WO2021228013A1

WO2021228013A1 - Electronic expansion valve

Info

Publication number: WO2021228013A1
Application number: PCT/CN2021/092626
Authority: WO
Inventors: 魏先让
Original assignee: 浙江三花智能控制股份有限公司
Priority date: 2020-05-11
Filing date: 2021-05-10
Publication date: 2021-11-18
Also published as: KR20230008854A; JP2023511556A; CN113639050A; JP7483014B2

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).

Description

Electronic expansion valve

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office, the application number is 202010392210.5, and the invention title is "Electronic Expansion Valve" on May 11, 2020, the entire content of which is incorporated into this application by reference.

【Technical Field】

This application relates to the technical field of refrigeration control, and in particular to electronic expansion valves.

【Background technique】

The refrigeration system includes a compressor, a throttling element, two heat exchangers, and other parts. The throttling element can use an electronic expansion valve to adjust the throttling of the refrigerant. The use of an electronic expansion valve can achieve relatively precise control and improve system energy efficiency. . The basic principle of the electronic expansion valve is to pass the specified pulse current signal through the stator coil, so that the rotor assembly of the electronic expansion valve is excited and rotated, and the rotary motion of the rotor is converted into the up and down movement of the valve shaft through the conversion of the screw feed mechanism. The valve core of the valve shaft head is close to or far from the valve port, changing the flow area of the valve port, so as to achieve the function of refrigerant flow adjustment and switching.

[Summary of the invention]

An object of one of the embodiments of the present invention is to provide an electronic expansion valve with relatively small frictional resistance from the screw feed mechanism.

In order to achieve the above objective, an embodiment of the present invention adopts the following technical solutions:

The electronic expansion valve is characterized by comprising 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, the nut assembly is fixedly connected to the valve seat, and the nut The assembly 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 than the internal thread portion, and the second guide Portion is farther away from the valve port than the internal thread portion, and 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, the valve shaft guide portion is in clearance fit with the second guide portion, and the valve shaft portion can be opposed to the The nut is relatively displaced along the axial direction of the nut; the valve shaft portion includes an external thread portion, and the external thread portion and the internal thread portion form a screw feed mechanism; the valve shaft portion includes a first through hole Part and a second through hole part, the inner diameter of the first through hole part is greater than the inner diameter of the second through hole part;

The valve needle includes a valve needle guide portion, the valve needle guide portion is in clearance fit with the first guide portion, and the valve needle is capable of relative displacement relative to the nut along the axial direction of the nut; the valve The outer diameter of the needle guide part is larger than the inner diameter of the second through hole part.

In the electronic expansion valve provided by this embodiment, the valve shaft portion includes a first through hole portion and a second through hole portion. Since the outer diameter of the valve needle guide portion is larger than the inner diameter of the second through hole portion of the valve shaft portion, If the electronic expansion valve has the same rotor diameter, housing diameter, stator coil diameter and volume, the nominal diameter of the screw feed mechanism only needs to be slightly larger than the outer diameter of the valve needle guide, that is, screw feed The nominal diameter of the mechanism can be made relatively small, which is beneficial to reduce the frictional resistance from the screw feed mechanism.

【Explanation of the drawings】

Fig. 1 is a schematic cross-sectional view of an electronic expansion valve in a closed state of the first embodiment;

2 is a schematic cross-sectional view of the electronic expansion valve of the first embodiment in an open state;

3 is a schematic diagram of the cooperation of the nut and the valve seat assembly of the first embodiment;

4 is a schematic diagram of the magnetic rotor assembly, the valve shaft portion and the valve needle of the first embodiment in cooperation;

5 is a schematic cross-sectional view of the electronic expansion valve in the closed state of the second embodiment;

6 is a schematic cross-sectional view of the electronic expansion valve of the second embodiment in an open state;

FIG. 7 is a schematic diagram of the structure of the nut assembly of the second embodiment;

8 is a partial cross-sectional view of the magnetic rotor assembly of the second embodiment in cooperation with the valve shaft portion and the valve needle;

Figure 9 is a top view of the nut assembly of the second embodiment;

10 is a schematic cross-sectional view of the electronic expansion valve in the closed state of the third embodiment;

11 is a schematic cross-sectional view of the electronic expansion valve of the third embodiment in an open state;

12 is a schematic diagram of the structure of the nut assembly of the third embodiment;

FIG. 13 is a schematic diagram of the matching structure of the valve shaft portion and the stopper in the third embodiment; FIG.

14 is a schematic diagram of the matching structure of the magnetic rotor assembly and the valve shaft portion, the valve needle and the stopper of the third embodiment;

15 is a schematic diagram of the structure of the connecting plate provided by the fourth embodiment;

16 is a partial cross-sectional view of the matching structure of the magnetic rotor assembly and the valve shaft portion, valve needle and other components provided by the fourth embodiment;

17 is a schematic diagram of the fifth embodiment of the electronic expansion valve in a fully closed state in a stop position;

Figure 18 is an enlarged view of part I in Figure 17;

Figure 19 is an enlarged view of part II in Figure 17;

20 is a cross-sectional view of the electronic expansion valve of the fifth embodiment when it is at the point of unloading the spring force;

Figure 21 is an enlarged view of part III in Figure 20;

Figure 22 is an enlarged view of part IV in Figure 20;

23 is a cross-sectional view of the electronic expansion valve of the fifth embodiment when it is at the critical point of opening;

Figure 24 is an enlarged view of part V in Figure 23;

Figure 25 is an enlarged view of part VI in Figure 23;

26 is a cross-sectional view of the fully opened state of the electronic expansion valve of the fifth embodiment;

Fig. 27 is a schematic structural view of an electronic expansion valve according to a sixth embodiment.

【Detailed ways】

In order to enable those skilled in the art to better understand the technical solutions provided by the present application, the technical solutions of the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

The first embodiment

Please refer to Figures 1 to 4, Figure 1 is a schematic structural diagram of the closed state of the electronic expansion valve of the first embodiment, Figure 2 is a structural schematic diagram of the closed state of the electronic expansion valve of the first embodiment, and Figure 3 is the first embodiment The structure diagram of the valve seat component of the embodiment. FIG. 4 is the structure diagram of the rotor and the screw valve needle assembly of the first embodiment.

As shown in Figure 1, the electronic expansion valve includes a valve body part and a coil part 40. The valve body part includes a valve seat 11, a connector 50, and a housing 30. The valve seat 11 can be made by metal cutting. A connecting piece 50 is provided on the upper side of the, and the connecting piece 50 and the valve seat 11 can be fixedly connected by welding, and at the same time fixedly connected with the housing 30, specifically, it can also be fixedly connected by welding. The housing 30 is made of thin-walled parts, and is generally cylindrical with an open end, and one end of the open end is hermetically welded to the valve seat 11. The valve seat 11 and the connecting piece 50 can be assembled by setting a step on the upper outer edge of the valve seat 11, and then installing the connecting piece 50 from above the valve seat 11 to facilitate the assembly and positioning of the two. Similarly, a step can also be provided on the outer edge of the upper side of the connecting member 50 to facilitate assembly and positioning with the housing 30, which facilitates the welding operation. That is, the valve seat 11 is connected to the housing through the connecting member 50, and a cavity is formed above the valve seat 11 for accommodating the magnetic rotor assembly, nut assembly and other components described below.

The valve seat 11 includes a valve port portion 113, a first port portion 111, and a second port portion 112. The first port portion 111 and the second port portion 112 are both used to connect to the refrigerant channel of the system, and the valve port portion 113 is provided with a valve port. 113a. In this embodiment, the first interface portion 111 is fixedly connected to the first connection pipe 10b, and the second interface portion 112 is fixedly connected to the second connection pipe 10c. 10c flows out, or it flows in from the second connecting pipe 10c, and flows out from the first connecting pipe 10b after passing through the valve port 113a.

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

The nut 121 has a through hole penetrating in its axial direction, and an internal thread portion 12b is provided on the inner side wall of the through hole for forming a spiral with the external thread portion 22c provided on the outer edge portion of the valve shaft portion 22 described below. Feeding mechanism. The inner side wall of the nut is also provided with a first guide portion 12a, which is provided below the female thread portion 12b, and can provide a guide and centering effect for the valve needle 21 in the circumferential direction. The “below” mentioned here means that the first guide portion 12a is closer to the valve port portion 113 than the female thread portion 12b. The valve needle 21 includes a valve needle guide portion 21b, that is, the first guide portion 12a and the valve needle guide portion 21b have a small clearance fit, and the valve needle 21 can move along the first guide portion 12a of the nut under the drive of the valve shaft portion 22 Rotate or move up and down. It should be noted that the first guide portion 12 here refers to a portion provided on the inner side wall of the nut, and the valve needle guide portion 21b refers to a portion provided on the outer edge of the valve needle. A second guide portion 12c is provided on the opposite upper portion of the inner side wall of the nut, which can provide the valve shaft portion 22 with a guide and centering effect in the circumferential direction. The outer edge of the valve shaft portion 22 is provided with a valve shaft guide portion 22b. The valve shaft guide portion 22b and the second guide portion 12c are in a small clearance fit. The valve shaft portion 22 can be driven by the magnetic rotor assembly along the second guide portion 12c rotates or shifts up and down. Wherein, the inner diameter of the second guide portion 12c is greater than the inner diameter of the nut first guide portion 12a, so that when the external thread portion 22c of the valve shaft portion 22 moves upward and gradually separates from the internal thread portion 12b, it will not be affected by the second guide portion 12c. Interference. It should be noted that the first guide portion 12a and the second guide portion 12c described above are both a part of the inner wall of the nut through hole, the shape of the outer edge of the nut and the location of the connecting piece 122 on the outer edge of the nut, It does not affect the arrangement of the first guide portion 12a and the second guide portion 12c.

The top outer edge of the nut 121 is provided with a fixed stop 12d, the fixed stop 12d at least partially protrudes from the upper end surface of the nut 121, or in other words, the fixed stop 12d at least partially protrudes from the ring of the nut in the axial direction. The shaped base body can either protrude from the annular base body in the radial direction, or it can be set so as not to protrude. The fixed stop portion 12d is used to cooperate with the movable stop portion 20a provided on the magnetic rotor assembly to realize the stop of the magnetic rotor assembly. That is, in this embodiment, the magnetic rotor component can be displaced in the axial direction, and the nut assembly 12 is fixedly connected to the valve seat 11. Therefore, when the magnetic rotor assembly moves down to the lowest end of the stroke, the movable stopper 20a can abut against the fixed stop 12d, so that the magnetic rotor assembly cannot continue to rotate, so that the downward movement stroke of the magnetic rotor component can be controlled.

The magnetic rotor assembly 27 can rotate by inducing 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 or integrally provided with the magnetic rotor 271. The connecting plate 272 is made of metal, such as powder metallurgy. The material, specifically, the connecting plate 272 can be used as an insert, and the magnetic rotor 271 can be injection-molded. The connecting plate 272 is fixedly connected to the valve shaft portion 22. Specifically, the rotor fixing portion 22a located at the outer edge of the upper end of the valve shaft portion 22 fits with the inner edge of the connecting plate 272, and can be fixed by welding. The magnetic rotor assembly includes a movable stop part 20 a. As a specific embodiment, the movable stop part 20 a may be integrally made of the connecting plate 272, that is, the movable stop part 20 a may be used as a part of the connecting plate 272.

The valve shaft portion 22 is a generally hollow cylindrical member including a large diameter portion 221 and a small diameter portion 222. Among them, a part of the outer edge of the large diameter portion 221 is formed as the rotor fixing portion 22a for fixed connection with the connecting plate 272 of the magnetic rotor assembly 27. The connection between the two can be fixed by welding or crimping. Another part of the outer edge of the large-diameter portion 221 is formed as a valve shaft guide portion 22b, which is used for a small clearance fit with the second guide portion 12c of the nut, thereby realizing guidance. That is, during the rotation of the rotor, the second guide portion 12c of the nut provides the valve shaft portion 22 with a guide and centering effect in the circumferential direction. As shown in FIG. 1, the rotor fixing portion 22 a is located relatively above the valve shaft guide portion 22 b, and the valve shaft guide portion 22 b is substantially located in the space enclosed by the magnetic rotor 271. The outer edge portion of the small diameter portion 222 is provided with an external thread portion 22c for forming a screw feed mechanism with the internal thread portion 12b provided on the nut. The valve shaft portion 22 includes a first through hole portion 22e and a second through hole portion 22d. The first through hole portion 22e roughly corresponds to the inner hole portion of the large diameter portion 221, and the second through hole portion 22d roughly corresponds to the small diameter portion. In this way, the inner diameter of the first through-hole portion 22e is larger than the inner diameter 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. In addition, the nominal diameter of the screw feeding mechanism is smaller than the inner diameter of the first through hole portion 22e, and the nominal diameter of the screw feeding mechanism is slightly larger than the outer diameter of the valve needle guide portion 21c. The "slightly larger" mentioned here means that when the valve needle moves upward, it will not be hindered or interfered by the internal threaded portion 12b.

The bushing 25 is fixedly connected to the valve shaft portion 22, the bushing 25 is generally hollow cylindrical, and at least part of the outer edge of the bushing 25 is matched with at least part of the inner edge of the first through hole 22e. In this way, the large-diameter portion 221 of the valve shaft portion 22 and the bushing 25 form a space, the compression spring 24 is located in the space, and the outer diameter of the compression spring 24 is larger than the inner diameter of the small-diameter portion 222. The upper end of the compression spring 24 abuts against the bottom end of the bushing 25. The abutment described here can be a direct abutment or an indirect abutment, for example, it is provided between the compression spring 24 and the bushing 25 A gasket realizes indirect abutment. The other end of the compression spring 24 is in contact with the washer portion 23. As for the washer portion 23, one end thereof abuts against the compression spring 24, and the other end abuts against the valve needle 21 described below. The maximum outer diameter of the compression spring 24 is larger than the inner diameter of the second through hole portion 22d. In this way, the diameter of the compression spring can be made relatively large when the electronic expansion valve of the same specification has the same rotor diameter, housing diameter, stator coil diameter and volume, thereby increasing the spring force and improving the electronic expansion. The ability of the valve to resist reverse pressure when it is fully closed.

The valve needle 21 penetrates through the central passage defined by the bushing 25, the valve shaft portion 22 and the nut 12, and the compression spring 24 is sleeved on the periphery of a part of the outer edge of the valve needle 21. The valve needle 21 is rod-shaped as a whole and has multiple different outer diameters. Based on the views shown in Figures 1 to 5, the bottom end of the valve needle 21 is the needle tip adjustment portion 21a. The shape of the mouth is related to the flow adjustment curve required by the electronic expansion valve, and can be set differently according to different needs. This application does not limit the specific shape of the needle tip adjustment portion 21a. The valve needle 21 includes a valve needle guide portion 21b, which is used for a small clearance fit with the first guide portion 12a of the nut. During the rotation of the magnetic rotor, the first guide portion 12a of the nut provides the valve needle 21 with a guide and centering effect in the circumferential direction. . The valve needle 21 includes a gasket abutting portion 21e for abutting against the gasket 23 so that the gasket 23 will not be displaced downward along the center axis of the valve needle after abutting against the valve needle. As a specific embodiment, as shown in FIG. 4, a first shaft portion 21c and a second shaft portion 21d are respectively provided above the valve needle guide portion of the valve needle 21, wherein the first shaft portion 21c The outer diameter is larger than the outer diameter of the second shaft-shaped portion 21d, and the outer diameter of the first shaft-shaped portion 21c is smaller 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-shaped portion 21c and the second shaft-shaped portion 21d, and the step can be used as a specific embodiment of the gasket abutting portion 21e, that is, the gasket abutting portion 21e is formed on The top of the first shaft-shaped portion 21c. The lower end surface of the gasket 23 abuts against the gasket abutment portion 21e. In this embodiment, the number of gaskets 23 is two, and the gasket 23 located on the lower side abuts against the gasket abutment portion 21e and is located on the upper side. A compression spring 24 is attached to the upper part of the washer 23 on the side, that is, the lower end of the compression spring 24 abuts against the washer 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 all accommodated in the space defined by the large diameter portion of the valve shaft portion 22 and the bush 25.

Specifically during assembly, the valve needle 21 is inserted into the central through hole of the valve shaft portion 22 from the bottom up as shown in FIG. Movement; the second shaft-shaped portion 21d penetrates the central through hole of the bushing 25, and penetrates the upper end surface of the bushing 25. The upper end of the second shaft portion 21d is fitted with a valve needle sleeve 26. 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 restricted by the valve needle sleeve 26. After the needle sleeve 26 is fixedly connected, the valve needle 21 will not fall out of the central through hole of the bushing 25 and the valve shaft portion 22 downward. In addition, a floating connection is formed between the valve needle 21 and the magnetic rotor assembly 27. 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 is within a limited range. 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 in clearance fit, and the second shaft portion 21d and the central through hole of the bush 25 are also in clearance fit, so the valve needle 21 is opposite to The valve shaft portion 22 may also be relatively rotated in the circumferential direction.

It should be noted that in this embodiment, from the outside, the valve needle 21 can be roughly divided into a three-stage stepped shaft structure in addition to the needle tip adjustment portion 21a. Among them, the valve needle section where the valve needle guide portion 21b is located is The diameter of the valve needle section where the first shaft-shaped portion 21c is located is slightly smaller, while the valve needle section where the second shaft-shaped portion 21d is located has the smallest diameter. Above, various equivalent structural modifications or substitutions can also be made. For example, for the valve needle guide 21b, since the nut is fixed to the valve seat, the valve needle can move up and down in the axial direction, that is, the valve needle can move up and down relative to the nut and has a certain stroke. In this stroke, the valve needle is provided with a relatively smooth valve needle guide portion 21b on the outer edge, which is used to form a guiding function with the first guide portion 12a of the nut. The entire outer edge of the valve needle with the largest diameter serves as the valve needle guide. In other words, it is completely possible to provide uneven structures such as grooves on the upper or lower outer edge of the valve needle section corresponding to the valve needle guide 21b. It is necessary to ensure that during the stroke of the valve needle, there is always a section of the valve needle guide portion 21b that matches with the first guide portion 12a of the nut to achieve the guiding effect. In addition, the first shaft-shaped portion 21c and the second shaft-shaped portion 21d are not limited to adopting a cylindrical shaft-like structure of equal diameter. For example, one more shaft-shaped step is provided on the first shaft-shaped portion 21c or the second shaft-shaped portion 21d. Etc., these equivalent technical feature transformations obviously also belong to the protection scope of this application.

In addition, the valve needle guide portion, the first shaft-shaped portion, and the second shaft-shaped portion described herein are all named after the role they play in the technical solution, and the valve needle cannot be understood mechanically or restricted only from the figure. The three-stage shaft-shaped part shown in 4 is combined. Alternatively, the valve needle 21 can be made in a form of segmented assembly, for example, a threaded connection or welding between two adjacent segments. In fact, as mentioned above, the structure shown in the figure is only an embodiment that facilitates processing.

In the valve needle structure provided by this embodiment, the outer diameters of the second shaft portion, the first shaft portion, and the valve needle section where the valve needle guide portion are located are successively increased, the manufacturing is relatively convenient, the coaxiality is relatively good, and the second The shaft part can enclose a space for accommodating the compression spring with the valve shaft part and the bushing, so that the outer diameter of the compression spring is no longer restricted by the outer diameter of the valve needle guide part, so that the electronic expansion valve of the same specification If you have the same rotor diameter, housing diameter, stator coil diameter and volume, you can directly increase the valve port diameter to obtain a larger diameter flow adjustment electronic expansion valve.

A return spring 28 is sleeved on the outer circumference of the valve needle sleeve 26. 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 contact position can be based on the relative position of the bushing 25 and the valve shaft portion 22. The relationship and the diameter of the return spring 28 are determined. As shown in Figure 4, the bushing 25 and the top end of the valve shaft portion 22 can be set to be flat or substantially flat. At this time, the return spring 28 can be set to abut against the valve shaft portion 22, or it can be set to be in contact with the bushing. 25 abuts, or abuts both the valve shaft portion 22 and the bushing 25 at the same time. 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 the outer periphery of the valve needle sleeve 26.

The coil 40 of the electronic expansion valve receives the 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 and the magnetic rotor 27 rotate synchronously and pass The screw feed mechanism between the valve shaft and the nut enables the magnetic rotor 27 to move in the axial direction while rotating, thereby driving the valve needle 21 to move in the axial direction, so that the needle tip adjustment part of the valve needle 21 21a is close to or far from the valve port 113a, so as to realize the linear switch adjustment function of the flow of the electronic expansion valve. When the needle tip adjusting portion 21a moves downward to abut against the valve port portion 113, that is, the needle tip adjusting portion 21a is at the lowest end of its stroke. At this time, the electronic expansion valve is in a fully closed state, as shown in FIG. 1. When the needle tip adjusting portion 21a is at a position 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 approximately 80% opening. When the magnetic rotor assembly 27 continues to rotate upward in the valve opening direction from the state shown in FIG. 2, until the external thread portion 22c of the valve shaft part upwardly escapes the internal thread portion 12b of the nut 12, at this time, the upper end of the return spring 28 has been connected to the housing 30. The top wall abuts against each other, and the return spring 28 is in a compressed state. Since the screw feed mechanism between the valve shaft portion 22 and the nut 12 has been separated from each other at this time, the magnetic rotor assembly 27 will not continue to move upward. When the valve closing action is required, the magnetic rotor assembly 27 will receive the downward spring force of the return spring 28 while rotating, so that the external thread portion 22c of the valve shaft portion 22 and the internal thread portion 12b of the nut can be restored to the thread again. Engage to ensure that the screw feed mechanism is reorganized.

In the electronic expansion valve provided by this embodiment, the valve shaft portion includes 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 The shape portion 21c and the second through-hole portion 22d are in clearance fit, the outer diameter of the valve needle guide portion 21b is also greater than the inner diameter of the second through-hole portion 22c, and the inner diameter of the second through-hole portion 22c corresponds to the screw feed mechanism the inside diameter of. Therefore, since the outer diameter of the valve needle guide portion 21b is larger than the inner diameter of the second through hole portion 22d of the valve shaft portion 22, the electronic expansion valve of the same specification, such as the same rotor diameter, housing diameter, stator coil diameter and volume In the case of the screw feed mechanism, the nominal diameter of the screw feed mechanism only needs to be slightly larger than the outer diameter of the valve needle guide 21b, that is, the nominal diameter of the screw feed mechanism can be made relatively small, which is beneficial to reduce the screw feed The frictional resistance to the mechanism.

Second embodiment

The second embodiment of the present application will be described below with reference to FIGS. 5-9.

For ease of description, the same reference numerals are used for the components that are basically the same in structure and function in this embodiment and the first embodiment, and only a brief description is given. Those skilled in the art can refer to the relevant description in the first embodiment for understanding. This embodiment will focus on the details of the differences from the first embodiment.

Please refer to FIGS. 5-9, where FIG. 5 is a schematic cross-sectional view of the electronic expansion valve of the second embodiment in a closed state, FIG. 6 is a schematic cross-sectional view of the electronic expansion valve of the second embodiment in an open state, and FIG. 7 is a schematic diagram of the electronic expansion valve in the second embodiment. The structure diagram of the nut assembly of the second embodiment, FIG. 8 is a partial cross-sectional view of the rotor assembly and the valve needle of the second embodiment, and FIG. 9 is a top view of the nut assembly of the second embodiment.

The electronic expansion valve includes a valve body part and a coil part 40. The valve body part includes a valve seat 11, a connector 50, and a housing 30. For the structure and cooperation of the valve seat 11, the connector 50, and the housing 30, please refer to the first embodiment. description of.

The electronic expansion valve includes a nut assembly 120 fixedly connected to the valve seat 11. Specifically, the nut assembly 120 includes a nut 1201 and a connecting piece 1202, and the nut 1201 and the connecting piece 1202 are fixedly connected. The nut 1201 has a through hole penetrating in its axial direction, and an internal thread portion 120b is provided on the inner side wall of the through hole to form a screw feed mechanism with the external thread portion 22c provided on the outer edge portion of the valve shaft portion 22. The valve shaft portion 22 is fixedly connected to the magnetic rotor assembly 27, so the valve shaft portion 22 can rotate synchronously with the rotation of the magnetic rotor. The magnetic rotor assembly 27 can be rotated by induction of 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 or integrally provided with the magnetic rotor 271. The connecting plate 272 is fixedly connected to the valve shaft portion 22. Generally, interference press-fitting connection or riveting connection may be adopted, or the connecting plate 272 and the valve shaft portion 22 may be welded and connected. The magnetic rotor assembly includes a movable stop part 20a. In this embodiment, the movable stop part 20a can be used as a part of the connecting plate 272 and protrudes axially toward the valve seat 11 relative to the connecting plate 272 for contact The fixed stop portion provided on the nut 12 cooperates to realize the stop function, and the fixed stop portion is specifically the following stop protrusion 1201c.

As shown in Figure 8, 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, and the valve shaft portion 22 drives the valve needle 21 to rotate. The valve needle 21 can be relative to the valve. The shaft portion 22 relatively moves in the axial direction within a limited elastic displacement range, and can also rotate relatively. The mating manner 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 repeated here.

The basic principle of the electronic expansion valve is that the coil 40 receives the driving pulse signal to generate a periodically changing magnetic field, and the magnetic rotor 27 is excited to rotate. Since the valve shaft 22 is fixedly connected to the connecting plate 272, the valve shaft 22 is synchronized with the magnetic rotor 27 Rotation, and through the screw feed mechanism between the valve shaft and the nut, the magnetic rotor 27 can also move in the axial direction while rotating, thereby driving the valve needle 21 to move in the axial direction, so that the valve needle 21 The needle tip adjustment portion 21a is close to or away from the valve port 113a, so as to realize the linear switch adjustment function of the flow of the electronic expansion valve. The electronic expansion valve shown in FIG. 5 is in the stop position of the fully closed state, that is, the needle tip adjustment portion 21a of the valve needle 21 is at the lowest end of its stroke, and the valve port 113a is in the fully closed state or at the set minimum opening at this time state. The coil 40 drives the magnetic rotor to move downwards. When the needle tip adjustment portion 21a is in the fully closed state or at the lowest position of its stroke, a stop mechanism needs to be provided to limit and stop the downward movement of the magnetic rotor assembly. In the embodiment, a fixed stop portion is provided on 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 the fully closed state, the movable stop part 20a will abut the corresponding mating surface of the fixed stop part, thereby realizing the limit stop of the magnetic rotor assembly, the valve shaft part, and the valve needle.

6 is a cross-sectional view of the electronic expansion valve of this embodiment in an open state, and the opening position shown in the figure is about 80% of the opening. At this time, the needle tip adjustment portion 21a of the valve needle 21 is in a position away from the valve port 113a, and the movable stopper 20a is also in a position away from the fixed stopper.

FIG. 7 is a schematic structural diagram of the nut assembly of this embodiment. The nut assembly 120 includes a connecting piece 1202 and a nut 1201. As a specific embodiment, the nut 1201 can be injection molded from a non-metallic material such as a resin material. The connecting piece 1202 is placed as an insert into the mold cavity, and the resin nut 1201 is molded by a resin injection method by an injection molding machine, and a part of the connecting piece 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. The nut assembly 120 is fixedly connected to the valve seat 11. Specifically, the part of the connecting piece 1202 that is 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 opening of the valve seat 11 by press-fitting.

The outer circumference of the nut 1201 is provided with at least one rib 1201a, and at least one rib 1201a extends to the end surface of the nut and protrudes from the upper end surface 1201d of the nut, defining the stop protrusion of the part of the nut 1201 protruding from the upper end surface. A portion 1201c, the stop protrusion 1201c constitutes a fixed stop portion of the electronic expansion valve. As shown in Figure 9, in this embodiment, the outer edge of the nut 1201 is provided with two ribs, one of the ribs 1201a protrudes from the upper end surface of the nut, and the rib protrudes from the upper end surface of the nut to form a stop At least a part of the movable protrusion 1201c, and the upper end of the other rib 1201b is flush with the upper end surface 1201d. The stop protrusion 1201c constitutes the fixed stop part of the electronic expansion valve. The width of the force receiving surface of the stop protrusion 1201c that can receive the collision of the movable stop part 20a is defined as K, and the thickness of the nut relative to the upper end is defined as t, Then it is satisfied: K>t.

The nut 1201 is provided with at least one rib 1201a on its outer edge, and one rib 1201a extends and protrudes from the end surface of the nut to form a part of the stop protrusion 1201c. The stop protrusion 1201c is arranged at the end of the rib 1201a close to the resin nut, and the protrusion amount (Kt) of the stop protrusion 1201c relative to the nut body in the radial direction and the rib relative to the nut body in the radial direction If the projection amount (Kt) of the two is set to be the same, the structure of the molding die can be simplified, and the upper and lower demolding can be facilitated. As shown in Figure 7, the stop protrusion 1201c includes a portion protruding upward along the end of the nut and a portion of the rib 1201a protruding from the end of the nut. The length in the circumferential direction is the width of the rib 1201a. At the same time, the convex ribs and the stop protrusion are integrally injection-molded, which also enhances the strength of the stop protrusion and improves the working life of the stop mechanism of the electronic expansion valve. In particular, due to the arrangement of the ribs, the correlation between the strength of the stop protrusion and the material thickness of the nut body (near the upper end portion) is greatly reduced, that is, even if a thinner nut body thickness is used, it will not The strength of the stop mechanism has too much influence, so that the consumption cost of the resin material can be further reduced. Moreover, generally speaking, the more the resin nut base material and the greater the thickness, the probability of pores in the interior due to injection molding will increase. The nut structure provided by this embodiment can ensure the strength of the stop protrusion. , Relatively less amount of resin can be used, reducing the possibility of pores and improving the dimensional accuracy and dimensional consistency of the resin nut.

It should be noted that in this embodiment, the structure of the nut is mainly described in detail, and the structure of the magnetic rotor assembly that matches it only needs to satisfy that the magnetic rotor assembly is provided with a protrusion on the side facing the nut as a movable stop. It is sufficient that the fixed stop portion provided by the nut can abut against the fixed stop portion to realize the stop. As for the specific structure of the movable stop portion, it will not affect the implementation of this embodiment. Those skilled in the art should understand that all Any magnetic rotor assembly that satisfies this structure can be applied to this embodiment. As for components such as valve seat, valve needle, valve shaft, etc., any possible structure can also be adopted to produce more electronic expansion valve implementations.

The third embodiment

The third embodiment of the present application will be described below with reference to FIGS. 10-14.

Please refer to Figures 10-14, where Figure 10 is a schematic cross-sectional view of the electronic expansion valve of the third embodiment in the closed state, Figure 11 is a schematic cross-sectional view of the electronic expansion valve of the third embodiment in the open state, and Figure 12 is a schematic cross-sectional view of the electronic expansion valve of the third embodiment in an open state. The structure diagram of the nut assembly of the third embodiment, FIG. 13 is a schematic diagram of the matching structure of the valve shaft portion and the stopper of the third embodiment, and FIG. 14 is the magnetic rotor assembly and the valve shaft portion, the valve needle and the stopper of the third embodiment Schematic diagram of the matching structure.

The electronic expansion valve includes a nut assembly 12 fixedly connected to the valve seat 11. Specifically, the nut assembly 12 includes a nut 121 and a connecting piece 122, and the nut 121 is fixedly connected to the connecting piece 122. As a specific embodiment, the nut 121 may be injection molded from a non-metallic material such as a resin material. Specifically, the connecting piece 122 may be used as an insert into the mold cavity, and the resin injection molding method is adopted by an injection molding machine. The resin nut 121 is molded, and a part of the connecting piece 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. The nut assembly 12 is fixedly connected to the valve seat 11. Specifically, the portion of the connecting piece 122 that is not covered by the nut is fixed to the valve seat 11 by welding or riveting, and the nut 121 can be inserted into the upper opening of the valve seat 11 by press-fitting. The nut 121 has a through hole penetrating in its axial direction, and a female threaded portion 12b is provided on the inner side wall of the through hole to form a screw feed mechanism with the male threaded portion 22c provided on the outer edge of the valve shaft portion 22. The valve shaft portion 22 is fixedly connected to the magnetic rotor assembly 27, so the valve shaft portion 22 can rotate synchronously with the rotation of the magnetic rotor. The magnetic rotor assembly 27 can be rotated by induction of 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 or integrally provided with the magnetic rotor 271. The connecting plate 272 is fixedly connected to the valve shaft portion 22. Generally, interference press-fitting connection or riveting connection may be adopted, or the connecting plate 272 and the valve shaft portion 22 may be welded and connected. The top outer edge of the nut 121 is provided with a fixed stop 12d, the fixed stop 12d at least partially protrudes from the upper end surface of the nut 121, or in other words, the fixed stop 12d at least partially protrudes from the ring of the nut in the axial direction. The fixed stop portion 12d shown in the drawings of the present embodiment also protrudes from the annular base in the radial direction, and of course it can also be set so as not to protrude.

As shown in Figure 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, and the valve shaft portion 22 drives the valve needle 21 to rotate. The valve needle 21 can be relative to the valve. The shaft portion 22 relatively moves in the axial direction within a limited elastic displacement range, and can also rotate relatively. The mating manner 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 repeated here.

The valve shaft portion 22 is a generally hollow cylindrical member including a large diameter portion 221 and a small diameter portion 222. For the assembly relationship of the valve shaft portion 22 with the bushing 25, the nut 12, and the valve needle 21, reference may be made to the description of the first embodiment.

The basic principle of the electronic expansion valve is that the coil 40 receives the driving pulse signal to generate a periodically changing magnetic field, and the magnetic rotor 27 is excited to rotate. Since the valve shaft 22 is fixedly connected to the connecting plate 272, the valve shaft 22 is synchronized with the magnetic rotor 27 Rotation, and through the screw feed mechanism between the valve shaft and the nut, the magnetic rotor 27 can also move in the axial direction while rotating, thereby driving the valve needle 21 to move in the axial direction, so that the valve needle 21 The needle tip adjustment portion 21a is close to or away from the valve port 113a, so as to realize the linear switch adjustment function of the flow of the electronic expansion valve. The electronic expansion valve shown in FIG. 10 is in the stop position of the fully closed state, that is, the needle tip adjustment portion 21a of the valve needle 21 is at the lowest end of its stroke, and the valve port 113a is in the fully closed state or at the set minimum opening at this time state. The coil 40 drives the magnetic rotor to move downwards. When the needle tip adjusting portion 21a is in the fully closed state or at the lowermost position of its stroke, a stop mechanism needs to be provided to limit the downward movement of the magnetic rotor assembly.

In this embodiment, a stopper 33 is further included, and the stopper 33 is directly or indirectly fixedly connected to the valve shaft portion 22. The indirect connection mentioned here means that the stopper 33 is fixedly connected to the valve shaft portion 22 through other parts. The stopper 33 is formed by punching and bending a metal plate, and its main body is ring-shaped, and at least a part of the material is bent in the axial direction to form a movable stop portion 33a. Specifically, a complete ring-shaped metal plate can be cut at any position, and then one of the ends can be bent toward the axial direction to form the movable stop 33a. Of course, as an alternative method, the ring-shaped stopper can be formed without bending, but the movable stopper and the stopper can be fixed by welding, etc., so that the movable stopper Protruding along the axial direction of the stopper can also be achieved.

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 relying on the upper surface of the convex ring portion 223. At least part of the stopper 33 can be positioned on the lower surface of the annular convex ring portion 223, so that the installation position of the stopper 33 can be conveniently and accurately positioned on the valve shaft portion 22. Of course, the convex ring portion 223 does not have to be provided. In fact, the relative position of the stopper 33 and the valve shaft portion 22 can be accurately restricted by means of tool positioning. The valve shaft portion 22 and the stopper 33 may be fixedly connected by welding, or may be fixedly connected by 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. Therefore, the stopper 33 will rotate synchronously with the magnetic rotor assembly 27. When the electronic expansion valve is in a fully closed state, or the needle tip adjustment portion 21a of the valve needle 21 of the electronic expansion valve is at the minimum opening degree set by the electronic expansion valve, the movable stop portion 33a of the stopper 33 bends downward It collides with the fixed stop 12d provided at the upper end of the nut assembly 12, thereby realizing the stop and limit of the magnetic rotor assembly, as shown in FIG. 10. When the magnetic rotor assembly rotates in the opposite direction, the stopper 33 also shifts upwards accordingly. At this time, the movable stopper 33a moves upward and separates from the fixed stopper 12d, as shown in FIG. 11. Fig. 11 is a cross-sectional view of the electronic expansion valve of this embodiment in an open state, and the opening position shown in the figure is about 80% of the opening. At this time, the needle tip adjusting portion 21a of the valve needle 21 is in a position away from the valve port 113a, and the movable stopper 33a is also in a position away from the fixed stopper 12d.

In the electronic expansion valve provided by this embodiment, the nut material is made of PPS resin or PEEK resin or PTFE resin. The process is relatively good, and the stopper made of metal material has better wear resistance, can increase the service life of the stop mechanism, and the production cost is relatively low.

Fourth embodiment

The fourth implementation manner of the present application will be described below with reference to FIGS. 15-16.

It should be noted that the difference between the present embodiment and the third embodiment lies in the difference of the movable stopper, so the present embodiment mainly focuses on the structure of the movable stopper. For the remaining parts, you can refer to the first embodiment and the third embodiment for understanding.

Please refer to Figures 15 and 16, where Figure 15 is a schematic structural diagram of a connecting plate provided by a fourth embodiment of the present application, and Figure 16 is a magnetic rotor assembly, valve shaft portion, valve needle, etc. provided by the fourth embodiment of the present application Partial cross-sectional view of the component matching structure. Taking the orientation shown in FIG. 16 as a reference, FIG. 15 shows a schematic diagram of the connecting plate from a bottom view. In this embodiment, the connecting plate 272 can be molded and sintered by metal powder, and generally has a plate-like 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. Generally, interference Press-fit connection, or riveting connection, or welding connection between the connecting plate 272 and the valve shaft portion 22. In order to increase the contact area between 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 used as an insert to place the inner cavity of the mold, 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 with a 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 on the side of the connecting plate. Specifically, the movable stop portion 2722 can be connected with The base body of the connecting plate is formed by integral molding and sintering of metal powder. This processing method can effectively improve the strength of the movable stop 2722, and is easy to process. It can be integrated with the connecting plate, and no additional need to be added for connecting with the nut The fixed stop is matched with the movable stop part. Of course, as an alternative manufacturing method, metal powder can also be used to inject a blank through a mold and then be wound into a shape.

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 then 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 relative to the valve shaft portion 22 in the axial direction within a limited elastic displacement range, and can also rotate relatively.

When the electronic expansion valve is in the fully closed state, or the needle tip adjustment part of the electronic expansion valve is at the minimum opening set by the electronic expansion valve, the downward rotation stroke of the magnetic rotor assembly needs to be stopped and 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, so as to achieve the stop and limit function. When the magnetic rotor assembly rotates in the valve opening direction, the movable stop portion 2722 rotates along with the rotor component and displaces upward, leaving the fixed stop portion 12d.

Fifth embodiment

The fifth embodiment of the present application will be described below with reference to FIGS. 17-26.

This embodiment is a further improvement made on the basis of the first embodiment. The components in this embodiment and the first embodiment that are basically the same in structure and function use the same reference numerals, and only a brief description is given. Those skilled in the art can refer to the relevant description in the first embodiment for understanding.

Fig. 17 is a schematic diagram of the electronic expansion valve of the fifth embodiment in a fully closed state 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, and Fig. 20 is an electronic expansion valve of the fifth embodiment The cross-sectional view of the expansion valve when the spring force is unloaded. Figure 21 is an enlarged view of part III in Figure 20, Figure 22 is an enlarged view of part IV in Figure 20, and Figure 23 is a cross-sectional view of the electronic expansion valve of the fifth embodiment at the critical point of opening 24 is an enlarged view of the V portion in FIG. 23, FIG. 25 is an enlarged view of the VI portion in FIG. 23, and FIG. 26 is a cross-sectional view of the electronic expansion valve of the fifth embodiment in a fully opened state.

The electronic expansion valve includes a valve body component and a coil component 40, wherein the valve body component includes a valve seat 11, a connecting piece 50, a housing 30, and the structure and cooperation of the valve seat 11, the connecting piece 50, the housing 30, and the nut 12 can be referred to the section Description of an embodiment. The valve seat 11 includes a valve port portion 113, a first port portion 111, and a second port portion 112, which define that the refrigerant flows from the first port portion 111 into the electronic expansion valve and flows out of the second port portion 112 through the valve port as the first flow direction , It is defined that the direction in which the refrigerant flows from the second interface 112 into the electronic expansion valve and flows out of the first interface 111 through the valve port is the second flow direction. In this embodiment, the first flow direction is taken as an example for description.

The electronic expansion valve includes a nut assembly 12 fixedly connected to the valve seat 11. The nut assembly 12 includes a nut 121 and a connecting piece 122, and the nut 121 is fixedly connected to the connecting piece 122. The nut 121 has a through hole penetrating in its axial direction, and an internal threaded portion 12b is provided on the inner side wall of the through hole, and the external threaded portion 22c provided on the outer edge of the valve shaft portion 22 forms a screw feed mechanism. The inner side wall of the nut is also provided with a first guide portion 12a, which is provided below the female threaded portion 12b, and can provide a circumferential direction and centering function for the valve needle 21. The valve needle 21 includes a valve needle guide portion 21b, That is, the first guide portion 12a and the valve needle guide portion 21b have a small clearance fit, and the valve needle 21 can rotate or move up and down along the first guide portion 12a of the nut under the drive of the valve shaft portion 22. The first guide portion 12 mentioned here refers to a portion provided on the inner side wall of the nut, and the valve needle guide portion 21b refers to a portion provided on the outer edge of the valve needle. A second guide portion 12c is provided on the opposite upper portion of the inner side wall of the nut, which can provide the valve shaft portion 22 with a guide and centering effect in the circumferential direction. The outer edge of the valve shaft portion 22 is provided with a valve shaft guide portion 22b. The valve shaft guide portion 22b and the second guide portion 12c are in a small clearance fit. The valve shaft portion 22 can be driven by the magnetic rotor assembly along the second guide portion 12c rotates or shifts up and down. The first guide portion 12a and the second guide portion 12c mentioned above are both part of the inner wall of the nut through hole. The shape of the outer edge of the nut and the position of the connecting piece 122 on the outer edge of the nut do not affect the first The setting of the guide part and the second guide part.

The top outer edge of the nut 121 is provided with a fixed stop portion 12d. 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 provided on the magnetic rotor assembly to realize the alignment of the magnetic rotor. The component achieves a stop. The movable stop part 20a and the fixed stop part 12d of this embodiment are the same as those in the first embodiment. Of course, the movable stop part can adopt the structure of the third embodiment or the fourth embodiment, and the fixed stop part is completely The structure of the second embodiment can be adopted. When the magnetic rotor assembly moves down to the lowest 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, so that the downward movement stroke of the magnetic rotor assembly can be controlled.

The magnetic rotor assembly 27 is capable of rotating by inducing 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 to the magnetic rotor 271 or integrally provided. The valve shaft portion 22 is a generally hollow cylindrical member including 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 the rotor fixing portion 22a for fixed connection with 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 the valve shaft guide portion 22b. It is used for small clearance fit with the second guide portion 12c of the nut, so as to realize the guide. The rotor fixing portion 22 a is located relatively above the valve shaft guide portion 22 b, and the valve shaft guide portion 22 b is substantially located in the space enclosed by the magnetic rotor 271. The outer edge portion of the small diameter portion 222 is provided with an external thread portion 22c for forming a screw feed mechanism with the internal thread portion 12b provided on the nut. The valve shaft portion 22 includes a first through hole portion 22e and a second through hole portion 22d. The first through hole portion 22e roughly corresponds to the inner hole portion of the large diameter portion 221, and the second through hole portion 22d roughly corresponds to the small diameter portion. In this way, the inner diameter of the first through-hole portion 22e is larger than the inner diameter 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.

The bushing 25 is fixedly connected to the valve shaft portion 22, the bushing 25 is generally hollow cylindrical, and at least part of the outer edge of the bushing 25 is matched with at least part of the inner edge of the first through hole 22e. The large diameter portion 221 of the valve shaft portion 22 and the bushing 25 form a space. The compression spring 24 is located in this space. The upper end of the compression spring 24 abuts against the bottom end of the bushing 25. It can be a direct abutment or an indirect abutment. For example, a gasket is provided between the spring and the bush to achieve indirect abutment. The other end of the compression spring 24 is in contact with the washer portion 23. As for the washer portion 23, one end thereof abuts against the compression spring 24, and the other end abuts against the valve needle 21.

The valve needle 21 penetrates through the central passage defined by the bushing 25, the valve shaft portion 22 and the nut 12, and the compression spring 24 is sleeved on the periphery of a part of the outer edge of the valve needle 21. The valve needle 21 is rod-shaped as a whole, and has multiple different outer diameters. The bottom end of the valve needle 21 is a needle tip adjustment portion 21a. The valve needle 21 includes a valve needle guide portion 21b, which is used to be smaller than the first guide portion 12a of the nut. With clearance fit, during the rotation of the magnetic rotor, the first guide portion 12a of the nut provides the valve needle 21 with a guide and centering effect in the circumferential direction. Similar to the first embodiment, it is only necessary to ensure that within the stroke of the valve needle, a relatively smooth valve needle guide portion 21b is provided on the outer edge of the valve needle to form a guiding function with the first guide portion 12a of the nut. The valve needle 21 includes a gasket abutting portion 21e for abutting against the gasket 23 so that the gasket 23 will not be displaced downward along the center axis of the valve needle after abutting against the valve needle. A first shaft-shaped portion 21c and a second shaft-shaped portion 21d are respectively provided above the valve needle guide portion of the valve needle 21, wherein the outer diameter of the first shaft-shaped portion 21c is larger than the outer diameter of the second shaft-shaped portion 21d, and The outer diameter of the first shaft-shaped portion 21c is smaller than the outer diameter of the valve needle in the valve needle guide portion. In this way, a step is formed between the first shaft-shaped portion 21c and the second shaft-shaped portion 21d, and the step can be used as a specific embodiment of the gasket abutting portion 21e. The abutting portion 21e abuts against each other. In this embodiment, the number of shim 23 is two, and the shim located on the lower side abuts on the shim abutting portion 21e, and a compression spring 24 is installed on the upper part of the shim 23, namely The lower end of the compression spring 24 abuts against the washer 23, and the upper end of the compression spring 24 abuts against the bottom end of the bush 25. The gasket 23 and the compression spring 24 are all accommodated in the space defined by the large diameter portion of the valve shaft portion 22 and the bush 25. Specifically during assembly, the valve needle 21 is inserted into the central through hole of the valve shaft portion 22 from the bottom up as shown in FIG. Movement; the second shaft-shaped portion 21d penetrates the central through hole of the bushing 25, and penetrates the upper end surface of the bushing 25. The upper end of the second shaft portion 21d is fitted with a valve needle sleeve 26. 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 restricted by the valve needle sleeve 26. After the needle sleeve 26 is fixedly connected, the valve needle 21 will not fall out of the central through hole of the bushing 25 and the valve shaft portion 22 downward. In addition, a floating connection is formed between the valve needle 21 and the magnetic rotor assembly 27. 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 is within a limited range. 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 in clearance fit, and the second shaft portion 21d and the central through hole of the bush 25 are also in clearance fit, so the valve needle 21 is opposite to The valve shaft portion 22 may also be relatively rotated in the circumferential direction.

It should be noted that, similar to the first embodiment, the valve needle guide portion, the first shaft-shaped portion, and the second shaft-shaped portion are all named after their roles in the technical solution, and cannot be mechanically understood or limited. The valve needle can only be composed of the three-section shaft-shaped part shown in FIG. 4. Alternatively, the valve needle 21 can be made in a form of segmented assembly, for example, a threaded connection or welding between two adjacent segments. In fact, as mentioned above, the structure shown in the figure is only an embodiment that facilitates processing.

A return spring 28 is sleeved on the outer circumference of the valve needle sleeve 26. 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 contact position can be based on the relative position of the bushing 25 and the valve shaft portion 22. The relationship and the diameter of the return spring 28 are determined. As shown in Figure 4, the bushing 25 and the top end of the valve shaft portion 22 can be set to be flat or substantially flat. At this time, the return spring can be set to abut against the valve shaft portion 22, or it can be set to contact the bushing 25. Abut against or simultaneously abut against 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 the outer periphery of the valve needle sleeve 26.

The coil 40 of the electronic expansion valve receives the 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 and the magnetic rotor 27 rotate synchronously and pass The screw feed mechanism between the valve shaft and the nut enables the magnetic rotor 27 to move in the axial direction while rotating, thereby driving the valve needle 21 to move in the axial direction, so that the needle tip adjustment part of the valve needle 21 21a is close to or far from the valve port 113a, so as to realize the linear switch adjustment function of the flow of the electronic expansion valve. The electronic expansion valve shown in Figure 17 is in the stop position of the fully closed state, that is, the needle tip adjusting portion 21a of the valve needle is at the lowest end of its stroke, and the valve needle and the valve port 113 conflict, and the valve port 113a is at full Close state. When the magnetic rotor assembly 27 continues to rotate upwards in the valve opening direction from the state shown in FIG. 17, until the external thread portion 22c of the valve shaft portion is upwardly out of the internal thread portion 12b of the nut 12, at this time, the upper end of the return spring 28 has been connected to the housing 30. The top wall abuts against each other, and the return spring 28 is in a compressed state. Since the screw feed mechanism between the valve shaft and the nut has been separated from each other at this time, the magnetic rotor assembly 27 will not continue to move upward. When the valve closing action is required, the magnetic rotor assembly 27 will receive the downward spring force of the return spring 28 while rotating, so that the external thread portion 22c of the valve shaft portion 22 and the internal thread portion 12b of the nut can be restored to the thread again. Engage to ensure that the screw feed mechanism is reorganized.

Please refer to FIGS. 18 and 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. Figure 17 is the stop position of the electronic expansion valve in the fully closed state, that is, the position where the movable stop part 20a just hits the fixed stop part 12d, at this time the needle tip adjustment part 21a of the valve needle 21 is at the lowest end of its stroke , And the valve needle abuts against the valve port 113. As shown in Figure 19, at this time, the valve needle 21 receives the spring force from the compression spring 24 through the washer 23 to the bottom of the figure, and the spring force is then transmitted through the valve needle 21 to the valve needle on the valve port 113. Location. In this embodiment, the number of gaskets is two for description. The gasket 23 includes a first gasket 231 and a second gasket 232. The first gasket 231 is located on the second gasket 232 based on the illustration in FIG. , And the first gasket 231 and the second gasket 232 abut against each other. As an alternative embodiment, the number of spacers may be one or two or more.

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 washer 231, and the lower end of the second washer 232 abuts against the pad of the valve needle 21 At this time, the lower end surface of the second gasket 232 is still a certain distance k from the valve shaft step portion 22f of the valve shaft portion 22. It can also be understood that the second gasket 232 can also face the figure The displacement of the distance k occurs below. 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 the sealing portion of the valve port that contacts the valve needle.

A valve needle sleeve 26 is sleeved and fixed on the upper end of the valve needle 21, and the lower end of the valve needle sleeve 26 has a certain distance h from the upper end of the bushing 25, and satisfies: h>k. In addition, as shown in FIG. 19, the outer diameter of the valve needle sleeve 26 of this 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 greater 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 greater than that of the bushing 25 When the height of the sleeve 25 is high, the valve needle sleeve 26 will not conflict with the bush 25 under any circumstances, but will conflict with the valve shaft portion 22 when it moves 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.

At the starting point of the state shown in FIG. 17, the magnetic rotor assembly 27 is driven by the excitation of the stator coil 40 to rotate upward, and the movable stop portion 20a starts to rotate away from the fixed stop portion 12d. Under the action of the screw feed mechanism, the magnetic rotor assembly 27 and the valve shaft 22 are displaced upwards synchronously. When the lifted height is just k, the electronic expansion valve is at the spring force unloading point.

Please refer to FIGS. 20-22, where FIG. 20 is a cross-sectional view of the electronic expansion valve of the fifth embodiment when the spring force is unloaded; FIG. 21 is an enlarged view of section III in FIG. 20; FIG. 22 is an enlarged view of section IV in FIG. 20 .

At this time, the distance between the lower end of the second gasket 232 and the valve shaft step portion 22f of the valve shaft portion is 0, that is, the spring force of the compression spring 24 is transmitted through the gasket 23, and will act on the valve needle as shown in FIG. The gasket abutment portion 21e of 21 is transferred to the valve shaft step portion 22f acting on the valve shaft portion 22 as shown in FIG. Then it receives 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 at a certain distance from the upper end of the bushing 25, and the distance is h-k. Of course, when the outer diameter of the valve needle sleeve 26 is set to be greater than the outer diameter of the bushing 25, the lower end of the valve needle sleeve 26 and the upper end of the valve shaft portion 22 also have a certain distance h-k.

From the fully closed state shown in FIG. 17 to the spring force unloading point state shown in FIG. 20, the upward displacement of the valve shaft portion 22 and the magnetic rotor assembly 27 is k, and the upward displacement of the valve needle 21 is zero.

As shown in Fig. 20, the magnetic rotor assembly 27 is driven by the excitation of the stator coil 40 to continue to rotate upward, and the magnetic rotor assembly 27 together with the valve shaft 22 continue to move upward synchronously due to the conversion effect of the spiral feeder climbing. When the lifting height is hk, the electronic expansion valve is at the critical point of opening.

Please refer to FIGS. 23-25, where FIG. 23 is a cross-sectional view of the electronic expansion valve in the fifth embodiment when it is at the critical point of opening; FIG. 24 is an enlarged view of the V portion in FIG. 23; FIG. 25 is an enlarged view of the VI portion in FIG. 23. At this time, the valve needle 21 is just in contact with the valve port 113, or it can be understood that as long as the valve needle 21 continues to be displaced upward, it can be separated from the valve port 113. 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 act on 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, that is, from the state of Fig. 20 to Fig. 23, the valve shaft 22 and the rotor are displaced upward in synchronization with 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 friction force of the valve needle 21 relative to the rotational movement of the valve shaft portion 22 will be significantly reduced. That is, at the moment when the valve needle contacts and separates from the valve port, since the valve needle 21 no longer receives the spring force of the compression spring 24, the frictional impact force of the relative rotation between the valve needle and the valve port can be reduced. Reduce the wear of the contact parts of the two and increase the service life of the electronic expansion valve.

From the fully closed state shown in FIG. 17 to the opening critical point state shown in FIG. 23, the upward displacement of the valve shaft portion 22 and the magnetic rotor assembly 27 is h, and the upward displacement of the valve needle 21 is zero.

Please refer to FIG. 26. FIG. 26 is a cross-sectional view of the electronic expansion valve of the fifth embodiment in a fully opened state. At this time, the valve needle 21 has moved away from the valve port 113. During the action from Figure 23 to Figure 26, that is, during the reciprocating action of the electronic expansion valve from the opening critical point to the maximum opening, the valve needle 21 follows the valve shaft. 22. Synchronize the lifting movement in the axial direction. The valve needle 21 is not always subjected to the spring force of the compression spring 24. This can reduce the relative rotation friction between the valve needle 21 and the valve shaft portion 22, and reduce the valve needle guide portion 21b and the nut. The wear between the first guide portions 12a can increase the service life of the electronic expansion valve. From the opening critical point shown in FIG. 23 to the fully opened 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.

The electronic expansion valve is from the unloading point of the spring force of FIG. 20 to the critical point of opening state shown in FIG. 23, the upward displacement of the valve shaft portion 22 and the magnetic rotor assembly 27 is h-k, and the upward displacement of the valve needle 21 is 0. From the fully closed state shown in FIG. 17 to the fully open state shown in FIG. 26, the upward displacement of the valve shaft 22 and the magnetic rotor assembly 27 is L, and the upward displacement of the valve needle 21 is L-h.

In addition, in this embodiment, both the first gasket and the second gasket are in the shape of a plate, and the bottom surface of the second through hole of the valve shaft portion (that is, the stepped portion of the valve shaft) is also flat. The marks of h and k are also shown as the distance in the axial direction between the two planes, but in fact, the contact part of the gasket or the second through hole is not limited to the contact of the two planes, but can be made Various changes, such as changing to the contact of two inclined surfaces in the axial direction, or contact of other irregular shapes, at this time, only need to understand h and k as the displacement difference of the two parts in the axial direction.

It should be noted that the fifth embodiment takes the first flow direction as an example. The fluid pressure of the first interface is greater than the fluid pressure of the second interface. Therefore, the valve needle of the electronic expansion valve is always Subject to the downward pressure differential force of the fluid medium.

In the state of the rotor part shown in FIG. 26, the valve needle 21 is not affected by the spring force generated by the compression spring 24. When there is no pressure difference between the fluid of the first interface part and the fluid of the second interface part, the valve needle 21 It is equivalent to being only affected by its own gravity, that is, after the valve needle 21 is fixedly connected to the valve needle sleeve 26, the valve needle 21 is relative to the valve shaft portion 22 without being subjected to the spring force generated by the compression spring 24. There is also a certain movable gap along its axial direction, the gap size is the same as the gap shown in Figure 25, which is hk.

In the electronic expansion valve provided by this embodiment, the valve needle is in sealing contact with the valve port from the open to the closed state; and from the closed to the open state, the spring force of the compression spring is not applied when the valve pin separates from the valve port. The valve needle can reduce the friction and impact force of the relative rotation of the two sealing parts, thereby reducing the wear of the contact parts and improving the service life of the electronic expansion valve. In addition, during the reciprocating movement of the electronic expansion from the minimum opening to the maximum opening, the spring force of the compression spring is never applied to the valve needle, which reduces the rotational friction between the valve needle and the valve shaft, thereby reducing the valve needle The wear between the guide part and the nut further improves the service life of the electronic expansion valve.

Sixth embodiment

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

In the above five embodiments, the first interface of the electronic expansion valve is connected to the first connecting pipe 10b, and the second interface is connected to the second connecting pipe 10a, that is, the electronic expansion valve is connected to the refrigeration system in the form of a connecting pipe. In fact, the electronic expansion valve of the above-mentioned embodiment can be applied to many fields, and the connection between the electronic expansion valve and the refrigeration system is not limited to the way of connecting pipes. For example, when it is applied to car air conditioners and other occasions that require quick maintenance, it is not necessary to use the structure of the first connection pipe and the second connection pipe, but the valve seat is directly fixedly connected with the integrated valve body integrated with multiple channels, such as adopting The method of flange sealing connection.

Please refer to FIG. 27. FIG. 27 is a schematic structural diagram of an electronic expansion valve according to a sixth embodiment of the present invention. This embodiment is an example in which the electronic expansion valve is applied to an automobile air-conditioning system. The valve seat 11 and the connecting piece 51a are fixed by welding, and then fixedly connected with the valve body 80 as a whole. Wherein, the connecting piece 51a can be adaptively designed into a shape suitable for connecting with the valve body. Specifically, the connecting piece 51a can be fixedly connected to the valve body 80 through a flange sealing connection (not shown in the figure), for example, a screw hole is provided in the disc-shaped part of the connecting piece, and then the connecting piece is connected by a screw. , Make the connecting piece and the valve body fixedly connect. And in order to ensure the sealing performance, a first sealing member 803 is provided before the connecting member and the valve body. In addition, a second sealing member 804 is provided between the valve seat 11 and the valve body 80. After the assembly is completed, the connecting member 51 and the valve seat 11 are fixedly connected to the valve body 80 and maintain good sealing performance.

The valve body 80 can be processed by metal cutting, and forms a first interface end 801 and a second interface end 802. The first interface end 801 and the second interface end 802 are used to connect with other components of the air conditioning system. Of course, the structures of the first interface end 801 and the second interface end 802 are not limited to those shown in FIG. 27, and different layouts can be made according to the needs of the system. In this way, when disassembly and maintenance are required, the valve seat and the connecting piece of the electronic expansion valve can be easily separated from the valve body.

It should be noted that the azimuth nouns such as up, down, left, and right mentioned in this article are all introduced based on the drawings in the specification for ease of description; and the "first" and "second" in the component names "" and other ordinal numbers are also introduced for the convenience of description, and do not imply any restriction on the order of the components. In addition, because the functions of some parts of the components provided in the above embodiments are the same, so This manual uses a unified naming method for these parts. The above gives a detailed introduction to the electronic expansion valve provided by the related technical solutions, and specific embodiments are used in this article to illustrate. The description of the above embodiments is only used to help understand the method and the core idea of the present invention, and is not intended to describe the present invention. Any form of restriction.

Claims

The electronic expansion valve is characterized by comprising 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, the nut assembly is fixedly connected to the valve seat, and the nut The assembly 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 than the internal thread portion, and the second guide Portion is farther away from the valve port than the internal thread portion, and 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, the valve shaft guide portion is in clearance fit with the second guide portion, and the valve shaft portion can be opposed to the The nut is relatively displaced along the axial direction of the nut; the valve shaft portion includes an external thread portion, and the external thread portion and the internal thread portion form a screw feed mechanism; the valve shaft portion includes a first through hole Part and a second through hole part, the inner diameter of the first through hole part is greater than the inner diameter of the second through hole part;

The valve needle includes a valve needle guide portion, the valve needle guide portion is in clearance fit with the first guide portion, and the valve needle is capable of relative displacement relative to the nut along the axial direction of the nut; the valve The outer diameter of the needle guide part is larger than the inner diameter of the second through hole part.
The electronic expansion valve of claim 1, wherein the valve shaft portion includes a large-diameter portion and a small-diameter portion, and the outer diameter of the large-diameter portion is larger than that of the small-diameter portion, and the large-diameter portion Farther away from the valve port portion with respect to the small diameter portion, the external thread portion is provided on the outer edge portion of the small diameter portion, and the valve shaft guide portion is provided on the outer edge portion of the large diameter portion.
The electronic expansion valve of claim 2, wherein the outer edge of the large-diameter portion is provided with a rotor fixing portion, the magnetic rotor assembly includes a magnetic rotor and a connecting plate, and the magnetic rotor is connected to the connecting plate. The plate is fixedly connected or is an integral structure, and the rotor fixing part is fixedly connected to the connecting plate.
The electronic expansion valve according to any one of claims 1 to 3, wherein the electronic expansion valve comprises a bushing, and at least part of the outer edge of the bushing and at least part of the first through hole part The inner edge part is matched, and the bush is fixedly connected with the valve shaft part.
The electronic expansion valve of claim 4, wherein the electronic expansion valve comprises a compression spring and a gasket, one end of the compression spring is in contact with the bushing, and the other end of the compression spring is in contact with the bushing. The gasket abuts, the valve needle includes a gasket abutment portion, and the gasket abuts the gasket abutment portion.
The electronic expansion valve according to claim 5, wherein a valve shaft step portion is provided between the first through hole portion and the second through hole portion, and the valve shaft step portion is capable of interacting with the pad The pieces meet each other.
The electronic expansion valve of claim 5 or 6, wherein the compression spring is accommodated in a space formed by the valve shaft portion and the bushing, and the maximum outer diameter of the compression spring is larger than that of the second The inner diameter of the through hole.
The electronic expansion valve according to claim 1, wherein the nominal diameter of the screw thread of the screw feed mechanism is smaller than the inner diameter of the first through hole, and the nominal diameter of the screw thread of the screw feed mechanism is slightly larger than the inner diameter of the first through hole. The outer diameter of the valve needle guide.
The electronic expansion valve of claim 1, wherein the valve needle includes a first shaft-shaped portion and a second shaft-shaped portion, and the outer diameter of the first shaft-shaped portion is larger than that of the second shaft-shaped portion The outer diameter of the first shaft-shaped portion is smaller than the outer diameter of the valve needle guide portion.
The electronic expansion valve according to claim 1, wherein the electronic expansion valve comprises a connecting piece, a first interface part, a second interface part and a valve body, and the valve body is formed by cutting and includes a first interface End and the second interface end, the valve seat is fixedly connected with the connecting piece, the connecting piece is connected with the valve body by a flange, and a first sealing piece is provided between the connecting piece and the valve body , A second sealing element is provided between the valve seat and the valve body.