Electronic expansion valve

Abstract

The utility model relates to the technical field of valves, in particular to an electronic expansion valve. The electronic expansion valve comprises a valve body assembly and a valve needle, the valve body assembly is provided with a valve cavity and a valve port communicated with the valve cavity, and the valve needle is movably installed in the valve cavity and can move in the direction close to or away from the valve port. A first flow guide face is arranged at the end, close to the valve cavity, of the valve port, and the inner diameter of the first flow guide face is gradually reduced in the axial direction of the valve port and in the direction from the valve cavity to the valve port. According to the electronic expansion valve, the problem that an existing electronic expansion valve can generate large flow noise during throttling operation is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of valves, in particular to an electronic expansion valve. BACKGROUND

[0002] As a key component in refrigeration and heating equipment, the electronic expansion valve realizes the purpose of adjusting flow and throttling pressure drop by controlling the opening degree of the valve port. However, when the electronic expansion valve is in throttling operation, due to the small diameter of the valve port, the fluid flow before and after the valve port will produce a sudden change, resulting in strong turbulent loss and abnormal noise, thereby affecting the user's comfort. CONTENT OF THE UTILITY MODEL

[0003] Therefore, it is necessary to provide an electronic expansion valve to solve the problem of large flow noise of the existing electronic expansion valve in throttling operation.

[0004] The present application provides an electronic expansion valve, which comprises a valve body assembly and a valve needle, the valve body assembly has a valve cavity and a valve port communicating with the valve cavity, the valve needle is movably installed in the valve cavity and can move towards or away from the valve port; wherein the valve port is provided with a first flow guide surface at one end close to the valve cavity, and the inner diameter of the first flow guide surface gradually decreases along the axial direction of the valve port and from the valve cavity to the valve port.

[0005] In one of the embodiments, the included angle between the first flow guide surface and the valve port axis is A, and 45°≤A≤55°.

[0006] In one of the embodiments, the included angle between the first flow guide surface and the valve port axis is A, and 15°≤A≤45°.

[0007] In one of the embodiments, the vertical distance between the two ends of the first flow guide surface along the axial direction of the valve port is H, and 0.2mm≤H≤1mm.

[0008] In one of the embodiments, the valve port is provided with a second flow guide surface at one end away from the valve cavity, and the inner diameter of the second flow guide surface gradually increases along the axial direction of the valve port and from the valve cavity to the valve port; wherein the included angle between the second flow guide surface and the valve port axis is B, and 60°≤B≤70°.

[0009] In one of the embodiments, the valve needle comprises a valve head, which is arranged at one end of the valve needle close to the valve port; wherein the outer surface of the valve head is arranged in an outward convex arc shape.

[0010] In one of the embodiments, the outer surface of the valve head is in a semispherical shape.

[0011] In one of the embodiments, the outer surface of the valve needle is formed with a stepped surface.

[0012] In one of the embodiments, the stepped surface is provided in plurality, and the plurality of stepped surfaces are arranged axially on the outer surface of the valve needle.

[0013] In one of the embodiments, the valve needle further comprises a tapered portion, which is connected to the end of the valve head portion away from the valve port, and the outer diameter of the tapered portion gradually decreases along the axial direction of the valve port from the valve cavity to the valve port; wherein the stepped surface is arranged on the outer surface of the tapered portion.

[0014] In one of the embodiments, the valve body assembly is further provided with a shunt hole, which is arranged at the end of the valve port away from the valve cavity and communicates with the valve port; wherein the inner diameter of the shunt hole gradually increases along the axial direction of the valve port from the valve cavity to the valve port.

[0015] In one of the embodiments, the valve port comprises a straight section and a flared section, which is arranged at the end of the straight section close to the valve cavity; wherein the inner diameter of the flared section gradually increases along the axial direction of the valve port from the valve port to the valve cavity.

[0016] In one of the embodiments, the electronic expansion valve further comprises a screw rod assembly, a rotor assembly, a nut sleeve and a guide sleeve, the nut sleeve is arranged in the valve cavity and connected with the valve body assembly, the guide sleeve is inserted and connected to the end of the nut sleeve close to the valve port; one end of the screw rod assembly penetrates the nut sleeve and is connected with the rotor assembly, the other end extends into the guide sleeve and is connected with the valve needle, and the screw rod assembly can rotate in response to the driving of the rotor assembly to drive the valve needle to move towards or away from the valve port; wherein the screw rod assembly comprises a screw rod, a spring sleeve, a bearing, a spring seat, an elastic member and a pressing sleeve, the spring sleeve is in sliding fit with the guide sleeve, the bearing and the spring seat are both installed in the spring sleeve, and the spring seat is in abutting fit with the outer ring of the bearing, one end of the screw rod is in threaded fit with the nut sleeve, the other end extends into the spring sleeve and is connected with the inner ring of the bearing, the end of the spring sleeve away from the screw rod is limited and connected with the valve needle through the pressing sleeve, and the two ends of the elastic member are respectively in abutting fit with the spring seat and the valve needle.

[0017] Compared with the prior art, the electronic expansion valve provided by the present application can realize slow transition of the fluid when flowing through the valve port, can slow down the fluid mutation or reduce the flow rate, thereby improving the flow performance of the fluid, improving the flow state of the fluid, effectively preventing abnormal noise caused by the fluid flowing through the valve port, and improving the user experience. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A cross-sectional view of an electronic expansion valve according to an embodiment provided in this application;

[0020] Figure 2 for Figure 1 Enlarged view at point M;

[0021] Figure 3 A cross-sectional view of the electronic expansion valve portion structure of another embodiment provided in this application;

[0022] Figure 4 This is a partial schematic diagram of a valve needle according to an embodiment of this application.

[0023] The symbols in the diagram represent the following meanings:

[0024] 100. Electronic expansion valve; 10. Valve body assembly; 101. Valve cavity; 102. Valve port; 1021. Straight section; 1022. Flared section; 103. First guide surface; 104. Second guide surface; 105. Diverter orifice; 11. Valve seat; 12. Outer cover; 20. Valve needle; 21. Valve head; 22. Conical part; 221. Stepped surface; 30. First connecting pipe; 40. Second connecting pipe; 50. Screw assembly; 51. Screw; 52. Spring sleeve; 53. Bearing; 54. Spring seat; 55. Elastic element; 56. Pressure sleeve; 60. Rotor assembly; 70. Nut sleeve; 80. Guide sleeve. Detailed Implementation

[0025] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0026] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application's specification are for illustrative purposes only and do not represent the only possible implementation.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0028] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0029] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.

[0030] As a key component in refrigeration and heating equipment, the electronic expansion valve regulates flow and reduces pressure by controlling the opening of the valve port. However, during throttling operation, the small valve port diameter causes abrupt changes in fluid flow before and after passing through the port, resulting in strong turbulence losses and abnormal noise, which affects user comfort.

[0031] Please see Figures 1-4To solve the problem that the existing electronic expansion valve generates large flow noise when throttling, the present application provides an electronic expansion valve 100, which comprises a valve body assembly 10 and a valve needle 20, the valve body assembly 10 has a valve cavity 101 and a valve port 102 communicating with the valve cavity 101, and the valve needle 20 is movably installed in the valve cavity 101 and can move towards or away from the valve port 102. Wherein, the outer peripheral wall of the valve body assembly 10 is connected with a first connecting pipe 30 communicating with the valve cavity 101, and the valve body assembly 10 is connected with a second connecting pipe 40 communicating with the valve port 102 at the valve port 102.

[0032] The electronic expansion valve 100 provided by the present application can be used as a bidirectional valve, that is, the fluid can flow into the valve cavity 101 through the first connecting pipe 30 and flow out through the valve port 102 and the second connecting pipe 40, or the fluid can flow into the valve cavity 101 through the second connecting pipe 40 via the valve port 102 and flow out through the first connecting pipe 30. During this period, the valve needle 20 controls the flow rate of the fluid flowing through the valve port 102 by cooperating with the valve port 102. And, the forward flow of the fluid is defined as the fluid flowing from the first connecting pipe 30 into and out of the second connecting pipe 40, and the reverse flow of the fluid is defined as the fluid flowing from the second connecting pipe 40 into and out of the first connecting pipe 30.

[0033] Further, as shown in Figure 2 and Figure 3 , the valve port 102 is provided with a first flow guide surface 103 at one end close to the valve cavity 101, and the inner diameter of the first flow guide surface 103 gradually decreases along the axial direction of the valve port 102 from the valve cavity 101 to the valve port 102.

[0034] In an embodiment, the included angle between the first flow guide surface 103 and the axis of the valve port 102 is A, and 45°≤A≤55°. In this way, the noise generated when the fluid flows forward can be reduced to a greater extent.

[0035] It can be understood that since the inner diameter of the passage at the valve port 102 is usually much smaller than the inner diameter of the first connecting pipe 30 and the second connecting pipe 40, whether the fluid flows forward or reversely, a large mutation will occur when the fluid enters or flows out of the valve port 102, resulting in strong turbulent loss and vortex. However, by providing the first flow guide surface 103 at one end of the valve port 102 close to the valve cavity 101, the slow transition of the fluid flowing through the valve port 102 when flowing forward can be realized, the fluid flow can be guided, and the fluid mutation can be slowed down, thereby improving the flow performance of the fluid, improving the flow state of the fluid, and by reasonably controlling the included angle A between the first flow guide surface 103 and the axis of the valve port 102, the turbulent loss can be effectively reduced, and the impact of the fluid flow on the wall surface and the like can be reduced. In this way, the abnormal noise caused by the fluid flowing through the valve port 102 is effectively prevented, and the user's experience is improved.

[0036] Optionally, the angle A can be set to 45°, 46°, 47°, 48°, 49°, 50°, 51°, 52°, 53°, 54°, or 55°, and the like, which are not listed one by one.

[0037] In another embodiment, the angle between the first flow guide surface 103 and the axis of the valve port 102 is A, and 15°≤A≤45°. In this way, the noise generated when the fluid flows in the reverse direction can be reduced to a greater extent.

[0038] It can be understood that when the fluid flows in the reverse direction through the valve port 102, if the valve port 102 does not have the first flow guide surface 103, the fluid flow is relatively concentrated and the flow rate is high, and the fluid washes the edges at the valve port 102 or concentrates on the edges of other components in the valve cavity 101, thereby possibly generating abnormal noise. In the present application, the fluid can be slowly transitioned through the surface of the first flow guide surface 103, the fluid can be diffused to a larger space, and the flow rate can be reduced, that is, after the fluid passes through the first flow guide surface 103, it will be dispersed, will not concentrate on the edges of other components in the valve cavity 101, and will not wash the edges at the valve port 102, effectively improving the abnormal refrigerant noise caused when the fluid flows through the valve port 102, and improving the user's experience.

[0039] Optionally, the angle A can be set to 15°, 20°, 25°, 30°, 35°, 40°, or 45°, and the like, which are not listed one by one.

[0040] Further, in an embodiment, the vertical distance between the two ends of the first flow guide surface 103 along the axis of the valve port 102 is H, and 0.2mm≤H≤1mm. In this way, the effective flow distance of the fluid on the first flow guide surface 103 can be ensured, thereby improving the buffering effect of the first flow guide surface 103 on the fluid, further preventing the fluid from changing abruptly, and reducing the generation of noise.

[0041] Optionally, the value of H can be set to 0.2mm, 0.4mm, 0.6mm, 0.8mm, or 1mm, and the like.

[0042] In an embodiment, as shown in Figure 2 The end of the valve port 102 away from the valve cavity 101 is provided with a second flow guide surface 104 along the axis of the valve port 102 and from the valve cavity 101 to the valve port 102, the inner diameter of the second flow guide surface 104 gradually increases. The angle between the second flow guide surface 104 and the axis of the valve port 102 is B, and 60°≤B≤70°. Similarly, the setting of the second flow guide surface 104 can further achieve slow transition of the fluid at the valve port 102, so that whether the fluid flows in the forward direction or the reverse direction, two-stage buffering and deceleration can be achieved at the valve port 102, thereby further reducing the flow loss of the fluid, which is conducive to reducing the generation of noise and optimizing the user's experience.

[0043] Optionally, the angle of B can be set to 60°, 61°, 62°, 63°, 64°, 65°, 66°, 67°, 68°, 68°, or 70°, and the like, which are not listed one by one here.

[0044] In an embodiment, as shown in Figure 2 and Figure 4 , the valve needle 20 includes a valve head 21, which is arranged at one end of the valve needle 20 close to the valve port 102. The outer surface of the valve head 21 is arranged in an outward convex arc shape. It can be understood that the valve head 21 is located at the end of the valve needle 20, and is easy to come into contact with the fluid during the throttling cooperation of the valve needle 20 and the valve port 102. On this basis, the outer surface of the valve head 21 is arranged in an outward convex arc shape, which can guide and buffer the fluid through the arc surface, avoid vortex at this place, and thus reduce the noise generated by the fluid flow.

[0045] Specifically, in an embodiment, the outer surface of the valve head 21 is in a semispherical shape, which makes the fluid flow more stable and uniform during the process of flowing through the outer surface of the valve head 21, and is beneficial to prevent the generation of vortex and reduce noise.

[0046] But not limited to this, in other embodiments, the outer surface of the valve head 21 can also be in a semicircular shape, etc.

[0047] In an embodiment, as shown in Figure 2 , the valve needle 20 further includes a tapered portion 22, which is connected to one end of the valve head 21 away from the valve port 102, and the outer diameter of the tapered portion 22 gradually decreases along the axial direction of the valve port 102 from the valve cavity 101 to the valve port 102. Here, the gradual decrease of the outer diameter of the tapered portion 22 mainly facilitates the insertion of the valve needle 20 into the valve port 102 to realize the cooperation of the two.

[0048] The outer surface of the valve needle 20 forms a stepped surface 221. Since the fluid is throttled at the valve port 102, the flow rate of the fluid in the valve port 102 reaches the maximum value in the electronic expansion valve 100. When the fluid flows in the opposite direction, the high-speed fluid will directly impact the surface of the tapered portion 22 of the valve needle 20, which not only causes impact noise, but also causes the valve needle 20 to vibrate and produce vibration noise. At this time, the stepped surface 221 arranged on the outer surface of the tapered portion 22 can slow down the flow rate of the fluid, reduce the collision noise, and also avoid the vibration noise caused by the shaking of the valve needle 20, further optimizing the user's experience. Here, the stepped surface 221 is preferably arranged on the outer surface of the tapered portion 22 and perpendicular to the axial direction of the valve port 102.

[0049] Further, in an embodiment, as shown in Figure 4As shown, the number of step surfaces 221 is multiple, and the multiple step surfaces 221 are arranged on the outer surface of the valve needle 20 at intervals to further slow down the fluid flow rate and avoid noise generation.

[0050] Specifically, two step surfaces 221 are arranged in the embodiment, which is simple to process. In other embodiments, three, four or more step surfaces can be arranged according to actual needs, which is not limited herein.

[0051] According to the experimental comparison, the peak noise of the traditional electronic expansion valve 100 structure is 93.3 dB, and the peak noise can be reduced by 4.42 dB compared with the traditional structure after the first flow guide surface 103 and the second flow guide surface 104 are arranged. The peak noise can be reduced by 0.33 dB compared with the traditional structure when only the hemispherical valve head 21 is arranged. The peak noise can be reduced by 1.46 dB compared with the traditional structure when only one step surface 221 is arranged. The peak noise can be reduced by 1.96 dB compared with the traditional structure when only two step surfaces 221 are arranged. Further, the peak noise can be reduced by 4.87 dB compared with the traditional structure when the first flow guide surface 103, the second flow guide surface 104 and the hemispherical valve head 21 are combined, and the peak noise can be reduced by 6.63 dB compared with the traditional structure when one step surface 221 is further combined, and the peak noise can be reduced by 7.28 dB compared with the traditional structure when two step surfaces 221 are combined.

[0052] In summary, the peak noise can be reduced to 86.02 dB by arranging the noise reduction structure of the present application, which is reduced by 7.8% compared with the traditional electronic expansion valve 100 structure. Moreover, the different noise reduction structures can have a synergistic effect, rather than just being combined in structure. For example, when the first flow guide surface 103, the second flow guide surface 104 and the hemispherical valve head 21 are combined, the noise peak value is reduced by 4.87 dB, which is greater than 4.42 dB+0.33 dB, and the effect is better than that of arranging the first flow guide surface 103, the second flow guide surface 104 and the hemispherical valve head 21 respectively. Similarly, when one step surface 221 is further combined on the basis of the above, the noise peak value is reduced by 6.63 dB, which is greater than 4.42 dB+0.33 dB+1.46 dB, and will be greater than the sum of the noise peak values when arranged respectively. When two step surfaces 221 are combined on the basis of the above, the noise peak value is reduced by 7.28 dB, which is greater than 4.42 dB+0.33 dB+1.46 dB+1.96 dB, and will be greater than the sum of the noise peak values when arranged respectively.

[0053] In an embodiment, as shown in FIG. 1, Figure 1 and Figure 2As shown, the valve body assembly 10 is further provided with a shunt hole 105, which is arranged at one end of the valve port 102 away from the valve cavity 101 and communicates with the valve port 102. In the axial direction of the valve port 102 and from the valve cavity 101 to the valve port 102, the inner diameter of the shunt hole 105 gradually increases. In this way, after the fluid flows through the valve port 102 in the forward direction, the fluid can diffuse to a larger space through the slow transition of the second flow guide surface 104 and the shunt hole 105, thereby reducing the fluid flow rate and effectively improving the abnormal noise caused by the fluid flowing through the valve port 102, optimizing the user experience.

[0054] In another embodiment, as shown in Figure 3 The valve port 102 includes a straight section 1021 and a flared section 1022 arranged at one end of the straight section 1021 close to the valve cavity 101. In the axial direction of the valve port 102 and from the valve port 102 to the valve cavity 101, the inner diameter of the flared section 1022 gradually increases. In this way, after the fluid flows through the valve port 102 in the reverse direction, the fluid can diffuse to a larger space through the slow transition of the flared section 1022 and the first flow guide surface 103, thereby reducing the fluid flow rate and effectively improving the abnormal noise caused by the fluid flowing through the valve port 102, optimizing the user experience.

[0055] In an embodiment, the valve body assembly 10 includes a valve seat 11 and an outer cover 12 connected to one end of the valve seat 11 and surrounding the valve seat 11 to form the valve cavity 101. The valve port 102 is arranged on the valve seat 11.

[0056] Further, in an embodiment, as shown in Figure 1 The electronic expansion valve 100 further includes a screw rod assembly 50, a rotor assembly 60, a nut sleeve 70 and a guide sleeve 80. The nut sleeve 70 is arranged in the valve cavity 101 and connected to the valve body assembly 10, specifically to the valve seat 11. The guide sleeve 80 is inserted and connected to one end of the nut sleeve 70 close to the valve port 102. One end of the screw rod assembly 50 penetrates the nut sleeve 70 and is connected to the rotor assembly 60, and the other end extends into the guide sleeve 80 and is connected to the valve needle 20. The screw rod assembly 50 can rotate in response to the driving of the rotor assembly 60 to move the valve needle 20 towards or away from the valve port 102, so as to realize the movement of the valve needle 20 in the valve cavity 101 and control the flow rate at the valve port 102.

[0057] Specifically, the screw assembly 50 comprises a screw 51, a spring sleeve 52, a bearing 53, a spring seat 54, an elastic member 55 and a pressing sleeve 56, the spring sleeve 52 is in sliding fit with the guide sleeve 80, the bearing 53 and the spring seat 54 are both installed in the spring sleeve 52, the spring seat 54 is in abutting fit with the outer ring of the bearing 53, one end of the screw 51 is in threaded fit with the nut sleeve 70, the other end of the screw 51 extends into the spring sleeve 52 and is connected with the inner ring of the bearing 53, the end of the spring sleeve 52 away from the screw 51 is connected with the valve needle 20 through the pressing sleeve 56, and the two ends of the elastic member 55 are respectively in abutting fit with the spring seat 54 and the valve needle 20. In this way, the reliability of the connection between the screw assembly 50 and the valve needle 20 is improved, and the probability of the valve needle 20 rotating when the screw 51 rotates is reduced, so that the abrasion of the valve needle 20 is reduced.

[0058] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but it should be considered that any combination of the technical features is within the scope of the present disclosure as long as the combination does not result in contradictions.

[0059] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent application scope. It should be noted that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these are within the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. An electronic expansion valve characterized by, The valve body assembly (10) has a valve cavity (101) and a valve port (102) in communication with the valve cavity (101), and the valve needle (20) is movably installed in the valve cavity (101) and can move towards or away from the valve port (102); Wherein, the valve port (102) is provided with a first flow guide surface (103) at one end close to the valve cavity (101), and the inner diameter of the first flow guide surface (103) gradually decreases along the axial direction of the valve port (102) from the valve cavity (101) to the valve port (102).

2. The electronic expansion valve according to claim 1, characterized in that The included angle between the first flow guide surface (103) and the axis of the valve port (102) is A, and 45°≤A≤55°.

3. The electronic expansion valve according to claim 1, wherein The included angle between the first flow guide surface (103) and the axis of the valve port (102) is A, and 15°≤A≤45°.

4. The electronic expansion valve according to claim 1, wherein The vertical distance between the two ends of the first flow guide surface (103) along the axial direction of the valve port (102) is H, and 0.2mm≤H≤1mm.

5. The electronic expansion valve according to claim 1, wherein The valve port (102) is provided with a second flow guide surface (104) at one end away from the valve cavity (101), and the inner diameter of the second flow guide surface (104) gradually increases along the axial direction of the valve port (102) from the valve cavity (101) to the valve port (102); Wherein, the included angle between the second flow guide surface (104) and the axis of the valve port (102) is B, and 60°≤B≤70°.

6. Electronic expansion valve according to any of claims 1-5, characterized in that The valve needle (20) includes a valve head (21) provided at one end of the valve needle (20) close to the valve port (102); Wherein, the outer surface of the valve head (21) is arranged in an outward convex arc shape.

7. The electronic expansion valve according to claim 6, characterized in that The outer surface of the valve head (21) is in a semispherical shape.

8. The electronic expansion valve according to claim 6, wherein The outer surface of the valve needle (20) is formed with a stepped surface (221).

9. The electronic expansion valve according to claim 8, characterized in that The number of the stepped surface (221) is multiple, and multiple stepped surfaces (221) are spaced apart on the outer surface of the valve needle (20) along the axial direction.

10. Electronic expansion valve according to claim 8 or 9, characterized in that The valve needle (20) further includes a conical portion (22) connected to one end of the valve head (21) away from the valve port (102), and the outer diameter of the conical portion (22) gradually decreases along the axial direction of the valve port (102) from the valve cavity (101) to the valve port (102); Wherein, the stepped surface (221) is arranged on the outer surface of the conical portion (22).

11. The electronic expansion valve according to claim 1, wherein The valve body assembly (10) is further provided with a shunt hole (105) arranged at one end of the valve port (102) away from the valve cavity (101) and in communication with the valve port (102); Wherein, the inner diameter of the shunt hole (105) gradually increases along the axial direction of the valve port (102) from the valve cavity (101) to the valve port (102).

12. The electronic expansion valve according to claim 1, wherein The valve port (102) includes a straight section (1021) and an expanded section (1022), and the expanded section (1022) is arranged at one end of the straight section (1021) close to the valve cavity (101); The inner diameter of the flared section (1022) gradually increases in the axial direction of the valve port (102) from the valve port (102) to the valve cavity (101).

13. The electronic expansion valve of claim 1, wherein The electronic expansion valve further comprises a screw rod assembly (50), a rotor assembly (60), a nut sleeve (70) and a guide sleeve (80), the nut sleeve (70) is arranged in the valve cavity (101) and connected with the valve body assembly (10), the guide sleeve (80) is inserted and connected to one end of the nut sleeve (70) close to the valve port (102); One end of the screw rod assembly (50) penetrates the nut sleeve (70) and is connected with the rotor assembly (60), the other end extends into the guide sleeve (80) and is connected with the valve needle (20), and the screw rod assembly (50) can rotate in response to the driving of the rotor assembly (60) to drive the valve needle (20) to move towards or away from the valve port (102); The screw rod assembly (50) comprises a screw rod (51), a spring sleeve (52), a bearing (53), a spring seat (54), an elastic member (55) and a pressing sleeve (56), the spring sleeve (52) is in sliding fit with the guide sleeve (80), the bearing (53) and the spring seat (54) are both installed in the spring sleeve (52), and the spring seat (54) is in abutting fit with the outer ring of the bearing (53), one end of the screw rod (51) is in threaded fit with the nut sleeve (70), the other end extends into the spring sleeve (52) and is connected with the inner ring of the bearing (53), one end of the spring sleeve (52) away from the screw rod (51) is limitingly connected with the valve needle (20) through the pressing sleeve (56), and the two ends of the elastic member (55) are respectively abutted against the spring seat (54) and the valve needle (20).

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