Valve needle assembly and electronic expansion valve

Abstract

The invention relates to the technical field of electronic expansion valves, in particular to a valve needle assembly and an electronic expansion valve. The valve needle assembly comprises a valve needle, a lead screw, a bearing and an elastic piece. The valve needle is provided with an inner cavity capable of containing the elastic piece, and a limiting part is arranged at the top of the inner cavity. The outer ring of the bearing is positioned below the limiting part; the bottom of the elastic piece abuts against the bottom wall of the inner cavity, and the top of the elastic piece abuts against the bottom of the outer ring of the bearing, so that the outer ring of the bearing can abut against the limiting part; the bottom of the lead screw is fixedly connected with an inner ring of the bearing. Therefore, the problems of poor sealing performance, high noise and low durability and reliability in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic expansion valves, and in particular to a valve needle assembly and an electronic expansion valve. Background Art

[0002] The electronic expansion valve uses the principle of a stepper motor to drive the magnetic rotor to rotate through a coil, and converts the rotational motion of the magnetic rotor into the axial motion of the screw rod. The screw rod drives the valve needle connected to it to rise or fall, thereby controlling the flow rate of the electronic expansion valve. The nut of the electronic expansion valve is provided with an internal thread, and the nut is fixed to the valve seat. The nut thread matches the external thread of the screw rod. When the screw rod rotates, the screw rod rotates through the thread to realize the up and down movement of the screw rod. The screw rod is connected to the valve needle, and the valve needle matches the valve port, thereby realizing the opening and closing effect of the valve needle controlling the valve port.

[0003] However, the existing electronic expansion valve technology has the following defects.

[0004] First, the rotation of the screw rod will drive the spring to rotate. The spring compression will generate a rotational sliding friction force, which will drive the valve needle to rotate. After long-term switching operation, the relative movement of the contact point between the valve needle and the valve seat will cause wear, resulting in a decrease in the tightness and shortening the service life of the expansion valve.

[0005] Second: Due to the relative rotational motion between the valve needle and the valve port, friction noise is generated between the two parts, and sliding friction between the screw rod and the valve needle also generates friction noise, which seriously affects the noise performance. Summary of the invention

[0006] The objects of the present invention include, for example, providing a valve needle assembly and an electronic expansion valve, which can improve the problems of poor sealing performance, high noise, and low durability and reliability in the prior art.

[0007] The embodiments of the present invention can be implemented as follows:

[0008] In a first aspect, the present invention provides a valve needle assembly, comprising:

[0009] Valve needles, screw rods, bearings and elastic parts;

[0010] The valve needle has an inner cavity capable of accommodating the elastic member, and a limiting portion is provided on the top of the inner cavity; the outer ring of the bearing is located below the limiting portion;

[0011] The bottom of the elastic member is pressed against the bottom wall of the inner cavity, and the top of the elastic member is pressed against the bottom of the outer ring of the bearing, so that the outer ring of the bearing can be pressed against the limiting portion;

[0012] The bottom of the screw rod is fixedly connected to the inner ring of the bearing.

[0013] In an optional embodiment, the elastic member is a spring, the top of the spring is pressed against the bottom of the outer ring of the bearing, and the bottom of the spring is pressed against the bottom wall of the inner cavity.

[0014] In an optional embodiment, there is a gap between the elastic member and the side wall of the inner cavity.

[0015] In an optional embodiment, a supporting plane is provided on the bottom wall of the inner cavity, and the bottom of the elastic member is provided on the supporting plane.

[0016] In an optional embodiment, the valve needle assembly further includes a first connecting portion and a second connecting portion;

[0017] The first connecting portion and the second connecting portion are both fixedly arranged at the lower portion of the screw rod;

[0018] Along the radial direction of the screw rod, the width of the first connecting portion and the second connecting portion is greater than the inner diameter of the inner ring of the bearing and smaller than the inner diameter of the outer ring of the bearing;

[0019] The first connection portion is located at the top of the inner ring of the bearing, and the second connection portion is located at the bottom of the inner ring of the bearing, so that the bearing can be fastened between the first connection portion and the second connection portion, thereby fixing the bearing to the screw rod.

[0020] In an optional embodiment, the first connecting portion is a boss disposed on the screw rod, and the boss is integrally formed with the screw rod.

[0021] In an optional embodiment, the second connecting portion is a screw bushing sleeved on the bottom of the screw.

[0022] In an optional embodiment, the top of the inner cavity forms an open top opening, and the limiting portion is a bearing sleeve arranged at the top opening of the inner cavity; the inner diameter of the bearing sleeve is greater than or equal to the inner diameter of the outer ring of the bearing.

[0023] In an optional embodiment, the top of the inner cavity forms an open top opening; the limiting portion is a riveted structure formed by riveting the side wall of the valve needle, and the riveted structure extends toward the center of the top opening; the inner diameter of the riveted structure is greater than or equal to the inner diameter of the outer ring of the bearing.

[0024] In a second aspect, the present invention provides an electronic expansion valve, comprising the valve needle assembly described in any one of the aforementioned embodiments.

[0025] The beneficial effects of the embodiments of the present invention include, for example:

[0026] The valve needle assembly of the present solution includes a valve needle, a screw rod, a bearing and an elastic member. The screw rod is movably connected to the valve needle through the bearing and the elastic member, and the screw rod is only connected to the inner ring of the bearing, and the outer ring of the bearing is matched with the inner wall of the inner cavity of the valve needle. Because the inner ring of the bearing and the outer ring of the bearing rotate relatively and the rotation resistance is very small, the screw rod and the valve needle will not directly contact each other, and the valve needle can remain stationary when the screw rod rotates. Compared with the prior art, when the screw rod rotates, the valve needle is driven to rotate, so that the valve needle and the valve port rotate relative to each other, and the valve needle and the valve port are worn, which leads to problems such as reduced sealing, abnormal noise and reduced reliability. In the present solution, a bearing is arranged between the valve needle and the screw rod, so that the valve needle and the valve port will not rotate relative to each other or rotate slightly, but can also be stationary due to the smaller rolling friction of the bearing at the moment when the valve needle just contacts the valve port, thereby improving the reliability problem of sealing failure due to wear between the valve needle and the valve port in the prior art. At the same time, the problem of poor sealing performance caused by the rotation of the screw rod driving the valve needle to rotate and finally wearing the valve port in the prior art is improved. In addition, when the valve needle assembly is working, that is, when the valve needle rises or falls, the valve needle and the valve port will not rotate relative to each other. At the same time, because a bearing is added between the screw rod and the valve needle, no sliding friction is generated between the screw rod and the valve needle, thereby improving the problem in the prior art that sliding friction between the screw rod and the valve needle causes greater friction between the nut and the screw thread, which in turn leads to greater wear of the nut during the durability test and ultimately causes failure of the nut component. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 This is a schematic structural diagram of a valve needle assembly according to Embodiment 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of an electronic expansion valve according to Embodiment 1 of the present invention;

[0030] Figure 3 Schematic diagram of the structure of the valve needle assembly according to the second embodiment of the present invention.

[0031] Icons: 10-valve needle assembly; 100-valve needle; 110-inner cavity; 111-top port; 112-support plane; 200-screw; 300-bearing; 310-inner ring; 320-outer ring; 400-elastic member; 500-limiting portion; 510-bearing sleeve; 520-rivet structure; 210-first connecting portion; 600-second connecting portion; 20-electronic expansion valve; 21-valve port; 22-valve seat; 23-sleeve; 24-magnet; 25-connecting plate; 26-nut member; 26a-slide groove; 27-stop rod; 28-slip ring; 29-slip ring extension. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0035] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0037] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0038] Embodiment 1

[0039] Please refer to Figure 1This embodiment provides a valve needle assembly 10 , including a valve needle 100 , a screw rod 200 , a bearing 300 and an elastic member 400 .

[0040] The valve needle 100 has an inner cavity 110 capable of accommodating the elastic member 400, and a limiting portion 500 is provided at the top of the inner cavity 110; the outer ring 320 of the bearing 300 is located below the limiting portion 500;

[0041] The bottom of the elastic member 400 is pressed against the bottom wall of the inner cavity 110, and the top of the elastic member 400 is pressed against the bottom of the outer ring 320 of the bearing 300, so that the outer ring 320 of the bearing 300 can be pressed against the limiting portion 500;

[0042] The bottom of the screw rod 200 is fixedly connected to the inner ring 310 of the bearing 300 .

[0043] The valve needle assembly 10 of the present solution includes a valve needle 100, a screw rod 200, a bearing 300 and an elastic member 400. The screw rod 200 is movably connected to the valve needle 100 through the bearing 300 and the elastic member 400, and the screw rod 200 is only connected to the inner ring 310 of the bearing 300, and the outer ring 320 of the bearing 300 is in clearance with the inner wall of the inner cavity 110. Because the inner ring 310 of the bearing 300 and the outer ring 320 of the bearing 300 rotate relatively and the rotation resistance is very small, the screw rod 200 and the valve needle 100 will not be in direct contact, and further, the valve needle 100 can remain stationary when the screw rod 200 rotates.

[0044] Compared with the prior art, when the screw rod 200 rotates, the valve needle is driven to rotate, so that the valve needle and the valve port rotate relative to each other, which causes the valve needle 100 and the valve port 21 to wear, thereby causing problems such as reduced sealing, abnormal noise and reduced reliability.

[0045] Specifically, the bearing 300 is arranged between the valve needle 100 and the screw rod 200 of the present solution so that the valve needle 100 will not rotate relative to the valve port 21 or will rotate slightly when in contact with the valve port 21, but can be stationary due to the small rolling friction of the bearing 300 when the valve needle 100 just contacts the valve port 21, thereby improving the reliability problem of sealing failure due to wear between the valve needle 100 and the valve port 21 in the prior art. At the same time, the problem of poor sealing performance in the prior art due to the rotation of the screw rod 200 driving the valve needle 100 to rotate and finally wearing the valve port 21 is improved.

[0046] In addition, when the valve needle assembly 10 is working, that is, when the valve needle 100 rises or falls, the valve needle 100 and the valve port 21 will not rotate relative to each other. At the same time, because the bearing 300 is added between the screw rod 200 and the valve needle 100, no sliding friction will be generated between the screw rod 200 and the valve needle 100, thereby improving the problem in the prior art that the sliding friction between the screw rod 200 and the valve needle 100 will cause a large friction force to be generated at the matching place between the nut and the screw rod 200 thread, which will lead to the failure of the nut parts due to the large force wear of the nut in the durability test. In summary, such a valve needle assembly 10 is simple and easy to set up, and can significantly improve the problems of poor sealing performance, high noise, and low durability reliability in the prior art.

[0047] Please continue reading Figure 1 and Figure 2 , to understand more structural details of the valve needle assembly 10. It should be noted that the elastic member 400 is configured to provide an elastic force for the bearing 300 to move toward the limiting portion 500 and to press against the limiting portion 500. And the screw rod 200 can drive the bearing 300 to move up and down in the inner cavity 110.

[0048] It should be noted that the elastic member 400 here provides elastic pre-tightening force for the movement of the valve needle assembly 10. As the screw rod 200 moves downward, the valve needle 100 is driven to move downward. When the valve needle 100 contacts the valve port 21, the valve needle 100 cannot continue to move downward. At this time, the screw rod 200 continues to move downward to press the elastic member 400. The elastic member 400 generates a compressive force on the valve needle 100 so that the valve needle 100 presses the valve port 21 to achieve the pre-tightening effect. At the same time, the elastic member 400 can also prevent the screw rod 200 from over-rotating and causing thread damage when the valve needle 100 and the valve port 21 are closed.

[0049] In an optional embodiment, the elastic member 400 is a spring, the top of the spring is pressed against the bottom of the outer ring 320 of the bearing 300, and the bottom of the spring is pressed against the bottom wall of the inner cavity 110. The elastic member 400 is a spring because the spring has the advantages of light weight, simple structure, low cost, and easy assembly. Optionally, the elastic member 400 is a compression spring. Specifically, the spring is sleeved at the bottom of the screw rod 200, and there is a gap between the spring and the peripheral wall at the bottom of the screw rod 200.

[0050] In an optional embodiment, there is a gap between the elastic member 400 and the side wall of the inner cavity 110. That is, there is a gap between the elastic member 400 and the side wall of the inner cavity 110 and the bottom peripheral wall of the screw rod 200, so that the elastic member 400 is only in contact with the outer ring 320 of the bearing 300 and the bottom wall of the inner cavity 110, thereby reducing the noise generated by the elastic member 400 when the valve needle assembly 10 is working; on the other hand, the flexibility of the movement of the elastic member 400 is improved.

[0051] In an optional embodiment, a support plane 112 is provided on the bottom wall of the inner cavity 110, and the bottom of the elastic member 400 is provided on the support plane 112. The support plane 112 is an annular step surface, and the support plane 112 can ensure that the elastic member 400 is stably provided on the bottom wall of the inner cavity 110, thereby ensuring the stability of the elastic member 400.

[0052] In an optional embodiment, the valve needle assembly 10 further includes a first connecting portion 210 and a second connecting portion 600; the first connecting portion 210 and the second connecting portion 600 are both fixedly disposed at the lower portion of the screw rod 200; along the radial direction of the screw rod 200, the width of the first connecting portion 210 and the second connecting portion 600 is greater than the inner diameter of the inner ring 310 of the bearing 300, and smaller than the inner diameter of the outer ring 320 of the bearing 300;

[0053] The first connection part 210 is located at the top of the inner ring 310 of the bearing 300, and the second connection part 600 is located at the bottom of the inner ring 310 of the bearing 300, so that the bearing 300 can be fastened between the first connection part 210 and the second connection part 600, so that the bearing 300 is fixedly connected to the screw rod 200. In this way, the first connection part 210 and the second connection part 600 cooperate with each other to ensure a stable connection between the screw rod 200 and the inner ring 310 of the bearing 300.

[0054] In an optional embodiment, the first connecting portion 210 is a boss disposed on the screw 200, and the boss is integrally formed with the screw 200. The top of the inner ring 310 of the bearing 300 is pressed against the boss. In an optional embodiment, the second connecting portion 600 is a bushing of the screw 200 sleeved on the bottom of the screw 200. Specifically, the bottom of the screw 200 is pressed against the inner ring 310 of the bearing 300 by the bushing of the screw 200.

[0055] It is not difficult to understand that in other embodiments of the present invention, the first connecting part 210 can also be a key block, sleeve or other connection methods, and the second connecting part 600 can also be an integrally formed boss, key block or other connection methods, as long as the bearing 300 and the screw rod 200 can be fixedly connected. This is just an example and is not limited.

[0056] In an optional embodiment, the top of the inner cavity 110 forms an open top opening 111, and the limiting portion 500 is a bearing sleeve 510 disposed at the top opening 111 of the inner cavity 110; the inner diameter of the bearing sleeve 510 is greater than or equal to the inner diameter of the outer ring 320 of the bearing 300. Specifically, the bearing sleeve 510 is pressed and fixed on the top opening 111 of the valve needle 100, and the top of the outer ring 320 of the bearing 300 is pressed against the bearing sleeve 510.

[0057] In a second aspect, the present invention provides an electronic expansion valve 20 , wherein the electronic expansion valve 20 comprises the valve needle assembly 10 of any one of the aforementioned embodiments.

[0058] Furthermore, the electronic expansion valve 20 also includes a fixing member, a rotor assembly, and a stopping mechanism.

[0059] The fixing part includes a valve port 21, a valve seat 22 and a sleeve 23; the valve seat 22 is fixedly connected to the upper end of the valve port 21, and the outer circular wall of the valve needle 100 is kept in clearance with the inner hole of the valve port 21; the sleeve 23 is fixedly connected to the valve seat 22 to enclose and form a receiving space; the rotor assembly and the stop mechanism are both located in the receiving space; the rotor assembly includes a magnet 24 and a connecting plate 25; the magnet 24 is fixedly connected to the connecting plate 25; the top of the screw rod 200 is fixedly connected to the connecting plate 25; the stop mechanism includes a nut 26, a stop rod 27, a slip ring 28, and a slip ring extension 29; the nut 26 is fixedly connected to the valve seat 22; the stop rod 2 7 is fixedly connected to the upper end of the connecting plate 25; the nut member 26 is loosely matched with the slip ring 28 and the slip ring 28 can freely rotate and slide up and down in the slide groove 26a of the nut member 26; the end of the slip ring 28 is provided with a slip ring extension 29 abutting against the stop rod 27; a stop groove is provided on the nut member 26, and the slip ring extension 29 can cooperate with the stop groove to limit the stroke position of the slip ring 28; the internal thread of the nut member 26 is matched with the external thread of the screw rod 200, so that when the magnet 24 rotates, the screw rod 200 is driven to rotate and the screw rod 200 can rise or fall, thereby controlling the opening and closing effect of the valve port 21.

[0060] This embodiment improves the reliability problem of seal failure caused by wear between the valve port 21 and the valve needle 100: because the screw rod 200 moves up and down and rotates at the same time when the existing expansion valve is working, the screw rod 200 drives the valve needle 100 to rotate, so that there is relative rotation between the valve needle 100 and the valve port 21 and friction is generated, so that abnormal wear will occur between the valve needle 100 and the valve port 21, and finally the seal failure will occur. While this embodiment meets the existing use requirements, a bearing 300 is arranged between the valve needle 100 and the screw rod 200, so that the valve needle 100 and the valve port 21 will not rotate relative to each other or rotate slightly when they contact, but can also stop at the moment when the valve needle 100 just contacts the valve port 21 due to the smaller rolling friction of the bearing 300, and finally there will be no wear between the valve needle 100 and the valve port 21, so that the reliability problem of seal failure will not occur.

[0061] The present embodiment improves the problem of poor sealing performance: when the present embodiment is working, the screw rod 200 moves up and down and rotates at the same time, and the valve needle 100 will generate friction with the contact surface of the valve port 21, or a smaller friction will be generated at the point where the valve needle 100 and the valve port 21 just meet. The above-mentioned friction ensures that when the screw rod 200 rotates, the valve needle 100 can remain stationary due to the action of the bearing 300, thereby improving the problem of poor sealing performance of the existing expansion valve caused by the rotation of the screw rod 200 driving the valve needle 100 to rotate and eventually wearing the valve port 21.

[0062] The present embodiment improves the problem of loud noise: when the present embodiment is working, the screw rod 200 moves up and down and rotates at the same time, and a static friction force is generated on the contact surface between the valve needle 100 and the valve port 21. The setting of the bearing 300 can ensure that when the screw rod 200 rotates, the valve needle 100 and the valve seat 22 do not rotate relative to each other, thereby not causing the problem of loud noise caused by friction between the two parts.

[0063] This embodiment improves the reliability of the nut thread: during operation, the screw rod 200 moves up and down and rotates at the same time, and the valve needle 100 and the valve port 21 do not rotate relative to each other. At the same time, because the bearing 300 is added between the screw rod 200 and the valve needle 100, no sliding friction is generated between the screw rod 200 and the valve needle 100. This improves the problem that sliding friction is generated between the screw rod 200 and the valve needle 100 of the existing expansion valve, and a large friction is generated at the matching place between the nut and the screw rod 200 thread, which leads to the problem that the nut is subjected to large force wear during the durability test and finally causes the nut component to fail.

[0064] Embodiment 2

[0065] See also Figure 3 , this embodiment is substantially the same as the embodiment, except that the specific setting mode of the position limiting part 500 is different. Specifically, in an optional embodiment, the top of the inner cavity 110 forms an open top opening 111; the position limiting part 500 is a riveted structure 520 formed by riveting the side wall of the valve needle 100, and the riveted structure 520 extends toward the center of the top opening 111; the inner diameter of the riveted structure 520 is greater than or equal to the inner diameter of the outer ring 320 of the bearing 300, so as to achieve the purpose of limiting the position of the bearing 300 and preventing it from falling out.

[0066] That is, the limiting part 500 of the riveting structure 520 and the valve needle 100 are an integrally formed structure, and the riveting structure 520 is easier to process, thereby simplifying the setting structure of the limiting part 500 while ensuring the clamping operation of the limiting part 500 on the outer ring 320 of the bearing 300.

[0067] In summary, the embodiment of the present invention provides a valve needle assembly 10 and an electronic expansion valve 20, which have at least the following advantages:

[0068] By providing a bearing 300 between the valve needle 100 and the screw rod 200, the valve needle 100 and the valve port 21 will not rotate relative to each other, thereby improving the problem in the prior art that the valve needle 100 rotates relative to the valve port 21, causing wear between the valve needle 100 and the valve port 21, resulting in poor sealing performance and further sealing reliability failure.

[0069] By disposing the bearing 300 between the valve needle 100 and the screw rod 200 , the valve needle 100 and the valve seat 22 do not rotate relative to each other, thereby improving the problem of the valve needle assembly 10 generating loud noise due to friction.

[0070] By arranging a bearing 300 between the valve needle 100 and the screw rod 200, no sliding friction is generated between the screw rod 200 and the valve needle 100, thereby improving the technical problem in the prior art that sliding friction is generated when the screw rod 200 rotates, which increases the friction between the nut and the screw rod 200 and causes failure of the nut components.

[0071] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A valve needle assembly, characterized in that: include: A valve needle (100), a screw rod (200), a bearing (300) and an elastic member (400); The valve needle (100) has an inner cavity (110) capable of accommodating the elastic member (400), and a limiting portion (500) is provided at the top of the inner cavity (110); the outer ring (320) of the bearing (300) is located below the limiting portion (500); The bottom of the elastic member (400) is pressed against the bottom wall of the inner cavity (110), and the top of the elastic member (400) is pressed against the bottom of the outer ring (320) of the bearing (300), so that the outer ring (320) of the bearing (300) can be pressed against the limiting portion (500); The bottom of the screw rod (200) is fixedly connected to the inner ring (310) of the bearing (300).

2. The valve needle assembly according to claim 1, characterized in that: The elastic member (400) is a spring, the top of the spring is pressed against the bottom of the outer ring (320) of the bearing (300), and the bottom of the spring is pressed against the bottom wall of the inner cavity (110).

3. The valve needle assembly according to claim 1, characterized in that: There is a gap between the elastic member (400) and the side wall of the inner cavity (110).

4. The valve needle assembly according to claim 1, characterized in that: A supporting plane (112) is provided on the bottom wall of the inner cavity (110), and the bottom of the elastic member (400) is provided on the supporting plane (112).

5. The valve needle assembly according to claim 1, characterized in that: The valve needle assembly further comprises a first connecting portion (210) and a second connecting portion (600); The first connecting portion (210) and the second connecting portion (600) are both fixedly arranged at the lower portion of the screw rod (200); Along the radial direction of the screw rod (200), the widths of the first connecting portion (210) and the second connecting portion (600) are greater than the inner diameter of the inner ring (310) of the bearing (300), and smaller than the inner diameter of the outer ring (320) of the bearing (300); The first connecting portion (210) is located at the top of the inner ring (310) of the bearing (300), and the second connecting portion (600) is located at the bottom of the inner ring (310) of the bearing (300), so that the bearing (300) can be fastened between the first connecting portion (210) and the second connecting portion (600), thereby fixing the bearing (300) to the screw rod (200).

6. The valve needle assembly according to claim 5, characterized in that: The first connecting portion (210) is a boss disposed on the screw rod (200), and the boss and the screw rod (200) are integrally formed.

7. The valve needle assembly according to claim 5, characterized in that: The second connecting portion (600) is a bushing of the screw rod (200) sleeved on the bottom of the screw rod (200).

8. The valve needle assembly according to claim 1, characterized in that: The top of the inner cavity (110) forms an open top opening (111), and the limiting portion (500) is a bearing sleeve (510) arranged at the top opening (111) of the inner cavity (110); the inner diameter of the bearing sleeve (510) is greater than or equal to the inner diameter of the outer ring (320) of the bearing (300).

9. The valve needle assembly according to claim 1, characterized in that: The top of the inner cavity (110) forms an open top opening (111); the limiting portion (500) is a riveted structure (520) formed by riveting the side wall of the valve needle (100), and the riveted structure (520) extends toward the center of the top opening (111); the inner diameter of the riveted structure (520) is greater than or equal to the inner diameter of the outer ring (320) of the bearing (300).

10. An electronic expansion valve, characterized in that: The electronic expansion valve comprises the valve needle assembly according to any one of claims 1-6.

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