Electronic expansion valve

Abstract

The electronic expansion valve comprises a first cavity, a valve seat nut assembly and a second cavity; the valve seat nut assembly comprises a valve seat, a nut assembly and a first balance part; the nut assembly comprises a nut and a connecting body which are integrally injection molded; the nut comprises a first nut matching part; the valve seat comprises a flow-through part and a first valve seat matching part, the first nut matching part is arranged in the first valve seat matching part, the connecting body is welded with the valve seat, the flow-through part is communicated with the first cavity and the first balance part, and the first balance part is communicated with the second cavity. The first balance part of the valve seat nut assembly and the flow-through part arranged on the valve seat can be used as a flow-through path for pressure balance of the first cavity and the second cavity.

Description

[Technical Field]

[0001] This invention relates to the field of refrigeration control technology, and in particular to an electronic expansion valve. [Background Technology]

[0002] Figure 8 An electronic expansion valve is shown, which includes a connecting piece 31', which is welded to a valve seat 12' to fix the valve seat and nut. The connecting piece 31' is provided with a through hole through its upper and lower surfaces.

[0003] The electronic expansion valve with the above structure is divided into two chambers by the connecting piece 31': the chamber above the connecting piece 31' and the chamber below the connecting piece 31'. The two chambers are mainly connected by the through hole provided on the connecting piece 31' to achieve pressure balance inside the electronic expansion valve body. [Summary of the Invention]

[0004] The purpose of this invention is to provide an electronic expansion valve having a flow path that provides pressure balance in a first chamber and a second chamber.

[0005] To achieve the above objectives, the following technical solution is adopted: an electronic expansion valve, comprising a first cavity, a valve seat nut assembly, and a second cavity;

[0006] The valve seat nut assembly includes a valve seat, a nut assembly, and a first balancing part; the nut assembly includes a nut and a connecting body, the nut and the connecting body are an integral structure, and the nut includes a first nut mating part;

[0007] The valve seat includes a flow section and a first valve seat mating section. The first nut mating section passes through the first valve seat mating section. The connecting body is welded and fixed to the valve seat. The flow section connects the first cavity and the first balance section. The first balance section connects to the second cavity.

[0008] The electronic expansion valve provided by the present invention has a first balancing part of the valve seat nut assembly and a flow part disposed on the valve seat, which can serve as a flow path for pressure balance in the first cavity and the second cavity. [Attached Image Description]

[0009] Figure 1 A cross-sectional view of a first embodiment of the electronic expansion valve provided by the present invention;

[0010] Figure 2 for Figure 1 Schematic diagram of the middle nut assembly;

[0011] Figure 3 A cross-sectional view of a second embodiment of the electronic expansion valve provided by the present invention;

[0012] Figure 4 for Figure 3 Schematic diagram of the middle nut assembly;

[0013] Figure 5 A cross-sectional view of the third embodiment of the electronic expansion valve provided by the present invention;

[0014] Figure 6 for Figure 5 Schematic diagram of the middle nut assembly;

[0015] Figure 7 for Figure 6 Top view of the middle valve seat;

[0016] Figure 8 This is a cross-sectional view of an electronic expansion valve in the background art.

[0017] The above figures include the following reference numerals:

[0018] Valve seat and nut assembly 1; Valve seat 11; Flow portion 111; First valve seat mating portion 112; First valve seat recess 1121; Second valve seat mating portion 113; Third valve seat recess 1131; Transition portion 114; Second valve seat recess 1141; First interface portion 115; Second interface portion 116; Valve port 117; Valve port sealing portion 1171; Nut assembly 12; Nut 121; First nut mating portion 1211; First nut recess 1212; Second nut Groove portion 1213; Second nut mating portion 1214; Third nut groove portion 1215; Connector 122; Rotor assembly 2; Magnetic rotor 21; Lead screw 22; Lead screw receiving portion 221; Lead screw inner mating portion 222; Lead screw abutment portion 223; Valve needle 23; Valve needle expansion portion 231; Spring 24; Fixing rod 25; Steel ball 26; First connecting pipe portion 3; Second connecting pipe portion 4; Housing 5; Fixing frame 6; Stopping assembly 7; Helical guide rail; Sliding ring 72; Stopping rod 73.

Detailed Implementation Methods

[0019] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Please refer to the following for details. Figure 1-2 , Figure 1 A cross-sectional view of a first embodiment of the electronic expansion valve provided by the present invention; Figure 2 for Figure 1 A schematic diagram of the structure of the nut assembly.

[0021] In one specific embodiment, the electronic expansion valve provided by the present invention comprises a valve body and a stator coil (not shown in the diagram). The valve body includes a valve seat nut assembly 1, a rotor assembly 2, and a housing 3. The stator coil of the electronic expansion valve is connected to a drive controller. After the drive controller is energized, it sends a pulse drive signal to the stator coil, which generates a periodically changing magnetic field, thereby driving the rotor assembly 2 of the electronic expansion valve to rotate in the forward or reverse direction. The rotor assembly 2 includes a magnetic rotor 21 and a lead screw 22. The magnetic rotor 21 is fixedly connected to the lead screw 22. When the magnetic rotor 21 rotates, it synchronously drives the lead screw 22 to rotate. The lead screw 22 of the rotor assembly 2 has an external thread, and the inner hole of the nut 121 of the nut assembly 12 has an internal thread. The lead screw 22 and the nut 121 are threadedly engaged. Thus, while the rotor assembly 2 rotates, the lead screw 1 will move along the axial direction, thereby driving the valve needle 23 to move axially to realize the opening and closing action of the valve port 117.

[0022] The valve seat nut assembly 1 provided in this embodiment includes a valve seat 11, a nut assembly 12 and a first balancing part 1A. The valve seat 11 includes a first interface part 15 and a second interface part 16. A first connecting part 3 is disposed on the first interface part 15 and the two are welded and fixed together. A second connecting part 4 is disposed on the second interface part 16 and the two are welded and fixed together.

[0023] The first connecting section 3 and the second connecting section 4 serve as inflow or outflow channels for the fluid medium in the electronic expansion valve, and are generally used to connect to the system piping when installed in refrigeration or heating systems such as air conditioning. The valve seat 21 is provided with a valve port 117 at approximately the center of the second connecting section 23, and a valve port sealing part 1171 is provided on the upper edge of the valve port 117.

[0024] On the upper side of the valve seat 11, a nut assembly 12 is coaxially disposed, the nut assembly 12 including a nut 121 and a connecting body 122. The nut 121 can be made of plastic, which is injection molded from resin material, and the nut 121 is fixedly connected to the connecting body 122 so that the nut 121 and the connecting body 122 are an integral structure. The nut 121 provided in this embodiment is generally hollow.

[0025] The rotor assembly 2 includes a magnetic rotor 21, a lead screw 22, a valve needle 23, a spring 24, and a fixed rod 25. The lead screw 22 is fixedly connected to the magnetic rotor 21. When the magnetic rotor 21 senses a change in the magnetic field and rotates, it can drive the lead screw 22 to rotate synchronously.

[0026] In this embodiment, the lead screw 22 is generally hollow, with a fixed rod 25 fixedly connected to its upper end. A spiral guide rail 71 is fixedly connected to the fixed rod 25, and the sliding ring 72 is located on the spiral guide rail 71.

[0027] Furthermore, the valve needle 23 is limitedly connected to the lead screw 22. Specifically, the lower end of the valve needle 23 can pass through the lower opening of the lead screw 22. At approximately the upper end of the valve needle 23, a valve needle expansion portion 231 extending radially is provided. The lead screw 22 includes a lead screw receiving portion 221 and a lead screw inner fitting portion 222, as well as a lead screw abutment portion 223 located between the two. When one end of the valve needle 12 is about to pass through the lead screw 22, the valve needle expansion portion 23 can abut against the lead screw abutment portion 223 to restrict the valve needle 23 from passing through the lead screw 22. In addition, the valve needle inner fitting portion 222 and the valve needle 23 are clearance-fitted, which can provide guidance for the movement of the valve needle 23 within the lead screw 22 to improve the stability of the valve needle 23 when moving relative to the lead screw 22 and improve the coaxiality of the valve needle 23 and the lead screw 22.

[0028] The valve needle 23 can be inserted through the upper opening of the lead screw 22, but the lead screw abutment 223 can restrict the valve needle 23 from being inserted through the lower opening of the lead screw 22.

[0029] When the valve needle expansion portion 231 is circular, the outer diameter of the valve needle expansion portion 231 is smaller than the inner diameter of the lead screw receiving portion 221 of the lead screw 22, and the outer diameter of the valve needle expansion portion 231 is larger than the inner diameter of the lead screw abutment portion 223. This setting can restrict the valve needle 23 from passing through the opening at the lower end of the lead screw 22, so as to realize the movable connection between the valve needle 23 and the lead screw 22.

[0030] A spring 24 and a steel ball 26 are provided inside the lead screw receiving portion 221, between the fixed rod 25 and the valve needle 23. When the electronic expansion valve closes the valve port 117 and the lead screw 22 is still moving downward, the spring 24 can provide pressure for the valve needle 23 to close the valve port 117. In addition, the steel ball 26 can reduce the possibility that the valve needle 23 will rotate synchronously due to friction when the lead screw 22 rotates, thereby reducing the possibility that the valve needle 23 will rotate relative to the valve port sealing portion 1171 after contact, and thus reducing the possibility of wear between the valve needle 23 and the valve port 117 due to relative rotation.

[0031] In addition, the electronic expansion valve provided in this embodiment also includes a housing 5 with one end open. The housing 5 is fitted outside the rotor assembly 2. The housing 5 is generally a cylindrical structure with one end open. Its opening is directly or indirectly welded to the valve seat 11 for sealing. In this embodiment, the valve seat 11 is fixedly connected to the fixing frame 6, and the housing 5 is fixedly connected to the fixing frame 6.

[0032] At the upper end of the outer casing 5, a stop rod 73 is fixedly connected. The cross-section of the stop rod 73 is roughly in the shape of a horizontally inverted "L". By using the cooperation of the stop rod 73, the sliding ring 72 and the spiral guide rail 71, the range of vertical movement of the rotor assembly 2 can be limited. The stop rod 73, the sliding ring 72 and the spiral guide rail 71 constitute the stop assembly 7 of the electronic expansion valve.

[0033] In this embodiment, the nut 121 includes a first nut mating part 1211, and the valve seat 11 includes a first valve seat mating part 112. The first nut mating part 1211 passes through the first valve seat mating part 112, that is, at this time, the projections of the first nut mating part 1211 and the valve seat mating part 112 in the axial direction along the central axis of the electronic expansion valve intersect.

[0034] At this point, the valve seat 11, nut 121, fixing bracket 6 and housing 5 generally define the first cavity A, and the valve seat 11 and nut 121 generally define the second cavity B.

[0035] The valve seat nut assembly 1 includes a first balancing part 1A. A flow part 111 is provided on the valve seat 11, which connects the first cavity A and the first balancing part 1A. The flow part 111 can be a notch or a through hole that penetrates the valve seat 11.

[0036] In this embodiment, the first nut mating portion 1211 and the first valve seat mating portion 112 are interference-fitted. In addition, the nut 121 also includes a first nut groove portion 1212. In this embodiment, there are two first nut groove portions 1212. The first nut groove portion 1212 is a structure formed by radially recessing the outer surface of the nut 121. At this time, the first nut groove portion 1211 connects the second cavity B and the flow portion 111. Since the flow portion 111 is connected to the first cavity A, the pressure between the first cavity A and the second cavity B can be balanced through the first nut groove portion 1212. At this time, the first balancing portion 1A includes the first nut groove portion 1212, that is, the first nut groove portion 1212 is at least a part of the first balancing portion 1A.

[0037] The valve seat nut assembly 1 configured as described above can provide a flow path for rapid pressure balance in the first cavity A and the second cavity B through the first nut groove 1212 provided in the nut 121 and the flow portion 111 provided in the valve seat 11, ensuring the working stability of the electronic expansion valve. At the same time, compared with the prior art where the refrigerant balance path is provided on the outside of the nut, the electronic expansion valve structure provided by the present invention is more compact, which is conducive to the miniaturization of the electronic expansion valve.

[0038] When the first nut mating part 1211 and the first valve seat mating part 112 are interference-fitted, the flow part 111 and the first nut groove 1212 need to be aligned to achieve conduction when the nut 121 is press-fitted onto the valve seat 11, which may slow down the working efficiency. At this time, in order to improve the assembly efficiency of the electronic expansion valve, the nut provided in this embodiment also includes a nut ring groove. The space between the nut ring groove and the valve seat 11 is connected to the flow part 111, and at the same time, it is connected to the first nut groove 1212. The nut ring groove is roughly a structure with a radially recessed structure on the surface of the nut 121, that is, the outer diameter of the nut ring groove is smaller than the outer diameter of the first nut mating part 1211. At this time, the nut ring groove and the valve seat 11 are clearance-fitted. Since the nut ring groove is circumferential, when assembling the nut 121 and the valve seat 11, it is not necessary to additionally align the first nut groove 1216 and the flow part 111, which can improve the assembly efficiency.

[0039] Of course, the assembly efficiency can also be improved by using the valve seat annular groove 118. Specifically, the space between the valve seat annular groove 118 and the nut 121 can be connected to the flow part 111 and the first nut groove 1212. The valve seat annular groove 118 is roughly a structure with radial recesses on the inner and outer walls of the valve seat 11, that is, the inner diameter of the valve seat annular groove 118 is larger than the inner diameter of the first valve seat mating part 112. At this time, the first nut mating part 1211 and the valve seat annular groove 118 are in clearance fit. Since the valve seat annular groove 118 is circumferential, when assembling the nut 121 and the valve seat 11, it is not necessary to align the first nut annular groove with the flow part 111, which can improve the assembly efficiency.

[0040] It is easy to understand that the setting of the nut ring groove and the valve seat ring groove 118 does not conflict. That is, when the valve seat 11 and the nut 121 are press-fitted together without aligning the first nut ring groove with the flow part 111, it is acceptable to set either the nut ring groove or the valve seat ring groove 118 or set them simultaneously.

[0041] Furthermore, the first nut mating part 1211 and the first valve seat mating part 112 are interference-fitted, which can achieve the pre-positioning of the nut 121 and the valve seat 11 before the connecting body 122 of the nut assembly 12 is welded and fixed to the valve seat 11, and can ensure the coaxiality of the nut 121 and the valve seat 11. It is worth noting that the mating relationship between the first nut mating part 1211 and the second valve seat mating part 113 does not take into account the first nut recess 1212.

[0042] In addition, in this embodiment, the valve seat nut assembly 1 also includes a second balancing part 1B, which connects the first balancing part 1A and the second cavity B. It can also provide a flow path for pressure balance in the first cavity A and the second cavity B, ensuring the working stability of the electronic expansion valve.

[0043] Specifically, the valve seat 11 includes a second valve seat mating portion 113 and a transition portion 114. The transition portion 114 is located between the first valve seat mating portion 112 and the second valve seat mating portion 113. Furthermore, the axial projected area of ​​the second valve seat mating portion 113 is smaller than the axial projected area of ​​the first valve seat mating portion 112.

[0044] At this time, there is a gap between the first nut mating part 1211 and the transition part 114, which defines the second balancing part 1B, that is, the gap is at least a part of the second balancing part 1B.

[0045] In this embodiment, after the connector 122 and the valve seat 11 are welded and fixed, the distance between the bottom surface of the welded part of the connector 122 and the valve seat 11 and the bottom surface of the first nut mating part 1211 is less than the distance between the top of the valve seat 11 and the transition part 114. At this time, an axial gap will be formed between the bottom surface of the transition part 114 and the first nut mating part 1211. This gap can provide a flow path for pressure balance between the first cavity A and the second cavity B, ensuring the working stability of the electronic expansion valve.

[0046] Compared to the electronic expansion valve structure in the prior art, the electronic expansion valve provided in this embodiment sets the balance channel between the valve seat 11 and the nut 121, which is compact and conducive to the miniaturization of the electronic expansion valve. The coaxiality of the valve seat 11 and the nut 121 can also be guaranteed.

[0047] In addition, the nut provided in this embodiment includes a second nut mating part 1214. The inner edge of the second nut mating part 1214 can provide guidance for the valve needle, thereby improving the concentricity of the valve needle with the valve port when it moves up and down.

[0048] In this embodiment, the second nut mating part 1214 and the second valve seat mating part 113 are clearance-fitted. The gap between the second nut mating part 1214 and the second valve seat mating part 113 can provide a flow path for pressure balance between the first cavity A and the second cavity B. The third balancing part 1C includes the gap between the second nut mating part 1214 and the second valve seat mating part 113. The third balancing part 1C connects the second cavity B and the second balancing part 1B, which can increase the axial length of the valve needle guided by the nut 121 to improve the concentricity of the valve needle with the valve port when it moves up and down, and still achieve the purpose of rapid pressure balance between the first cavity A and the second cavity B. At the same time, the mating of the second nut mating part 1214 and the second valve seat mating part 113 also increases the mating length between the nut 121 and the valve seat 11, which can increase the working reliability of the valve seat nut assembly 1.

[0049] The electronic expansion valve provided in this embodiment, through the flow portion 111 provided on the valve seat 11 and the first balance portion 1A, the second balance portion 1B and the third balance portion 1C formed by the valve seat 11 and the nut assembly 12, can connect the first cavity A and the second cavity B, thereby enabling the pressure in the first cavity A and the second cavity B to be quickly balanced, ensuring the working stability of the electronic expansion valve.

[0050] Furthermore, the electronic expansion valve provided in this embodiment also includes a nut pressure portion 1217 and a nut flow hole portion 1218. Specifically, the nut pressure portion 1217 is located axially below the internal thread of the nut, and the inner diameter of the nut pressure portion 1217 is larger than the outer diameter of the valve needle 23 excluding the valve needle expansion portion 231. At this time, a certain space is formed between the nut pressure portion 1217 and the valve needle 23. In addition, the nut flow hole portion 1218 includes penetrations through the inner and outer surfaces of the nut 121, and the nut flow hole portion 1218 connects the nut pressure portion 26 and the aforementioned first balance portion 1A.

[0051] With the above settings, the pressure inside the nut 121 can be balanced with the pressure outside the nut 121 through the nut flow hole 1218, thereby improving the working stability of the electronic expansion valve.

[0052] Please refer to the specific details. Figure 3-4 ,in, Figure 3 This is a cross-sectional view of a second embodiment of the electronic expansion valve provided by the present invention. Figure 4 for Figure 3 Schematic diagram of the middle nut assembly;

[0053] For ease of description, components with the same structure and function as those in the first embodiment are referred to by the same reference numerals. The description of each component in the first embodiment is also applicable to the second embodiment. The differences from the first embodiment will be described in detail below.

[0054] In this embodiment, the valve seat nut assembly 12 includes a first balancing part 1A. A flow part 111 is provided on the valve seat 11, which connects the first cavity A and the first balancing part 1A. The flow part 111 can be a notch or a through hole provided on the valve seat 11.

[0055] In this embodiment, the first nut mating part 1211 and the first valve seat mating part 112 are fitted with a clearance. In addition, the valve seat 11 also includes a first valve seat groove part 1121, which is a structure formed by radially recessing the inner surface of the valve seat 11. At this time, the first valve seat groove part 1121 connects the second cavity B and the flow part 111. Since the flow part 111 is connected to the first cavity A, the pressure between the first cavity A and the second cavity B can be balanced through the clearance between the first valve seat groove part 1121 and the first valve seat mating part 112 and the first nut mating part 1211. At this time, the first balancing part 1A includes the first valve seat groove part 1121, that is, the first valve seat groove part 1121 is a component of the first balancing part 1A. At the same time, the clearance between the first nut mating part 1211 and the first valve seat mating part 112 can also provide a flow path for pressure balance between the first cavity A and the second cavity B, ensuring the stability of the electronic expansion valve.

[0056] It is worth noting that when A is mentioned in this specification as defining B, it means that A is at least a part of B, but it does not mean that all the components of B are A. For example, in the first embodiment, the first nut groove 1212 is a flow passage connecting the first cavity A and the second cavity B, and the first nut groove 1212 defines the first balancing part 1A. In this embodiment, the first valve seat groove 1121 is a component of the first balancing part 1A. At the same time, the gap between the first nut mating part 1A and the first valve seat mating part 112 can also provide a flow passage for pressure balance between the first cavity A and the second cavity B. The first valve seat groove 1121 also defines the first balancing part 1A.

[0057] In addition, in this embodiment, the valve seat nut assembly 1 also includes a second balancing part 1B, which connects to the first balancing part 1A and the second cavity B. It can also provide a flow path for pressure balance in the first cavity A and the second cavity B, ensuring the working stability of the electronic expansion valve.

[0058] Specifically, the valve seat 11 includes a second valve seat mating portion 113 and a transition portion 114. The transition portion 114 is located between the first valve seat mating portion 112 and the second valve seat mating portion 113. Furthermore, the axial projected area of ​​the second valve seat mating portion 113 is smaller than the axial projected area of ​​the first valve seat mating portion 112.

[0059] At this time, there is a flow channel between the first nut mating part 1211 and the transition part 114, and the second balancing part 1B includes the flow channel, that is, the gap is at least a part of the second balancing part 1B.

[0060] In this embodiment, after the connector 122 and the valve seat 11 are welded and fixed, the distance between the bottom surface of the welded part of the connector 122 and the valve seat 11 and the bottom surface of the first nut mating part 1211 is equal to the distance between the top surface of the welded connector 122 and the transition part 114. At this time, in order to make the first cavity A and the second cavity B conductive, the nut 121 includes a second nut groove 1213. The second nut groove 1213 is formed by the recess at the point where the nut 121 and the transition part 114 abut. At this time, an axial gap will be formed on the bottom surface of the transition part 114 and the first nut mating part 1211. This gap can provide a flow path for pressure balance between the first cavity A and the second cavity B, ensuring the working stability of the electronic expansion valve.

[0061] Similar to the first embodiment, in order to increase the axial length of the valve needle guided by the nut 121 and improve the concentricity of the valve needle with the valve port when moving up and down, the nut 121 provided in this embodiment includes a second nut mating part 1214. The inner edge of the second nut mating part 1214 can provide guidance for the valve needle, thereby improving the concentricity of the valve needle with the valve port when moving up and down. At the same time, the second nut mating part 1214 and the second valve seat mating part 113 cooperate, which also increases the mating length between the nut 121 and the valve seat 11, thereby increasing the working reliability of the valve seat nut assembly 1.

[0062] In this embodiment, the second nut mating portion 1214 is interference-fitted with the second valve seat mating portion 113. The nut 121 is provided with a third nut groove portion 1215 formed by a radial indentation on the surface of the second nut mating portion 1214. The third nut groove portion 1215 can connect the second balance portion 1B and the second cavity B. Thus, the third nut groove portion 1215 can provide a flow path for pressure balance between the first cavity A and the second cavity B. The third balance portion 1C includes the third nut groove portion 1215 and connects the second cavity B and the second balance portion 1B.

[0063] The electronic expansion valve provided in this embodiment, through the flow portion 111 provided on the valve seat 11 and the first balance portion 1A, the second balance portion 1B and the third balance portion 1C formed by the valve seat 11 and the nut assembly 12, can connect the first cavity A and the second cavity B, thereby enabling the pressure in the first cavity A and the second cavity B to be quickly balanced, ensuring the working stability of the electronic expansion valve.

[0064] Please refer to the following for details. Figure 5-7 ,in, Figure 5 This is a cross-sectional view of the third embodiment of the electronic expansion valve provided by the present invention. Figure 6 for Figure 5 Schematic diagram of the middle nut assembly. Figure 7 for Figure 6 Top view of the valve seat.

[0065] For ease of description, components with the same structure and function as those in the first embodiment are referred to by the same reference numerals. The description of each component in the first embodiment is also applicable to the third embodiment. The differences from the first embodiment will be described in detail below.

[0066] The valve seat nut assembly 1 includes a first balancing part 1A. A flow part 111 is provided on the valve seat 11, which connects the first cavity A and the first balancing part 1A. The flow part 111 can be a notch or a through hole provided on the valve seat 11.

[0067] In this embodiment, the first nut mating part 1211 and the first valve seat mating part 112 are fitted with a clearance. At this time, the pressure between the first cavity A and the second cavity B can be balanced through the clearance between the first valve seat mating part 112 and the first nut mating part 1211. At this time, the clearance between the first nut mating part 1211 and the second nut mating part 1214 defines the first balancing part 1A. The clearance between the first nut mating part 1211 and the first valve seat mating part 112 (the first balancing part 1A) can provide a flow path for pressure balance between the first cavity A and the second cavity B, ensuring the stability of the electronic expansion valve.

[0068] In addition, in this embodiment, the valve seat nut assembly 1 also includes a second balancing part 1B, which connects the first balancing part 1A and the second cavity B. It can also provide a flow path for pressure balance in the first cavity A and the second cavity B, ensuring the working stability of the electronic expansion valve.

[0069] Furthermore, the valve seat 11 includes a second valve seat mating portion 113 and a transition portion 114. The transition portion 114 is located between the first valve seat mating portion 112 and the second valve seat mating portion 113, and the axial projected area of ​​the second valve seat mating portion 113 is smaller than the axial projected area of ​​the first valve seat mating portion 112.

[0070] At this time, there is a flow channel between the first nut mating part 1211 and the transition part 114, which defines the second balancing part 1B, that is, the flow channel is at least a part of the second balancing part 1B.

[0071] In this embodiment, after the connector 122 and the valve seat 11 are welded and fixed, the distance between the bottom surface of the welded part of the connector 122 and the valve seat 11 and the bottom surface of the first nut mating part 1211 is equal to the distance between the top surface of the valve seat 11 and the connector 122 and the transition part 114. At this time, in order to make the first cavity A and the second cavity B conductive, the transition part 114 includes a second valve seat groove 1141. The second valve seat groove 1141 is formed by the recess at the point where the nut 121 and the transition part 114 abut. At this time, an axial gap will be formed on the bottom surface of the transition part 114 and the first nut mating part 1211. This gap can provide a flow path for pressure balance between the first cavity A and the second cavity B, ensuring the working stability of the electronic expansion valve.

[0072] Similar to the first embodiment, in order to increase the axial length of the valve needle guided by the nut 121 and improve the concentricity of the valve needle with the valve port when moving up and down, the nut 121 provided in this embodiment includes a second nut mating part 1214. The inner edge of the second nut mating part 1214 can provide guidance for the valve needle, thereby improving the concentricity of the valve needle with the valve port when moving up and down. At the same time, the second nut mating part 1214 and the second valve seat mating part 113 cooperate, which also increases the mating length between the nut 121 and the valve seat 11, thereby increasing the working reliability of the valve seat nut assembly 1.

[0073] In this embodiment, the second nut mating part 1214 and the second valve seat mating part 113 are in clearance fit. The valve seat 11 is provided with a third valve seat groove 1131 formed by a radial indentation on the surface of the second valve seat mating part 113. The third valve seat groove 1131 can connect the second balance part 1B and the second cavity B. Thus, the third valve seat groove 1131 can provide a flow passage for pressure balance between the first cavity A and the second cavity B. The third balance part 1C includes the third valve seat groove 1131 and connects the second cavity B and the second balance part 1B.

[0074] It is worth noting that, in this embodiment, A limiting B means that A is at least a part of B, but it does not mean that all the components of B are A. For example, in this embodiment, the second nut mating part 1214 and the second valve seat mating part 113 are in clearance fit. The first cavity A and the second cavity B can be connected through the third valve seat groove part 1141, or through the gap between the second nut mating part 1214 and the second valve seat mating part 113. In this case, the third valve seat groove part 1131 still limits the third balance part 1C.

[0075] It should be noted that the directional terms such as up, down, left, and right mentioned in this specification are all based on the accompanying drawings and are introduced for ease of description; and the ordinal numbers such as "first" and "second" in the component names are also introduced for ease of description and do not imply any limitation on the order of the components. The connection mentioned in this specification includes direct connection and indirect connection.

[0076] The electronic expansion valve provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. An electronic expansion valve characterized by, The valve seat nut assembly (1) comprises a valve seat (11), a nut assembly (12), and a first balance part (1A); The valve seat nut assembly (1) comprises a valve seat (11), a nut assembly (12), and a first balance part (1A); The nut assembly (12) comprises a nut (121) and a connecting body (122), the nut (121) and the connecting body (122) are an integral structure, the nut (121) comprises a first nut matching part (1211); The valve seat (11) comprises a flow-through part (111) and a first valve seat matching part (112), the first nut matching part (1211) is arranged in the first valve seat matching part (112); the connecting body (122) is welded and fixed with the valve seat (11), and the connecting body (122) is located below a magnetic rotor (21) in a rotor assembly (2); the flow-through part (111) communicates the first cavity (A) and the first balance part (1a), and the first balance part (1A) communicates the second cavity (B); The valve seat nut assembly (1) comprises a second balance part (1B), the second balance part (1B) communicates the first balance part (1A) and the second cavity (B), the valve seat (11) comprises a second valve seat matching part (113) and a transition part (114), an axial projection area of the second valve seat matching part (113) is smaller than an axial projection area of the first valve seat matching part (112), the transition part (114) is located between the first valve seat matching part (112) and the second valve seat matching part (113), the first nut matching part (1211) and the transition part (114) have a gap or a channel, and the second balance part (1B) comprises the gap or the channel; The first nut matching part (1211) and the transition part (114) have an axial gap, and the second balance part (1B) comprises the axial gap between the first nut matching part (1211) and the transition part (114); The nut pressure part (1217) is located below the internal thread of the nut (121) in the axial position, so that a certain space is formed between the nut pressure part (1217) and the valve needle (23); the nut flow-through hole part (1218) penetrates the inner and outer surfaces of the nut (121), and the nut flow-through hole part (1218) communicates the nut pressure part (1217) and the first balance part (1A).

2. The electronic expansion valve according to claim 1, characterized in that The nut (121) comprises a first nut groove portion (1212) communicating the second cavity (B) and the flow-through portion (111), the first balance portion comprises the first nut groove portion (1212), and / or the first valve seat fitting portion (112) comprises a first valve seat groove portion (1121) communicating the second cavity (B) and the flow-through portion (111), and the first balance portion (1A) comprises the first valve seat groove portion (1121).

3. The electronic expansion valve according to claim 2, wherein The first nut fitting portion (1211) is interference-fitted with the first valve seat fitting portion (112), the valve seat (11) comprises a valve seat ring groove portion (118) having an inner diameter greater than that of the first valve seat fitting portion (112), the valve seat ring groove portion (118) communicates with the first balance portion (1A) and the flow-through portion (111); And / or, the first nut fitting portion (1211) is interference-fitted with the first valve seat fitting portion (112), the nut (121) comprises a nut ring groove portion having an outer diameter greater than that of the first nut fitting portion (1211), the nut ring groove portion communicates with the first balance portion (1A) and the flow-through portion (111).

4. The electronic expansion valve according to claim 1, wherein The first nut fitting portion (1211) is clearance-fitted with the first valve seat fitting portion (112), and the first balance portion (1A) comprises a clearance between the first valve seat fitting portion (112) and the first nut fitting portion (1211).

5. The electronic expansion valve according to claim 1, wherein The nut (121) comprises a second nut groove portion (1213) communicating the first balance portion (1A) and the second cavity (B), the second balance portion (1B) comprises the second nut groove portion (1213), and / or the transition portion (114) comprises a second valve seat groove portion (1141) communicating the first balance portion (1A) and the second cavity (B), and the second balance portion (1B) comprises the second valve seat groove portion (1141).

6. The electronic expansion valve according to claim 1, wherein The nut (121) comprises a second nut fitting portion (1214) passing through the second valve seat fitting portion (113), and the valve seat nut assembly (1) comprises a third balance portion (1C) communicating the second balance portion (1B) and the second cavity (B).

7. The electronic expansion valve according to claim 6, characterized in that The valve seat nut assembly (1) comprises a third balance part (1C), the nut (121) comprises a third nut groove part (1215), the third nut groove part (1215) communicates the second balance part (1B) and the second cavity (B), the third balance part (1C) comprises the third nut groove part (1215), and / or, the second valve seat matching part (113) comprises a third valve seat groove part (1131), the third valve seat groove part (1131) communicates the second balance part (1B) and the second cavity (B), the third balance part (1C) comprises the third valve seat groove part (1131).

8. The electronic expansion valve according to claim 7, characterized in that The second nut matching part (1214) and the second valve seat matching part (113) are gap matched, the third balance part (1C) comprises the gap between the second valve seat matching part (113) and the second nut matching part (1214).

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