Electronic expansion valve

Abstract

The utility model discloses an electronic expansion valve, which includes: a shell, the shell having a first cavity, a second cavity, a first connecting hole and a first valve port; a first valve needle, the first valve needle can be moved along the axial direction of the shell to block the first valve port, the first valve needle has a third cavity, the first valve needle has a second valve port connected to the third cavity, and the peripheral wall of the first valve needle has a second connecting hole connected to the third cavity and the first cavity; a second valve needle, the second valve needle can be moved along the axial direction of the shell to block the second valve port, the second valve needle has a first flow channel, the first flow channel is connected to the second cavity, the first valve needle and the second valve needle are provided with a total of a plurality of balancing flow channels, and the balancing flow channels connect the first flow channel and the first valve port. According to the electronic expansion valve of the utility model, the refrigerant flow path can be increased, the probability of impurities blocking the balancing flow channel can be reduced, the pressure balance in the electronic expansion valve can be guaranteed, and the normal movement of the first valve needle and the second valve needle can be avoided from being affected.

Description

Technical Field

[0001] The utility model relates to the technical field of refrigerant control elements, in particular to an electronic expansion valve. Background Art

[0002] With the rapid development of the automobile industry, there are more and more devices and functions on the car. As a medium connecting multiple flow paths, valves are becoming more and more important in the production and manufacturing process of automobiles. In the prior art, due to the presence of impurities in the refrigerant, the presence of impurities can easily cause the balancing hole to be blocked, which in turn leads to unbalanced pressure in the valve and affects the normal movement of the valve needle. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes an electronic expansion valve, which can increase the flow path of the refrigerant, reduce the probability of impurities blocking the balance flow channel, ensure the pressure balance in the electronic expansion valve, and avoid affecting the normal movement of the first valve needle and the second valve needle.

[0004] The electronic expansion valve according to the embodiment of the utility model comprises: a shell, the shell having a first cavity, a second cavity, a first connecting hole and a first valve port, the first cavity and the second cavity are arranged in the axial direction of the shell, the first connecting hole is arranged on the peripheral wall of the first cavity and is connected with the first cavity, the first valve port is arranged on the axial end face of the first cavity away from the second cavity; a first valve needle, the first valve needle is arranged in the shell and partially extends into the first cavity, the first valve needle can be moved along the axial direction of the shell to block the first valve port, the first valve needle has a third cavity, and the first valve needle has a third cavity on the axial end face away from the second cavity There is a second valve port connected to the third cavity, and a second communicating hole connected to the third cavity and the first cavity is provided on the peripheral wall of the first valve needle; a second valve needle, part of the second valve needle is arranged in the third cavity, the second valve needle is movable along the axial direction of the shell to block the second valve port, and the second valve needle has a first flow channel therein, the first flow channel is located on the side of the third cavity away from the second valve port, and is located on the side of the second cavity facing the first cavity, the first flow channel is connected with the second cavity, and a plurality of balancing flow channels are provided on the first valve needle and the second valve needle in total, and the balancing flow channel connects the first flow channel and the first valve port.

[0005] According to the electronic expansion valve of the embodiment of the utility model, the shell has a first cavity, a second cavity, a first connecting hole and a first valve port, the first valve needle is movable along the axial direction of the shell to block the first valve port, the first valve needle has a third cavity, a second valve port and a second connecting hole, the second valve needle is movable along the axial direction of the shell to block the second valve port, and when the first valve needle blocks the first valve port, the coordination between the second valve needle and the second valve port can be adjusted to achieve precise control of the small flow stage of the electronic expansion valve and improve the performance of the electronic expansion valve. In addition, a first flow channel is provided in the second valve needle, and the first flow channel is connected to the second cavity. A plurality of balancing flow channels are provided on the first valve needle and the second valve needle in total. The balancing flow channels are connected to the first flow channel and the first valve port, which can increase the flow path of the refrigerant and reduce the probability of impurities clogging the balancing flow channel, thereby ensuring that the pressure in the second cavity is consistent with that at the first valve port, ensuring that the electronic expansion valve is always in a pressure balance state during the movement of the first valve needle and the second valve needle, avoiding affecting the normal movement of the first valve needle and the second valve needle along the axial direction of the shell, ensuring the reliability and stability of the first valve blocking the first valve port and the second valve blocking the second valve port, and the provision of multiple balancing flow channels can establish the balance inside the electronic expansion valve more quickly, reduce the risk of failure of the electronic expansion valve, improve the performance of the electronic expansion valve, and extend the service life of the electronic expansion valve.

[0006] In addition, the electronic expansion valve according to the utility model may also have the following additional technical features:

[0007] In some embodiments, the plurality of balancing flow channels include a first balancing flow channel, the first balancing flow channel is disposed on the first valve needle, the inner bottom wall of the first flow channel has a first balancing hole, and the first balancing hole connects the first flow channel and the first balancing flow channel.

[0008] In some embodiments, the first balancing flow channel includes a first sub-balancing flow channel and a second sub-balancing flow channel, and the first valve needle includes: a first component and a second component, the second component is located on the side of the first component facing the first valve port, the first sub-balancing flow channel is formed between the second component and the first component, the second sub-balancing flow channel is arranged on the second component and passes through the second component along the axial direction of the shell, the second sub-balancing flow channel is spaced apart from the third cavity, and the second sub-balancing flow channel is spaced apart from the second connecting hole, the second sub-balancing flow channel is connected to the first sub-balancing flow channel, and the first balancing hole connects the first sub-balancing flow channel and the first flow channel.

[0009] In some embodiments, the first sub-balancing flow channel is annular and extends along the circumferential direction of the second valve needle, the second sub-balancing flow channel is a plurality of the second sub-balancing flow channels arranged at intervals along the circumferential direction of the first valve needle, and the plurality of second sub-balancing flow channels are all connected to the first sub-balancing flow channel; and / or, the first balancing hole is a plurality of the first balancing hole arranged at intervals along the circumferential direction of the second valve needle, and the plurality of first balancing holes are all connected to the first sub-balancing flow channel.

[0010] In some embodiments, the first component includes a first sub-component and a second sub-component arranged and connected along the axial direction of the shell, the second sub-component is located on the side of the first sub-component facing the first valve port, the second component is arranged in the second sub-component and spaced apart from the first sub-component to define the first sub-balancing flow channel, along the axial direction of the shell, one end of the second sub-component close to the first valve port is located on the side of the second connecting hole away from the first valve port, and the second connecting hole directly connects the first cavity and the third cavity; or, along the axial direction of the shell, one end of the second sub-component close to the first valve port is located on the side of the second connecting hole facing the first valve port, and the side wall of the second sub-component is provided with a third connecting hole, and the third connecting hole is arranged opposite to the second connecting hole to connect the first cavity and the second connecting hole.

[0011] In some embodiments, the plurality of balancing flow channels further include a second balancing flow channel, which is disposed on the bottom wall of the first flow channel and penetrates the bottom wall of the first flow channel along the axial direction of the shell.

[0012] In some embodiments, a peripheral wall of the first flow channel has a second balancing hole, and the second balancing hole connects the first flow channel and the second cavity.

[0013] In some embodiments, the second balancing holes are multiple and spaced apart along the circumferential direction of the second valve needle.

[0014] In some embodiments, the portion where the first valve needle fits the housing is a guide section, and along the axial direction of the housing, the length of the guide section is a, the length of the first valve needle is b, and the following condition is satisfied: a>1 / 2b.

[0015] In some embodiments, a sealing gasket is disposed in the first valve port, the sealing gasket extends in a ring shape along the circumferential direction of the housing, and the first valve needle is suitable for abutting against the sealing gasket to seal the first valve port.

[0016] In some embodiments, the inner peripheral wall of the first valve port is provided with a first limit member and a second limit member spaced apart in the axial direction of the housing, and the sealing gasket is located between the first limit member and the second limit member.

[0017] In some embodiments, in a direction toward a central axis of the first valve port, at least one of the surfaces of the first limiting member and the second limiting member facing away from each other is inclined toward the sealing gasket.

[0018] In some embodiments, a sealing ring is provided between the sealing gasket and one of the first limiting member and the second limiting member that faces away from the first cavity, and the sealing ring abuts against an inner peripheral wall of the first valve port.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0021] Figure 1 is a three-dimensional cross-sectional view of an electronic expansion valve according to an embodiment of the utility model;

[0022] Figure 2 yes Figure 1 Enlarged view of point E in the middle;

[0023] Figure 3 It is a cross-sectional view of an electronic expansion valve according to an embodiment of the utility model.

[0024] Reference numerals:

[0025] 100. Electronic expansion valve;

[0026] 1. Shell; 11. First cavity; 12. Second cavity; 13. First communication hole; 14. First valve port; 141. Sealing pad; 142. First stopper; 143. Second stopper; 144. Sealing ring; 15. Sleeve; 16. First valve seat;

[0027] 2. First valve needle; 21. First component; 211. First subcomponent; 212. Second subcomponent; 213. First sealing ring; 22. Second component; 221. Third cavity; 222. Second valve port; 223. Second communicating hole; 224. Second sealing ring; 225. Second valve seat; 23. First balancing flow channel; 231. First sub-balancing flow channel; 232. Second sub-balancing flow channel; 24. Second flow channel; 241. Annular protrusion; 242. First elastic member;

[0028] 3. second valve needle; 31. first flow channel; 311. first balancing hole; 312. bushing; 32. second balancing flow channel; 33. limiting boss; 34. second elastic member;

[0029] 4. Driving assembly; 41. Rotor component; 411. Fixing piece; 42. Screw; 421. Bearing; 422. Guide piece; 43. Nut; 431. Connecting piece. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0033] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] The electronic expansion valve 100 according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0035] like Figure 1 and Figure 3As shown, the electronic expansion valve 100 according to the embodiment of the present utility model includes a housing 1 , a first valve needle 2 and a second valve needle 3 .

[0036] Specifically, refer to the attached Figure 1 and attached Figure 3 As shown, the housing 1 can protect the internal structure of the electronic expansion valve 100, which is beneficial to prolonging the service life of the electronic expansion valve 100. Figure 1 and attached Figure 3 As shown, the housing 1 has a first cavity 11, a second cavity 12, a first communicating hole 13 and a first valve port 14. The first cavity 11 and the second cavity 12 are arranged in the axial direction of the housing 1 (see the attached Figure 1 The first connecting hole 13 is arranged on the peripheral wall of the first cavity 11 and is connected to the first cavity 11. The first valve port 14 is arranged on the axial end surface of the first cavity 11 away from the second cavity 12. The refrigerant can flow into the first cavity 11 from one of the first connecting hole 13 and the first valve port 14, and flow out from the other of the first connecting hole 13 and the first valve port 14.

[0037] Further, see Attachment Figure 1 and attached Figure 3 As shown, the first valve needle 2 is arranged in the shell 1 and partially extends into the first cavity 11. The first valve needle 2 extends along the axial direction of the shell 1. The first valve needle 2 is movable along the axial direction of the shell 1 to block the first valve port 14. When the first valve needle 2 blocks the first valve port 14, the first communicating hole 13 and the first valve port 14 are no longer connected, and the refrigerant cannot flow into the first cavity 11 from the first valve port 14, and the refrigerant in the first cavity 11 cannot flow out of the first valve port 14.

[0038] Further, see Appendix Figure 1 and attached Figure 2 As shown, the first valve needle 2 has a third cavity 221 therein, and the first valve needle 2 has a second valve port 222 on the axial end face facing away from the second cavity 12, which is connected to the third cavity 221, and the second valve port 222 is coaxially arranged with the first valve port 14. The first valve needle 2 has a second connecting hole 223 on the peripheral wall thereof, which is connected to the third cavity 221 and the first cavity 11. The refrigerant can enter the first cavity 11 through the first connecting hole 13, and flow into the third cavity 221 through the second connecting hole 223, and finally flow out of the electronic expansion valve 100 through the second valve port 222 and the first valve port 14 in sequence, or the refrigerant can enter the third cavity 221 through the first valve port 14 and the second valve port 222 in sequence, enter the first cavity 11 through the second connecting hole 223, and finally flow out of the electronic expansion valve 100 through the first connecting hole 13.

[0039] Further, see the attached Figure 1 and attached Figure 3As shown, part of the second valve needle 3 is arranged in the third cavity 221, and the second valve needle 3 extends along the axial direction of the shell 1. The second valve needle 3 is movable along the axial direction of the shell 1 to block the second valve port 222. When the second valve needle 3 blocks the second valve port 222, the second connecting hole 223 and the second valve port 222 are no longer connected, and the refrigerant cannot flow from the second valve port 222 into the third cavity 221, and the refrigerant in the third cavity 221 cannot flow out from the second valve port 222.

[0040] It can be understood that, compared with the large-flow single-valve needle electronic expansion valve in the prior art, the utility model is provided with a second valve port 222 and a second valve needle 3 for blocking the second valve port 222 in the first valve needle 2. When the first valve needle 2 blocks the first valve port 14, the second valve needle 3 can be adjusted to cooperate with the second valve port 222 to achieve precise control of the small-flow stage of the electronic expansion valve 100 and improve the performance of the electronic expansion valve 100.

[0041] Further, see Attachment Figure 1 and attached Figure 2 As shown, the second valve needle 3 has a first flow channel 31 therein, the first flow channel 31 is located on the side of the third cavity 221 away from the second valve port 222, and is located on the side of the second cavity 12 facing the first cavity 11, the first flow channel 31 is connected with the second cavity 12, the first valve needle 2 and the second valve needle 3 are provided with a total of a plurality of balancing flow channels, the balancing flow channels connect the first flow channel 31 and the first valve port 14, the refrigerant can enter the balancing flow channel from the first valve port 14, and enter the first flow channel 31 from the balancing flow channel, and finally flow into the second cavity 12 from the first flow channel 31, so that the pressure in the second cavity 12 is consistent with that at the first valve port 14, ensuring that the electronic expansion valve 100 is always in a pressure balance state during the movement of the first valve needle 2 and the second valve needle 3, avoiding affecting the normal movement of the first valve needle 2 and the second valve needle 3 along the axial direction of the shell 1, and ensuring the reliability and stability of the first valve needle 2 blocking the first valve port 14 and the second valve needle 3 blocking the second valve port 222.

[0042] In the prior art, conventional refrigerants may contain impurities, such as refrigeration oil or other impurities, and the presence of impurities may easily cause blockage of the balancing flow channel. However, by providing a total of multiple balancing flow channels on the first valve needle 2 and the second valve needle 3, the flow path of the refrigerant can be increased, and the probability of impurities blocking the balancing flow channel can be reduced, thereby ensuring that the pressure in the second cavity 12 is consistent with that at the first valve port 14, and ensuring that the electronic expansion valve 100 is always in a pressure balance state during the movement of the first valve needle 2 and the second valve needle 3, avoiding affecting the normal movement of the first valve needle 2 and the second valve needle 3 along the axial direction of the shell 1, and ensuring the reliability and stability of the first valve needle 2 blocking the first valve port 14 and the second valve needle 3 blocking the second valve port 222. In addition, the provision of multiple balancing flow channels can establish the balance inside the electronic expansion valve 100 more quickly, reduce the risk of failure of the electronic expansion valve 100, improve the performance of the electronic expansion valve 100, and extend the service life of the electronic expansion valve 100.

[0043] It can be understood that, regarding the multiple balancing flow channels provided on the first valve needle 2 and the second valve needle 3, the first valve needle 2 may be provided with multiple balancing flow channels, while the second valve needle 3 may not be provided with a balancing flow channel; the second valve needle 3 may be provided with multiple balancing flow channels, while the first valve needle 2 may not be provided with a balancing flow channel; or both the first valve needle 2 and the second valve needle 3 may be provided with balancing flow channels, and the number of balancing flow channels is multiple. For example, the total number of balancing flow channels on the first valve needle 2 and the second valve needle 3 may be two, three, four, five or six. In a specific example, refer to the attached Figure 2 As shown, two balancing flow passages are provided on the first valve needle 2 and the second valve needle 3 , and each of the first valve needle 2 and the second valve needle 3 has one balancing flow passage.

[0044] Further, see Attachment Figure 1 and attached Figure 3 As shown, a bushing 312 is provided at one end of the first flow channel 31 away from the first valve port 14, and the bushing 312 is interference fit with the second valve needle 3. The electronic expansion valve 100 also includes a drive assembly 4, which is arranged on the shell 1 and includes a coil assembly, a rotor component 41, a screw 42 and a nut 43. The coil assembly is sleeved outside the shell 1, and the rotor component 41 is arranged in the shell 1. The coil assembly is located radially outside the rotor component 41 and is opposite to at least part of the rotor component 41, and is used to drive the rotor component 41 to rotate. The length direction of the screw 42 (refer to the attached Figure 1 One end of the second valve needle 3 is connected to the rotor component 41, and the other end is provided with a bearing 421, and the bearing 421 is riveted to the screw 42. The bearing 421 is located on the side of the bushing 312 facing the first valve port 14, and is used to abut against the bushing 312. The nut 43 is fixed on the housing 1 and is threadedly connected to the screw 42, so that the screw 42 drives the second valve needle 3 to move along the axial direction of the housing 1.

[0045] Specifically, refer to the attached Figure 1 and attached Figure 3 As shown, a fixing piece 411 is provided at one end of the rotor component 41 away from the first valve port 14, and the screw 42 is inserted into the fixing piece 411, which can limit the screw 42 and prevent the screw 42 from deviating during the rotation process. Optionally, the nut 43 is a plastic part, and a connecting piece 431 is embedded in the nut 43, and the connecting piece 431 is a metal part, and the nut 43 can be welded and fixed to the housing 1 through the connecting piece 431.

[0046] It can be understood that when the coil component is energized, the coil component drives the rotor component 41 to rotate, the screw 42 is welded to the rotor component 41, and the rotor component 41 drives the screw 42 to rotate together. The screw 42 and the nut 43 are threadedly matched to form a thread pair. The nut 43 is fixed on the shell 1, so that the screw 42 moves along the axial direction of the shell 1, and then drives the rotor component 41 to move along the axial direction of the shell 1. In the process of the rotor component 41 moving along the axial direction of the shell 1, at least a part of the rotor component 41 is opposite to the coil component to ensure that the coil component drives the rotor component 41 to rotate normally.

[0047] Further, see Appendix Figure 1 and attached Figure 2 As shown, a second flow channel 24 is provided on the end face of the first valve needle 2 facing away from the first valve port 14, an annular protrusion 241 is provided at one end of the second flow channel 24 away from the first valve port 14, the second valve needle 3 is penetrated in the second flow channel 24 and is spaced apart from the annular protrusion 241 in the radial direction, a limiting boss 33 is provided on the outer peripheral wall of the second valve needle 3, the limiting boss 33 extends along the circumferential direction of the second valve needle 3, and is used to stop against the surface of the annular protrusion 241 facing the first valve port 14, a first elastic member 242 is provided on the outer sleeve of the second valve needle 3, and the length direction of the first elastic member 242 (refer to the attached Figure 2 The two ends of the second valve needle 3 (in the direction f shown in the figure) respectively abut against the limiting boss 33 and the inner bottom wall of the second flow channel 24, so as to drive the second valve needle 3 to move in the direction away from the first valve port 14.

[0048] Further, see the attached Figure 1 and attached Figure 2 As shown, the screw rod 42 is provided with a guide member 422 on its outer sleeve, the guide member 422 abuts against the bearing 421 and is located on the side of the bearing 421 facing the first valve port 14, and the guide member 422 is provided with a second elastic member 34 on its outer sleeve, and the second elastic member 34 has a longitudinal direction (see attached Figure 2 One end of the bearing 421 (in the direction f shown in the figure) is fixedly connected to the guide member 422, and the other end abuts against the inner bottom wall of the second flow channel 24, so as to drive the bearing 421 to move toward the direction close to the bushing 312.

[0049] It can be understood that the process of gradual closing of the electronic expansion valve 100 is: when the first valve needle 2 opens the first valve port 14, the first connecting hole 13 is connected to the first valve port 14 through the first cavity 11, and the refrigerant can flow into the first cavity 11 from one of the first connecting hole 13 and the first valve port 14, and flow out from the other. At this time, the limit boss 33 and the surface of the annular protrusion 241 facing the first valve port 14 are stopped; the screw 42 moves toward the direction close to the first valve port 14, and the screw 42 drives the first valve needle 2 and the second valve needle 3 to move toward the direction close to the first valve port 14. At this time, the first valve needle 2 and the second valve needle 3 will not move relative to each other in the axial direction of the shell 1.

[0050] When the first valve needle 2 blocks the first valve port 14, the first valve needle 2 cannot continue to move toward the first valve port 14, and the screw 42 continues to push the second valve needle 3 to move toward the direction close to the first valve port 14. The first elastic member 242 is compressed, and the limiting boss 33 is gradually separated from the annular protrusion 241, so that the first valve port 14 is completely blocked. At this time, the refrigerant can enter the first cavity 11 through the first connecting hole 13, and flow into the third cavity 221 through the second connecting hole 223, and then flow out of the first valve through the second valve port 222. Port 14, or, the refrigerant can pass through the first valve port 14 and the second valve port 222 in sequence into the third cavity 221, enter the first cavity 11 through the second connecting hole 223, and finally flow out from the first connecting hole 13; when the second valve needle 3 blocks the second valve port 222, the second valve needle 3 cannot continue to move toward the second valve port 222, the bearing 421 pushes the guide member 422 to compress the second elastic member 34 and move toward the second valve port 222, and the bearing 421 is spaced apart from the bushing 312, thereby achieving complete blocking of the second valve port 222.

[0051] The process of gradual opening of the electronic expansion valve 100: the screw 42 drives the bearing 421 to move in the direction away from the second valve port 222 until the bearing 421 abuts against the bushing 312, and the second elastic member 34 gradually returns to its original position, and then the screw 42 continues to move in the direction away from the second valve port 222, driving the second valve needle 3 to move in the direction away from the first valve port 14, and the second valve port 222 opens. At this time, the refrigerant can enter the first cavity 11 through the first connecting hole 13, and flow into the third cavity 221 through the second connecting hole 223, and then flow out of the first valve port 14 through the second valve port 222, or the refrigerant can pass through the first valve port 14 and the second valve port 222 in sequence to enter the third cavity 221, enter the first cavity 11 through the second connecting hole 223, and finally flow out from the first connecting hole 13.

[0052] As the screw 42 continues to drive the second valve needle 3 to move in the direction away from the first valve port 14, the first elastic member 242 gradually returns to its original position until the limiting boss 33 abuts against the annular protrusion 241, and the screw 42 drives the first valve needle 2 and the second valve needle 3 to move together in the direction away from the first valve port 14 to open the first valve port 14. At this time, the first valve needle 2 and the second valve needle 3 do not move relative to each other in the axial direction of the shell 1, thereby achieving full opening of the first valve port 14, and the refrigerant can flow into the first cavity 11 from one of the first connecting hole 13 and the first valve port 14, and flow out from the other.

[0053] According to the electronic expansion valve 100 of the embodiment of the utility model, the shell 1 has a first cavity 11, a second cavity 12, a first connecting hole 13 and a first valve port 14, the first valve needle 2 is movable along the axial direction of the shell 1 to block the first valve port 14, the first valve needle 2 has a third cavity 221, a second valve port 222 and a second connecting hole 223, the second valve needle 3 is movable along the axial direction of the shell 1 to block the second valve port 222, and when the first valve needle 2 blocks the first valve port 14, by adjusting the matching condition between the second valve needle 3 and the second valve port 222, the small flow stage of the electronic expansion valve 100 can be precisely controlled, thereby improving the performance of the electronic expansion valve 100. In addition, the second valve needle 3 has a first flow channel 31 therein, and the first flow channel 31 is connected to the second cavity 12. A total of multiple balancing flow channels are provided on the first valve needle 2 and the second valve needle 3. The balancing flow channels connect the first flow channel 31 and the first valve port 14, which can increase the flow path of the refrigerant, reduce the probability of impurities blocking the balancing flow channel, ensure that the pressure in the second cavity 12 is consistent with that at the first valve port 14, and ensure that the electronic expansion valve 100 is always in a pressure balance state during the movement of the first valve needle 2 and the second valve needle 3, avoiding affecting the normal movement of the first valve needle 2 and the second valve needle 3 along the axial direction of the shell 1, and ensuring the reliability and stability of the first valve needle 2 blocking the first valve port 14 and the second valve needle 3 blocking the second valve port 222. In addition, the provision of multiple balancing flow channels can establish the balance inside the electronic expansion valve 100 more quickly, reduce the risk of failure of the electronic expansion valve 100, improve the performance of the electronic expansion valve 100, and extend the service life of the electronic expansion valve 100.

[0054] In some embodiments of the present invention, refer to the attached Figure 1 and attached Figure 2As shown, the multiple balancing channels include a first balancing channel 23, the first balancing channel 23 is arranged on the first valve needle 2, the inner bottom wall of the first channel 31 has a first balancing hole 311, the first balancing hole 311 connects the first channel 31 and the first balancing channel 23, the refrigerant can enter the first balancing channel 23 from the first valve port 14, then flow into the first channel 31 through the first balancing hole 311, and finally flow into the second cavity 12 from the first channel 31, so that the pressure in the second cavity 12 is consistent with that at the first valve port 14, ensuring that the electronic expansion valve 100 is always in a pressure balance state during the movement of the first valve needle 2 and the second valve needle 3, avoiding affecting the normal movement of the first valve needle 2 and the second valve needle 3 along the axial direction of the shell 1, and ensuring the reliability and stability of the first valve needle 2 blocking the first valve port 14 and the second valve needle 3 blocking the second valve port 222.

[0055] In a further embodiment of the present invention, refer to the attached Figure 1 and attached Figure 2 As shown, the first balancing channel 23 includes a first sub-balancing channel 231 and a second sub-balancing channel 232, the first valve needle 2 includes a first component 21 and a second component 22, the second component 22 is located on the side of the first component 21 facing the first valve port 14, and a first sub-balancing channel 231 is formed between the second component 22 and the first component 21, the second sub-balancing channel 232 is arranged on the second component 22 and passes through the second component 22 along the axial direction of the shell 1, the second sub-balancing channel 232 is spaced apart from the third cavity 221, and the second sub-balancing channel 232 is spaced apart from the second connecting hole 223, the second sub-balancing channel 232 is connected to the first sub-balancing channel 231, and the first balancing hole 311 connects the first sub-balancing channel 231 and the first channel 31.

[0056] It can be understood that the refrigerant can flow from the first valve port 14 into the second sub-balancing channel 232, then flow into the first sub-balancing channel 231 defined by the first component 21 and the second component 22, and then flow into the first channel 31 through the first balancing hole 311, and finally flow to the second cavity 12, so that the pressure in the second cavity 12 is consistent with that at the first valve port 14, ensuring that the electronic expansion valve 100 is always in a pressure balance state during the movement of the first valve needle 2 and the second valve needle 3, avoiding affecting the normal movement of the first valve needle 2 and the second valve needle 3 along the axial direction of the shell 1, and ensuring the reliability and stability of the first valve needle 2 blocking the first valve port 14 and the second valve needle 3 blocking the second valve port 222.

[0057] It should be noted that if Figure 2As shown, by limiting the spacing between the second sub-balancing flow channel 232 and the third cavity 221, and separating the second sub-balancing flow channel 232 from the second connecting hole 223, it is possible to avoid the second sub-balancing flow channel 232 from being connected to the second connecting hole 223 or the third cavity 221 in the second component 22, and to avoid the refrigerant from entering the second connecting hole 223 or the third cavity 221 through the second sub-balancing flow channel 232 when the first valve needle 2 blocks the first valve port 14 and the second valve needle 3 blocks the second valve port 222, thereby causing the second valve needle 3 to fail in blocking the second valve port 222.

[0058] In a further embodiment of the present invention, refer to the attached Figure 1 and attached Figure 2 As shown, the first sub-balancing flow channel 231 is annular and extends along the circumferential direction of the second valve needle 3. The annular first sub-balancing flow channel 231 can ensure the connection with the second sub-balancing flow channel 232, and can store a small amount of refrigerant to avoid flow interruption from the second sub-balancing flow channel 232 to the first flow channel 31.

[0059] Further, the second sub-balancing flow channel 232 is a plurality of second sub-balancing flow channels 232 arranged at intervals along the circumferential direction of the first valve needle 2, and the plurality of second sub-balancing flow channels 232 are all connected to the first sub-balancing flow channel 231, which can increase the flow path of the refrigerant from the first valve port 14 to the first sub-balancing flow channel 231, reduce the probability of impurities blocking the balancing flow channel, ensure that the pressure at the second cavity 12 and the first valve port 14 is consistent, ensure that the electronic expansion valve 100 is always in a pressure balance state during the movement of the first valve needle 2 and the second valve needle 3, avoid affecting the normal movement of the first valve needle 2 and the second valve needle 3 along the axial direction of the shell 1, and ensure the reliability and stability of the first valve needle 2 blocking the first valve port 14 and the second valve needle 3 blocking the second valve port 222. For example, the second sub-balancing flow channel 232 can be two, three, four, five or six second sub-balancing flow channels 232 arranged at intervals along the circumferential direction of the first valve needle 2, each second sub-balancing flow channel 232 extends along the axial direction of the shell 1, and one end is connected to the first sub-balancing flow channel 231, and the other end is open.

[0060] Furthermore, the first balancing holes 311 are arranged in a plurality of intervals along the circumferential direction of the second valve needle 3, and the plurality of first balancing holes 311 are all connected to the first sub-balancing flow channel 231, which can improve the efficiency of the refrigerant flowing from the first sub-balancing flow channel 231 to the first flow channel 31, facilitate the electronic expansion valve 100 to establish internal balance more quickly, reduce the risk of failure of the electronic expansion valve 100, improve the performance of the electronic expansion valve 100, and extend the service life of the electronic expansion valve 100. In addition, the flow path from the first sub-balancing flow channel 231 to the first flow channel 31 can be increased, and the probability of impurities blocking the balancing flow channel can be reduced, so that the pressure at the second cavity 12 and the first valve port 14 is kept consistent, ensuring that the electronic expansion valve 100 is always in a pressure balance state during the movement of the first valve needle 2 and the second valve needle 3, avoiding affecting the normal movement of the first valve needle 2 and the second valve needle 3 along the axial direction of the shell 1, and ensuring the reliability and stability of the first valve needle 2 blocking the first valve port 14 and the second valve needle 3 blocking the second valve port 222.

[0061] For example, there may be two, three, four, five or six first balancing holes 311 spaced apart along the circumferential direction of the second valve needle 3 , and each first balancing hole 311 is connected to the first sub-balancing flow channel 231 .

[0062] In a further embodiment of the present invention, refer to the attached Figure 1 and attached Figure 2 As shown, the first component 21 includes a first sub-component 211 and a second sub-component 212 arranged and connected along the axial direction of the shell 1, the second sub-component 212 is located on the side of the first sub-component 211 facing the first valve port 14, the second component 22 is arranged in the second sub-component 212 and is spaced apart from the first sub-component 211 to define a first sub-balancing channel 231, and the gas flowing in from the second sub-balancing channel 232 can flow into the first sub-balancing channel 231 jointly defined by the first sub-component 211 and the second sub-component 212.

[0063] Further, see Attachment Figure 1 and attached Figure 2As shown, along the axial direction of the housing 1, the end of the second subcomponent 212 close to the first valve port 14 is located on the side of the second connecting hole 223 away from the first valve port 14, and the second connecting hole 223 directly connects the first cavity 11 and the third cavity 221, which can reduce the difficulty of production and processing of the first valve needle 2, facilitate the refrigerant to flow from the first cavity 11 to the third cavity 221 or from the third cavity 221 to the first cavity 11, and ensure the reliability and stability of the electronic expansion valve 100. It can be understood that the refrigerant can enter the first cavity 11 through the first connecting hole 13, and flow into the third cavity 221 through the second connecting hole 223, and finally flow out of the electronic expansion valve 100 through the second valve port 222 and the first valve port 14 in sequence, or the refrigerant can enter the third cavity 221 through the first valve port 14 and the second valve port 222 in sequence, enter the first cavity 11 through the second connecting hole 223, and finally flow out of the electronic expansion valve 100 through the first connecting hole 13.

[0064] Optionally, the first component 21 and the second component 22 are interference fit and / or welded. When the first component 21 and the second component 22 are welded, an avoidance groove can be opened so that the welding position is located in the avoidance groove, thereby ensuring that the welding surface formed after welding the first component 21 and the second component 22 is located in the avoidance groove, thereby avoiding the welding surface formed after welding from affecting the assembly of the electronic expansion valve 100.

[0065] In other embodiments of the utility model, along the axial direction of the shell 1, one end of the second subcomponent 212 close to the first valve port 14 is located on the side of the second connecting hole 223 facing the first valve port 14, and the side wall of the second subcomponent 212 is provided with a third connecting hole, and the third connecting hole is arranged opposite to the second connecting hole 223 to connect the first cavity 11 and the second connecting hole 223, and the refrigerant can enter the first cavity 11 through the first connecting hole 13, and flow into the third cavity 221 through the third connecting hole and the second connecting hole 223 in turn, and finally flow out of the electronic expansion valve 100 through the second valve port 222 and the first valve port 14 in turn, or, the refrigerant can enter the third cavity 221 through the first valve port 14 and the second valve port 222 in turn, enter the first cavity 11 through the second connecting hole 223 and the third connecting hole in turn, and finally flow out of the electronic expansion valve 100 through the first connecting hole 13.

[0066] In a further embodiment of the present invention, refer to the attached Figure 1 and attached Figure 2As shown, the multiple balancing flow channels also include a second balancing flow channel 32, which is arranged on the bottom wall of the first flow channel 31 and penetrates the bottom wall of the first flow channel 31 along the axial direction of the shell 1. The refrigerant can enter the second balancing flow channel 32 from the first valve port 14, and then flow into the first flow channel 31 along the axial direction of the shell 1, and finally flow into the second cavity 12 from the first flow channel 31, so that the pressure in the second cavity 12 is consistent with that at the first valve port 14, ensuring that the electronic expansion valve 100 is always in a pressure balance state during the movement of the first valve needle 2 and the second valve needle 3, avoiding affecting the normal movement of the first valve needle 2 and the second valve needle 3 along the axial direction of the shell 1, and ensuring the reliability and stability of the first valve needle 2 blocking the first valve port 14 and the second valve needle 3 blocking the second valve port 222.

[0067] In some embodiments of the utility model, the peripheral wall of the first flow channel 31 has a second balancing hole, and the second balancing hole connects the first flow channel 31 and the second cavity 12. The refrigerant in the first flow channel 31 can flow to the second cavity 12 through the second balancing hole to ensure that the refrigerant in the first flow channel 31 flows smoothly into the second cavity 12, so that the pressure in the second cavity 12 is consistent with that at the first valve port 14, ensuring that the electronic expansion valve 100 is always in a pressure balance state during the movement of the first valve needle 2 and the second valve needle 3, avoiding affecting the normal movement of the first valve needle 2 and the second valve needle 3 along the axial direction of the shell 1, and ensuring the reliability and stability of the first valve needle 2 blocking the first valve port 14 and the second valve needle 3 blocking the second valve port 222.

[0068] In a further embodiment of the utility model, the second balancing holes are arranged in a plurality of intervals along the circumferential direction of the second valve needle 3, which can improve the efficiency of the refrigerant flowing from the first flow channel 31 to the second cavity 12, facilitate the electronic expansion valve 100 to establish internal balance faster, reduce the risk of failure of the electronic expansion valve 100, improve the performance of the electronic expansion valve 100, and extend the service life of the electronic expansion valve 100. In addition, the flow path from the first flow channel 31 to the second cavity 12 can be increased, and the probability of impurities blocking the second balancing holes can be reduced, so that the pressure of the second cavity 12 and the first valve port 14 are kept consistent, ensuring that the electronic expansion valve 100 is always in a pressure balance state during the movement of the first valve needle 2 and the second valve needle 3, avoiding affecting the normal movement of the first valve needle 2 and the second valve needle 3 along the axial direction of the shell 1, and ensuring the reliability and stability of the first valve needle 2 blocking the first valve port 14 and the second valve needle 3 blocking the second valve port 222. For example, the second balancing holes can be two, three, four, five or six arranged in intervals along the circumferential direction of the second valve needle 3.

[0069] In some embodiments of the present invention, refer to the attached Figure 1 and attached Figure 2As shown, the part where the first valve needle 2 fits with the shell 1 is a guide section. Along the axial direction of the shell 1, the length of the guide section is a, the length of the first valve needle 2 is b, and it satisfies: a>1 / 2b, which can relatively increase the length a of the guide section, reduce the probability of the first valve needle 2 shaking in the shell 1, ensure the reliability of the fit between the first valve needle 2 and the shell 1, avoid the refrigerant from flowing from the gap between the first valve needle 2 and the shell 1 to the second cavity 12, avoid leakage, avoid flow fluctuations in the electronic expansion valve 100, ensure the performance of the electronic expansion valve 100, and ensure the coaxiality of the first valve needle 2 and the second valve needle 3, ensure the sealing reliability of the first valve needle 2 to the first valve port 14 and the sealing reliability of the second valve needle 3 to the second valve port 222.

[0070] It should be noted that the reference Figure 1 and attached Figure 2 As shown, the shell 1 includes a sleeve 15 and a first valve seat 16 which are arranged and connected in sequence in the axial direction of the shell 1, the sleeve 15 defines a second cavity 12, the first valve needle 2 and the second valve needle 3 are movably arranged in the first valve seat 16, the first valve seat 16 defines a first cavity 11, the first connecting hole 13 is arranged on the side wall of the first valve seat 16, the first valve port 14 is arranged at the end of the first valve seat 16 away from the sleeve 15, and a first sealing ring 213 is provided between the outer peripheral wall of the guide section and the inner peripheral wall of the first valve seat 16, which can prevent the refrigerant from flowing from the gap between the guide section and the first valve seat 16 to the second cavity 12, avoid refrigerant leakage, avoid flow fluctuation in the electronic expansion valve 100, and ensure the performance of the electronic expansion valve 100.

[0071] Further, see Attachment Figure 1 and attached Figure 2 As shown, a second sealing ring 224 is provided between the outer circumferential wall of the second valve needle 3 and the inner circumferential wall of the first valve needle 2, which can prevent the refrigerant from flowing from the gap between the second valve needle 3 and the first valve needle 2 to the second cavity 12, avoid refrigerant leakage, avoid flow fluctuations in the electronic expansion valve 100, and ensure the performance of the electronic expansion valve 100.

[0072] Furthermore, the movement length of the first valve needle 2 in the axial direction of the shell 1 is c, and the movement length of the second valve needle 3 in the axial direction of the shell 1 is d, and they satisfy: a>c+d, which further ensures the length of the guide section, reduces the probability of the first valve needle 2 shaking in the shell 1, ensures the reliability of the fit between the first valve needle 2 and the shell 1, avoids the refrigerant from flowing from the gap between the first valve needle 2 and the shell 1 to the second cavity 12, avoids leakage, avoids flow fluctuations in the electronic expansion valve 100, ensures the performance of the electronic expansion valve 100, and can ensure the coaxiality of the first valve needle 2 and the second valve needle 3, ensures the reliability of the first valve needle 2 sealing the first valve port 14 and the second valve needle 3 sealing the second valve port 222.

[0073] It should be noted that, along the axial direction of the shell 1, the movement length c of the first valve needle 2 is the movement distance of the first valve needle 2 from the fully open state to the fully blocked state, and the movement length d of the second valve needle 3 is the movement distance of the second valve needle 3 from the fully open state to the fully blocked state.

[0074] In some embodiments of the present invention, refer to the attached Figure 1 and attached Figure 2 As shown, a sealing gasket 141 is provided in the first valve port 14, and the sealing gasket 141 extends in a ring shape along the circumferential direction of the shell 1. The first valve needle 2 is suitable for abutting against the sealing gasket 141 to seal the first valve port 14. Through the cooperation of the sealing gasket 141 and the first valve needle 2, the sealing effect of the first valve needle 2 on the first valve port 14 can be improved, and the reliability of the sealing of the first valve needle 2 on the first valve port 14 is guaranteed, and the inflow or outflow of refrigerant when the first valve needle 2 blocks the first valve port 14 is avoided.

[0075] Furthermore, the sealing gasket 141 is a plastic part with good elasticity, light weight, good corrosion resistance, good wear resistance, high strength and low cost. PTFE (polytetrafluoroethylene), PPS (polyphenylene sulfide), PEI (polyethyleneimine) or HNBR (hydrogenated nitrile rubber) is preferred. Alternatively, the sealing gasket 141 is obtained by adding carbon fiber, glass fiber, carbon powder and other materials to the above materials, which can further improve the structural strength and hardness of the sealing gasket 141.

[0076] In a further embodiment of the present invention, refer to the attached Figure 1 and attached Figure 2 As shown, the inner circumferential wall of the first valve port 14 is provided with a first limit piece 142 and a second limit piece 143 which are spaced apart along the axial direction of the shell 1, and the sealing gasket 141 is located between the first limit piece 142 and the second limit piece 143. The setting of the first limit piece 142 and the second limit piece 143 can limit and fix the sealing gasket 141 from both sides of the sealing gasket 141 along the axial direction of the shell 1, thereby preventing the sealing gasket 141 from moving in the axial direction of the shell 1, ensuring the cooperation between the sealing gasket 141 and the first valve needle 2, and ensuring the sealing effect of the first valve needle 2 on the first valve port 14.

[0077] In a further embodiment of the present invention, refer to the attached Figure 1 and attached Figure 2 As shown, in the direction toward the central axis of the first valve port 14, at least one of the surfaces of the first limit member 142 and the second limit member 143 that face away from each other is inclined toward the sealing gasket 141, which can reduce the flow resistance of the refrigerant flowing through the first limit member 142 or the second limit member 143 and reduce the noise when the refrigerant flows through the first limit member 142 or the second limit member 143.

[0078] It can be understood that, in the direction toward the central axis of the first valve port 14, only the surface of the first limit member 142 facing away from the second limit member 143 may be inclined toward the sealing gasket 141, or only the surface of the second limit member 143 facing away from the first limit member 142 may be inclined toward the sealing gasket 141, or both the surfaces of the first limit member 142 and the second limit member 143 facing away from each other may be inclined toward the sealing gasket 141.

[0079] In a specific example, see the attached Figure 1 and attached Figure 2 As shown, the first stopper 142 is located on the side of the second stopper 143 facing the second cavity 12, the first stopper 142 and the housing 1 are an integral part, which can facilitate the production and processing of the first stopper 142 and reduce the assembly process of the electronic expansion valve 100, and the second stopper 143 and the housing 1 are separate parts, which can facilitate the assembly of the second stopper 143. Further, the sealing gasket 141 and the housing 1 are clearance fit or interference fit, and the second stopper 143 and the housing 1 are interference fit and / or welded.

[0080] In a further embodiment of the present invention, refer to the attached Figure 1 and attached Figure 2 As shown, a sealing ring 144 is provided between the one of the first limit member 142 and the second limit member 143 that is away from the first cavity 11 and the sealing gasket 141, and the sealing ring 144 is against the inner circumferential wall of the first valve port 14. It can be understood that when the first valve needle 2 blocks the first valve port 14, the first valve needle 2 squeezes the sealing gasket 141, and the sealing gasket 141 will produce a certain deformation, thereby causing a gap between the radial outer side of the sealing gasket 141 and the inner wall of the shell 1, forming a leakage channel, and the setting of the sealing ring 144 can prevent the refrigerant from flowing into the gap between the sealing ring 144 and the shell 1, avoid affecting the sealing effect of the first valve needle 2 on the first valve port 14, and ensure the effectiveness of the electronic expansion valve 100.

[0081] In some embodiments of the present invention, refer to the attached Figure 1 and attached Figure 2 As shown, a second valve seat 225 is provided at one end of the first valve needle 2 close to the first valve port 14. The second valve seat 225 defines a second valve port 222. The second valve seat 225 is pressed onto the first valve needle 2 by interference fit. The second valve seat 225 and the first valve needle 2 are designed as a separate body, which can reduce the difficulty of manufacturing the first valve needle 2 and the production and processing cost of the electronic expansion valve 100. The second valve seat 225 is a metal part, which can ensure the structural strength of the second valve seat 225 and avoid deformation due to the blocking of the second valve needle 3.

[0082] Other structures and operations of the electronic expansion valve 100 according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0083] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0084] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An electronic expansion valve, characterized in that: include: A housing (1), the housing (1) comprising a first cavity (11), a second cavity (12), a first communicating hole (13) and a first valve port (14), the first cavity (11) and the second cavity (12) being arranged in the axial direction of the housing (1), the first communicating hole (13) being arranged on the peripheral wall of the first cavity (11) and being in communication with the first cavity (11), and the first valve port (14) being arranged on the axial end surface of the first cavity (11) facing away from the second cavity (12); a first valve needle (2), the first valve needle (2) being arranged in the housing (1) and partially extending into the first cavity (11), the first valve needle (2) being movable along the axial direction of the housing (1) to block the first valve port (14), a third cavity (221) being provided in the first valve needle (2), a second valve port (222) being communicated with the third cavity (221) being provided on the axial end face of the first valve needle (2) facing away from the second cavity (12), and a second communication hole (223) being communicated with the third cavity (221) and the first cavity (11) being provided on the peripheral wall of the first valve needle (2); A second valve needle (3), part of which is arranged in the third cavity (221), and the second valve needle (3) is movable along the axial direction of the shell (1) to block the second valve port (222), and the second valve needle (3) has a first flow channel (31), and the first flow channel (31) is located on the side of the third cavity (221) away from the second valve port (222), and is located on the side of the second cavity (12) facing the first cavity (11), and the first flow channel (31) is connected with the second cavity (12), and a plurality of balancing flow channels are provided on the first valve needle (2) and the second valve needle (3), and the balancing flow channels connect the first flow channel (31) and the first valve port (14).

2. The electronic expansion valve according to claim 1, characterized in that: The plurality of balancing flow channels include a first balancing flow channel (23), wherein the first balancing flow channel (23) is arranged on the first valve needle (2), and the inner bottom wall of the first flow channel (31) has a first balancing hole (311), and the first balancing hole (311) connects the first flow channel (31) and the first balancing flow channel (23).

3. The electronic expansion valve according to claim 2, characterized in that: The first balancing flow channel (23) comprises a first sub-balancing flow channel (231) and a second sub-balancing flow channel (232), and the first valve needle (2) comprises: A first component (21) and a second component (22), wherein the second component (22) is located on a side of the first component (21) facing the first valve port (14), and the first sub-balancing flow channel (231) is formed between the second component (22) and the first component (21); the second sub-balancing flow channel (232) is arranged on the second component (22) and penetrates the second component (22) along the axial direction of the shell (1); the second sub-balancing flow channel (232) is spaced apart from the third cavity (221), and the second sub-balancing flow channel (232) is spaced apart from the second connecting hole (223); the second sub-balancing flow channel (232) is connected to the first sub-balancing flow channel (231), and the first connecting hole (311) connects the first sub-balancing flow channel (231) and the first flow channel (31).

4. The electronic expansion valve according to claim 3, characterized in that: The first sub-balancing flow channel (231) is annular and extends in the circumferential direction of the second valve needle (3). The second sub-balancing flow channels (232) are multiple and spaced apart along the circumferential direction of the first valve needle (2), and the multiple second sub-balancing flow channels (232) are all in communication with the first sub-balancing flow channel (231); And / or, the first balancing holes (311) are multiple and spaced apart along the circumferential direction of the second valve needle (3), and the multiple first balancing holes (311) are all connected to the first sub-balancing flow channel (231).

5. The electronic expansion valve according to claim 3, characterized in that: The first component (21) comprises a first subcomponent (211) and a second subcomponent (212) which are arranged and connected along the axial direction of the housing (1); the second subcomponent (212) is located on a side of the first subcomponent (211) facing the first valve port (14); the second component (22) is arranged in the second subcomponent (212) and is spaced apart from the first subcomponent (211) to define the first sub-balancing flow channel (231); Along the axial direction of the housing (1), one end of the second subcomponent (212) close to the first valve port (14) is located on a side of the second communicating hole (223) away from the first valve port (14), and the second communicating hole (223) directly connects the first cavity (11) and the third cavity (221); Alternatively, along the axial direction of the shell (1), one end of the second subcomponent (212) close to the first valve port (14) is located on the side of the second connecting hole (223) facing the first valve port (14), and a third connecting hole is provided on the side wall of the second subcomponent (212), and the third connecting hole is arranged opposite to the second connecting hole (223) to connect the first cavity (11) and the second connecting hole (223).

6. The electronic expansion valve according to claim 2, characterized in that: The plurality of balancing flow channels further include a second balancing flow channel (32), wherein the second balancing flow channel (32) is arranged on the bottom wall of the first flow channel (31) and penetrates the bottom wall of the first flow channel (31) along the axial direction of the shell (1).

7. The electronic expansion valve according to claim 1, characterized in that: The peripheral wall of the first flow channel (31) has a second balancing hole, and the second balancing hole communicates with the first flow channel (31) and the second cavity (12).

8. The electronic expansion valve according to claim 7, characterized in that: The second balancing holes are multiple and are arranged at intervals along the circumferential direction of the second valve needle (3).

9. The electronic expansion valve according to claim 1, characterized in that: The portion where the first valve needle (2) fits the housing (1) is a guide section. Along the axial direction of the housing (1), the length of the guide section is a, the length of the first valve needle (2) is b, and the following condition is satisfied: a>1 / 2b.

10. The electronic expansion valve according to claim 1, characterized in that: A sealing gasket (141) is provided in the first valve port (14), and the sealing gasket (141) extends in a ring shape along the circumferential direction of the housing (1). The first valve needle (2) is suitable for abutting against the sealing gasket (141) to seal the first valve port (14).

11. The electronic expansion valve according to claim 10, characterized in that: The inner peripheral wall of the first valve port (14) is provided with a first limiting member (142) and a second limiting member (143) which are arranged at intervals along the axial direction of the housing (1), and the sealing gasket (141) is located between the first limiting member (142) and the second limiting member (143).

12. The electronic expansion valve according to claim 11, characterized in that: In the direction toward the central axis of the first valve port (14), at least one of the surfaces of the first limiting member (142) and the second limiting member (143) facing away from each other is inclined toward the sealing gasket (141).

13. The electronic expansion valve according to claim 11, characterized in that: A sealing ring (144) is provided between the one of the first limiting member (142) and the second limiting member (143) that is away from the first cavity (11) and the sealing gasket (141), and the sealing ring (144) abuts against the inner peripheral wall of the first valve port (14).

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