Electronic expansion valve

Abstract

The application provides an electronic expansion valve, and relates to the technical field of expansion valves. The electronic expansion valve comprises a valve body, a valve needle assembly and a driving assembly. The valve body is provided with a mounting cavity, a first opening, a second opening and a third opening which are communicated with the mounting cavity. The valve needle assembly is movably mounted in the mounting cavity. The driving assembly is mounted in the mounting cavity and connected with the valve body, and is in transmission connection with the valve needle assembly. The driving assembly can drive the valve needle assembly to move, so that the first opening and the second opening are selectively communicated with or blocked from the third opening. The electronic expansion valve can improve the flow control precision.

Description

Technical Field

[0001] This invention relates to the field of electronic expansion valves, and more specifically, to an electronic expansion valve. Background Technology

[0002] An electronic expansion valve uses an electrical signal generated by the regulated parameter to control the voltage or current applied to the expansion valve, thereby regulating the liquid supply.

[0003] In order to achieve precise flow control, existing technologies have introduced dual-valve needle electronic expansion valves. However, existing dual-valve needle electronic expansion valves only have one inlet and one outlet for both high and low flow rates, which still results in low flow control accuracy. Summary of the Invention

[0004] The object of the present invention includes, for example, providing an electronic expansion valve that can improve the flow control accuracy of the electronic expansion valve.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] In a first aspect, the present invention provides an electronic expansion valve, comprising a valve body, a valve needle assembly, and a drive assembly;

[0007] The valve body has a mounting cavity and a first opening, a second opening and a third opening communicating with the mounting cavity;

[0008] The valve needle assembly is movably mounted within the mounting cavity;

[0009] The drive assembly is installed in the mounting cavity and connected to the valve body, and is drivenly connected to the valve needle assembly. The drive assembly can drive the valve needle assembly to move so that the first opening and the second opening can selectively communicate with or block communication with the third opening.

[0010] In an optional embodiment, the valve needle assembly includes a large valve needle and a small valve needle;

[0011] A valve seat is provided inside the mounting cavity, and the third opening is provided in the valve seat;

[0012] The large valve needle is movably mounted in the mounting cavity;

[0013] The large valve needle is provided with an assembly cavity, and the bottom end of the assembly cavity is provided with a through hole;

[0014] The small valve needle is movably installed in the assembly cavity, and the bottom end of the small valve needle passes through the through hole;

[0015] The drive assembly is connected to the small valve needle in a transmission manner. The drive assembly can drive the small valve needle to move downward so that the small valve needle abuts against the second opening to block the communication between the second opening and the mounting cavity.

[0016] The drive assembly can drive the small valve needle to move upward, thereby releasing the small valve needle from contact with the second opening and allowing the second opening to communicate with the mounting cavity;

[0017] The small valve needle can drive the large valve needle to move downward, so that the large valve needle abuts against the valve seat to block the communication between the first opening and the mounting cavity;

[0018] The small valve needle can drive the large valve needle to move upward, so that the large valve needle can disengage from the valve seat, thereby enabling the first opening to communicate with the mounting cavity.

[0019] In an optional embodiment, the second opening includes a radial flow channel and an axial flow channel;

[0020] The first opening is located at the top of the valve seat, the radial flow channel is disposed in the valve body and located at the bottom of the valve seat, the axial flow channel is disposed in the valve seat, and one end of the radial flow channel is connected to the mounting cavity, and the other end is connected to the radial flow channel.

[0021] The small valve needle can move down to abut against the opening of the axial flow channel to block the communication between the axial flow channel and the mounting cavity;

[0022] The upward movement of the small valve needle can release it from contact with the opening of the axial flow channel, allowing the axial flow channel to communicate with the mounting cavity.

[0023] In an optional embodiment, the axial flow channel is disposed along the axial direction of the valve body, and the third opening is disposed at the outer periphery of the axial flow channel.

[0024] In an optional implementation, the flow area of ​​the first opening is greater than the flow area of ​​the second opening.

[0025] In an optional implementation, there are multiple first openings, second openings, and third openings.

[0026] In an optional embodiment, the electronic expansion valve further includes a sealing ring, and a sealing ring groove is provided above the first opening for the large valve needle. The sealing ring is disposed in the sealing ring groove, and the sealing ring can achieve a seal between the side wall of the large valve needle and the side wall of the mounting cavity.

[0027] In an optional embodiment, the small valve needle is provided with a balanced flow channel;

[0028] The balancing channel allows the small valve needle to balance the pressure difference across the large valve needle when it is in the open state.

[0029] In an optional embodiment, when the large valve needle abuts against the valve seat, the large valve needle and the valve seat enclose and form a balance cavity;

[0030] The balancing channel includes a first channel passing through the top of the small valve needle and a horizontal channel disposed at the bottom of the small valve needle. One end of the horizontal channel is connected to the first channel, and the other end is connected to the balancing cavity.

[0031] In an optional embodiment, the diameter of the through hole is larger than the diameter of the bottom end of the small valve needle, and the side wall of the small valve needle is provided with a connecting flow channel, which can balance the pressure difference between the two ends of the small valve needle.

[0032] The beneficial effects of the embodiments of the present invention include, for example:

[0033] This application provides a first opening and a second opening that communicate with the mounting cavity on the valve body, and installs the valve needle assembly in the mounting cavity. The movement of the valve needle assembly allows the first and second openings to selectively communicate with a third opening. This enables the electronic expansion valve to select different flow channels for different flow rates, thereby making the flow control of the electronic expansion valve more precise. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A schematic diagram of the structure of the electronic expansion valve provided in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the electronic expansion valve in the closed state provided in an embodiment of the present invention;

[0037] Figure 3 A cross-sectional schematic diagram of the valve body of the electronic expansion valve provided in an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the valve body of the electronic expansion valve provided in an embodiment of the present invention;

[0039] Figure 5 A cross-sectional view of the electronic expansion valve provided in an embodiment of the present invention, in the state where the small valve needle is open and the large valve needle is closed;

[0040] Figure 6 This is a cross-sectional view of the electronic expansion valve provided in an embodiment of the present invention, showing that both the small valve needle and the large valve needle are in the open state.

[0041] Icons: 100-Electronic expansion valve; 110-Valve body; 111-Mounting cavity; 113-First opening; 115-Second opening; 117-Third opening; 119-Valve seat; 121-Radial flow channel; 123-Axial flow channel; 130-Drive assembly; 131-Drive nut; 133-Rotor; 135-Slide groove; 150-Valve needle assembly; 151-Large valve needle; 153-Small valve needle; 155-Assembly cavity; 157-Through hole; 159-Valve needle body; 161-Abutment part; 163-Sealing part; 165-Body part; 167-Connecting part; 169-Through hole; 171-Sealing ring groove; 173-Balance flow channel; 175-First flow channel; 177-Horizontal flow channel; 179-Balance cavity; 191-Spring; 193-Sealing ring. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0046] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0047] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0048] Example

[0049] In order to achieve precise flow control, the existing technology has introduced a dual-valve needle electronic expansion valve 100. However, the existing dual-valve needle electronic expansion valve 100 only has one inlet and one outlet for large and small flow rates, which still has the problem of low flow control accuracy.

[0050] Please refer to Figure 1 This embodiment provides an electronic expansion valve 100, which can improve the control accuracy of the flow rate of the electronic expansion valve 100.

[0051] Please refer to Figure 2 and Figure 3 In this embodiment, the electronic expansion valve 100 includes a valve body 110, a valve needle assembly 150, and a drive assembly 130. The valve body 110 has a mounting cavity 111 and a first opening 113, a second opening 115, and a third opening 117 communicating with the mounting cavity 111. The valve needle assembly 150 is movably mounted within the mounting cavity 111. The drive assembly 130 is mounted within the mounting cavity 111 and connected to the valve body 110, and is drively connected to the valve needle assembly 150. The drive assembly 130 can drive the valve needle assembly 150 to move, so that the first opening 113 and the second opening 115 selectively communicate with or block communication with the third opening 117.

[0052] In this embodiment, a first opening 113 and a second opening 115 communicating with the mounting cavity 111 are provided on the valve body 110, and the valve needle assembly 150 is installed in the mounting cavity 111. Thus, the movement of the valve needle assembly 150 allows the first opening 113 and the second opening 115 to selectively communicate with the third opening 117. In this way, the electronic expansion valve 100 can select different flow channels for liquid flow under different flow rates, thereby making the flow control of the electronic expansion valve 100 more precise.

[0053] It should be noted that in this embodiment, the first opening 113 and the second opening 115 can be used as liquid inlets and the third opening 117 can be used as liquid outlets. Alternatively, the third opening 117 can be used as a liquid inlet and the first opening 113 and the second opening 115 can be used as liquid outlets.

[0054] It should also be noted that selectively connecting or blocking the connection between the first opening 113 and the second opening 115 and the third opening 117 can include the following methods:

[0055] The first opening 113 is connected to the third opening 117, while the second opening 115 is blocked from connecting to the third opening 117.

[0056] The second opening 115 is connected to the third opening 117, while the first opening 113 is blocked from connecting to the third opening 117.

[0057] Both the first opening 113 and the second opening 115 are connected to the third opening 117;

[0058] Both the first opening 113 and the second opening 115 are blocked from communicating with the third opening 117.

[0059] To more clearly explain the principle of this embodiment, the first opening 113 and the second opening 115 will be used as liquid inlets in the following description.

[0060] Please continue to refer to Figure 2 and Figure 3 In this embodiment, the valve needle assembly 150 includes a large valve needle 151 and a small valve needle 153. A valve seat 119 is provided in the mounting cavity 111, and a third opening 117 is provided in the valve seat 119. The large valve needle 151 is movably mounted in the mounting cavity 111. An assembly cavity 155 is provided in the large valve needle 151, and a through hole 157 is provided at the bottom end of the assembly cavity 155. The small valve needle 153 is movably mounted in the assembly cavity 155, and the bottom end of the small valve needle 153 passes through the through hole 157. The drive assembly 130 is drively connected to the small valve needle 153. The small valve needle 153 is drively connected to the large valve needle 151.

[0061] Please refer to Figure 2 , Figure 5 and Figure 6 The drive assembly 130 can drive the small valve needle 153 downward to abut against the second opening 115, thereby blocking the communication between the second opening 115 and the mounting cavity 111, and thus blocking the communication between the second opening 115 and the third opening 117. The drive assembly 130 can also drive the small valve needle 153 upward to disengage from the second opening 115, allowing the second opening 115 to communicate with the mounting cavity 111, and thus allowing the second opening 115 to communicate with the third opening. The small valve needle 153 can also drive the large valve needle 151 downward, allowing the large valve needle 151 to abut against the valve seat 119, thereby blocking the communication between the first opening 113 and the mounting cavity 111, and thus blocking the communication between the first opening 113 and the third opening 117. The small valve needle 153 can drive the large valve needle 151 to move upward, so that the large valve needle 151 can disengage from the valve seat 119, thereby connecting the first opening 113 with the mounting cavity 111, and thus connecting the first opening 113 and the third opening 117.

[0062] In this embodiment, by drivingly connecting the small valve needle 153 and the large valve needle 151, and drivingly connecting the small valve needle 153 and the drive assembly 130, the first opening 113 and the second opening 115 can be selectively connected to or blocked from the third opening 117 by moving the large valve needle 151 and the small valve needle 153 up and down.

[0063] In this embodiment, the flow area of ​​the first opening 113 is larger than the flow area of ​​the second opening 115. Specifically, multiple first openings 113 and second openings 115 are arranged circumferentially on the valve body 110. The sum of the flow areas of the multiple first openings 113 is greater than the flow area of ​​the second opening 115. By setting different flow areas, more precise flow control can be achieved.

[0064] Please refer to Figure 4 and Figure 5 In this embodiment, the second opening 115 includes a radial flow channel 121 and an axial flow channel 123. The first opening 113 is located at the top of the valve seat 119. The radial flow channel 121 is disposed on the valve body 110 and located at the bottom of the valve seat 119. The axial flow channel 123 is disposed on the valve seat 119, with one end of the radial flow channel 121 communicating with the mounting cavity 111 and the other end communicating with the axial flow channel 123. The small valve needle 153 can move downward to abut against the opening of the axial flow channel 123 to block the communication between the axial flow channel 123 and the mounting cavity 111. The small valve needle 153 can move upward to release the abutment against the opening of the axial flow channel 123 to allow the axial flow channel 123 to communicate with the mounting cavity 111.

[0065] In this embodiment, the second opening 115 and the first opening 113 are configured in such a way that the small valve needle 153 can easily control the second opening 115.

[0066] In this embodiment, the axial flow channel 123 is located along the axial direction of the valve body 110, and the third opening 117 is located on the outer periphery of the axial flow channel 123. This arrangement facilitates the easy installation of the small valve needle 153 into the mounting cavity 111 of the large valve needle 151, and also ensures a good seal and opening of the axial flow channel 123.

[0067] In this embodiment, the axial flow channel 123 is located at the center of the valve seat 119, and the third opening 117 is located at the edge of the valve seat 119. There are multiple third openings 117, surrounding the periphery of the axial flow channel 123. Support ribs are formed between adjacent third openings 117 to support the sidewalls of the axial flow channel. There are also multiple radial flow channels 121, each located within a support rib. Liquid flowing into the multiple radial flow channels 121 converges into the axial flow channel 123, then flows axially to the mounting cavity 111, and finally flows out through the third opening 117. The total flow area of ​​the multiple radial flow channels 121 is greater than the flow area of ​​the axial flow channel 123. The sum of the flow areas of the multiple third openings 117 is also greater than the sum of the flow areas of the multiple first openings 113 and the multiple second openings 115.

[0068] This configuration makes it easier to selectively connect the first opening 113 and the second opening 115 with the third opening 117.

[0069] Please refer to Figure 5 It should be noted that when the electronic expansion valve 100 is operating at a low flow rate, the small valve needle 153 moves upward while the large valve needle 151 remains stationary. Liquid flows from the radial flow channel 121 into the axial flow channel 123, then through the axial flow channel 123 into the mounting cavity 111, and finally flows out through the third opening 117. Please refer to... Figure 6 When the electronic expansion valve 100 operates at high flow rates, the small valve needle 153 moves upward, causing the large valve needle 151 to move upward as well. Part of the liquid flows from the radial flow channel 121 into the axial flow channel 123, then flows through the axial flow channel 123 into the mounting cavity 111, and finally flows out through the third opening 117. The other part flows into the mounting cavity 111 through the first opening 113 and then out through the third opening 117. This achieves two different liquid inflow rates.

[0070] Please refer to Figure 5 and Figure 6In this embodiment, the large valve needle 151 includes a valve needle body 159 and an abutment member 161. An assembly cavity 155 is disposed in the valve needle body 159, and a through hole 157 is disposed at the bottom of the valve needle body 159. The small valve needle 153 includes a sealing portion 163, a body portion 165, and a connecting portion 167 connected in sequence. The diameter of the body portion is larger than the diameters of the sealing portion 163 and the connecting portion 167. The sealing portion 163 passes through the through hole 157 and extends to the outside of the bottom of the large valve needle 151. The abutment 161 has a through hole 169 in the middle. The connector is sleeved on the connecting part 167 through the through hole 169. The main body 165 is movably installed in the assembly cavity 155. The abutment 161 is fixedly installed on the top of the assembly cavity 155. The distance between the assembly cavity 155 and the abutment 161 is greater than the height of the main body. In this way, when the small valve needle 153 moves up a certain distance, the large valve needle 151 can remain stationary. When the small valve needle 153 continues to move up until the main body 165 abuts against the abutment 161, it can drive the large valve needle 151 to move up.

[0071] In this embodiment, a sealing layer is integrally formed at the bottom end of the valve needle body 159 by molding and sealing, and the sealing layer abuts against the valve seat 119. The sealing layer can be made of fluoropolymer (e.g., PTFE, FEP, PFA, ETFE) or rubber (e.g., EPDM, NBR, HNBR, SIL, FKM) for molding and sealing, which can solve the problem of low internal leakage sealing in dual-valve needle products, and also prevent detachment.

[0072] Please refer to Figure 6 In this embodiment, the electronic expansion valve 100 also includes a spring 191. The spring 191 is sleeved on one end of the abutment member 161 and abuts against the abutment member 161, and the other end abuts against the valve body 110. The spring 191 can provide downward pressure to the valve needle 151 so that the valve needle 151 abuts against the valve seat 119, thereby blocking the communication between the first opening 113 and the third opening 117.

[0073] In this embodiment, the transmission assembly includes a drive nut 131, a rotor 133, and a coil (not shown in the figure). The drive nut 131 is connected to the small valve needle 153. The valve body 110 is provided with a slide groove 135, and the drive nut 131 is installed in the slide groove 135. The slide groove 135 can restrict the rotation of the drive nut 131. The rotor 133 assembly is rotatably installed above the mounting cavity 111. The rotor 133 has a rotating shaft, and the bottom end of the rotating shaft is provided with a thread. The rotating shaft is installed on the drive nut 131 through the thread. The coil is installed on the outside of the valve body 110. When the coil is energized, it can drive the rotor 133 to rotate. The rotation of the rotor 133 can drive the drive nut 131 to move along the slide groove 135, thereby driving the small valve needle 153 to move. The movement of the small valve needle 153 can drive the large valve needle 151 to move.

[0074] Generally, the valve body 110 can be divided into three parts: upper, middle, and lower. These parts are manufactured separately, and then the valve needle assembly 150, drive assembly 130, etc., are assembled and welded together into a whole by means of laser welding or other methods. This facilitates the assembly of the electronic expansion valve 100.

[0075] In this embodiment, in order to ensure that the large valve needle 151 can block the first opening 113 and the third opening 117 when it is closed, the valve seat 119 is provided with a sealing slope, and a sealing platform is formed below the sealing slope. The third opening 117 and the axial flow channel 123 are disposed on the sealing platform.

[0076] In this embodiment, in order to achieve pressure balance on both sides of the valve needle, the electronic expansion valve 100 also includes a sealing ring 193. The large valve needle 151 is provided with a sealing ring groove 171 above the first opening 113, and the sealing ring 193 is disposed in the sealing ring groove 171. The sealing ring 193 can achieve sealing between the side wall of the large valve needle 151 and the side wall of the mounting cavity 111.

[0077] The sealing ring 193 is provided to prevent liquid from entering the top of the large valve needle 151 from the side wall of the large valve needle 151 and the mounting cavity 111, thus avoiding the problem of high pressure at the top of the large valve needle 151 preventing it from opening.

[0078] In this embodiment, the small valve needle 153 is provided with a balancing flow channel 173. The balancing flow channel 173 enables the small valve needle 153 to balance the pressure difference across the large valve needle 151 when it is in the open state.

[0079] Please refer to Figure 5 and Figure 6 In this embodiment, a balance flow channel 173 is provided in the small valve needle 153, so that the pressure difference between the two ends of the large valve needle 151 can be balanced when the valve is closed.

[0080] In this embodiment, when the large valve needle 151 abuts against the valve seat 119, the large valve needle 151 and the valve seat 119 enclose and form a balance cavity 179. The balance flow channel 173 includes a first flow channel 175 penetrating the top of the small valve needle 153 and a horizontal flow channel 177 disposed at the bottom of the small valve needle 153. One end of the horizontal flow channel 177 is connected to the first flow channel 175, and the other end is connected to the balance cavity 179.

[0081] In this embodiment, the balance channel 173 is provided so that the balance chamber 179 located below the main body 165 and the chamber located on the main body 165 can always be connected, thus balancing the pressure difference between the two ends of the small valve needle 153 and the pressure difference between the two ends of the large valve needle 151.

[0082] In other embodiments of this application, the diameter of the through hole 157 may be larger than the diameter of the bottom end of the small valve needle 153. The side wall of the small valve needle 153 is provided with a connecting flow channel, which can balance the pressure difference between the two ends of the small valve needle 153. The connecting flow channel keeps the two ends of the body 165 connected, thereby balancing the pressure difference between the large valve needle 151 and the small valve needle 153.

[0083] In summary, the working principle and beneficial effects of the electronic expansion valve 100 provided in this embodiment of the invention include:

[0084] In this embodiment, a first opening 113 and a second opening 115 communicating with the mounting cavity 111 are provided on the valve body 110, and the valve needle assembly 150 is installed in the mounting cavity 111. Thus, the movement of the valve needle assembly 150 allows the first opening 113 and the second opening 115 to selectively communicate with the third opening 117. In this way, the electronic expansion valve 100 can select different flow channels for liquid flow under different flow rates, thereby making the flow control of the electronic expansion valve 100 more precise.

[0085] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An electronic expansion valve, characterized in that, It includes a valve body (110), a valve needle assembly (150), and a drive assembly (130). The valve body (110) has a mounting cavity (111) and a first opening (113), a second opening (115) and a third opening (117) communicating with the mounting cavity (111). The valve needle assembly (150) is movably installed in the mounting cavity (111); The drive assembly (130) is installed in the mounting cavity (111) and connected to the valve body (110), and is drivenly connected to the valve needle assembly (150). The drive assembly (130) can drive the valve needle assembly (150) to move so that the first opening (113) and the second opening (115) can selectively communicate with or block communication with the third opening (117). The valve needle assembly (150) includes a large valve needle (151) and a small valve needle (153); a valve seat (119) is provided in the mounting cavity (111), and a third opening (117) is provided in the valve seat (119); the large valve needle (151) is movably mounted in the mounting cavity (111); an assembly cavity (155) is provided in the large valve needle (151), and a through hole (157) is provided at the bottom end of the assembly cavity (155); The small valve needle (153) is movably installed in the assembly cavity (155), and the bottom end of the small valve needle (153) passes through the through hole (157). The large valve needle (151) includes a valve needle body (159), an abutment (161), and a spring (191). The assembly cavity (155) is disposed on the valve needle body (159), and the through hole (157) is disposed at the bottom of the valve needle body (159). The abutment (161) is fixedly installed on the top of the assembly cavity (155). The spring (191) is sleeved on one end of the abutment (161) and abuts against the abutment (161), and the other end abuts against the valve body (110). The spring (191) provides downward pressure to the large valve needle (151) so that the large valve needle (151) abuts against the valve seat (119) and blocks the communication between the first opening (113) and the third opening (117). The drive assembly (130) is connected to the small valve needle (153) in a transmission connection. The drive assembly (130) can drive the small valve needle (153) to move downward so that the small valve needle (153) abuts against the second opening (115) to block the second opening (115) from communicating with the mounting cavity (111). The drive assembly (130) can drive the small valve needle (153) to move upward, so that the small valve needle (153) can disengage from the second opening (115) and allow the second opening (115) to communicate with the mounting cavity (111); The small valve needle (153) can drive the large valve needle (151) to move down, so that the large valve needle (151) can abut against the valve seat (119) to block the communication between the first opening (113) and the mounting cavity (111); The small valve needle (153) can drive the large valve needle (151) to move upward, so that the large valve needle (151) can disengage from the valve seat (119), thereby enabling the first opening (113) to communicate with the mounting cavity (111).

2. The electronic expansion valve according to claim 1, characterized in that, The second opening (115) includes a radial flow channel (121) and an axial flow channel (123). The first opening (113) is located at the top of the valve seat (119), the radial flow channel (121) is disposed on the valve body (110) and located at the bottom of the valve seat (119), the axial flow channel (123) is disposed on the valve seat (119), and one end of the axial flow channel (123) is connected to the mounting cavity (111), and the other end is connected to the radial flow channel (121); The small valve needle (153) moves down to abut against the opening of the axial flow channel (123) to block the communication between the axial flow channel (123) and the mounting cavity (111); The upward movement of the small valve needle (153) can release it from contact with the opening of the axial flow channel (123), so that the axial flow channel (123) can communicate with the mounting cavity (111).

3. The electronic expansion valve according to claim 2, characterized in that, The axial flow channel (123) is located in the axial direction of the valve body (110), and the third opening (117) is located on the outer periphery of the axial flow channel (123).

4. The electronic expansion valve according to any one of claims 1-3, characterized in that, The flow area of ​​the first opening (113) is greater than the flow area of ​​the second opening (115).

5. The electronic expansion valve according to any one of claims 1-3, characterized in that, The number of the first opening (113), the second opening (115) and the third opening (117) are all multiple.

6. The electronic expansion valve according to any one of claims 1-3, characterized in that, The electronic expansion valve also includes a sealing ring (193). The large valve needle (151) is provided with a sealing ring groove (171) above the first opening (113). The sealing ring (193) is disposed in the sealing ring groove (171). The sealing ring (193) can achieve the sealing between the side wall of the large valve needle (151) and the side wall of the mounting cavity (111).

7. The electronic expansion valve according to any one of claims 1-3, characterized in that, The small valve needle (153) is provided with a balanced flow channel (173). The balance channel (173) allows the small valve needle (153) to balance the pressure difference across the large valve needle (151) when the small valve needle (153) is in the open state.

8. The electronic expansion valve according to claim 7, characterized in that, When the large valve needle (151) abuts against the valve seat (119), the large valve needle (151) and the valve seat (119) enclose to form a balance cavity (179). The balance channel (173) includes a first channel (175) that passes through the top of the small valve needle (153) and a horizontal channel (177) disposed at the bottom of the small valve needle (153). One end of the horizontal channel (177) is connected to the first channel (175), and the other end is connected to the balance cavity (179).

9. The electronic expansion valve according to any one of claims 1-3, characterized in that, The diameter of the through hole (157) is larger than the diameter of the bottom end of the small valve needle (153). The side wall of the small valve needle (153) is provided with a connecting flow channel, which can balance the pressure difference between the two ends of the small valve needle (153).

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