Valve needle assembly and electronic expansion valve

Abstract

The utility model 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 utility model relates to electronic expansion valve technical field, specifically, relate to a valve needle subassembly and electronic expansion valve. BACKGROUND

[0002] The electronic expansion valve is utilized the principle of step motor, rotates through the coil drive magnetic rotor, and the rotation movement of magnetic rotor is converted into the axial movement of screw rod, and the valve needle connected with the screw rod is driven to ascend or descend by the screw rod, and the flow size of electronic expansion valve is controlled. The nut of electronic expansion valve is provided with internal thread, and the nut is fixed with valve seat, and the nut thread cooperates with the external thread of screw rod, when the screw rod rotates, the screw rod will rotate through thread to realize the up and down movement of screw rod, the screw rod is connected with valve needle, and the valve needle cooperates with valve port, thereby realizing the opening and closing effect of valve needle control valve port.

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

[0004] Firstly, the rotation of the screw rod will drive the spring to rotate, and the rotating sliding friction caused by the spring compression will drive the valve needle to rotate. After a long period of opening and closing 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 sealing performance and a shortening of the service life of the expansion valve.

[0005] Secondly, the relative rotational movement between the valve needle and the valve port will cause friction noise between the two parts, and the sliding friction between the screw rod and the valve needle will also cause friction noise, which seriously affects the noise performance. INVENTION CONTENTS

[0006] The utility model aims to, for example, provide a valve needle subassembly and 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 utility model can be implemented as follows:

[0008] In a first aspect, the utility model provides a valve needle subassembly, which comprises:

[0009] a valve needle, a screw rod, a bearing and an elastic member;

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

[0011] The bottom of the elastic member abuts against the bottom wall of the inner cavity, and the top of the elastic member abuts against the bottom of the outer ring of the bearing, so that the outer ring of the bearing can abut against the limiting portion.

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

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

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

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

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

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

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

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

[0020] In an optional embodiment, the first connecting portion is a boss arranged 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 rod bushing sleeved on a bottom of the screw rod.

[0022] In an optional embodiment, a 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; an inner diameter of the bearing sleeve is greater than or equal to an inner diameter of the outer ring of the bearing.

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

[0024] In a second aspect, the utility model provides a kind of electronic expansion valve, and the electronic expansion valve includes the valve needle assembly of any one of the foregoing embodiments.

[0025] The beneficial effects of the embodiments of the utility model include, for example:

[0026] The valve needle assembly of the scheme comprises a valve needle, a screw rod, a bearing and an elastic member. The screw rod is movably connected with the valve needle through the bearing and the elastic member, and the screw rod is connected with only the inner ring of the bearing, and the outer ring of the bearing is in clearance fit 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 relative to each other and the rotating resistance is very small, the screw rod does not directly contact the valve needle, 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 rotates, the valve needle and the valve port relatively rotate, the valve needle and the valve port are abraded, the sealing performance is reduced, noise and abnormal sound are generated, and the reliability is reduced. The bearing is arranged between the valve needle and the screw rod, so that the valve needle and the valve port do not relatively rotate or slightly rotate, but the valve needle can be stationary at the moment when the valve needle just contacts the valve port due to the small rolling friction of the bearing, thereby improving the problem of sealing failure and reliability caused by the abrasion 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 abrasion of the valve port due to the rotation of the screw rod to drive the valve needle to rotate is improved. In addition, when the valve needle assembly works, that is, when the valve needle rises or falls, the valve needle and the valve port do not relatively rotate. Because the bearing is arranged between the screw rod and the valve needle, the screw rod and the valve needle do not generate sliding friction, thereby improving the problem that the nut and the screw rod threadedly matched place generate large friction due to the sliding friction between the screw rod and the valve needle in the prior art, and the nut is abraded due to stress, and finally the nut component fails. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0028] Figure 1 The structure diagram of the valve needle assembly of the first embodiment of the present application;

[0029] Figure 2 The structure diagram of the electronic expansion valve of the first embodiment of the present application;

[0030] Figure 3 The structure diagram of the valve needle assembly of the second embodiment of the present application.

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

[0032] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0033] Therefore, the detailed description of the embodiments of the present application provided in the drawings below is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0034] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0035] In the description of the present application, it should be noted that if the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, which is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0036] In addition, if the terms "first", "second" and the like appear, they are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0037] It should be noted that the features in the embodiments of the present application can be combined with each other without conflict.

[0038] Embodiment one

[0039] Reference should be made to Figure 1 The embodiment provides a valve needle assembly 10, which comprises a valve needle 100, a screw rod 200, a bearing 300 and an elastic piece 400.

[0040] The valve needle 100 has an inner cavity 110 capable of accommodating the elastic piece 400, and a limiting portion 500 is arranged 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 piece 400 abuts against the bottom wall of the inner cavity 110, and the top of the elastic piece 400 abuts against the bottom of the outer ring 320 of the bearing 300, so that the outer ring 320 of the bearing 300 can abut against the limiting portion 500;

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

[0043] The valve needle assembly 10 provided by the scheme comprises the valve needle 100, the screw rod 200, the bearing 300 and the elastic piece 400. The screw rod 200 is movably connected with the valve needle 100 through the bearing 300 and the elastic piece 400, the screw rod 200 is only connected with the inner ring 310 of the bearing 300, and the outer ring 320 of the bearing 300 is gap-fitted 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 rotating resistance is very small, the screw rod 200 and the valve needle 100 do not directly 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 relatively rotate, the valve needle 100 and the valve port 21 are abraded, and the problems of sealing performance decline, noise and abnormal sound and reliability reduction are caused.

[0045] Specifically, the bearing 300 is arranged between the valve needle 100 and the screw rod 200, so that when the valve needle 100 contacts the valve port 21, there is no relative rotation or slight rotation, but the valve needle 100 can be stationary at the moment when the valve needle 100 just contacts the valve port 21 due to the small rolling friction of the bearing 300, thereby improving the problems of sealing failure and reliability caused by abrasion between the valve needle 100 and the valve port 21 in the prior art. Meanwhile, the problem of poor sealing performance caused by the rotation of the screw rod 200 to drive the valve needle 100 to rotate and finally abrade the valve port 21 is improved.

[0046] In addition, the valve needle assembly 10 does not have relative rotation between the valve needle 100 and the valve port 21 when the valve needle 100 is raised or lowered, and the bearing 300 is arranged between the screw rod 200 and the valve needle 100, so that the sliding friction between the screw rod 200 and the valve needle 100 is eliminated, thereby improving the problem that the nut and the screw rod 200 are abraded due to the sliding friction between the screw rod 200 and the valve needle 100, and the nut is finally damaged due to the abrasion. In summary, the valve needle assembly 10 is simple and convenient to arrange, and can significantly improve the problems of poor sealing performance, large noise, and low durability and reliability in the prior art.

[0047] Please continue to refer to Figure 1 and Figure 2 for 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 moving the bearing 300 towards the limiting portion 500 and abutting against the limiting portion 500. 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 provides an elastic pre-tightening force for the movement of the valve needle assembly 10. When the screw rod 200 moves downward, the valve needle 100 moves downward, and 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 compress the elastic member 400, and the elastic member 400 generates a compression force on the valve needle 100 to press the valve needle 100 against the valve port 21, thereby achieving the pre-tightening effect. At the same time, the elastic member 400 can also prevent the screw rod 200 from being over-rotated to damage the threads when the valve needle 100 is closed with the valve port 21.

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

[0050] In an optional embodiment, a gap is formed between the elastic member 400 and the side wall of the inner cavity 110. That is, gaps are formed between the elastic member 400 and the side wall of the inner cavity 110 and the peripheral wall of the bottom of the screw rod 200, so that the elastic member 400 only contacts 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 works, and improving the flexibility of the movement of the elastic member 400.

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

[0052] In an optional embodiment, the valve needle assembly 10 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 on the lower part of the screw rod 200; in 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 connecting portion 210 is located on the top of the inner ring 310 of the bearing 300, and the second connecting portion 600 is located on the bottom of the inner ring 310 of the bearing 300, so that the bearing 300 can be tightly fixed between the first connecting portion 210 and the second connecting portion 600, thereby realizing the fixed connection between the bearing 300 and the screw rod 200. In this way, the stable connection between the screw rod 200 and the inner ring 310 of the bearing 300 can be ensured through the cooperation of the first connecting portion 210 and the second connecting portion 600.

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

[0055] It can be understood that, in other embodiments of the present application, the first connecting portion 210 can also be a key block, a sleeve, or other connecting modes, and the second connecting portion 600 can also be an integrally formed boss, a key block, or other connecting modes, as long as the bearing 300 can be fixedly connected with the screw rod 200. Here, it is only 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 arranged on 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 tightly fixed on the top opening 111 of the valve needle 100, and the top of the outer ring 320 of the bearing 300 abuts against the bearing sleeve 510.

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

[0058] Further, the electronic expansion valve 20 further comprises a fixed part, a rotor assembly, and a stop mechanism.

[0059] The fixed part comprises a valve port 21, a valve seat 22, and a sleeve 23; the valve seat 22 is fixedly connected with the upper end of the valve port 21, and the outer wall of the valve needle 100 is in gap cooperation with the inner hole of the valve port 21; the sleeve 23 is fixedly connected with the valve seat 22 to form an accommodation space; the rotor assembly and the stop mechanism are located in the accommodation space; the rotor assembly comprises a magnet 24 and a connecting plate 25; the magnet 24 is fixedly connected with the connecting plate 25; the top of the screw rod 200 is fixedly connected with the connecting plate 25; the stop mechanism comprises a nut part 26, a stop rod 27, a sliding ring 28, and a sliding ring extension 29; the nut part 26 is fixedly connected with the valve seat 22; the stop rod 27 is fixedly connected with the upper end of the connecting plate 25; the nut part 26 is in gap cooperation with the sliding ring 28, and the sliding ring 28 can freely rotate and slide up and down in the sliding groove 26a of the nut part 26; the end of the sliding ring 28 is provided with the sliding ring extension 29 which abuts against the stop rod 27; the nut part 26 is provided with a stop groove, and the sliding ring extension 29 can cooperate with the stop groove to limit the stroke position of the sliding ring 28; the internal thread of the nut part 26 cooperates 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 at the same time the screw rod 200 can rise or fall, thereby controlling the opening and closing effect of the valve port 21.

[0060] The embodiment improves the reliability problem of sealing failure caused by wear between the valve port 21 and the valve needle 100: in the existing expansion valve, when the screw rod 200 moves up and down while rotating, the valve needle 100 is rotated by the screw rod 200, so that the valve needle 100 and the valve port 21 have relative rotation and generate friction, thereby causing abnormal wear between the valve needle 100 and the valve port 21 and ultimately leading to sealing failure. In the embodiment, the bearing 300 is arranged between the valve needle 100 and the screw rod 200, so that when the valve needle 100 contacts the valve port 21, the valve needle 100 is static due to the small rolling friction of the bearing 300, and ultimately the problem of sealing failure caused by wear between the valve needle 100 and the valve port 21 does not occur.

[0061] The embodiment improves the poor sealing performance problem: when the screw rod 200 moves up and down while rotating, the valve needle 100 generates a friction force with the contact surface of the valve port 21, or a small friction force is generated at the junction of the valve needle 100 and the valve port 21; the above friction force ensures that the valve needle 100 can remain static due to the action of the bearing 300 when the screw rod 200 rotates, thereby improving the problem of poor sealing performance caused by the rotation of the valve needle 100 driven by the rotation of the screw rod 200 and the wear of the valve port 21.

[0062] The embodiment improves the problem of large noise: when the embodiment works, the screw rod 200 moves up and down while rotating, a static friction force is generated between the valve needle 100 and the valve port 21, and the bearing 300 is arranged to enable the valve needle 100 to not rotate relative to the valve seat 22 when the screw rod 200 rotates, so that the problem of large noise caused by friction between the two parts is avoided.

[0063] The embodiment improves the problem of reliability of the nut thread: when the embodiment works, the screw rod 200 moves up and down while rotating, the valve needle 100 does not rotate relative to the valve port 21, and the bearing 300 is arranged between the screw rod 200 and the valve needle 100 to avoid sliding friction between the screw rod 200 and the valve needle 100, thereby improving the problem that the existing expansion valve generates sliding friction between the screw rod 200 and the valve needle 100, which causes large friction between the nut and the screw rod 200, and further causes the nut to be abraded due to stress, and finally causes the nut to fail.

[0064] Embodiment two

[0065] Please refer to Figure 3 The embodiment is basically the same as the first embodiment, except that the specific arrangement of the limiting part 500 is different. Specifically, in the optional embodiment, the top of the inner cavity 110 forms an open top opening 111; the limiting part 500 is a riveting structure 520 riveted on the side wall of the valve needle 100, and the riveting structure 520 extends towards the center of the top opening 111; the inner diameter of the riveting structure 520 is greater than or equal to the inner diameter of the outer ring 320 of the bearing 300, so that the bearing 300 cannot be limited to be pulled out.

[0066] That is, the limiting part 500 of the riveting structure 520 is an integral structure with the valve needle 100, and the riveting structure 520 is easier to process, thereby simplifying the setting structure of the limiting part 500 on the premise of ensuring the pressing operation of the limiting part 500 on the outer ring 320 of the bearing 300.

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

[0068] By arranging the bearing 300 between the valve needle 100 and the screw rod 200, the valve needle 100 and the valve port 21 are prevented from rotating relative to each other, thereby improving the problem that the valve needle 100 and the valve port 21 are abraded due to the rotation of the valve needle 100 relative to the valve port 21 in the prior art, which causes poor sealing performance and further causes sealing failure.

[0069] By arranging the bearing 300 between the valve needle 100 and the screw rod 200, the valve needle 100 and the valve seat 22 are prevented from rotating relative to each other, thereby improving the problem of the valve needle assembly 10 caused by friction and large noise.

[0070] By setting the bearing 300 between the valve needle 100 and the screw rod 200, the sliding friction force between the screw rod 200 and the valve needle 100 is not generated, thereby improving the technical problem that the sliding friction is generated when the screw rod 200 rotates, the friction force between the nut and the screw rod 200 is large, and the nut component is damaged.

[0071] The above is only a specific implementation manner of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A valve needle assembly, characterized in that The valve needle (100), the screw rod (200), the bearing (300) and the elastic member (400) are included. The valve needle (100) has an inner cavity (110) capable of accommodating the elastic member (400), and a limiting portion (500) is arranged 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) abuts against the bottom wall of the inner cavity (110), and the top of the elastic member (400) abuts against the bottom of the outer ring (320) of the bearing (300), so that the outer ring (320) of the bearing (300) can abut against the limiting portion (500); The bottom of the screw rod (200) is fixedly connected with the inner ring (310) of the bearing (300).

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

3. The valve needle assembly according to claim 1, wherein: The elastic member (400) has a gap with the side wall of the inner cavity (110).

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

5. The valve needle assembly according to claim 1, wherein: 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 on the lower part of the screw rod (200); In 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); 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 tightly fixed between the first connecting portion (210) and the second connecting portion (600), thereby realizing the fixed connection between the bearing (300) and the screw rod (200).

6. The valve needle assembly according to claim 5, wherein: The first connecting portion (210) is a boss arranged on the screw rod (200), and the boss is integrally formed with the screw rod (200).

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

8. The valve needle assembly according to claim 1, wherein: ​ 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 of claim 1, wherein: The top of the inner cavity (110) forms an open top opening (111); the limiting portion (500) is a riveting structure (520) formed by riveting the side wall of the valve needle (100), and the riveting structure (520) extends towards the center of the top opening (111); the inner diameter of the riveting 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, comprising: The electronic expansion valve comprises the valve needle assembly according to any one of claims 1-6.

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