.

[0060] Furthermore, the fool-proofing portion 213 is configured as three bosses formed on the threaded sleeve 21, and the three bosses are respectively defined as a first boss 2131, a second boss 2132, and a third boss 2133. The first boss 2131, the second boss 2132, and the third boss 2133 are arranged in sequence along the circumferential direction of the threaded sleeve 21, wherein the sizes of the first boss 2131, the second boss 2132, and the third boss 2133 are not equal; accordingly, the fool-proofing fitting portion 231 is configured as three grooves opened on the connecting plate 23, and the three grooves are respectively defined as a first groove 2311, a second groove 2312, and a third groove 2313, and the first groove 2311 and the first boss 2131, as well as the third groove 2313 and the third boss 2133 are respectively limited by a slightly interference fit, and the second groove 2312 and the second boss 2132 are limited by a loose fit. The anti-foolproofing portion 213 and the anti-foolproofing matching portion 231 are not limited to those shown in the figure. For those skilled in the art, the number of bosses in the anti-foolproofing portion 213 can also be one or two, or the anti-foolproofing portion 213 can be configured as a groove formed on the threaded sleeve 21, and the anti-foolproofing matching portion 231 can be configured as a boss matching the groove, which will not be elaborated here.

[0061] like Figure 4 As shown, the threaded sleeve 21 also has a connecting portion 214, and the first portion 211 and the second portion 212 on the threaded sleeve 21 are connected by the connecting portion 214; wherein, the first portion 211, the second portion 212 and the connecting portion 214 can be enclosed together to form a cavity 210, and the cavity 210 is connected to the first connecting pipe 110. In this way, on the one hand, the amount of material required for the preparation of the threaded sleeve 21 can be reduced, which has the effect of reducing costs; on the other hand, the internal space formed between the valve seat assembly 10 and the threaded sleeve 21 can be further increased, which has the effect of reducing noise. Here, the cavity 210 is configured as a circular ring structure; in addition, the setting of the cavity 210 makes the thickness of the first portion 211, the second portion 212 and the connecting portion 214 uniform, so as to prevent the problem of poor injection molding such as whitening due to the uneven thickness of the first portion 211, the second portion 212 and the connecting portion 214 when the threaded sleeve 21 is injected. Specifically, the thickness of the first portion 211, the thickness of the second portion 212 and the thickness of the connecting portion 214 can be equal to each other. In other embodiments, the wall thickness of the first portion 211, the second portion 212 and the connecting portion 214 on the threaded sleeve 21 can also be set to be unequal, and the wall thickness of the three is not much different, so that the wall thickness of the first portion 211, the second portion 212 and the connecting portion 214 on the threaded sleeve 21 is relatively uniform, so that the wall thickness is thicker than that of the rest of the threaded sleeve 21, thereby avoiding the problem of poor injection molding of the threaded sleeve 21. Finally, the setting of the cavity 210 can also prevent the heat from being transferred to the first portion 211 of the inner periphery of the threaded sleeve 21 during the welding of the connecting plate 23 and the valve seat assembly 10.

[0062] like Figure 3 As shown, the screw rod 22 partially extends into the valve needle assembly 30; wherein, the screw rod 22 is sleeved with a bearing 221 on the portion extending into the valve needle assembly 30, and the inner ring of the bearing 221 is interference fit with the corresponding position of the screw rod 22. In this way, the inner ring of the bearing 221 rotates with the screw rod 22, while the outer ring of the bearing 221 does not rotate, so that the screw rod 22 can reduce the friction resistance between the valve needle assembly 30 and the valve port 101 position on the valve seat assembly 10 in the process of driving the valve needle assembly 30 to open or close the electronic expansion valve, thereby reducing the wear of the valve needle assembly 30 and the valve port 101 corresponding position, and facilitating the movement of the valve needle assembly 30. Here, the axis of the threaded sleeve 21 is consistent with the axis of the valve port 101.

[0063] In summary, the electronic expansion valve 100 of the present application can reduce the noise generated during operation, and has the effect of improving the product performance of the electronic expansion valve 100.

[0064] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, appropriate changes and modifications to the above embodiments are within the scope of protection required by the present invention.

Claims

1. An electronic expansion valve, characterized in that: The electronic expansion valve (100) comprises: A valve seat assembly (10), wherein a valve port (101) is formed on the valve seat assembly (10), and a first connecting pipe (110) is connected to the valve seat assembly (10), and the first connecting pipe (110) is in communication with the valve port (101); A screw assembly (20), the screw assembly (20) comprising a threaded sleeve (21), the threaded sleeve (21) being fixedly mounted on the valve seat assembly (10); A valve needle assembly (30), wherein the valve needle assembly (30) is capable of controlling the on / off state of the valve port (101); Wherein, the threaded sleeve (21) has a first part (211), and the first part (211) is guided and matched with the valve needle assembly (30); and along the axial direction of the threaded sleeve (21), the end surface (2111) of the first part (211) facing one end of the valve port (101) is not lower than the inner wall (111) of the first connecting tube (110).

2. The electronic expansion valve according to claim 1, characterized in that: A preset gap A is formed between the end surface of the open end where the first connecting pipe (110) and the valve seat assembly (10) are connected and the outer side wall of the first part (211) of the threaded sleeve (21) opposite thereto, wherein 0.5 mm ≤ A ≤ 2.5 mm.

3. The electronic expansion valve according to claim 1, characterized in that: The threaded sleeve (21) further comprises a second portion (212), the valve seat assembly (10) comprises a connecting portion (11), and the second portion (212) is connected to the connecting portion (11) in an interference fit manner.

4. The electronic expansion valve according to claim 3, characterized in that: A step surface (12) is formed on the valve seat assembly (10), and the step surface (12) can abut against the second part (212) pressed into the connecting part (11), so as to limit the press-fitting depth of the second part (212) on the connecting part (11); In the axial direction of the threaded sleeve (21), the axial height of the second portion (212) pressed into the connecting portion (11) is set to B, where 5 mm ≥ B ≥ 1.5 mm.

5. The electronic expansion valve according to claim 3, characterized in that: The electronic expansion valve (100) further comprises a connecting plate (23), wherein the connecting plate (23) is sleeved on the threaded sleeve (21) and abuts against the second portion (212); Wherein, the connecting plate (23) is connected to the connecting portion (11) by welding.

6. The electronic expansion valve according to claim 5, characterized in that: The connecting plate (23) is connected to the connecting portion (11) by laser welding; In the axial direction of the threaded sleeve (21), the connecting plate (23) partially protrudes outward relative to the connecting portion (11), and the thickness of the portion of the connecting plate (23) protruding from the connecting portion (11) is set to E, wherein 0.8 mm>E≥0.1 mm.

7. The electronic expansion valve according to claim 5, characterized in that: The threaded sleeve (21) is formed with an anti-foolproof portion (213), and the connecting plate (23) is formed with an anti-foolproof matching portion (231), and the anti-foolproof matching portion (231) can be limitedly matched with the anti-foolproof portion (213).

8. The electronic expansion valve according to claim 1, characterized in that: The threaded sleeve (21) further comprises a second portion (212) and a connecting portion (214); the threaded sleeve (21) can be fixedly connected to the valve seat assembly (10) via the second portion (212); and the connecting portion (214) is arranged between the second portion (212) and the first portion (211); The first part (211), the second part (212) and the connecting part (214) can together enclose a cavity (210), and the cavity (210) is in communication with the first connecting pipe (110).

9. The electronic expansion valve according to claim 8, characterized in that: The thickness of the first part (211), the thickness of the second part (212) and the thickness of the connecting part (214) are uniform, and the thickness difference between any two walls is less than or equal to 1 mm.

10. The electronic expansion valve according to claim 1, characterized in that: The screw assembly (20) further comprises a screw (22), wherein a portion of the screw (22) extends into the valve needle assembly (30), a bearing (221) is sleeved on the portion of the screw (22) extending into the valve needle assembly (30), and the screw (22) is interference fit with an inner ring of the bearing (221); Wherein, the axis of the threaded sleeve (21) is consistent with the axis of the valve port (101).

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