CN216242310U

CN216242310U - Electronic expansion valve

Info

Publication number: CN216242310U
Application number: CN202122859274.4U
Authority: CN
Inventors: 康志军; 朱方英
Original assignee: Zhejiang DunAn Hetian Metal Co Ltd
Current assignee: Zhejiang DunAn Hetian Metal Co Ltd
Priority date: 2021-11-19
Filing date: 2021-11-19
Publication date: 2022-04-08
Anticipated expiration: 2031-11-19
Also published as: WO2023088253A1

Abstract

The utility model provides an electronic expansion valve, comprising: the valve shell is provided with a valve cavity and a valve port which are communicated; the nut seat is arranged in the valve cavity, is connected with the valve shell and is provided with a threaded through hole; the valve needle is movably arranged in the threaded through hole in a penetrating mode, is provided with a first end and a second end which are arranged oppositely, and is provided with an external thread; the magnetic rotor is rotatably arranged in the valve cavity; the connecting plate is arranged between the magnetic rotor and the valve needle and is provided with a first through hole, the first end of the valve needle penetrates through the first through hole and is fixedly connected with the connecting plate, and the outer ring of the connecting plate is connected with the magnetic rotor; and the stopper is arranged on the periphery of the nut seat, the upper surface of the stopper is connected with the bottom surface of the connecting plate, and a stopping structure is arranged between the stopper and the nut seat. Through the technical scheme provided by the application, the problem of complex structure in the prior art is solved.

Description

Electronic expansion valve

Technical Field

The utility model relates to the field of electronic expansion valves, in particular to an electronic expansion valve.

Background

At present, an existing electronic expansion valve generally comprises a valve body, a nut, a valve needle, a magnetic rotor, a connecting plate, a stop ring and a screw rod. When the valve is used, the nut, the valve needle, the magnetic rotor, the connecting plate and the screw rod are all arranged inside the valve body, the nut is assembled on the valve body, the screw rod is movably assembled in the nut, the valve needle is installed inside the screw rod, the magnetic rotor is arranged on the periphery and covers a part of the nut, the stop ring is sleeved in the magnetic rotor, and the screw rod is fixed with the connecting plate.

Among the prior art, the lead screw is fixed with the connecting plate, and the needle setting is inside the lead screw to realize reciprocating of needle, so set up, make electronic expansion valve inner structure complicated, cause the installation difficulty, greatly increased manufacturing cost.

SUMMERY OF THE UTILITY MODEL

The utility model provides an electronic expansion valve, which aims to solve the problems of complex structure and difficult installation in the prior art.

The utility model provides an electronic expansion valve, comprising: the valve shell is provided with a valve cavity and a valve port, and the valve port is communicated with the valve cavity; the nut seat is arranged in the valve cavity and is fixedly connected with the valve shell, and a threaded through hole is formed in the nut seat; the valve needle is movably arranged in the threaded through hole in a penetrating mode and provided with a first end and a second end which are arranged oppositely, an external thread is arranged on the valve needle and is in threaded connection with the threaded through hole, the second end of the valve needle is arranged corresponding to the valve port, and the second end of the valve needle is used for controlling the opening degree of the valve port; the magnetic rotor is rotatably arranged in the valve cavity; the connecting plate is arranged between the magnetic rotor and the valve needle, a first through hole is formed in the connecting plate, the first end of the valve needle penetrates through the first through hole and is fixedly connected with the connecting plate, and the outer ring of the connecting plate is fixedly connected with the magnetic rotor; and the stopper is arranged on the periphery of the nut seat, the upper surface of the stopper is fixedly connected with the bottom surface of the connecting plate, and a stopping structure is arranged between the stopper and the nut seat to limit the stroke of the valve needle.

By applying the technical scheme of the utility model, the electronic expansion valve comprises a valve shell, a nut seat, a valve needle, a magnetic rotor, a connecting plate and a stopper. The outer ring of the connecting plate is fixedly connected with the magnetic rotor, the valve needle is fixedly connected with the connecting plate through the first through hole, and the upper surface of the retainer is fixedly connected with the bottom surface of the connecting plate. When the electronic expansion valve works, the magnetic rotor drives the connecting plate to rotate, the connecting plate drives the valve needle and the retainer to rotate respectively, and the connecting plate is fixedly connected with the valve needle to ensure the coaxiality of the valve needle and a valve port.

Furthermore, a second through hole is formed in the retainer, the second through hole and the first through hole are coaxially arranged, the second through hole comprises a first hole section and a second hole section which are communicated with each other, the valve needle sequentially penetrates through the second through hole and the first through hole, the inner wall of the first hole section and the valve needle are in transition fit, one end, far away from the valve port, of the nut seat extends into the second hole section, and the stopping structure is arranged between the second hole section and the nut seat. The needle passes first hole section and with first hole section transitional coupling, can effectively prevent the slope of needle, avoids rocking of needle.

Further, the stopper structure includes: the first stop boss and the second stop boss are arranged on the inner wall of the second hole section at intervals along the circumferential direction of the second through hole; the stopping part is arranged on the outer side wall of the nut seat, the stopping part is positioned between the first stopping boss and the second stopping boss, the valve needle has a maximum opening position for opening the valve port and a closing position for blocking the valve port, when the valve needle moves to the closing position, the first stopping boss is abutted against the stopping part, and when the valve needle moves to the maximum opening position, the second stopping boss is abutted against the stopping part. So set up, confirm the needle range of motion from top to bottom, both avoided the needle to rise the displacement too high and make the valve body volume too big, avoided the needle to produce when dropping again and assault the valve port and cause the damage of needle or valve port, improved this electronic expansion valve's life.

Furthermore, the upper surface of the retainer is provided with a protruding part, the connecting plate is provided with a mounting hole, and the protruding part is riveted in the mounting hole. The mounting hole is matched with the shape of the protruding part so as to ensure the connection stability between the mounting hole and the protruding part.

Furthermore, the number of the protruding parts is multiple, the number of the mounting holes is multiple, and the protruding parts and the mounting holes are arranged in a one-to-one correspondence mode. By such arrangement, relative displacement between the mounting plate and the stopper can be avoided.

Further, the stopper is provided integrally with the connecting plate. The coaxiality between the retainer and the connecting plate is better, and the structural stability between the retainer and the connecting plate is improved.

Further, the valve needle is connected with the connecting plate in a welding mode. Therefore, the valve needle and the connecting plate can be firmly connected, and the valve needle can be prevented from shaking.

Further, the connecting plate and the stopper are disposed inside the magnetic rotor, and an outer side wall of the stopper is attached to an inner wall of the magnetic rotor. Therefore, the stopper cannot shake in the rotating process, and the running stability of the stopper is ensured.

Furthermore, the retainer is also provided with a demolding through hole which is arranged along the axial direction and corresponds to the second stopping boss. The processing steps of the stopper are simplified to ensure that the demolding process can be smoothly performed.

Furthermore, the stopping part is arranged on the side wall of one end, far away from the valve port, of the nut seat, the stopping part extends along the circumferential direction of the nut seat, and the stopping part is provided with a first end surface and a second end surface which are oppositely arranged; the first stopping boss is provided with a first stopping surface, the second stopping boss is provided with a second stopping surface, one of the first end surface and the second end surface is used for being attached to and abutted against the first stopping surface, and the other of the first end surface and the second end surface is used for being attached to and abutted against the second stopping surface. The end face and the stopping face are in contact with each other through the face, so that the pressure intensity can be effectively reduced, and the damage of the stopping structure or the stopping part caused by impact force when the end face is in contact with the stopping face is avoided.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the utility model and, together with the description, serve to explain the utility model and not to limit the utility model. In the drawings:

FIG. 1 is a schematic diagram of an electronic expansion valve provided by the present invention;

FIG. 2 is a schematic view showing the construction of a stopper provided by the present invention;

FIG. 3 is another schematic view showing the construction of a stopper provided by the present invention;

fig. 4 shows a schematic structural view of the nut seat provided by the utility model.

Wherein the figures include the following reference numerals:

10. a valve housing; 11. a valve cavity; 12. a valve port; 20. a valve needle; 21. a first end; 22. a second end; 30. a nut seat; 31. a threaded through hole; 32. a stopper portion; 40. a magnetic rotor; 50. a connecting plate; 60. a stopper; 61. a stop structure; 611. a first stop boss; 612. a second stop boss; 62. a second through hole; 621. a first bore section; 622. a second bore section; 63. demolding the through hole; 64. a raised portion.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the utility model, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 and 2, an embodiment of the present invention provides an electronic expansion valve including a valve housing 10, a nut seat 30, a valve needle 20, a magnetic rotor 40, a connecting plate 50, and a stopper 60. The valve housing 10 has a valve chamber 11 and a valve port 12, the valve port 12 communicating with the valve chamber 11. The nut seat 30 is disposed in the valve chamber 11 and is fixedly connected to the valve housing 10, and the nut seat 30 is provided with a threaded through hole 31. The valve needle 20 is movably disposed in the threaded through hole 31, the valve needle 20 has a first end 21 and a second end 22 disposed opposite to each other, an external thread is disposed on the valve needle 20, the external thread is threadedly connected to the threaded through hole 31, the second end 22 of the valve needle 20 is disposed corresponding to the valve port 12, and the second end 22 of the valve needle 20 is used for controlling the opening degree of the valve port 12. The magnet rotor 40 is rotatably disposed within the valve chamber 11. The connecting plate 50 is arranged between the magnetic rotor 40 and the valve needle 20, a first through hole is arranged on the connecting plate 50, the first end 21 of the valve needle 20 penetrates through the first through hole and is fixedly connected with the connecting plate 50, and the outer ring of the connecting plate 50 is fixedly connected with the magnetic rotor 40. The stopper 60 is disposed at an outer circumference of the nut seat 30, an upper surface of the stopper 60 is fixedly connected with a bottom surface of the coupling plate 50, and a stopper structure 61 is provided between the stopper 60 and the nut seat 30 to limit a stroke of the valve needle 20.

By the technical solution of the present application, the electronic expansion valve includes a valve housing 10, a nut seat 30, a valve needle 20, a magnetic rotor 40, a connection plate 50, and a stopper 60. Wherein, the outer ring of the connecting plate 50 is fixedly connected with the magnetic rotor 40, the valve needle 20 is fixedly connected with the connecting plate 50 through the first through hole, and the upper surface of the stopper 60 is fixedly connected with the bottom surface of the connecting plate 50. When the electronic expansion valve works, the magnetic rotor 40 drives the connecting plate 50 to rotate, the connecting plate 50 drives the valve needle 20 and the stopper 60 to rotate respectively, and the connecting plate 50 is fixedly connected with the valve needle 20 to ensure the coaxiality of the valve needle 20 and the valve port 12.

The stopper 60 is provided with a second through hole 62, the second through hole 62 is coaxial with the first through hole, the second through hole 62 comprises a first hole section 621 and a second hole section 622 which are communicated with each other, the valve needle 20 sequentially penetrates through the second through hole 62 and the first through hole, the inner wall of the first hole section 621 and the valve needle 20 are in transition fit, one end of the nut seat 30, which is far away from the valve port 12, extends into the second hole section 622, and the stopping structure 61 is arranged between the second hole section 622 and the nut seat 30. The valve needle 20 passes through the first hole section 621 and is in transition connection with the first hole section 621, so that the valve needle 20 can be effectively prevented from being inclined, the valve needle 20 is prevented from shaking, and the coaxiality between the magnetic rotor 40, the connecting plate 50, the valve needle 20, the stopper 60 and the valve port 12 is further ensured.

As shown in fig. 2 and 4, the stop structure 61 includes a first stop boss 611 and a second stop boss 612, and the first stop boss 611 and the second stop boss 612 are disposed on the inner wall of the second hole section 622 at intervals in the circumferential direction of the second through hole 62. The stopper 32 is disposed on the outer sidewall of the nut seat 30, the stopper 32 is located between the first stopper boss 611 and the second stopper boss 612, the valve needle 20 has a maximum opening position for opening the valve port 12 and a closing position for closing the valve port 12, the first stopper boss 611 abuts against the stopper 32 when the valve needle 20 moves to the closing position, and the second stopper boss 612 abuts against the stopper 32 when the valve needle 20 moves to the maximum opening position. In this embodiment, the first stop boss 611 is located above the second stop boss 612, the stop portion 32 is disposed on the outer side wall of the nut seat 30, when the stop portion 32 abuts against the first stop boss 611, the valve needle 20 moves to the lowest position, the valve needle 20 is closed with the valve port 12, and fluid is prevented from passing through; when the stopper portion 32 abuts against the second stopper boss 612, the needle 20 moves to the highest position, and the opening degree between the needle 20 and the valve port 12 is maximized. By the arrangement, the vertical movement range of the valve needle 20 is determined, so that the phenomenon that the valve body is too large due to too high ascending displacement of the valve needle 20 is avoided, the damage to the valve needle 20 or the valve port 12 caused by impact on the valve port 12 when the valve needle 20 falls is avoided, and the service life of the electronic expansion valve is prolonged.

As shown in fig. 3, the stopper 60 is provided with a projection 64 on an upper surface thereof, and the connecting plate 50 is provided with a mounting hole in which the projection 64 is riveted. Optionally, the protrusion 64 is a non-cylindrical body, and the mounting hole is matched with the shape of the protrusion 64 to ensure the connection stability between the two, so as to prevent the relative displacement between the stopper 60 and the connecting plate 50 during the rotation process. In other embodiments, the connecting plate 50 may be fixedly connected to the stopper 60 by welding or the like. Further, there are a plurality of bosses 64 and a plurality of mounting holes, and the bosses 64 are disposed in one-to-one correspondence with the mounting holes. The projection 64 may be provided in one or more, and in the present application, a plurality of projections 64 are provided. As shown in fig. 3, three protrusions 64 are provided, so that relative displacement between the mounting plate and the stopper 60 can be prevented, and structural stability between the mounting plate and the stopper 60 can be ensured.

Specifically, the valve needle 20 is welded to the connecting plate 50. Therefore, the valve needle 20 and the connecting plate 50 are firmly connected, the valve needle 20 can be prevented from shaking, the coaxiality between the valve needle 20 and the valve port 12 can be guaranteed to be good, welding is adopted, and the valve needle is high in efficiency and good in economical efficiency.

Specifically, the connecting plate 50 and the stopper 60 are disposed inside the magnetic rotor 40, and the outer side wall of the stopper 60 is attached to the inner wall of the magnetic rotor 40. The magnetic rotor 40 drives the connecting plate 50 and the stopper 60 to rotate simultaneously, and because the outer side wall of the stopper 60 is attached to the inner wall of the magnetic rotor, the stopper 60 does not shake in the rotating process, and the running stability of the stopper 60 is ensured. The outer side wall of the stopper 60 is attached to the inner wall of the magnetic rotor 40, the structural stability between the stopper 60 and the magnetic rotor 40 is good, so that the coaxiality between the first through hole and the valve port 12 is good, and the first through hole and the valve needle 20 are in transition fit, so that the valve needle 20 and the valve port 12 have good coaxiality.

Further, the stopper 60 is further provided with a mold release through hole 63, and the mold release through hole 63 is axially provided corresponding to the second stopper boss 612. The upper surface of the first stopping boss 611 is attached to the upper surface of the second hole section 622, a certain distance is reserved between the second stopping boss 612 and the upper surface of the second hole section 622, and the retainer 60 is integrally injection-molded, so that the retainer 60 is provided with the demolding through hole 63, and the second stopping boss 612 axially corresponds to the demolding through hole 63, so that the processing steps of the retainer 60 can be simplified. Optionally, the structural size of the demolding through hole 63 is slightly larger than that of the second stopping boss 612, so as to ensure that the demolding process can be smoothly performed and the demolding effect is ensured.

The stopper 32 is disposed on a sidewall of one end of the nut seat 30 far away from the valve port 12, the stopper 32 extends along a circumferential direction of the nut seat 30, and the stopper 32 has a first end surface and a second end surface which are disposed opposite to each other. The first stopping boss 611 has a first stopping surface, the second stopping boss 612 has a second stopping surface, one of the first end surface and the second end surface is used for being attached to and abutted against the first stopping surface, and the other of the first end surface and the second end surface is used for being attached to and abutted against the second stopping surface. The end face and the stopping face are in contact with each other through the face, so that the pressure intensity can be effectively reduced, and the damage of the stopping structure or the stopping part caused by impact force when the end face is in contact with the stopping face is avoided. Specifically, the stopper portion 32 extends in the circumferential direction of the nut holder 30, and the first end surface and the second end surface are located on both end surfaces of the stopper portion 32 extending in the axial direction. The first stopping boss 611 and the second stopping boss 612 extend along the radial direction of the second hole section, the first stopping surface is located on the side surface of the first stopping boss 611, the second stopping surface is located on the side surface of the second stopping boss 612, the first end surface and the first stopping surface are arranged in parallel, the second end surface and the second stopping surface are arranged in parallel, and the arrangement enables the stopping portion 32 to be completely attached to the stopping surface when the stopping portion 32 rotates to the maximum opening position or the closing position.

Through the technical scheme of this application, the first end of needle 20 and the first through-hole fixed connection of connecting plate 50, the external screw thread that needle 20 middle part set up and the threaded through-hole 31 threaded connection of nut seat 30, valve body inner structure is simple, and the part is less, simple to operate, easy and simple to operate.

The second embodiment of the present invention provides an electronic expansion valve, which is different from the first embodiment in that: the stopper 60 is integrally provided with the connecting plate 50. The retainer 60 may be integrally injection molded with the connecting plate 50, and thus, the coaxiality between the retainer 60 and the connecting plate 50 is improved, and the structural stability between the retainer 60 and the connecting plate 50 is improved. In addition, the manufacturing steps of the stopper 60 and the connecting plate 50 are simplified, the installation efficiency is improved, and the labor is saved.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc. are usually based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and in the case of not making a reverse description, these orientation words do not indicate and imply that the device or element being referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore, should not be considered as limiting the scope of the present invention; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An electronic expansion valve, comprising:

a valve housing (10), the valve housing (10) having a valve cavity (11) and a valve port (12), the valve port (12) being in communication with the valve cavity (11);

the nut seat (30) is arranged in the valve cavity (11) and is fixedly connected with the valve shell (10), and a threaded through hole (31) is formed in the nut seat (30);

the valve needle (20) is movably arranged in the threaded through hole (31) in a penetrating manner, the valve needle (20) is provided with a first end (21) and a second end (22) which are arranged oppositely, an external thread is arranged on the valve needle (20) and is in threaded connection with the threaded through hole (31), the second end (22) of the valve needle (20) is arranged corresponding to the valve port (12), and the second end (22) of the valve needle (20) is used for controlling the opening degree of the valve port (12);

a magnet rotor (40), the magnet rotor (40) being rotatably disposed within the valve cavity (11);

the connecting plate (50) is arranged between the magnetic rotor (40) and the valve needle (20), a first through hole is formed in the connecting plate (50), the first end (21) of the valve needle (20) penetrates through the first through hole and is fixedly connected with the connecting plate (50), and the outer ring of the connecting plate (50) is fixedly connected with the magnetic rotor (40);

and the stopper (60) is arranged on the periphery of the nut seat (30), the upper surface of the stopper (60) is fixedly connected with the bottom surface of the connecting plate (50), and a stopping structure (61) is arranged between the stopper (60) and the nut seat (30) so as to limit the stroke of the valve needle (20).

2. An electronic expansion valve according to claim 1, wherein the retainer (60) is provided with a second through hole (62), the second through hole (62) is coaxially arranged with the first through hole, the second through hole (62) comprises a first hole section (621) and a second hole section (622) which are communicated with each other, the valve needle (20) is sequentially arranged through the second through hole (62) and the first through hole, the inner wall of the first hole section (621) and the valve needle (20) are in transition fit, one end of the nut seat (30) far away from the valve port (12) extends into the second hole section (622), and the stop structure (61) is arranged between the second hole section (622) and the nut seat (30).

3. An electronic expansion valve according to claim 2, wherein the stop structure (61) comprises:

a first stopping boss (611) and a second stopping boss (612) which are arranged on the inner wall of the second hole section (622) at intervals along the circumferential direction of the second through hole (62);

a stopper (32) disposed on an outer sidewall of the nut seat (30), the stopper (32) being located between the first stopper boss (611) and the second stopper boss (612), the valve needle (20) having a maximum opening position for opening the valve port (12) and a closing position for closing the valve port (12), the first stopper boss (611) abutting against the stopper (32) when the valve needle (20) moves to the closing position, and the second stopper boss (612) abutting against the stopper (32) when the valve needle (20) moves to the maximum opening position.

4. An electronic expansion valve according to claim 1, wherein the stopper (60) is provided at an upper surface thereof with a projection (64), and the connecting plate (50) is provided with a mounting hole, the projection (64) being riveted into the mounting hole.

5. An electronic expansion valve according to claim 4, wherein the number of the protrusions (64) is plural, the number of the mounting holes is plural, and the protrusions (64) are provided in one-to-one correspondence with the mounting holes.

6. An electronic expansion valve according to claim 1, wherein the stopper (60) is provided integrally with the connection plate (50).

7. An electronic expansion valve according to claim 1, wherein the valve needle (20) is in welded connection with the connection plate (50).

8. An electronic expansion valve according to claim 1, wherein the connection plate (50) and the stopper (60) are arranged inside the magnetic rotor (40), an outer side wall of the stopper (60) abutting against an inner wall of the magnetic rotor (40).

9. The electronic expansion valve according to claim 3, wherein the stopper (60) is further provided with a knockout through-hole (63), the knockout through-hole (63) being provided in correspondence with the second stopper boss (612) in the axial direction.

10. The electronic expansion valve of claim 3,

the stopping part (32) is arranged on a side wall of one end of the nut seat (30) far away from the valve port (12), the stopping part (32) extends along the circumferential direction of the nut seat (30), and the stopping part (32) is provided with a first end surface and a second end surface which are oppositely arranged;

the first stopping boss (611) is provided with a first stopping surface, the second stopping boss (612) is provided with a second stopping surface, one of the first end surface and the second end surface is used for being jointed and abutted with the first stopping surface, and the other of the first end surface and the second end surface is used for being jointed and abutted with the second stopping surface.