Electronic expansion valve

Abstract

An electronic expansion valve, comprising a valve seat (11), a nut assembly (12), a valve shaft part (22), a valve needle (21), and a magnet rotor assembly (27). The valve seat (11) comprises a valve port part (113); the nut assembly (12) is fixedly connected to the valve seat (11); the nut assembly (12) comprises a nut (121) and a connecting piece (122); the nut (121) comprises a first guide part (12a), an inner thread part (12b), and a second guide part (12c); the first guide part (12a) is closer to the valve port part (113) with respect to the inner thread part (12b), and the second guide part (12c) is farther away from the valve port part (113) with respect to the inner thread part (12b); the inner diameter of the first guide part (12a) is less than that of the second guide part (12c); the valve shaft part (22) is fixedly connected to the magnet rotor assembly (27) and comprises a valve shaft guide part (22b); the valve shaft guide part (22b) is in clearance fit with the second guide part (12c); the valve shaft part (22) can perform relative displacement, relative to the nut (121), in an axial direction along the nut (121). Fig. 1

Description

Electronic expansion valve

[0001] The present application claims priority to the Chinese patent application No. 202010392210.5, filed on May 11, 2020, and entitled "Electronic expansion valve", the content of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The present application relates to the technical field of refrigeration control, in particular to an electronic expansion valve.

BACKGROUND

[0003] A refrigeration system includes a compressor, a throttling element, two heat exchangers, and other components. The throttling element can be an electronic expansion valve, which is used for throttling adjustment of refrigerant. The use of an electronic expansion valve can achieve relatively precise control and improve system efficiency. The basic principle of an electronic expansion valve is that a predetermined pulse current signal is passed through a stator coil to cause the rotor assembly of the electronic expansion valve to rotate under excitation. Through a screw feed mechanism, the rotational motion of the rotor is converted into the up-and-down movement of the valve shaft, so that the valve core at the head of the valve shaft approaches or moves away from the valve port, thereby changing the flow area of the valve port and achieving refrigerant flow regulation and switching function.

[0004]

SUMMARY

[0005] One embodiment of the present application aims to provide an electronic expansion valve with relatively small frictional resistance from a screw feed mechanism.

[0006] To achieve the above-mentioned purpose, one embodiment of the present application adopts the following technical scheme:

[0007] An electronic expansion valve, characterized in that it comprises a valve seat, a nut assembly, a valve shaft part, a valve needle, and a magnetic rotor assembly. The valve seat comprises a valve port part. The nut assembly is fixedly connected with the valve seat. The nut assembly comprises a nut and a connecting plate. The nut comprises a first guide part, an internal thread part, and a second guide part. The first guide part is closer to the valve port part than the internal thread part. The second guide part is farther away from the valve port part than the internal thread part. The inner diameter of the first guide part is smaller than that of the second guide part.

[0008] The valve shaft part is fixedly connected with the magnetic rotor assembly. The valve shaft part comprises a valve shaft guide part. The valve shaft guide part is in clearance fit with the second guide part. The valve shaft part can be relatively displaced along the axial direction of the nut. The valve shaft part comprises an external thread part. The external thread part and the internal thread part constitute a screw feed mechanism. The valve shaft part comprises a first through hole part and a second through hole part. The inner diameter of the first through hole part is larger than that of the second through hole part.

[0009] The valve needle includes a valve needle guide portion which is in clearance fit with the first guide portion, and the valve needle is relatively displaceable along the axial direction of the nut; the outer diameter of the valve needle guide portion is greater than the inner diameter of the second through hole portion.

[0010] The electronic expansion valve provided by the embodiment includes a first through hole portion and a second through hole portion, and because the outer diameter of the valve needle guide portion is greater than the inner diameter of the second through hole portion of the valve shaft portion, in the case of the same specification of electronic expansion valve, such as the same rotor diameter, shell diameter, stator coil diameter and volume, the nominal diameter of the screw feed mechanism only needs to be slightly greater than the outer diameter of the valve needle guide portion, that is, the nominal diameter of the screw feed mechanism can be relatively small, which is beneficial to reducing the frictional resistance from the screw feed mechanism. BRIEF DESCRIPTION OF DRAWINGS

[0011] Fig. 1 is a cross-sectional view of an electronic expansion valve in a closed valve state according to a first embodiment;

[0012] Fig. 2 is a cross-sectional view of the electronic expansion valve in an open valve state according to the first embodiment;

[0013] Fig. 3 is a schematic view of the cooperation between a nut and a valve seat assembly according to the first embodiment;

[0014] Fig. 4 is a schematic view of the cooperation between a magnetic rotor assembly and a valve shaft portion and a valve needle according to the first embodiment;

[0015] Fig. 5 is a cross-sectional view of an electronic expansion valve in a closed valve state according to a second embodiment;

[0016] Fig. 6 is a cross-sectional view of the electronic expansion valve in an open valve state according to the second embodiment;

[0017] Fig. 7 is a schematic view of a nut assembly according to the second embodiment;

[0018] Fig. 8 is a partial cross-sectional view of the cooperation between a magnetic rotor assembly and a valve shaft portion and a valve needle according to the second embodiment;

[0019] Fig. 9 is a top view of the nut assembly according to the second embodiment;

[0020] Fig. 10 is a cross-sectional view of an electronic expansion valve in a closed valve state according to a third embodiment;

[0021] Fig. 11 is a cross-sectional view of the electronic expansion valve in an open valve state according to the third embodiment;

[0022] Fig. 12 is a schematic view of a nut assembly according to the third embodiment;

[0023] Fig. 13 is a schematic view of the cooperation between a valve shaft portion and a stopper according to the third embodiment;

[0024] Fig. 14 is a schematic view of the cooperation structure of the magnetic rotor assembly of the third embodiment with the valve shaft portion, valve needle, and stopper;

[0025] Fig. 15 is a schematic view of the connection plate structure provided by the fourth embodiment;

[0026] Fig. 16 is a partial sectional view of the cooperation structure of the magnetic rotor assembly of the fourth embodiment with the valve shaft portion, valve needle, and other components;

[0027] Fig. 17 is a schematic view of the electronic expansion valve of the fifth embodiment in the full-closed state and in the stop position;

[0028] Fig. 18 is an enlarged view of part I in Fig. 17;

[0029] Fig. 19 is an enlarged view of part II in Fig. 17;

[0030] Fig. 20 is a sectional view of the electronic expansion valve of the fifth embodiment at the spring force unloading point;

[0031] Fig. 21 is an enlarged view of part III in Fig. 20;

[0032] Fig. 22 is an enlarged view of part IV in Fig. 20;

[0033] Fig. 23 is a sectional view of the electronic expansion valve of the fifth embodiment at the opening critical point;

[0034] Fig. 24 is an enlarged view of part V in Fig. 23;

[0035] Fig. 25 is an enlarged view of part VI in Fig. 23;

[0036] Fig. 26 is a sectional view of the electronic expansion valve of the fifth embodiment in the fully-opened state;

[0037] Fig. 27 is a schematic view of the structure of the electronic expansion valve of the sixth embodiment.

DETAILED DESCRIPTION

[0038] In order to make the skilled in the art better understand the technical solutions provided by the present application, the technical solutions of the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0039] First Embodiment

[0040] Please refer to Figs. 1-4, Fig. 1 is a schematic view of the structure of the electronic expansion valve of the first embodiment in the closed state, Fig. 2 is a schematic view of the structure of the electronic expansion valve of the first embodiment in the closed state, Fig. 3 is a schematic view of the structure of the valve seat portion of the first embodiment, and Fig. 4 is a schematic view of the structure of the rotor and screw valve needle assembly of the first embodiment.

[0041] As shown in Fig. 1, the electronic expansion valve comprises a valve body component and a coil component 40, wherein the valve body component comprises a valve seat 11, a connecting piece 50, and a shell 30. The valve seat 11 can be formed by metal cutting, and the connecting piece 50 is fixedly connected with the valve seat 11 by welding and is also fixedly connected with the shell 30. The shell 30 is a thin-walled piece and is generally in the shape of a cylinder with one end open. The open end of the shell 30 is hermetically welded with the valve seat 11. The valve seat 11 and the connecting piece 50 can be assembled and positioned by setting a stepped portion on the upper side of the valve seat 11 and then loading the connecting piece 50 from the upper side of the valve seat 11. Similarly, a stepped portion can also be set on the upper side of the connecting piece 50 to facilitate assembly and positioning with the shell 30, thus facilitating welding operation. That is, the valve seat 11 is connected with the shell through the connecting piece 50, and a cavity is formed above the valve seat 11 for accommodating the magnetic rotor assembly, the nut assembly, and other components described below.

[0042] The valve seat 11 comprises a valve port portion 113, a first interface portion 111, and a second interface portion 112. The first interface portion 111 and the second interface portion 112 are used to connect with the refrigerant channel of the system. The valve port portion 113 is provided with a valve port 113a. In the embodiment, the first interface portion 111 is fixedly connected with a first connecting pipe 10b, and the second interface portion 112 is fixedly connected with a second connecting pipe 10c. The refrigerant can flow into from the first connecting pipe 10b, pass through the valve port 113a, and then flow out from the second connecting pipe 10c, or flow into from the second connecting pipe 10c, pass through the valve port 113a, and then flow out from the first connecting pipe 10b.

[0043] The electronic expansion valve comprises a nut assembly 12 fixedly connected with the valve seat 11. Specifically, the upper end of the valve seat 11 is provided with an opening, and the nut assembly 12 can be loaded into the valve seat 11 from top to bottom. The nut assembly 12 comprises a nut 121 and a connecting piece 122 fixedly connected with the nut 121. As a specific embodiment, the connecting piece 122 can be formed by stamping a metal plate, and the nut 121 is formed by injection molding with the connecting piece 122 as an insert using a non-metallic material such as engineering plastic. The nut 121 is press-fitted into the valve seat 11, and the connecting piece 122 is fixedly connected with the valve seat 11 by welding. The material of the nut can be PPS modified resin, PEEK modified resin, or PTFE modified resin, etc.

[0044] The nut 121 has a through hole along its axial direction, and an inner thread part 12b is arranged on the inner side wall of the through hole, which is used to form a screw feeding mechanism with an outer thread part 22c arranged on the outer edge part of the valve shaft part 22 described below. The inner side wall of the nut is further provided with a first guide part 12a, which is arranged below the inner thread part 12b and can provide a circumferential direction guiding and centering effect for the valve needle 21. Here, below refers to the fact that the first guide part 12a is closer to the valve port part 113 than the inner thread part 12b. The valve needle 21 includes a valve needle guide part 21b, i.e., the first guide part 12a and the valve needle guide part 21b are in a small gap fit, and the valve needle 21 can rotate or move up and down along the first guide part 12a of the nut under the driving of the valve shaft part 22. It should be noted that the first guide part 12 here refers to a part arranged on the inner side wall of the nut, and the valve needle guide part 21b refers to a part arranged on the outer edge part of the valve needle. The opposite upper part of the inner side wall of the nut is provided with a second guide part 12c, which can provide a circumferential direction guiding and centering effect for the valve shaft part 22. The outer edge part of the valve shaft part 22 is provided with a valve shaft guide part 22b, which is in a small gap fit with the second guide part 12c, and the valve shaft part 22 can rotate or move up and down along the second guide part 12c under the driving of the magnetic rotor assembly. Among them, the inner diameter of the second guide part 12c is larger than the inner diameter of the first guide part 12a of the nut, so that when the outer thread part 22c of the valve shaft part 22 moves upward and gradually separates from the inner thread part 12b, it will not be interfered by the second guide part 12c. It should be noted that the first guide part 12a and the second guide part 12c described above are both part of the inner wall of the through hole of the nut, and the shape of the outer edge part of the nut and the setting position of the connecting piece 122 on the outer edge part of the nut do not affect the setting of the first guide part 12a and the second guide part 12c.

[0045] The top outer edge of the nut 121 is provided with a fixed stop part 12d, which at least partially protrudes from the upper end surface of the nut 121, or in other words, the fixed stop part 12d at least partially protrudes in the axial direction from the annular base body of the nut, and can protrude in the radial direction from the annular base body or can be arranged not to protrude. The fixed stop part 12d is used to cooperate with the movable stop part 20a arranged on the magnetic rotor assembly to achieve the stop of the magnetic rotor assembly. That is, in the present embodiment, the magnetic rotor part can displace in the axial direction, and the nut assembly 12 is fixedly connected with the valve seat 11, so that when the magnetic rotor assembly moves downward to the lowermost end of the stroke, the movable stop part 20a can abut against the fixed stop part 12d, so that the magnetic rotor assembly cannot continue to rotate, thereby controlling the stroke of the downward movement of the magnetic rotor part.

[0046] The magnetic rotor assembly 27 is capable of sensing the electromagnetic force of the electromagnetic coil and rotating, including a magnetic rotor 271 with magnetic poles in the circumferential direction and a connecting plate 272 fixedly connected or integrally provided with the magnetic rotor 271, the connecting plate 272 is made of metal, such as powder metallurgy material, specifically, the connecting plate 272 can be used as an insert, and the magnetic rotor 271 is injection molded. The connecting plate 272 is fixedly connected with the valve shaft part 22, specifically, the rotor fixing part 22a located at the upper end of the outer edge part of the valve shaft part 22 cooperates with the inner edge part of the connecting plate 272, and can be fixed by welding. The magnetic rotor assembly includes a movable stop part 20a, as a specific embodiment, the movable stop part 20a can be integrally made of the connecting plate 272, that is, the movable stop part 20a can be part of the connecting plate 272.

[0047] The valve shaft part 22 is a generally hollow cylindrical part, including a large diameter part 221 and a small diameter part 222. Among them, a part of the outer edge part of the large diameter part 221 is formed as a rotor fixing part 22a, which is used for fixed connection with the connecting plate 272 of the magnetic rotor assembly 27, and the connection mode can adopt welding fixing or pressure fixing and other fixing modes. Another part of the outer edge part of the large diameter part 221 is formed as a valve shaft guide part 22b, which is used for small gap cooperation with the second guide part 12c of the nut, so as to realize the guide. That is, in the process of rotor rotation, the valve shaft part 22 is provided with circumferential direction guiding and centering action by the second guide part 12c of the nut. As shown in FIG. 1, the rotor fixing part 22a is located opposite the upper valve shaft guide part 22b, and the valve shaft guide part 22b is generally located in the space surrounded by the magnetic rotor 271. The outer edge part of the small diameter part 222 is provided with an external thread part 22c, which is used for forming a screw feed mechanism with the internal thread part 12b provided on the nut. The valve shaft part 22 includes a first through hole part 22e and a second through hole part 22d, wherein the first through hole part 22e generally corresponds to the inner hole part of the large diameter part 221, and the second through hole part 22d generally corresponds to the inner hole part of the small diameter part 222, so that the inner diameter of the first through hole part 22e is larger than the inner diameter of the second through hole part 22d, and a valve shaft step part 22f is formed between the first through hole part 22e and the second through hole part 22d. And the nominal diameter of the screw feed mechanism is smaller than the inner diameter of the first through hole part 22e, and the nominal diameter of the screw feed mechanism is slightly larger than the outer diameter of the valve needle guide part 21c. Here, "slightly larger" means that the valve needle can move upward without being hindered or interfered by the internal thread part 12b.

[0048] The bushing 25 is fixedly connected to the valve shaft portion 22, and the bushing 25 is substantially hollow cylindrical. At least a portion of the outer edge of the bushing 25 cooperates with at least a portion of the inner edge of the first through-hole portion 22e. In this way, the large-diameter portion 221 of the valve shaft portion 22 and the bushing 25 form a space in which the compression spring 24 is located, and the outer diameter of the compression spring 24 is greater than the inner diameter of the small-diameter portion 222. The upper end of the compression spring 24 abuts the bottom end of the bushing 25. The abutment described here can be direct abutment or indirect abutment, such as indirect abutment achieved by providing a gasket between the compression spring 24 and the bushing 25. The other end of the compression spring 24 abuts the gasket portion 23. For the gasket portion 23, one end abuts the compression spring 24, and the other end abuts the valve needle 21 described below. The maximum outer diameter of the compression spring 24 is greater than the inner diameter of the second through-hole portion 22d. In this way, for electronic expansion valves of the same specification, such as electronic expansion valves having the same rotor diameter, shell diameter, stator coil diameter, and volume, the diameter of the compression spring can be relatively large, thereby increasing the spring force and improving the ability of the electronic expansion valve to resist reverse pressure when in the fully closed state.

[0049] The valve needle 21 is arranged in a central passage defined by the bushing 25, the valve shaft portion 22, and the nut 12, and the compression spring 24 is arranged around a portion of the outer periphery of the valve needle 21. The valve needle 21 is in the form of a rod as a whole, and has a plurality of different outer diameters. In the view shown in FIGS. 1-5, the lowermost end of the valve needle 21 is a needle tip adjusting portion 21a. The shape of the needle tip adjusting portion 21a is related to the shape of the valve port portion and the flow rate adjustment curve required by the electronic expansion valve, and can be set differently according to different requirements. The specific shape of the needle tip adjusting portion 21a is not limited in the present application. The valve needle 21 includes a valve needle guide portion 21b for small gap cooperation with the first guide portion 12a of the nut. During rotation of the magnetic rotor, the first guide portion 12a of the nut provides a circumferential direction guiding and centering function for the valve needle 21. The valve needle 21 includes a gasket abutting portion 21e for abutting against the gasket 23, so that the gasket 23 does not displace downward along the central axis of the valve needle after abutting against the valve needle. As a specific embodiment, as shown in FIG. 4, the valve needle guide portion of the valve needle 21 is provided with a first shaft portion 21c and a second shaft portion 21d above the valve needle guide portion, respectively. The outer diameter of the first shaft portion 21c is greater than the outer diameter of the second shaft portion 21d, and the outer diameter of the first shaft portion 21c is less than the outer diameter of the valve needle at the valve needle guide portion. In this way, a step is formed between the first shaft portion 21c and the second shaft portion 21d, which can be a specific embodiment of the gasket abutting portion 21e, i.e., the gasket abutting portion 21e is formed at the top of the first shaft portion 21c. The lower end surface of the gasket 23 abuts against the gasket abutting portion 21e. In the present embodiment, the number of gaskets 23 is two, and the lower gasket 23 abuts against the gasket abutting portion 21e. The upper gasket 23 has the compression spring 24 installed on the upper portion thereof, i.e., the lower end of the compression spring 24 abuts against the gasket 23, and the upper end of the compression spring 24 abuts against the bottom end of the bushing 25. The gasket 23 and the compression spring 24 are accommodated in a space defined by the large diameter portion of the valve shaft portion 22 and the bushing 25.

[0050] Specifically, during assembly, the valve needle 21 is inserted into the central through hole of the valve shaft portion 22 from the lower direction as shown in FIG. 4, so that the first shaft portion is arranged in the through hole of the small diameter portion 222 of the valve shaft portion and can move relative to each other; the second shaft portion 21d is arranged in the central through hole of the bushing 25 and extends out of the upper end surface of the bushing 25. The upper end portion of the second shaft portion 21d is sleeved and fixed with the valve needle sleeve 26, and the outer diameter of the valve needle sleeve 26 is larger than the inner diameter of the bushing 25. Therefore, the valve needle 21 is limited by the valve needle sleeve 26, and after the valve needle 21 is fixedly connected with the valve needle sleeve 26, the valve needle 21 will not be pulled out of the central through hole of the bushing 25 and the valve shaft portion 22 downward. In addition, the valve needle 21 and the magnetic rotor assembly 27 are connected in a floating manner, and when the valve needle 21 moves upward relative to the valve shaft portion 22, the compression spring 24 can be further compressed in the axial direction, and the valve needle 21 and the valve shaft portion 22 can move relative to each other within a limited range. The first shaft portion 21c of the valve needle and the second through hole portion 22d of the valve shaft portion 22 are clearance fit, and the second shaft portion 21d and the central through hole of the bushing 25 are also clearance fit. Therefore, the valve needle 21 can also rotate relative to the valve shaft portion 22 in the circumferential direction.

[0051] It should be noted that in the present embodiment, from the outside, the valve needle 21 can be roughly divided into three stepped shaft structures except for the needle tip adjusting portion 21a, wherein the outer diameter of the valve needle segment where the valve needle guide portion 21b is located is the largest, the outer diameter of the valve needle segment where the first shaft portion 21c is located is slightly smaller, and the outer diameter of the valve needle segment where the second shaft portion 21d is located is the smallest. However, this is only a specific embodiment for easy processing, and various equivalent structural modifications or alternatives can also be made on this basis. For example, for the valve needle guide portion 21b, since the nut is fixed relative to the valve seat, the valve needle can be displaced upward and downward in the axial direction, that is, the valve needle can move upward and downward relative to the nut and has a certain stroke. It is only necessary to ensure that within the stroke, the valve needle is provided with a relatively smooth valve needle guide portion 21b at the outer edge for guiding the first guide portion 12a of the nut, and it is not required that the entire section of the outer edge with the largest outer diameter of the valve needle is the valve needle guide portion as shown in the present embodiment. In other words, a recess or other uneven structure can be provided on the outer edge of the relatively upper or relatively lower portion of the valve needle segment corresponding to the valve needle guide portion 21b. It is only necessary to ensure that within the stroke of the valve needle, a section of the valve needle guide portion 21b is always matched with the first guide portion 12a of the nut to achieve the guiding effect. In addition, the first shaft portion 21c and the second shaft portion 21d are not limited to the cylindrical shaft structure with equal diameters, and for example, an additional shaft step can be provided on the first shaft portion 21c or the second shaft portion 21d. These equivalent technical feature transformations are obviously within the protection scope of the present application.

[0052] In addition, the valve needle guide, the first shaft-like portion, and the second shaft-like portion are named according to the functions thereof in the technical solution, and the valve needle cannot be mechanically understood or limited to be composed of the three shaft-like portions shown in FIG. 4. Alternatively, the valve needle 21 can be manufactured in a segmented assembly form, such as a threaded connection or welding between adjacent two segments. In fact, as described above, the structure shown is only an embodiment for facilitating processing.

[0053] The valve needle structure provided by the embodiment has the following advantages: the outer diameters of the second shaft-like portion, the first shaft-like portion, and the valve needle guide are sequentially increased, the valve needle is relatively easy to manufacture, the coaxiality is relatively good, the second shaft-like portion can form a space for accommodating the compression spring together with the valve shaft portion and the bushing, the outer diameter of the compression spring is no longer restricted by the size of the outer diameter of the valve needle guide, and in the case of the same specification of the electronic expansion valve, such as the same rotor diameter, the same housing diameter, the same stator coil diameter, and the same volume, the valve port diameter can be directly increased to obtain an electronic expansion valve with larger port flow regulation.

[0054] The valve needle sleeve 26 is sleeved with a return spring 28, and the lower end of the return spring 28 abuts against the upper end surface of the bushing 25 or the valve shaft portion 22. The specific abutting position can be determined according to the relative position relationship between the bushing 25 and the valve shaft portion 22 and the diameter of the return spring 28. As shown in FIG. 4, the top end of the bushing 25 and the valve shaft portion 22 can be arranged to be flush or substantially flush, and in this case, the return spring 28 can be arranged to abut against the valve shaft portion 22, or abut against the bushing 25, or abut against both the valve shaft portion 22 and the bushing 25. The height of the return spring 28 is greater than the distance between the valve needle sleeve 26 and the housing 30, so that the return spring 28 will not fall off from the outer periphery of the valve needle sleeve 26.

[0055] The coil 40 of the electronic expansion valve receives a driving pulse signal to generate a periodically changing magnetic field, and the magnetic rotor 27 is excited to rotate. Since the valve shaft portion 22 is fixedly connected to the connecting plate 272, the valve shaft portion 22 rotates synchronously with the magnetic rotor 27. The magnetic rotor 27 is moved axially through the screw feed mechanism between the valve shaft portion and the nut, so that the valve needle 21 is moved axially, and the needle tip adjusting portion 21a of the valve needle 21 approaches or moves away from the valve port 113a, thereby realizing the linear opening and closing regulation function of the electronic expansion valve. When the needle tip adjusting portion 21a moves downward to abut against the valve port portion 113, i.e., the needle tip adjusting portion 21a is at the lowermost end of its stroke, the electronic expansion valve is in a fully closed state, as shown in Fig. 1. When the needle tip adjusting portion 21a is away from the valve port portion 113, the electronic expansion valve is in an open state. Fig. 2 shows a cross-sectional view of the electronic expansion valve at about 80% opening. When the magnetic rotor assembly 27 continues to rotate upward from the state shown in Fig. 2 toward the opening direction, the external threaded portion 22c of the valve shaft portion is disengaged from the internal threaded portion 12b of the nut 12, and the upper end of the return spring 28 abuts against the top wall of the housing 30, so that the return spring 28 is compressed. Since the screw feed mechanism between the valve shaft portion 22 and the nut 12 is disengaged at this time, the magnetic rotor assembly 27 cannot continue to move upward. When the valve closing action is required, the magnetic rotor assembly 27 is rotated while being subjected to the downward spring force of the return spring 28, so that the external threaded portion 22c of the valve shaft portion 22 is re-engaged with the internal threaded portion 12b of the nut 12, thereby ensuring the re-formation of the screw feed mechanism.

[0056] The electronic expansion valve provided by the present embodiment has the valve shaft portion including a first through hole portion and a second through hole portion, and the outer diameter of the valve needle guide portion 21b is greater than the outer diameter of the first shaft portion 21c, and the first shaft portion 21c is in clearance fit with the second through hole portion 22d. Therefore, the outer diameter of the valve needle guide portion 21b is also greater than the inner diameter of the second through hole portion 22c, which corresponds to the inner diameter of the screw feed mechanism. Thus, since the outer diameter of the valve needle guide portion 21b is greater than the inner diameter of the second through hole portion 22d of the valve shaft portion 22, the nominal diameter of the screw feed mechanism only needs to be slightly greater than the outer diameter of the valve needle guide portion 21b in the case of the same specifications of the electronic expansion valve, such as the same rotor diameter, housing diameter, stator coil diameter and volume, i.e., the nominal diameter of the screw feed mechanism can be relatively small, which is beneficial to reducing the frictional resistance from the screw feed mechanism.

[0057] Second Embodiment

[0058] The second embodiment of the present application will be described below with reference to Figs. 5-9.

[0059] For the convenience of description, the same reference numerals are used for the components having substantially the same structure and function as those in the first embodiment, and only a brief description is given, and those skilled in the art can refer to the relevant description in the first embodiment for understanding. The second embodiment focuses on the differences from the first embodiment and will be described in detail.

[0060] Please refer to FIG. 5-9, wherein FIG. 5 is a cross-sectional view of the electronic expansion valve in the second embodiment in the closed state, FIG. 6 is a cross-sectional view of the electronic expansion valve in the second embodiment in the open state, FIG. 7 is a structural view of the nut assembly in the second embodiment, FIG. 8 is a partial cross-sectional view of the rotor assembly and the valve needle in the second embodiment, and FIG. 9 is a top view of the nut assembly in the second embodiment.

[0061] The electronic expansion valve comprises a valve body component and a coil component 40, wherein the valve body component comprises a valve seat 11, a connecting piece 50, and a housing 30. The structure and cooperation of the valve seat 11, the connecting piece 50, and the housing 30 can refer to the description of the first embodiment.

[0062] The electronic expansion valve comprises a nut assembly 120 fixedly connected with the valve seat 11. Specifically, the nut assembly 120 comprises a nut 1201 and a connecting plate 1202, and the nut 1201 is fixedly connected with the connecting plate 1202. The nut 1201 has a through hole along the axial direction thereof, and an internal thread portion 120b is arranged on the inner side wall of the through hole, which is used to form a screw feeding mechanism with an external thread portion 22c arranged on the outer edge of the valve shaft portion 22. The valve shaft portion 22 is fixedly connected with the magnetic rotor assembly 27, so that the valve shaft portion 22 can rotate synchronously with the rotation of the magnetic rotor. The magnetic rotor assembly 27 can rotate by the electromagnetic force of the electromagnetic coil, and comprises a magnetic rotor 271 with magnetic poles in the circumferential direction and a connecting plate 272 fixedly connected with or integrally arranged with the magnetic rotor 271, and the connecting plate 272 is fixedly connected with the valve shaft portion 22. Generally, interference press fitting connection or rivet press connection can be used, or the connecting plate 272 and the valve shaft portion 22 can be welded. The magnetic rotor assembly comprises a movable stop portion 20a, which can be part of the connecting plate 272 in the second embodiment, and protrudes in the axial direction towards the valve seat 11, which is used to cooperate with a fixed stop portion arranged on the nut 1201 to realize the stop function, and the fixed stop portion is specifically a stop protrusion 1201c described below.

[0063] As shown in FIG. 8, the magnetic rotor assembly 27 is fixedly connected with the valve shaft portion 22 through the connecting plate 272, the magnetic rotor assembly drives the valve shaft portion 22 to rotate, and the valve shaft portion 22 drives the valve needle 21 to rotate. The valve needle 21 can relatively move in the axial direction within a limited elastic displacement range relative to the valve shaft portion 22, or can relatively rotate. The cooperation of the valve shaft portion 22 and the valve needle 21 can refer to the relevant description of the first embodiment, which will not be repeated here.

[0064] The basic principle of the electronic expansion valve is that the coil 40 receives a driving pulse signal to generate a periodically changing magnetic field, the magnetic rotor 27 is excited to rotate, and since the valve shaft portion 22 is fixedly connected to the connecting plate 272, the valve shaft portion 22 rotates synchronously with the magnetic rotor 27, and through the screw feed mechanism between the valve shaft portion and the nut, the magnetic rotor 27 can move axially while rotating, thereby driving the valve needle 21 to move axially, so that the needle tip adjusting portion 21a of the valve needle 21 approaches or moves away from the valve port 113a, thereby realizing the linear on-off adjustment function of the electronic expansion valve. The electronic expansion valve shown in FIG. 5 is in a full-off state stop position, that is, the needle tip adjusting portion 21a of the valve needle 21 is at the lowermost end of its stroke, and the valve port 113a is in a full-off state or in a set minimum opening state. The coil 40 drives the magnetic rotor to move downward, and when the needle tip adjusting portion 21a is in a full-off state or at the lowermost end of its stroke, a stop mechanism needs to be provided to limit the downward movement of the magnetic rotor assembly. Therefore, in this embodiment, a fixed stop portion is provided at the upper end of the nut 1201, and a corresponding movable stop portion 20a is provided on the magnetic rotor assembly 27. When the electronic expansion valve is in a full-off state, the movable stop portion 20a will abut against the corresponding abutting surface of the fixed stop portion, thereby limiting the movement of the magnetic rotor assembly, the valve shaft portion, and the valve needle.

[0065] FIG. 6 is a cross-sectional view of the electronic expansion valve in an open state according to the embodiment, and the opening degree position shown in the figure is about 80% of the opening degree. At this time, the needle tip adjusting portion 21a of the valve needle 21 is away from the valve port 113a, and the movable stop portion 20a is also in a position state away from the fixed stop portion.

[0066] FIG. 7 is a structural schematic view of the nut assembly according to the embodiment. The nut assembly 120 includes a connecting sheet 1202 and a nut 1201. As a specific embodiment, the nut 1201 can be injection molded by using a non-metallic material such as a resin material. Specifically, the connecting sheet 1202 can be placed as an insert in a mold cavity, and a resin nut 1201 can be formed by using a resin injection molding machine, and a part of the connecting sheet 1202 is not covered by the nut. The material of the nut can be PPS modified resin, or PEEK modified resin, or PTFE modified resin, etc. The nut assembly 120 is fixedly connected to the valve seat 11. Specifically, the part of the connecting sheet 1202 not covered by the nut is fixed to the valve seat 11 by welding or riveting, and the nut 1201 can be inserted into the upper end opening of the valve seat 11 by press fitting.

[0067] The outer circumference of the nut 1201 is provided with at least one rib 1201a, and the at least one rib 1201a extends to the end face of the nut and protrudes from the upper end face 1201d of the nut, defining the stop protruding portion 1201c of the nut 1201 protruding from the upper end face thereof, which constitutes the fixed stop portion of the electronic expansion valve. As shown in FIG. 9, in the present embodiment, the outer edge portion of the nut 1201 is provided with two ribs, one of which, the rib 1201a, protrudes from the upper end face of the nut, and the rib 1201a protruding from the upper end face of the nut forms at least part of the stop protruding portion 1201c, and the other rib 1201b has an upper end portion flush with the upper end face 1201d. The stop protruding portion 1201c constitutes the fixed stop portion of the electronic expansion valve, and the width of the force receiving surface of the stop protruding portion 1201c that can receive the impact of the movable stop portion 20a is defined as K, and the thickness of the nut relative to the upper end is defined as t, and K > t is satisfied.

[0068] The nut 1201 is provided with at least one rib 1201a at the outer edge portion thereof, and one of the ribs 1201a extends and protrudes from the end face of the nut to form part of the stop protruding portion 1201c. The stop protruding portion 1201c is provided at the end portion of the rib 1201a close to the resin nut, and the protrusion amount (K-t) of the stop protruding portion 1201c relative to the nut body in the radial direction is set to be the same as the protrusion amount (K-t) of the rib relative to the nut body in the radial direction, so that the structure of the mold pressing mold can be simplified, and the mold can be easily demolded. As shown in FIG. 7, the stop protruding portion 1201c includes a portion protruding upward along the end face of the nut and a portion of the rib 1201a protruding from the end face of the nut, the former has a length along the circumference greater than the length along the circumference of the latter, and the length along the circumference of the latter is the width of the rib 1201a. At the same time, the rib is integrally injection molded with the stop protruding portion, which also enhances the strength of the stop protruding portion and improves the service life of the stop mechanism of the electronic expansion valve. In particular, due to the provision of the rib, the correlation between the strength of the stop protruding portion and the thickness of the material of the nut body (close to the upper end portion) is greatly reduced, that is, even if a thinner thickness of the nut body is used, it will not have a great impact on the strength of the stop mechanism, so that the cost of the amount of resin material can be further reduced. Furthermore, generally speaking, the more the amount of resin nut base material and the greater the thickness, the greater the probability of internal pores caused by injection molding, and the nut structure provided in the present embodiment can use less resin amount on the premise of ensuring the strength of the stop protruding portion, reducing the possibility of generating pores and improving the dimensional accuracy and dimensional consistency of the resin nut.

[0069] It should be noted that in the present embodiment, the structure of the nut is mainly described in detail, and the structure of the matching magnetic rotor assembly only needs to meet the condition that the magnetic rotor assembly is provided with a protruding portion on the side facing the nut as a movable stop portion which can abut against the fixed stop portion provided on the nut to achieve stop. As for the specific structure of the movable stop portion, it will not affect the implementation of the present embodiment, and those skilled in the art should understand that all magnetic rotor assemblies meeting the structure can be applied to the present embodiment. As for components such as valve seat, valve needle, valve shaft portion, etc., any possible structure can also be adopted to generate more electronic expansion valve embodiments.

[0070] Third Embodiment

[0071] The third embodiment of the present application will be described below in combination with FIGS. 10-14.

[0072] For the convenience of description, the same reference numerals are used for the components having the same structure and function as those in the first embodiment, and only brief description is made, and those skilled in the art can refer to the related description in the first embodiment for understanding. The present embodiment mainly describes the differences from the first embodiment in detail.

[0073] Please refer to FIGS. 10-14, wherein FIG. 10 is a cross-sectional view of the electronic expansion valve in the third embodiment in the valve closing state, FIG. 11 is a cross-sectional view of the electronic expansion valve in the third embodiment in the valve opening state, FIG. 12 is a structure diagram of the nut assembly in the third embodiment, FIG. 13 is a structure diagram of the cooperation between the valve shaft portion and the stop member in the third embodiment, and FIG. 14 is a structure diagram of the cooperation between the magnetic rotor assembly and the valve shaft portion, valve needle and stop member in the third embodiment.

[0074] The electronic expansion valve comprises a valve body component and a coil component 40, wherein the valve body component comprises a valve seat 11, a connecting member 50 and a housing 30. The structure and cooperation mode of the valve seat 11, the connecting member 50 and the housing 30 can refer to the description in the first embodiment.

[0075] The electronic expansion valve includes a nut assembly 12 fixedly connected with the valve seat 11. Specifically, the nut assembly 12 includes a nut 121 and a connecting plate 122 fixedly connected with the nut 121. As a specific embodiment, the nut 121 can be injection molded with a non-metallic material such as a resin material. Specifically, the connecting plate 122 can be placed as an insert in a mold cavity, and the resin nut 121 is formed by injection molding with resin, and a part of the connecting plate 122 is not covered by the nut. The material of the nut can be PPS modified resin, or PEEK modified resin, or PTFE modified resin, etc. The nut assembly 12 is fixedly connected with the valve seat 11. Specifically, the part of the connecting plate 122 not covered by the nut is fixedly connected with the valve seat 11 by welding or riveting, and the nut 121 can be inserted into the upper end opening of the valve seat 11 by press fitting. The nut 121 has a through hole penetrating in the axial direction thereof, and an internal thread portion 12b is arranged on the inner side wall of the through hole, for forming a screw feeding mechanism with an external thread portion 22c arranged on the outer edge portion of the valve shaft portion 22. The valve shaft portion 22 is fixedly connected with the magnetic rotor assembly 27, so that the valve shaft portion 22 can rotate synchronously with the rotation of the magnetic rotor. The magnetic rotor assembly 27 can rotate by inducting the electromagnetic force of the electromagnetic coil, and includes a magnetic rotor 271 with magnetic poles in the circumferential direction, and a connecting plate 272 fixedly connected with or integrally arranged with the magnetic rotor 271, and the connecting plate 272 is fixedly connected with the valve shaft portion 22. Generally, interference press fitting connection or riveting connection can be adopted, or the connecting plate 272 and the valve shaft portion 22 can be welded. The top outer edge of the nut 121 is provided with a fixed stop portion 12d, which at least partially protrudes from the upper end surface of the nut 121, or in other words, the fixed stop portion 12d at least partially protrudes in the axial direction from the annular base body of the nut. The fixed stop portion 12d shown in the drawings of the present embodiment also protrudes in the radial direction from the annular base body, and of course can also be arranged not to protrude.

[0076] As shown in FIG. 14, the magnetic rotor assembly 27 is fixedly connected with the valve shaft portion 22 through the connecting plate 272, and drives the valve shaft portion 22 to rotate, and the valve shaft portion 22 drives the valve needle 21 to rotate. The valve needle 21 can relatively move in the axial direction within a limited elastic displacement range relative to the valve shaft portion 22, or can relatively rotate. The cooperation mode of the valve shaft portion 22 and the valve needle 21 can refer to the related description of the first embodiment, which will not be described here.

[0077] The valve shaft portion 22 is a generally hollow cylindrical component, including a large diameter portion 221 and a small diameter portion 222. The assembly relationship of the valve shaft portion 22 with the bushing 25, the nut 12, and the valve needle 21 can refer to the description of the first embodiment.

[0078] The basic principle of the electronic expansion valve is that the coil 40 receives a driving pulse signal to generate a periodically changing magnetic field, the magnetic rotor 27 is excited to rotate, and since the valve shaft portion 22 is fixedly connected to the connecting plate 272, the valve shaft portion 22 rotates synchronously with the magnetic rotor 27, and through the screw feed mechanism between the valve shaft portion and the nut, the magnetic rotor 27 can move axially while rotating, thereby driving the valve needle 21 to move axially, so that the needle tip adjusting portion 21a of the valve needle 21 approaches or moves away from the valve port 113a, thereby realizing the linear on-off adjustment function of the electronic expansion valve. The electronic expansion valve shown in FIG. 10 is in the stop position of the full-off state, that is, the needle tip adjusting portion 21a of the valve needle 21 is at the lowermost end of its stroke, and the valve port 113a is in the full-off state or in the set minimum opening state. The coil 40 drives the magnetic rotor to move downward, and when the needle tip adjusting portion 21a is in the full-off state or at the lowermost end of its stroke, a stop mechanism is needed to limit and stop the downward movement of the magnetic rotor assembly.

[0079] In the present embodiment, a stopper 33 is also included, which is directly or indirectly fixedly connected to the valve shaft portion 22. The indirect connection here refers to that the stopper 33 is fixedly connected to the valve shaft portion 22 through other parts. The stopper 33 is made of a metal plate material punched and bent, and its main body is annular, and at least part of the material is bent in the axial direction to form a movable stop portion 33a. Specifically, a complete annular metal plate material can be cut at any position, and then one end portion is bent towards the axial direction to form the movable stop portion 33a. Of course, as an alternative, the movable stop portion can also be fixed to the stopper by welding or other means after the annular stopper is formed without bending, so that the movable stop portion protrudes along the axial direction of the stopper, which also achieves the same effect.

[0080] In order to facilitate positioning, in this embodiment, the valve shaft portion 22 is provided with an annular convex ring portion 223 on the outer edge of the large diameter portion 221, so that the connecting plate 272 can be positioned by the upper surface of the convex ring portion 223, and at least part of the stopper 33 can be positioned by the lower surface of the annular convex ring portion 223, so that the installation position of the stopper 33 on the valve shaft portion 22 can be accurately positioned. Of course, the convex ring portion 223 is not necessarily provided, and in fact, the relative position of the stopper 33 and the valve shaft portion 22 can be accurately positioned by positioning with a tool. The valve shaft portion 22 and the stopper 33 can be fixedly connected by welding or other methods such as riveting. The stopper 33 is fixedly connected to the valve shaft portion 22, and the valve shaft portion 22 is fixedly connected to the magnetic rotor assembly 27, so the stopper 33 rotates synchronously with the magnetic rotor assembly 27. When the electronic expansion valve is in a fully closed state, or when the needle tip adjusting portion 21a of the valve needle 21 is in the smallest opening degree set by the electronic expansion valve, the movable stop portion 33a of the stopper 33 bends downward and collides with the fixed stop portion 12d provided on the upper end of the nut assembly 12, thereby achieving stop positioning of the magnetic rotor assembly, as shown in FIG. 10. When the magnetic rotor assembly rotates in the opposite direction, the stopper 33 also moves upward, at which time the movable stop portion 33a moves upward and is separated from the fixed stop portion 12d, as shown in FIG. 11. FIG. 11 is a cross-sectional view of the electronic expansion valve in an open state according to this embodiment, and the opening degree position shown in the figure is about 80% of the opening degree. At this time, the needle tip adjusting portion 21a of the valve needle 21 is away from the valve port 113a, and the movable stop portion 33a is also in a position state separated from the fixed stop portion 12d.

[0081] As shown in FIG. 14, the magnetic rotor assembly 27 is fixedly connected to the valve shaft portion 22 through the connecting plate 272, the magnetic rotor assembly drives the valve shaft portion 22 to rotate, the valve shaft portion 22 drives the valve needle 21 to rotate, and the valve needle 21 can relatively move in the axial direction within a limited elastic displacement range relative to the valve shaft portion 22, or can relatively rotate. The cooperation mode of the valve shaft portion 22 and the valve needle 21 can refer to the related description of the first embodiment, which will not be described here.

[0082] The electronic expansion valve provided by this embodiment is made of PPS resin, PEEK resin or PTFE resin by injection molding, the upper end of the resin nut is integrally injection molded with a fixed stop portion, the stopper can be punched from a metal plate, the processing technology of the part is relatively good, the metal stopper has better wear resistance, can improve the service life of the stop mechanism, and the production cost is relatively low.

[0083] Fourth embodiment

[0084] The fourth embodiment of the present application will be described below with reference to FIGS. 15-16.

[0085] It should be noted that the difference between the present embodiment and the third embodiment is the difference in the movable stop portion, and therefore the present embodiment mainly describes the structure of the movable stop portion. For the remaining components, reference can be made to the first embodiment and the third embodiment for understanding.

[0086] Please refer to FIG. 15 and FIG. 16, wherein FIG. 15 is a schematic diagram of the connecting plate structure provided by the fourth embodiment of the present application, and FIG. 16 is a partial sectional view of the cooperation structure of the magnetic rotor assembly and the valve shaft portion, the valve needle and other components. With the orientation shown in FIG. 16 as the reference, the connecting plate shown in FIG. 15 is a schematic diagram of the connecting plate from the bottom view. In the present embodiment, the connecting plate 272 can be formed by metal powder die sintering, and generally has a plate structure with a central through hole. The inner wall portion 2721 of the central through hole is used for fixed connection with the valve shaft portion 22, and generally can adopt interference press-fit connection, or rivet connection, or welding connection between the connecting plate 272 and the valve shaft portion 22. In order to increase the contact area of the connecting plate 272 and the valve shaft portion 22, the height of the inner wall portion 2721 can be appropriately increased, so that the longitudinal section of the connecting plate 272 is generally L-shaped. As described in the first embodiment, the connecting plate 272 and the magnetic rotor 271 can be fixedly connected by injection molding, that is, the connecting plate 272 is placed in the cavity of the mold as an insert, and then the magnetic material is injected to form the magnetic rotor 271. In this way, the plate-shaped outer edge portion 2723 of the connecting plate 272 is covered by the magnetic material. The side of the connecting plate 272 facing the valve port direction is provided with a movable stop portion 2722, that is, the movable stop portion 2722 protrudes from the surface of the side of the connecting plate. Specifically, the movable stop portion 2722 can be integrally formed with the base body of the connecting plate by metal powder die sintering. This processing method can effectively improve the strength of the movable stop portion 2722, and is simple to process and can be integrally manufactured with the connecting plate without the need for additional movable stop portion parts for cooperation with the fixed stop portion of the nut. Of course, as an alternative manufacturing method, the metal powder can also be formed into a blank by mold injection and then wound into a sintered material.

[0087] When the magnetic rotor 271 is excited to rotate, the connecting plate 272 and the valve shaft portion 22 will rotate synchronously, and the valve shaft portion 22 will drive the valve needle 21 and other components arranged inside the valve shaft portion to rotate. The valve needle 21 is sleeved in the inner hole of the valve shaft portion 22, and the valve needle 21 and the valve shaft portion 22 are elastically connected. The valve needle 21 can move axially relative to the valve shaft portion 22 within a limited elastic displacement range, and can also rotate relative to the valve shaft portion 22.

[0088] When the electronic expansion valve is in the full-closed state, or the needle tip adjusting portion of the valve needle of the electronic expansion valve is in the minimum opening degree set by the electronic expansion valve, the downward rotation stroke of the magnetic rotor assembly needs to be limited, at this time, the movable stop portion 2722 protruding downward of the connecting plate 272 abuts against the fixed stop portion 12d provided at the upper end of the nut, thereby achieving the effect of limiting stop. When the magnetic rotor assembly rotates in the opening valve direction, the movable stop portion 2722 rotates together with the rotor component and is displaced upward, and is separated from the fixed stop portion 12d.

[0089] Fifth embodiment

[0090] The fifth embodiment of the present application will be described below with reference to Figs. 17-26.

[0091] The present embodiment is a further improvement based on the first embodiment. The same reference numerals are used for the components having the same structure and function as those in the first embodiment, and only a brief description will be given, and the skilled person can refer to the relevant description in the first embodiment for understanding.

[0092] Fig. 17 is a schematic view of the electronic expansion valve in the full-closed state of the fifth embodiment in the stop position, Fig. 18 is an enlarged view of part I in Fig. 17, Fig. 19 is an enlarged view of part II in Fig. 17, Fig. 20 is a sectional view of the electronic expansion valve of the fifth embodiment at the spring force unloading point, Fig. 21 is an enlarged view of part III in Fig. 20, Fig. 22 is an enlarged view of part IV in Fig. 20, Fig. 23 is a sectional view of the electronic expansion valve of the fifth embodiment at the opening threshold point, Fig. 24 is an enlarged view of part V in Fig. 23, Fig. 25 is an enlarged view of part VI in Fig. 23, and Fig. 26 is a sectional view of the electronic expansion valve of the fifth embodiment in the full-open state.

[0093] The electronic expansion valve comprises a valve body component and a coil component 40, wherein the valve body component comprises a valve seat 11, a connecting piece 50, and a housing 30. The structure and cooperation mode of the valve seat 11, the connecting piece 50, the housing 30, and the nut 12 can refer to the description of the first embodiment. The valve seat 11 comprises a valve port portion 113, a first interface portion 111, and a second interface portion 112. The direction in which the refrigerant flows from the first interface portion 111 into the electronic expansion valve, passes through the valve port, and flows out of the second interface portion 112 is defined as the first flow direction, and the direction in which the refrigerant flows from the second interface portion 112 into the electronic expansion valve, passes through the valve port, and flows out of the first interface portion 111 is defined as the second flow direction. The present embodiment is described by taking the first flow direction as an example.

[0094] The electronic expansion valve comprises a nut assembly 12 fixedly connected with the valve seat 11. The nut assembly 12 comprises a nut 121 and a connecting plate 122 fixedly connected with the nut 121. The nut 121 has a through hole along the axial direction thereof, and an inner thread portion 12b is arranged on the inner side wall of the through hole, and the outer thread portion 22c arranged on the outer edge portion of the valve shaft portion 22 forms a screw feeding mechanism. A first guide portion 12a is further arranged on the inner side wall of the nut, and the first guide portion 12a is arranged below the inner thread portion 12b and can provide a circumferential direction guiding and centering effect for the valve needle 21. The valve needle 21 comprises a valve needle guide portion 21b, that is, the first guide portion 12a and the valve needle guide portion 21b are in a small gap fit, and the valve needle 21 can rotate along the first guide portion 12a of the nut or move up and down under the driving of the valve shaft portion 22. The first guide portion 12a herein refers to a portion arranged on the inner side wall of the nut, and the valve needle guide portion 21b refers to a portion arranged on the outer edge portion of the valve needle. A second guide portion 12c is arranged on the opposite upper portion of the inner side wall of the nut, and can provide a circumferential direction guiding and centering effect for the valve shaft portion 22. The outer edge portion of the valve shaft portion 22 is provided with a valve shaft guide portion 22b, and the valve shaft guide portion 22b is in a small gap fit with the second guide portion 12c, and the valve shaft portion 22 can rotate along the second guide portion 12c or move up and down under the driving of the magnetic rotor assembly. The first guide portion 12a and the second guide portion 12c described above are both part of the inner wall of the through hole of the nut, and the shape of the outer edge portion of the nut and the arrangement position of the connecting plate 122 on the outer edge portion of the nut do not affect the arrangement of the first guide portion and the second guide portion.

[0095] A fixed stop portion 12d is arranged on the top outer edge of the nut 121, and the fixed stop portion 12d at least partially protrudes from the upper end surface of the nut 121 and cooperates with the movable stop portion 20a arranged on the magnetic rotor assembly to achieve the stop of the magnetic rotor assembly. The movable stop portion 20a and the fixed stop portion 12d of the present embodiment are the same as those of the first embodiment, and of course, the movable stop portion can also adopt the structure of the third embodiment or the fourth embodiment, and the fixed stop portion can also adopt the structure of the second embodiment. When the magnetic rotor assembly moves downward to the lowermost end of the stroke, the movable stop portion 20a can abut against the fixed stop portion 12d, so that the magnetic rotor assembly cannot continue to rotate, thereby controlling the stroke of the downward movement of the magnetic rotor assembly.

[0096] The magnetic rotor assembly 27 is capable of rotating in response to the electromagnetic force of the electromagnetic coil, and includes a magnetic rotor 271 having magnetic poles arranged in a circumferential direction, and a connecting plate 272 fixedly connected to or integrally provided with the magnetic rotor 271. The valve shaft portion 22 is a substantially hollow cylindrical member, and includes a large-diameter portion 221 and a small-diameter portion 222. The valve shaft portion 22 is fixedly connected to the connecting plate 272. A part of the outer edge of the large-diameter portion 221 is formed as a rotor fixing portion 22a for fixedly connecting to the connecting plate 272 of the magnetic rotor assembly 27, and another part of the outer edge of the large-diameter portion 221 is formed as a valve shaft guide portion 22b for small-gap fitting with the second guide portion 12c of the nut, thereby achieving guiding. The rotor fixing portion 22a is located above the valve shaft guide portion 22b, and the valve shaft guide portion 22b is substantially located in the space surrounded by the magnetic rotor 271. The outer edge of the small-diameter portion 222 is provided with an external thread portion 22c for forming a screw feeding mechanism with the internal thread portion 12b of the nut. The valve shaft portion 22 includes a first through-hole portion 22e substantially corresponding to the inner hole of the large-diameter portion 221, and a second through-hole portion 22d substantially corresponding to the inner hole of the small-diameter portion 222, so that the inner diameter of the first through-hole portion 22e is larger than that of the second through-hole portion 22d, and a valve shaft step portion 22f is formed between the first through-hole portion 22e and the second through-hole portion 22d.

[0097] The bushing 25 is fixedly connected to the valve shaft portion 22, and is substantially a hollow cylindrical member. At least a part of the outer edge of the bushing 25 is fitted with at least a part of the inner edge of the first through-hole portion 22e. The large-diameter portion 221 of the valve shaft portion 22 and the bushing 25 form a space, and the compression spring 24 is located in the space. The upper end of the compression spring 24 is in abutment with the bottom end of the bushing 25. The abutment can be direct abutment or indirect abutment, for example, a gasket is arranged between the spring and the bushing to achieve indirect abutment. The other end of the compression spring 24 is in abutment with the washer portion 23. The washer portion 23 has one end in abutment with the compression spring 24 and the other end in abutment with the valve needle 21.

[0098] The valve needle 21 is arranged in the central passage defined by the bushing 25, the valve shaft portion 22 and the nut 12, and the compression spring 24 is arranged around the outer periphery of the valve needle 21. The valve needle 21 is in the form of a rod and has different outer diameters in different sections. The bottom end of the valve needle 21 is the needle tip adjusting portion 21a. The valve needle 21 includes the valve needle guide portion 21b which is arranged in small clearance with the first guide portion 12a of the nut 12 and provides the valve needle 21 with the circumferential direction guiding and centering action during the rotation of the magnetic rotor. Similar to the first embodiment, it is only required to ensure that the valve needle has a relatively smooth valve needle guide portion 21b arranged on the outer periphery and used for guiding the first guide portion 12a of the nut 12 within the stroke of the valve needle. The valve needle 21 includes the gasket abutting portion 21e which is arranged in abutment with the gasket 23 and prevents the gasket 23 from moving downward along the central axis of the valve needle after the abutment. The upper portion of the valve needle guide portion of the valve needle 21 is provided with the first shaft portion 21c and the second shaft portion 21d. The outer diameter of the first shaft portion 21c is larger than that of the second shaft portion 21d, and the outer diameter of the first shaft portion 21c is smaller than the outer diameter of the valve needle guide portion. Thus, a step is formed between the first shaft portion 21c and the second shaft portion 21d, which can be used as a specific embodiment of the gasket abutting portion 21e. The lower end surface of the gasket 23 is arranged in abutment with the gasket abutting portion 21e. In this embodiment, the number of the gaskets 23 is two. The lower gasket is arranged in abutment with the gasket abutting portion 21e. The upper portion of the gasket 23 is provided with the compression spring 24. The lower end of the compression spring 24 is arranged in abutment with the gasket 23, and the upper end of the compression spring 24 is arranged in abutment with the bottom end of the bushing 25. The gasket 23 and the compression spring 24 are accommodated in the space defined by the large diameter portion of the valve shaft portion 22 and the bushing 25. During assembly, the valve needle 21 is inserted into the central through hole of the valve shaft portion 22 from the lower direction as shown in FIG. 4, so that the first shaft portion is arranged in the through hole of the small diameter portion 222 of the valve shaft portion and can move relative to each other. The second shaft portion 21d is arranged in the central through hole of the bushing 25 and protrudes from the upper end surface of the bushing 25. The upper end portion of the second shaft portion 21d is provided with the valve needle sleeve 26. The outer diameter of the valve needle sleeve 26 is larger than the inner diameter of the bushing 25. Thus, the valve needle 21 is limited by the valve needle sleeve 26. After the valve needle 21 is fixedly connected with the valve needle sleeve 26, the valve needle 21 cannot be pulled out of the central through hole of the bushing 25 and the valve shaft portion 22. Furthermore, the valve needle 21 is connected with the magnetic rotor assembly 27 in a floating manner. When the valve needle 21 moves upward relative to the valve shaft portion 22, the compression spring 24 can be further compressed in the axial direction. Within the limited range, the valve needle 21 and the valve shaft portion 22 can move relative to each other. The first shaft portion 21c of the valve needle and the second through hole portion 22d of the valve shaft portion 22 are arranged in clearance fit. The second shaft portion 21d and the central through hole of the bushing 25 are also arranged in clearance fit. Thus, the valve needle 21 can also rotate relative to the valve shaft portion 22 in the circumferential direction.

[0099] Need to explain, similar to the first embodiment, the valve needle guide, the first shaft, the second shaft are named in its role in this technical solution, can not be mechanically understood or limited to the valve needle only by the three segment shaft combination shown in Figure 4. Or, the valve needle 21 can be made in the form of segmented assembly, such as using adjacent two segments between the threaded connection or the way of welding. In fact, as described above, the structure shown is only an embodiment for easy processing.

[0100] The outer periphery of the valve needle sleeve 26 is sleeved with a return spring 28, the lower end of the return spring 28 abuts against the upper end surface of the bushing 25 or the valve shaft portion 22, and the specific abutting position can be determined according to the relative position relationship of the bushing 25 and the valve shaft portion 22 and the diameter of the return spring 28. As shown in Figure 4, the top end of the bushing 25 and the valve shaft portion 22 can be arranged to be flush or substantially flush, at this time the return spring can be arranged to abut against the valve shaft portion 22, or abut against the bushing 25, or abut against both the valve shaft portion 22 and the bushing 25. The height of the return spring 28 is greater than the distance between the valve needle sleeve 26 and the shell 30, so that the return spring 28 will not fall off from the outer periphery of the valve needle sleeve 26.

[0101] The coil 40 of the electronic expansion valve receives a driving pulse signal to generate a periodically changing magnetic field, the magnetic rotor 27 is excited to rotate, since the valve shaft portion 22 is fixedly connected with the connecting plate 272, the valve shaft portion 22 rotates synchronously with the magnetic rotor 27, and through the screw feed mechanism between the valve shaft portion and the nut, the magnetic rotor 27 can move axially while rotating, thereby driving the valve needle 21 to move axially, so that the needle tip adjusting portion 21a of the valve needle 21 approaches or moves away from the valve port 113a, thereby realizing the linear on-off adjustment function of the electronic expansion valve flow. The electronic expansion valve shown in Figure 17 is in the full-closed stop position, that is, the needle tip adjusting portion 21a of the valve needle is at the lowermost end of its stroke, and the valve needle abuts against the valve port portion 113, at this time the valve port 113a is in the full-closed state. When the magnetic rotor assembly 27 continues to rotate upward from the state shown in Figure 17 to the opening direction, until the external threaded portion 22c of the valve shaft portion is disengaged from the internal threaded portion 12b of the nut 12, at this time, the upper end of the return spring 28 has abutted against the top wall of the shell 30, and the return spring 28 is in a compressed state. Since at this time, the screw feed mechanism between the valve shaft portion and the nut has been disengaged, the magnetic rotor assembly 27 will not continue to move upward. When the closing action is needed, the magnetic rotor assembly 27 will be subjected to the downward spring force of the return spring 28 while rotating, so that the external threaded portion 22c of the valve shaft portion 22 and the internal threaded portion 12b of the nut can be re-engaged, thereby ensuring that the screw feed mechanism is reassembled.

[0102] Please refer to FIG. 18, FIG. 19, FIG. 18 is an enlarged view of part I in FIG. 17, and FIG. 19 is an enlarged view of part II in FIG. 17. FIG. 17 is a stop position of the electronic expansion valve in a full-closed state, that is, a position where the movable stop portion 20a just hits the fixed stop portion 12d, at this time, the needle tip adjusting portion 21a of the valve needle 21 is at the lowermost end of its stroke, and the valve needle is in abutment with the valve port portion 113. As shown in FIG. 19, at this time, the valve needle 21 is subjected to a spring force transmitted from the compression spring 24 to the lower side in the drawing through the gasket 23, and the spring force is further transmitted to a portion in abutment with the valve needle on the valve port portion 113 through the valve needle 21. The present embodiment is described with the number of gaskets being two, and the gasket 23 includes a first gasket 231 and a second gasket 232, and the first gasket 231 is located above the second gasket 232 with reference to the drawing of FIG. 17, and the first gasket 231 and the second gasket 232 are in abutment. As an alternative embodiment, the number of gaskets can be one or more than two.

[0103] The upper end of the compression spring 24 abuts against the lower end of the bushing 25, the lower end of the compression spring abuts against the upper end surface of the first gasket 231, and the lower end of the second gasket 232 abuts against the gasket abutment portion 21e of the valve needle 21, at this time, the lower end surface of the second gasket 232 is apart from the valve shaft step portion 22f of the valve shaft portion 22 by a certain distance k, and it can also be understood that the second gasket 232 can be displaced by a displacement amount k toward the lower side in the drawing. At this time, the spring force of the compression spring 24 is transmitted through the gasket 23 and the valve needle 21, and finally acts on a sealing portion in abutment with the valve needle on the valve port portion.

[0104] The upper end of the valve needle 21 is fitted with the valve needle sleeve 26, and the lower end of the valve needle sleeve 26 is apart from the upper end of the bushing 25 by a certain distance h, and h > k is satisfied. In addition, according to the drawing shown in FIG. 19, the outer diameter of the valve needle sleeve 26 of the present embodiment is smaller than the outer diameter of the bushing 25. Those skilled in the art can understand that, as an alternative, the outer diameter of the valve needle sleeve 26 can also be set to be larger than the outer diameter of the bushing 25, in this case, when the height of the valve shaft portion 22 in the axial direction is larger than the height of the bushing 25, the valve needle sleeve 26 will not abut against the bushing 25 in any case, but will abut against the valve shaft portion 22 when it is displaced downward. At this time, h is the distance between the lower end of the valve needle sleeve 26 and the upper end of the valve shaft portion 22.

[0105] From the starting point of the state shown in FIG. 17, the magnetic rotor assembly 27 is driven to rotate upward by the excitation of the stator coil 40, and the movable stop portion 20a begins to rotate away from the fixed stop portion 12d, under the action of the screw feed mechanism, the magnetic rotor assembly 27 is displaced upward synchronously with the valve shaft portion 22, when the lifting height is just k, the electronic expansion valve is at the spring force unloading point.

[0106] Please refer to FIG. 20-22, wherein FIG. 20 is a sectional view of the fifth embodiment electronic expansion valve at the spring force unloading point; FIG. 21 is an enlarged view of III part in FIG. 20; FIG. 22 is an enlarged view of IV part in FIG. 20.

[0107] At this time, the lower end of the second gasket 232 is 0 distance from the valve shaft step part 22f of the valve shaft part, i.e. the spring force of the compression spring 24 is transmitted through the gasket 23, and will be transferred from the gasket abutting part 21e of the valve needle 21 shown in FIG. 17 to the valve shaft step part 22f of the valve shaft part 22 shown in FIG. 20, i.e. at this time the electronic expansion valve is at the spring force unloading point of the compression spring 24, and the valve needle 21 is no longer subjected to the spring force transmitted by the compression spring 24. As shown in FIG. 21, at this time the lower end of the valve needle sleeve 26 is still a certain distance from the upper end of the bushing 25, and the distance is h-k. Of course, in the case where the outer diameter of the valve needle sleeve 26 is set to be larger than the outer diameter of the bushing 25, then the lower end of the valve needle sleeve 26 is still a certain distance from the upper end of the valve shaft part 22, and the distance is h-k.

[0108] From the full-closed state shown in FIG. 17 to the spring force unloading point state shown in FIG. 20, the upward displacement amount of the valve shaft part 22 and the magnetic rotor assembly 27 is k, and the upward displacement amount of the valve needle 21 is 0.

[0109] Taking FIG. 20 as the reference, the magnetic rotor assembly 27 is continuously rotated upward by the excitation drive of the stator coil 40, and the conversion effect of the screw feed machine climbing, the magnetic rotor assembly 27 continues to synchronously displace upward together with the valve shaft part 22, when the lifting height is h-k, the electronic expansion valve is at the opening critical point.

[0110] Referring to Figs. 23-25, Fig. 23 is a sectional view of the fifth embodiment electronic expansion valve at the opening threshold point, Fig. 24 is an enlarged view of section V in Fig. 23, and Fig. 25 is an enlarged view of section VI in Fig. 23. At this time, the valve needle 21 is in contact with the valve port portion 113, or it can be understood that the valve needle 21 will be separated from the valve port portion 113 as long as the valve needle 21 continues to move upward. At this time, the lower end of the second gasket 232 is in contact with the valve shaft step portion 22f of the valve shaft portion 22, and the spring force of the compression spring 24 is transmitted through the gasket 23 to the valve shaft step portion 22f. As shown in Fig. 24, at this time, the distance between the lower end of the valve needle sleeve 26 and the upper end of the bushing 25 is 0, i.e., from the state of Fig. 20 to Fig. 23, the valve shaft portion 22 and the rotor are displaced upward by h-k. At this time, the valve needle 21 is no longer subjected to the spring force transmitted by the compression spring 24, and the spring force has been unloaded from the valve needle 21, and the frictional force of the rotational movement of the valve needle 21 relative to the valve shaft portion 22 is significantly reduced. That is, at the moment when the valve needle and the valve port portion are in contact and separated, the valve needle 21 is no longer subjected to the spring force of the compression spring 24, so the frictional impact force of the relative rotation between the valve needle and the valve port portion can be reduced, thereby reducing the wear of the contact portion between the valve needle and the valve port portion and improving the service life of the electronic expansion valve.

[0111] From the fully closed state shown in Fig. 17 to the opening threshold point shown in Fig. 23, the valve shaft portion 22 and the magnetic rotor assembly 27 are displaced upward by h, and the valve needle 21 is displaced upward by 0.

[0112] Referring to Fig. 26, Fig. 26 is a sectional view of the fifth embodiment electronic expansion valve at the fully open state. At this time, the valve needle 21 is away from the valve port portion 113. During the operation from Fig. 23 to Fig. 26, i.e., during the reciprocating operation of the electronic expansion valve from the opening threshold point to the maximum opening, the valve needle 21 is synchronously subjected to the axial lifting movement of the valve shaft portion 22, and the valve needle 21 is always not subjected to the spring force of the compression spring 24, so the frictional force of the relative rotation between the valve needle 21 and the valve shaft portion 22 can be reduced, the wear between the valve needle guide portion 21b and the first guide portion 12a of the nut can be reduced, and thus the service life of the electronic expansion valve can be improved. From the opening threshold point shown in Fig. 23 to the fully open state shown in Fig. 26, the relative position of the valve needle 21 and the valve shaft portion 22 in the axial direction remains unchanged.

[0113] From the spring force unloading point of Fig. 20 to the opening threshold point shown in Fig. 23, the valve shaft portion 22 and the magnetic rotor assembly 27 are displaced upward by h-k, and the valve needle 21 is displaced upward by 0. From the fully closed state shown in Fig. 17 to the fully open state shown in Fig. 26, the valve shaft portion 22 and the magnetic rotor assembly 27 are displaced upward by L, and the valve needle 21 is displaced upward by L-h.

[0114] In addition, in the present embodiment, the first gasket and the second gasket are both plate-shaped, and the bottom surface of the second through-hole portion of the valve shaft portion (i.e., the valve shaft step portion) is also planar, so the indications of h and k in the drawing also show the distance between the two planes in the axial direction. In fact, the contact positions of the gaskets or the second through-hole portion are not limited to the contact between two planes, but can be varied in various ways, such as the contact between two axial inclined surfaces, or other irregular shapes. In this case, h and k should only be understood as the displacement difference between the two components in the axial direction.

[0115] It should be noted that the fifth embodiment is described by taking the first flow direction as an example, and the fluid pressure of the first interface portion is greater than that of the second interface portion, so the valve needle of the electronic expansion valve is always subjected to the pressure difference force of the fluid medium in the above-mentioned states.

[0116] The state of the rotor component shown in FIG. 26 is that the valve needle 21 is not subjected to the spring force generated by the compression spring 24, and when there is no pressure difference between the fluid of the first interface portion and the fluid of the second interface portion, the valve needle 21 is equivalent to being subjected to only its own gravity, i.e., equivalent to the state that after the valve needle 21 is fixedly connected with the valve needle sleeve 26, the valve needle 21 has a certain activity gap in the axial direction thereof relative to the valve shaft portion 22, and the size of the gap is the same as the gap shown in FIG. 25, which is h-k.

[0117] The electronic expansion valve provided by the present embodiment can reduce the friction impact force of the relative rotation of the sealing portions of the valve needle and the valve port portion when the spring force of the compression spring is not applied to the valve needle at the moment of the sealing contact of the valve needle with the valve port portion from the open state to the closed state, and at the moment of the disengagement of the valve needle from the valve port portion from the closed state to the open state, thereby reducing the wear of the contact portions and improving the service life of the electronic expansion valve. Moreover, the spring force of the compression spring is not applied to the valve needle during the reciprocating operation of the electronic expansion valve from the minimum opening degree to the maximum opening degree, thereby reducing the rotational friction force between the valve needle and the valve shaft portion, and thus reducing the wear between the valve needle guide portion and the nut, thereby further improving the service life of the electronic expansion valve.

[0118] Sixth Embodiment

[0119] The sixth embodiment of the present application will be described below with reference to FIG. 27.

[0120] In the above five embodiments, the first interface part of the electronic expansion valve is connected with the first connecting pipe 10b, and the second interface part is connected with the second connecting pipe 10a, that is, the electronic expansion valve is connected with the refrigeration system in the form of connecting pipes. In fact, the electronic expansion valve of the above embodiments can be applied to many fields, and the connection between the electronic expansion valve and the refrigeration system is not limited to the connecting pipe connection mode. For example, when applied to automobile air conditioners and other occasions requiring quick maintenance, the first connecting pipe and the second connecting pipe structure can not be used, and the valve seat can be directly fixedly connected with an integrated valve body integrated with multiple channels, such as a flange sealing connection mode.

[0121] Please refer to FIG. 27, which is a structural schematic diagram of the electronic expansion valve of the sixth embodiment of the present application. The present embodiment is an example of the electronic expansion valve applied to an automobile air conditioning system. The valve seat 11 is fixedly connected with the connecting piece 51a by welding, and then fixedly connected with the valve body 80 as a whole. Among them, the connecting piece 51a can be adaptively designed to be suitable for the shape of the valve body. Specifically, the connecting piece 51a can be fixedly connected with the valve body 80 in a flange sealing connection mode (not shown in the figure), for example, a screw hole is provided at the disc plate part of the connecting piece, and then the connecting piece is fixedly connected with the valve body by screw connection. And in order to ensure the sealing performance, a first sealing piece 803 is arranged between the connecting piece and the valve body. In addition, a second sealing piece 804 is arranged between the valve seat 11 and the valve body 80, and when the assembly is completed, the connecting piece 51 and the valve seat 11 are fixedly connected with the valve body 80, and good sealing performance is maintained.

[0122] The valve body 80 can be machined from metal and form a first interface end 801 and a second interface end 802 for connecting with other parts of the air conditioning system. Of course, the structure of the first interface end 801 and the second interface end 802 is not limited to that shown in FIG. 27, and different layouts can be made according to system needs. In this way, when disassembly and maintenance are needed, the valve seat and the connecting piece of the electronic expansion valve can be easily separated from the valve body.

[0123] It should be noted that the above, below, left, right and other directional terms mentioned in this paper are all based on the drawings of the specification as the reference, introduced for the convenience of description; and the ordinal numbers in the component names, such as "first", "second", etc., are also introduced for the convenience of description, and do not mean any limitation on the order of the components. In addition, since the functions of some parts between the components provided by the above embodiments are the same, the parts are uniformly named in the specification. The electronic expansion valve provided by the related technical solutions has been described in detail above, and specific embodiments have been described in this paper. The above embodiment description is only used to help understand the method of the present application and its core idea, and does not limit the present application in any form.

Claims

1. An electronic expansion valve, characterized in that, The device includes a valve seat, a nut assembly, a valve shaft portion, a valve needle, and a magnetic rotor assembly. The valve seat includes a valve port portion. The nut assembly is fixedly connected to the valve seat and includes a nut and a connecting piece. The nut includes a first guide portion, an internal thread portion, and a second guide portion. The first guide portion is closer to the valve port portion than the internal thread portion, and the second guide portion is farther away from the valve port portion than the internal thread portion. The inner diameter of the first guide portion is smaller than the inner diameter of the second guide portion. The valve shaft portion is fixedly connected to the magnetic rotor assembly. The valve shaft portion includes a valve shaft guide portion, which is clearance-fitted with a second guide portion. The valve shaft portion is capable of relative displacement with respect to the nut along the axial direction of the nut. The valve shaft portion includes an external thread portion, which, together with the internal thread portion, forms a helical feeding mechanism. The valve shaft portion includes a first through hole portion and a second through hole portion, wherein the inner diameter of the first through hole portion is larger than the inner diameter of the second through hole portion. The valve needle includes a valve needle guide portion, which is clearance-fitted with the first guide portion. The valve needle is capable of relative displacement with respect to the nut along the axial direction of the nut. The outer diameter of the valve needle guide portion is larger than the inner diameter of the second through hole portion.

2. The electronic expansion valve as described in claim 1, characterized in that, The valve shaft portion includes a large-diameter portion and a small-diameter portion. The outer diameter of the large-diameter portion is larger than the outer diameter of the small-diameter portion. The large-diameter portion is further away from the valve port portion than the small-diameter portion. The external thread portion is disposed on the outer edge portion of the small-diameter portion, and the valve shaft guide portion is disposed on the outer edge portion of the large-diameter portion.

3. The electronic expansion valve as described in claim 2, characterized in that, The outer edge of the large-diameter portion is provided with a rotor fixing part. The magnetic rotor assembly includes a magnetic rotor and a connecting plate. The magnetic rotor and the connecting plate are fixedly connected or are an integral structure. The rotor fixing part is fixedly connected to the connecting plate.

4. The electronic expansion valve according to any one of claims 1-3, characterized in that, The electronic expansion valve includes a bushing, at least a portion of the outer edge of the bushing mates with at least a portion of the inner edge of the first through hole, and the bushing is fixedly connected to the valve shaft.

5. The electronic expansion valve as described in claim 4, characterized in that, The electronic expansion valve includes a compression spring and a gasket. One end of the compression spring abuts against the bushing, and the other end of the compression spring abuts against the gasket. The valve needle includes a gasket abutting portion, and the gasket abuts against the gasket abutting portion.

6. The electronic expansion valve as described in claim 5, characterized in that, A valve shaft step is provided between the first through hole and the second through hole, and the valve shaft step can abut against the gasket.

7. The electronic expansion valve as described in claim 5 or 6, characterized in that, The compression spring is housed in the space formed by the valve shaft and the bushing, and the maximum outer diameter of the compression spring is greater than the inner diameter of the second through hole.

8. The electronic expansion valve as described in claim 1, characterized in that, The nominal diameter of the thread of the spiral feed mechanism is smaller than the inner diameter of the first through hole, and the nominal diameter of the thread of the spiral feed mechanism is slightly larger than the outer diameter of the valve needle guide.

9. The electronic expansion valve as described in claim 1, characterized in that, The valve needle includes a first axial portion and a second axial portion, wherein the outer diameter of the first axial portion is larger than the outer diameter of the second axial portion, and the outer diameter of the first axial portion is smaller than the outer diameter of the valve needle guide portion.

10. The electronic expansion valve as claimed in claim 1, characterized in that, The electronic expansion valve includes a connector, a first interface portion, a second interface portion, and a valve body. The valve body is formed by machining and includes a first interface end and a second interface end. The valve seat is fixedly connected to the connector. The connector and the valve body are connected by a flange. A first sealing element is provided between the connector and the valve body. A second sealing element is provided between the valve seat and the valve body.