Electronic expansion valve

Abstract

The invention provides an electronic expansion valve. The electronic expansion valve comprises a shell; the valve seat is provided with a mounting cavity and a valve cavity which are communicated with each other, and a valve port is formed in the valve cavity and located in the end, away from the mounting cavity, of the valve cavity; the rotor assembly is arranged in the shell and is provided with a rotor cavity; the valve needle assembly is arranged in the shell, and the valve needle assembly can be driven by the rotor assembly to adjust the flow at the valve port; the guide sleeve is provided with a first section and a second section which are sequentially connected in the axial direction, the first section is partially located in the shell, and the second section is arranged in the mounting cavity; the circulation channel is arranged between the second section and / or the mounting cavity, one end of the circulation channel is communicated with the valve cavity, the other end of the circulation channel is communicated with the rotor cavity, and when the electronic expansion valve is in a fully-closed state, the distance between the side, close to the valve cavity, of the rotor connecting plate and the end, close to the rotor cavity, of the circulation channel is H. According to the technical scheme, the problem that in the prior art, resonance noise is generated when fluid flows through the electronic expansion valve can be solved.

Description

[0001] This application claims priority to a patent application filed with the State Intellectual Property Office of China on September 29, 2023, with application number 2023112840432 and name “Electronic Expansion Valve”. Technical Field

[0002] The present invention relates to the technical field of control valves, and in particular to an electronic expansion valve. Background Art

[0003] The electronic expansion valve in the prior art mainly includes a valve needle assembly, a valve seat, a guide sleeve and a rotor assembly. The valve seat has a valve cavity and a valve port. The valve needle assembly can cooperate with the guide sleeve under the drive of the rotor assembly to approach or move away from the valve port, thereby adjusting the flow rate of the fluid at the valve port. When the fluid passes through the valve cavity of the valve seat, the valve seat will vibrate due to the impact of the fluid. At this time, the space inside the rotor assembly will resonate with the valve cavity, causing resonance noise when the fluid flows through the electronic expansion valve, affecting user use. Summary of the invention

[0004] The present invention provides an electronic expansion valve to solve the problem that the electronic expansion valve in the prior art generates resonance noise when in use.

[0005] The present application provides an electronic expansion valve, which comprises: a shell having an installation space; a valve seat, the valve seat having an installation cavity and a valve cavity which are interconnected, and a valve port is arranged on the valve seat; a rotor assembly arranged in the shell, the rotor assembly comprising a magnetic rotor and a rotor connecting plate, the magnetic rotor being sleeved on the outer side of the rotor connecting plate, and the magnetic rotor having a rotor cavity; a valve needle assembly arranged in the shell, the valve needle assembly being connected to the rotor connecting plate, the valve needle assembly being arranged corresponding to the valve port, and the valve needle assembly being capable of adjusting the flow at the valve port under the drive of the rotor assembly; a guide sleeve, the valve needle assembly being arranged through the guide sleeve, the guide sleeve having a first section and a second section which are sequentially connected along the axial direction, the first section being partially located in the shell, and the second section being arranged in the installation cavity; a circulation channel arranged between the second section and / or the installation cavity, one end of the circulation channel being communicated with the valve cavity, and the other end of the circulation channel being communicated with the rotor cavity, and when the electronic expansion valve is in a fully closed state, a distance H is provided between a side of the rotor connecting plate close to the valve cavity and an end of the circulation channel close to the rotor cavity, Among them, A is the flow area of ​​the flow channel, c is the air propagation velocity, L is the axial length of the second section, D1 is the diameter of the rotor cavity, and D2 is the diameter of the first section.

[0006] By applying the technical solution of the present application, the electronic expansion valve includes a shell, a valve seat, a rotor assembly, a valve needle assembly and a guide sleeve. By setting a flow channel to connect the valve cavity and the rotor cavity, the pressure in the valve cavity and the rotor cavity can be ensured to be consistent, which facilitates the rotor assembly to drive the valve needle assembly to rotate. However, this will cause the valve cavity and the rotor cavity to resonate when the fluid flows through the electronic expansion valve, thereby causing the fluid to generate a large noise when flowing through the electronic expansion valve. According to the Helmholtz resonance principle, when the relevant dimensions are designed according to the above formula, the resonance frequency of the rotor cavity and the valve cavity can be reduced to a level that the human ear can sensitively feel, thereby reducing the noise generated by the fluid when flowing through the electronic expansion valve, ensuring the noise reduction effect, and improving the comfort of user experience.

[0007] Furthermore, the side wall of the second section has a section structure, and a circulation channel is formed between the section structure and the inner wall of the installation cavity. Through the above arrangement, the rotor cavity can be entered through the circulation channel to ensure the pressure balance in the valve cavity and the rotor cavity, and at the same time, the pressure fluctuation generated when a small fluid flows through the valve cavity can be reduced, and the noise generated when the fluid flows through the electronic expansion valve can be further reduced, thereby improving the user's comfort experience.

[0008] Furthermore, the second section is provided with a flow hole, and the flow hole forms a flow channel. In this way, the flow hole can connect the rotor cavity and the installation cavity, thereby reducing the working noise of the electronic expansion valve.

[0009] Furthermore, the side wall of the second section has a plurality of section structures, and the plurality of section structures are symmetrically arranged along the axis of the guide sleeve. Through the above arrangement, it is possible to ensure that the force on the guide sleeve when impacted by the fluid is relatively balanced, reduce the disturbance on the guide sleeve, and ensure the accuracy of the electronic expansion valve in controlling the valve port opening.

[0010] Furthermore, the valve needle assembly has a first threaded section and a first guide section connected in sequence, the first guide section is arranged close to the valve port, the guide sleeve has a second threaded section and a second guide section connected in sequence, the first threaded section and the second threaded section are threadedly matched, the valve needle assembly rotates relative to the guide sleeve to approach or move away from the valve port, and the first guide section and the second guide section are guided and matched. Through the above arrangement, the first threaded section and the second threaded section are matched, and the first guide section and the second guide section are matched, so that the movement and guidance of the valve needle assembly relative to the valve port can be realized, and the use effect of the electronic expansion valve is improved.

[0011] Furthermore, the guide sleeve also includes a third section, which is connected to the second section and is located in the valve cavity, and the outer diameter of the third section is smaller than the outer diameter of the second section. Through the above arrangement, the axial limit of the guide sleeve in the installation cavity can be achieved, ensuring the working stability of the electronic expansion valve.

[0012] Furthermore, the diameter of the end of the third section close to the valve port gradually decreases in the direction away from the rotor cavity. Through the above arrangement, when the refrigerant fluid enters the valve cavity, the third section can achieve a flow guiding effect on the fluid, thereby reducing the noise generated when the fluid flows through the valve cavity.

[0013] Furthermore, the first section, the second section and the third section are an integrally formed structure; or the second section is a metal part, and the guide sleeve is injection molded with the second section as an insert. Through the above arrangement, the overall structural stability of the guide sleeve can be improved, and the guide sleeve can be prevented from loosening under the impact of the fluid.

[0014] Furthermore, the second section of the guide sleeve is installed in the installation cavity with interference fit. Through the above arrangement, the shaking amplitude of the guide sleeve caused by the impact of the fluid can be reduced, and the stability of the guide sleeve during the operation of the electronic expansion valve can be ensured.

[0015] Furthermore, the second section of the guide sleeve is riveted to the valve seat. The above arrangement can conveniently limit the position of the guide sleeve and ensure the stability of the guide sleeve.

[0016] Furthermore, the valve seat has a first hole section and a second hole section connected to each other, the first hole section forms a mounting cavity, the second hole section forms a valve cavity, and a riveting protrusion is annularly arranged on the end surface of the valve seat close to the rotor assembly, the riveting protrusion is annularly arranged on the periphery of the first hole section, and the riveting protrusion is used to cooperate with the end surface of the second section to fix the guide sleeve on the valve seat. Through the above arrangement, the riveting protrusion will not block the guide sleeve from entering the mounting cavity, and at the same time, the second section of the guide sleeve can be easily riveted to the valve seat, which is convenient for the assembly and processing of the electronic expansion valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 A schematic diagram of the structure of an electronic expansion valve provided by a first embodiment of the present invention is shown;

[0019] Figure 2 Shows Figure 1 A partial enlarged view of the middle A;

[0020] Figure 3 A top view of a guide sleeve provided by a first embodiment of the present invention is shown;

[0021] Figure 4 A top view of the guide sleeve and the valve seat provided in the first embodiment of the present invention is shown;

[0022] Figure 5A schematic structural diagram of a guide sleeve provided in a first embodiment of the present invention is shown;

[0023] Figure 6 A schematic structural diagram of a valve needle assembly provided by the present invention is shown;

[0024] Figure 7 A schematic diagram of the structure of the valve seat provided by the present invention is shown;

[0025] Figure 8 A schematic diagram of the structure of an electronic expansion valve provided by a second embodiment of the present invention is shown;

[0026] Fig. 9 A top view of a guide sleeve provided in the second embodiment of the present application is shown.

[0027] The above drawings include the following reference numerals:

[0028] 10. Shell;

[0029] 20. valve seat; 21. valve cavity; 22. riveting protrusion; 23. installation cavity; 24. first hole section; 25. second hole section; 201. valve port;

[0030] 30. rotor assembly; 31. magnetic rotor; 32. rotor connecting plate;

[0031] 40. Valve needle assembly; 41. First threaded section; 42. First guide section;

[0032] 50, guide sleeve; 51, first section; 52, second section; 521, flow hole; 53, third section; 54, second threaded section; 55, second guide section;

[0033] 100. Section structure; 200. Circulation channel. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. 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.

[0035] like Figures 1 to 9As shown, an embodiment of the present application provides an electronic expansion valve, which includes a housing 10, a valve seat 20, a rotor assembly 30, a valve needle assembly 40, a guide sleeve 50 and a circulation channel 200. The housing 10 has an installation space. The valve seat 20 has an installation cavity 23 and a valve cavity 21 that are interconnected. The installation cavity 23 and the valve cavity 21 are arranged in a stepped manner. A valve port 201 is arranged on the valve cavity 21. The valve port 201 is located at one end of the valve cavity 21 away from the installation cavity 23. The rotor assembly 30 is arranged in the housing 10. The rotor assembly 30 includes a magnetic rotor 31 and a rotor connecting plate 32. The magnetic rotor 31 is sleeved on the outer side of the rotor connecting plate 32. The magnetic rotor 31 has a rotor cavity. The valve needle assembly 40 is arranged in the housing 10. The valve needle assembly 40 is connected to the rotor connecting plate 32. The valve needle assembly 40 is arranged corresponding to the valve port 201. The valve needle assembly 40 can adjust the flow at the valve port 201 under the drive of the rotor assembly 30. The valve needle assembly 40 is arranged through the guide sleeve 50. The guide sleeve 50 has a first section 51 and a second section 52 connected in sequence along the axial direction. The first section 51 is partially located in the housing 10. The circulation channel 200 is arranged between the second section 52 and / or the installation cavity 23. One end of the circulation channel 200 is communicated with the valve cavity 21, and the other end of the circulation channel 200 is communicated with the rotor cavity. When the electronic expansion valve is in a fully closed state, the distance between the side of the rotor connecting plate 32 close to the valve cavity 21 and the end of the circulation channel 200 close to the rotor cavity is H. Wherein, A is the flow area of ​​the flow channel 200 , c is the air propagation velocity, L is the axial length of the second section 52 , D1 is the diameter of the rotor cavity, and D2 is the diameter of the first section 51 .

[0036] By applying the technical solution of the present application, the electronic expansion valve includes a housing 10, a valve seat 20, a rotor assembly 30, a valve needle assembly 40 and a guide sleeve 50. By setting a flow channel 200 to connect the valve cavity 21 and the rotor cavity, it is possible to ensure that the pressure in the valve cavity 21 and the rotor cavity is consistent, prevent the pressure difference between the valve cavity 21 and the rotor cavity, and facilitate the rotor assembly to drive the valve needle assembly 40 to rotate. However, this will cause the valve cavity 21 and the rotor cavity to resonate when the fluid flows through the electronic expansion valve, thereby causing the fluid to generate a large noise when flowing through the electronic expansion valve. According to the Helmholtz resonance principle, the resonance frequency Where V is the volume of the rotor chamber, V = π × (D1 2 / 4-D2 2 / 4)×H, H is the distance between the side of the rotor connecting plate 32 close to the valve cavity 21 and the side of the valve seat 20 close to the rotor cavity when the electronic expansion valve is in the fully closed state, A is the flow area of ​​the flow channel 200, c is the air propagation speed, and the minimum frequency of sound that the human ear can sensitively feel is 1000Hz. By setting the resonance frequency f≤1000Hz, it can be obtained By the above arrangement, when the electronic expansion valve is in the fully closed state, the distance between the side of the rotor connecting plate 32 close to the valve cavity 21 and the side of the flow channel 200 close to the rotor cavity satisfies That is, the resonance frequency of the rotor cavity and the valve cavity 21 can be reduced to a level that the human ear can sensitively feel, thereby reducing the noise generated when the fluid flows through the electronic expansion valve, ensuring the noise reduction effect, and improving the comfort of user experience.

[0037] Reference Figures 1 to 5 As shown, in the first embodiment of the present application, the side wall of the second section 52 has a section structure 100, and a circulation channel 200 is formed between the section structure 100 and the inner wall of the installation cavity 23. Through the above arrangement, when the fluid flows through the valve cavity 21, it can enter the rotor cavity through the circulation channel 200, thereby ensuring the pressure balance between the valve cavity 21 and the rotor cavity, reducing the pressure difference that needs to be overcome when the valve needle assembly 40 opens or blocks the valve port 201, and facilitating the electronic expansion valve to quickly adjust the flow rate. At the same time, it can also reduce the pressure fluctuations generated when the fluid flows through the valve cavity 21, further reduce the noise generated when the fluid flows through the electronic expansion valve, and improve the user comfort experience. Among them, when the circulation channel 200 is formed between the section structure 100 and the inner wall of the installation cavity 23, D3 is the diameter of the installation cavity 23 minus the distance between the side wall of the second section 52 and the inner wall of the installation cavity 23 , and D4 is the diameter of the second section 52 .

[0038] Furthermore, the side wall of the second section 52 has a plurality of section structures 100, and the plurality of section structures 100 are symmetrically arranged along the axis of the guide sleeve 50. Through the above arrangement, when the fluid enters the rotor cavity from the valve cavity 21 along the circulation channel 200, the plurality of section structures 100 are symmetrically arranged along the axis of the guide sleeve 50, which can ensure as much as possible that the force on the guide sleeve 50 when impacted by the fluid is relatively balanced, reduce the disturbance on the guide sleeve 50, and ensure the accuracy of the electronic expansion valve in controlling the valve opening. In a specific embodiment of the present application, two section structures 100 are provided, and the two section structures 100 are symmetrically arranged along the axis of the guide sleeve 50. Correspondingly, there are also two circulation channels 200. Through the above arrangement, the two circulation channels 200 can reduce the noise generated when the fluid flows through the electronic expansion valve while ensuring the stability of the guide sleeve 50 in the installation cavity 23, thereby improving the noise reduction effect of the electronic expansion valve.

[0039] Reference Figure 8 and Fig. 9 As shown, in the second embodiment of the present application, the second section 52 is provided with a through flow hole 521, and the flow hole 521 forms a flow channel 200. Similar to the section structure 100, a plurality of flow holes 521 can also be provided, and the plurality of flow holes 521 are symmetrically arranged along the axis of the guide sleeve 50. When the flow hole 521 forms a flow channel 200, then Wherein, A is the cross-sectional area of ​​the flow hole 521 along the direction perpendicular to the extension direction.

[0040] like Figure 5 and Figure 6 As shown, in the present application, the valve needle assembly 40 has a first threaded section 41 and a first guide section 42 connected in sequence, the first guide section 42 is arranged close to the valve port, the guide sleeve 50 has a second threaded section 54 and a second guide section 55 connected in sequence, the first threaded section 41 and the second threaded section 54 are threadedly matched, the valve needle assembly 40 rotates relative to the guide sleeve 50 to approach or move away from the valve port, and the first guide section 42 and the second guide section 55 are guided and matched. Through the above arrangement, the first threaded section 41 can rotate relative to the second threaded section 54 under the drive of the rotor assembly 30, and the first threaded section 41 and the second threaded section 54 are threadedly matched, so that the valve needle assembly 40 can move up and down along the approach to or away from the valve port, thereby realizing the closing or opening of the valve port. At the same time, the first guide section 42 and the second guide section 55 are guided and matched, which can ensure the accuracy of the matching between the valve needle assembly 40 and the valve port, and improve the use effect of the electronic expansion valve.

[0041] Furthermore, the guide sleeve 50 further includes a third section 53, which is connected to the second section 52 and is located in the valve cavity 21, and the outer diameter of the third section 53 is smaller than the outer diameter of the second section 52. Through the above arrangement, a step surface is formed between the second section 52 and the third section 53, and the step surface can cooperate with the mounting cavity 23 to limit the position, thereby realizing the axial limit of the guide sleeve 50 in the mounting cavity 23, preventing the guide sleeve 50 from moving toward the valve cavity 21 driven by the valve needle assembly 40, and ensuring the stability of the electronic expansion valve.

[0042] Furthermore, the diameter of the end of the third section 53 close to the valve port gradually decreases in the direction away from the rotor cavity. Since bubbles will burst when passing through the valve port, through the above arrangement, when the refrigerant fluid enters the valve cavity 21, the third section 53 can guide the bubbles in the fluid, so that the bubbles can enter the circulation channel 200 more smoothly, reduce the number of bubbles passing through the valve port, and thus reduce the noise generated when the fluid flows through the valve cavity 21.

[0043] In the present application, the first section 51, the second section 52 and the third section 53 are an integrally formed structure; or, the second section 52 is a metal part, and the guide sleeve 50 is injection molded with the second section 52 as an insert. Through the above arrangement, the overall structural stability of the guide sleeve 50 can be improved, and the guide sleeve 50 can be prevented from loosening under the impact of the fluid. At the same time, the integrally formed manufacturing process can also facilitate the production and processing of the guide sleeve 50. In a specific embodiment of the present application, the guide sleeve 50 is injection molded with the second section 52 as a metal seat, and the injection molding material is made of engineering plastic material. The engineering plastic has good heat resistance, cold resistance, machinability and structural stability, which is convenient for the processing and molding of the guide sleeve 50.

[0044] Furthermore, the second section 52 of the guide sleeve 50 is interference-mounted in the mounting cavity 23. Through the above arrangement, the gap that may appear between the outer wall of the second section 52 and the inner wall of the mounting cavity 23 can be reduced, the shaking amplitude of the guide sleeve 50 caused by the impact of the fluid can be reduced, and the stability of the guide sleeve 50 during the operation of the electronic expansion valve can be ensured.

[0045] In a specific embodiment of the present application, the second section 52 of the guide sleeve 50 is riveted to the valve seat 20. The above arrangement can conveniently limit the position of the guide sleeve 50 and ensure the stability of the guide sleeve 50.

[0046] like Figure 7 As shown, the valve seat 20 has a first hole section 24 and a second hole section 25 connected to each other, the first hole section 24 forms a mounting cavity 23, and the second hole section 25 forms a valve cavity 21. A riveting protrusion 22 is annularly arranged on the end surface of the valve seat 20 close to the rotor assembly 30. The riveting protrusion 22 is annularly arranged on the periphery of the first hole section 24, and the riveting protrusion 22 is used to cooperate with the end surface of the second section 52 to fix the guide sleeve 50 on the valve seat 20. Through the above arrangement, during the installation of the guide sleeve 50, the riveting protrusion 22 will not block the guide sleeve 50 from entering the mounting cavity 23. When the second section of the guide sleeve 50 is installed into the first hole section 24 by interference fit, the riveting protrusion 22 can be bent, so that the second section 52 of the guide sleeve 50 is riveted to the valve seat 20. The above method is simple in structure and easy to process, and is convenient for assembly and processing of the electronic expansion valve.

[0047] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0048] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0049] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0050] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0051] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An electronic expansion valve, characterized in that: The electronic expansion valve comprises: A housing (10) having an installation space; A valve seat (20), the valve seat (20) having a mounting cavity (23) and a valve cavity (21) that are connected to each other, and a valve port (201) is provided on the valve seat (20); A rotor assembly (30) is arranged in the housing (10), the rotor assembly (30) comprising a magnetic rotor (31) and a rotor connecting plate (32), the magnetic rotor (31) is sleeved on the outer side of the rotor connecting plate (32), and the magnetic rotor (31) has a rotor cavity; A valve needle assembly (40) is arranged in the housing (10), the valve needle assembly (40) is connected to the rotor connecting plate (32), the valve needle assembly (40) is arranged corresponding to the valve port (201), and the valve needle assembly (40) can adjust the flow at the valve port (201) under the drive of the rotor assembly (30); a guide sleeve (50), wherein the valve needle assembly (40) passes through the guide sleeve (50), and the guide sleeve (50) comprises a first section (51) and a second section (52) which are connected in sequence along the axial direction, wherein a portion of the first section (51) is located in the housing (10), and the second section (52) is arranged in the mounting cavity (23); A circulation channel (200) is arranged between the second section (52) and / or the installation cavity (23); one end of the circulation channel (200) is in communication with the valve cavity (21); the other end of the circulation channel (200) is in communication with the rotor cavity; when the electronic expansion valve is in a fully closed state, a distance H is between a side of the rotor connecting plate (32) close to the valve cavity (21) and an end of the circulation channel (200) close to the rotor cavity; Wherein, A is the flow area of ​​the flow channel (200), c is the air propagation velocity, L is the axial length of the second section (52), D1 is the diameter of the rotor cavity, and D2 is the diameter of the first section (51).

2. The electronic expansion valve according to claim 1, characterized in that: The side wall of the second section (52) has a section structure (100), and the flow channel (200) is formed between the section structure (100) and the inner wall of the installation cavity (23).

3. The electronic expansion valve according to claim 1, characterized in that: The second section (52) is provided with a circulation hole (521), and the circulation hole (521) forms the circulation channel (200).

4. The electronic expansion valve according to claim 2, characterized in that: The side wall of the second section (52) has a plurality of the section structures (100), and the plurality of section structures (100) are symmetrically arranged along the axis of the guide sleeve (50).

5. The electronic expansion valve according to claim 1, characterized in that: The valve needle assembly (40) comprises a first threaded section (41) and a first guide section (42) connected in sequence, the first guide section (42) being arranged close to the valve port (201), the guide sleeve (50) comprises a second threaded section (54) and a second guide section (55) connected in sequence, the first threaded section (41) and the second threaded section (54) being threadedly matched, the valve needle assembly (40) being rotated relative to the guide sleeve (50) to approach or move away from the valve port, the first guide section (42) and the second guide section (55) being guidedly matched.

6. The electronic expansion valve according to claim 1, characterized in that: The guide sleeve (50) further comprises a third section (53), the third section (53) being connected to the second section (52), and the third section (53) being located in the valve cavity (21), and the outer diameter of the third section (53) being smaller than the outer diameter of the second section (52).

7. The electronic expansion valve according to claim 6, characterized in that: The diameter of the end of the third section (53) close to the valve port (201) gradually decreases in a direction away from the rotor chamber.

8. The electronic expansion valve according to claim 6, characterized in that: The first section (51), the second section (52) and the third section (53) are an integrally formed structure; or, the second section (52) is a metal part, and the guide sleeve (50) is injection molded with the second section (52) as an insert.

9. The electronic expansion valve according to claim 1, characterized in that: The second section (52) of the guide sleeve (50) is interference-fitted in the mounting cavity (23).

10. The electronic expansion valve according to claim 1, characterized in that: The second section (52) of the guide sleeve (50) is riveted to the valve seat (20).

11. The electronic expansion valve according to claim 10, characterized in that: The valve seat (20) has a first hole section (24) and a second hole section (25) which are connected to each other, the first hole section (24) forms the installation cavity (23), and the second hole section (25) forms the valve cavity (21). A riveted protrusion (22) is annularly arranged on the end surface of the valve seat (20) close to the rotor assembly (30), and the riveted protrusion (22) is annularly arranged on the periphery of the first hole section (24). The riveted protrusion is used to cooperate with the end surface of the second section (52) to fix the guide sleeve (50) on the valve seat (20).

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