Electronic expansion valve

Abstract

The utility model provides an electronic expansion valve which comprises a valve seat assembly, a valve core assembly and a valve core assembly. The valve needle assembly is movably arranged in the valve cavity so as to adjust the flow of fluid passing through the valve port; a sealing piece is arranged between the valve needle assembly and the inner wall of the valve cavity, and the valve cavity located on the side, away from the valve port, of the sealing piece is a back pressure cavity. The valve seat assembly comprises a guide sleeve provided with a guide hole, the valve port is located at one end of the guide sleeve, and the valve needle assembly is in guide fit with the guide hole. The balance channel comprises a balance hole which penetrates through the guide sleeve, one end of the balance hole is communicated with the valve port, and the other end of the balance channel is communicated with the backpressure cavity. According to the technical scheme, the problem that in the prior art, a balance channel is difficult to machine can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of control valves, and more particularly, to an electronic expansion valve. Background Art

[0002] Currently, in the technical field of electronic expansion valves, a balance channel is usually provided on the valve needle of the electronic expansion valve. When the valve needle seals the valve port, the balance channel is used to guide the fluid at the valve port to the chamber where the end of the valve needle away from the valve port is located, so as to balance the fluid pressure received at both ends of the valve needle, reduce the pressure generated by the fluid pressure difference on the electronic expansion valve, and avoid the pressure affecting the valve opening performance of the electronic expansion valve.

[0003] Among them, in order to connect the valve port in the existing electronic expansion valve, it is usually necessary to drill holes at the end of the valve needle that cooperates with the valve port. However, the existing valve needle sizes are usually small. Due to reasons such as fixtures and machining accuracy, when processing the balance channel on the valve needle, the process is difficult and the efficiency is low. Summary of the Utility Model

[0004] The utility model provides an electronic expansion valve to solve the problem that the processing of the balance channel in the existing technology is relatively difficult.

[0005] The utility model provides an electronic expansion valve, which includes: a valve seat assembly having a valve cavity and a valve port communicating with each other; a valve needle assembly movably disposed in the valve cavity to adjust the flow rate of the fluid passing through the valve port; a seal is disposed between the valve needle assembly and the inner wall of the valve cavity, and the valve cavity on the side of the seal away from the valve port is a back pressure cavity; the valve seat assembly includes a guide sleeve having a guide hole, the valve port is located at one end of the guide sleeve, and the valve needle assembly is in guiding cooperation with the guide hole; the balance channel includes a balance hole that penetrates the guide sleeve, one end of the balance hole communicates with the valve port, and the other end of the balance channel communicates with the back pressure cavity.

[0006] Further, the balance hole penetrates the guide sleeve along the axial direction of the guide sleeve.

[0007] Further, the inner wall of the guide sleeve has a seal groove, the seal is disposed in the seal groove, and there is a sealing fit between the inner wall of the seal and the outer wall of the valve needle assembly, or the outer wall of the valve needle assembly has a seal groove, the seal is disposed in the seal groove, and there is a sealing fit between the outer wall of the seal and the inner wall of the guide sleeve.

[0008] Further, when the seal groove is disposed on the inner wall of the guide sleeve, the guide sleeve further has a mounting hole communicating with the guide hole, the diameter of the mounting hole is larger than the diameter of the guide hole, the valve seat assembly further has a plugging member having an avoidance hole, the valve needle assembly passes through the avoidance hole, and a seal groove is formed between the plugging member and the guide sleeve.

[0009] Furthermore, the guide sleeve is provided with a circulation hole and a connecting groove, the connecting groove is annularly arranged on the end face of the guide sleeve, the sealing member cover is arranged at the notch of the connecting groove, and the sealing member is provided with an opening, the circulation hole and the connecting groove form a balancing hole, and the balancing hole and the opening are connected.

[0010] Furthermore, when the sealing groove is arranged on the inner wall of the guide sleeve, the diameter of the sealing ring formed by the sealing area between the seal and the valve needle assembly is D1, and the diameter of the sealing ring formed by the sealing area between the valve needle assembly and the valve port is D2, 0.005mm≤D1-D2≤0.02mm, or, 0.005mm≤D2-D1≤0.02mm.

[0011] Furthermore, the end portion of the valve needle assembly close to one end of the valve port is directly in sealing cooperation with the valve port.

[0012] Furthermore, the valve needle assembly has a main body section and a protruding section that are connected to each other. The protruding section is located on the side of the main body section close to the valve port. The maximum diameter of the protruding section is greater than the diameter of the main body section. The end of the protruding section away from the main body section is a sealing fitting section. The diameter of the sealing fitting section gradually decreases in the direction close to the valve port. The diameter of the annular sealing ring formed by the sealing fitting section and the valve port is D2, and the maximum outer diameter of the protruding section is greater than D2.

[0013] Furthermore, the valve port has a straight section and a chamfered section at the end of the straight section. The diameter of the annular sealing ring formed by the sealing fitting section and the chamfered section is D2, and D2 is larger than the diameter D3 of the straight section.

[0014] Furthermore, the body section is in guiding cooperation with the inner wall of the guide hole, and the inner diameter of the guide hole is larger than the maximum diameter of the protruding section.

[0015] Furthermore, the valve needle assembly also includes a flow regulating section, the body section, the protruding section, the sealing fitting section and the flow regulating section are arranged in sequence, and the diameter of the flow regulating section gradually decreases in the direction away from the protruding section.

[0016] Furthermore, a sealing gasket is sleeved on the valve needle assembly, and the sealing gasket is used for sealing with the valve port.

[0017] Furthermore, the valve needle assembly includes a valve needle body and a connector, the valve needle body has a connector hole, the connector is plugged into the connector hole, an axially arranged installation gap is provided between the end face of the valve needle body and the connector, and a sealing gasket is arranged in the installation gap.

[0018] Furthermore, a pressure relief hole is provided on the valve needle body, the plug hole is communicated with the pressure relief hole, and the pressure relief hole is communicated with the back pressure chamber.

[0019] Through the technical solution of the present utility model, the seal isolates the valve ports at both ends of the valve needle assembly from the back pressure chamber, and the balance channel provided on the valve seat assembly can communicate the valve port with the back pressure chamber, introducing the fluid at the valve port into the back pressure chamber to balance the fluid pressure acting on both ends of the valve needle assembly, reducing the pressure on the electronic expansion valve caused by the fluid pressure difference, ensuring the opening and closing valve performance of the electronic expansion valve, and making the opening and closing of the valve smoother. Specifically, by arranging the balance channel on the guide sleeve in this application, the processing difficulty of the valve needle assembly can be reduced, the processing efficiency can be improved, and the processing accuracy of the balance channel can be guaranteed. In addition, the guide sleeve is in guiding cooperation with the valve needle assembly at the same time, preventing the valve needle assembly from moving obliquely. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings forming a part of this application are used to provide a further understanding of the present utility model. The schematic embodiments and descriptions thereof of the present utility model are used to explain the present utility model and do not constitute an improper limitation of the present utility model. In the drawings:

[0021] Figure 1 shows a schematic structural diagram of an electronic expansion valve provided by the first embodiment of the present utility model;

[0022] Figure 2 shows a schematic structural diagram of an electronic expansion valve provided by the second embodiment of the present utility model;

[0023] Figure 3 shows a schematic structural diagram of the guide sleeve provided by the second embodiment of the present utility model;

[0024] Figure 4 shows a schematic structural diagram of the valve needle assembly provided by the third embodiment of the present utility model;

[0025] Figure 5 shows Figure 2 a partial enlarged view at A in;

[0026] Figure 6 shows a schematic structural diagram of the valve needle assembly provided by the fourth embodiment of the present utility model.

[0027] Among them, the above-mentioned accompanying drawings include the following reference numerals:

[0028] 100, valve seat assembly;

[0029] 101, valve port; 1011, straight section; 1012, chamfered section;

[0030] 102, guide hole;

[0031] 103, mounting hole;

[0032] 110, valve seat body; 111, back pressure chamber; 112, valve seat ring;

[0033] 120. Guide sleeve; 121. Flow-through hole; 122. Connecting groove;

[0034] 130. Sealing element;

[0035] 140. Plugging element; 141. Opening;

[0036] 150. Elastic element;

[0037] 200. Valve needle assembly;

[0038] 201. Sealing gasket; 202. Valve needle body; 203. Insertion part; 204. Pressure relief hole;

[0039] 210. Body section; 220. Protruding section; 230. Sealing and mating section; 240. Flow rate regulating section;

[0040] 300. Driving assembly; 301. Accommodating cavity;

[0041] 310. Sleeve; 320. Driving device;

[0042] 400. Balancing channel;

[0043] 500. Valve chamber. Detailed implementation manner

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way constitutes a limitation to the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0045] Such as Figure 1 And Figure 2As shown in the figure, an embodiment of the present utility model provides an electronic expansion valve, which includes a valve seat assembly 100, a valve needle assembly 200, and a driving assembly 300. The driving assembly 300 includes a sleeve 310 and a driving device 320. The sleeve 310 is arranged on the valve seat assembly 100, and the driving device 320 is arranged in the accommodation cavity 301 of the sleeve 310 and is drivingly connected to the valve needle assembly 200. Among them, the valve seat assembly 100 has a valve cavity and a valve port 101. The valve port 101 is located at the bottom of the valve cavity. The valve seat assembly 100 is provided with an inlet. The valve cavity communicated with the inlet in the valve seat assembly 100 is a valve chamber 500. The external fluid flows into the valve chamber 500 after passing through the inlet and then flows out from the valve port 101. The valve needle assembly 200 is movably arranged in the valve cavity to adjust the flow rate of the fluid at the valve port 101.

[0046] Specifically, a seal 130 is arranged between the valve needle assembly 200 and the inner wall of the valve cavity. The valve cavity on the side of the seal 130 away from the valve port 101 is a back pressure cavity 111. The seal 130 can block the gap between the valve needle assembly 200 and the inner wall of the valve cavity, prevent the back pressure cavity 111 from communicating with the valve chamber 500, and ensure that the back pressure cavity 111 can communicate with the valve port 101 when the valve port is closed. The valve port and the back pressure cavity 111 are respectively located at both ends of the valve needle assembly 200. The valve seat assembly 100 is provided with a balance channel 400. One end of the balance channel 400 is communicated with the valve port 101, and the other end of the balance channel 400 is communicated with the back pressure cavity 111.

[0047] Specifically in this application, the valve seat assembly 100 includes a valve seat main body 110 and a guide sleeve 120 connected to each other. The valve seat main body 110 and the guide sleeve 120 jointly enclose the back pressure cavity 111. The guide sleeve 120 has a guide hole 102, and the guide hole 102 is communicated with the valve cavity. The valve port 101 is located at one end of the guide sleeve 120 away from the valve seat main body 110. The valve needle assembly 200 is in guiding cooperation with the guide hole 102, that is, the valve needle assembly 200 can move up and down along the inner wall of the guide hole 102 to prevent the valve needle assembly from being deflected during the movement. The balance channel 400 includes a balance hole, and the balance hole penetrates through the guide sleeve 120 along the valve axis. Both the balance hole and the guide hole 102 are located in the guide sleeve 120, and the guide sleeve 120 is an integral structure, which can simplify the overall structure of the electronic expansion valve.

[0048] The balance channel 400 can ensure that the electronic expansion valve is an internal balance valve, that is, ensure that the fluid pressures at both ends of the valve needle assembly 200 are equal, reduce the force exerted by the fluid on the valve needle assembly 200, and make the opening and closing of the valve smoother. The end of the valve needle assembly 200 in this embodiment that seals the valve port is a solid pointed shape. Therefore, the structure of the valve needle assembly in this embodiment is not conducive to machining the balance channel 400. By arranging the balance channel 400 on the guide sleeve 120 instead of on the valve needle assembly 200 in this embodiment, the difficulty of machining the balance channel 400 can be reduced. At the same time, compared with the prior art, arranging the through hole 121 on the guide sleeve 120 can also keep the balance channel 400 away from the turbulent flow area after throttling, and improve the stability of the internal balance pressure.

[0049] Specifically, a valve seat ring 112 is arranged on the valve seat body 110. The valve seat ring 112 is arranged on the outer periphery of the valve needle assembly 200 to further limit the movement of the valve needle assembly 200 in the valve radial direction, prevent the valve needle assembly 200 from deflecting too much in the valve radial direction during rotation, and further ensure the stability of the movement of the valve needle assembly 200. There is a gap between the valve seat ring 112 and the valve needle assembly 200 to form a flow gap. The flow gap is part of the balance channel, and the flow gap communicates the accommodation cavity 301 and the back pressure cavity 111.

[0050] In some feasible embodiments of the present application, an elastic member 150 is further arranged in the back pressure cavity 111 of the valve cavity. One end of the elastic member 150 abuts against the valve seat assembly 100, and the other end of the elastic member 150 abuts against the valve needle assembly 200 to provide an elastic force in the direction of the valve port 101 for the valve needle assembly 200. In the prior art, the driving device 320 usually includes a rotor, a nut, and a screw rod. The rotor is fixedly connected to the screw rod, the screw rod is drivingly connected to the valve needle assembly 200, the nut is sleeved outside the screw rod, and the rotor can rotate in the accommodation cavity 301 under the drive of the electromagnetic coil to drive the screw rod to rotate. The screw rod drives the valve needle assembly 200 to move linearly relative to the valve port 101 through the thread fit with the nut to achieve the adjustment of the fluid flow rate. By arranging the elastic member 150 in the valve cavity, the elastic member 150 can provide an elastic force for the valve needle assembly 200 and the screw rod fixedly connected to the valve needle assembly 200 in the axial direction, eliminate the gap between the screw rod and the nut in the thread fit, and ensure the accuracy of the pulse generated by the electromagnetic coil when driving the screw rod.

[0051] The elastic member 150 also provides an elastic force for the valve needle assembly 200 in the direction away from the valve port 101 to ensure the sealing performance when the valve port is closed.

[0052] Specifically, the elastic member 150 is a tower-shaped spring. With this setting, the risk of the elastic member 150 being compressed and causing thread self-locking between the screw and the nut can be reduced, ensuring the stability of the operation of the electronic expansion valve. Further, when the elastic member 150 is arranged in the valve cavity, the elastic member 150 can be sleeved on the valve needle assembly 200. In this case, the inner diameter of the valve cavity needs to be appropriately enlarged to meet the installation requirements of the elastic member 150.

[0053] To install the seal member 130, in some embodiments of the present application, the inner wall of the guide sleeve 120 has a seal groove, and the seal member 130 is arranged in the seal groove. The inner wall of the seal member 130 is in sealing fit with the outer wall of the valve needle assembly 200 to block the gap between the guide hole 102 and the valve needle assembly 200, reducing the internal leakage of the electronic expansion valve.

[0054] In still other embodiments of the present application, the seal groove can also be arranged on the outer wall of the valve needle assembly 200.

[0055] Specifically in the present application, the seal member 130 is a seal ring made of an elastic material to improve the sealing effect of the seal member 130.

[0056] When the seal groove is arranged on the inner wall of the guide sleeve 120, the guide sleeve 120 further has an installation hole 103 communicating with the guide hole 102. The diameter of the installation hole 103 is larger than that of the guide hole 102. The valve seat assembly 100 further has a plugging member 140 with an avoidance hole. The valve needle assembly 200 is arranged in the avoidance hole, and a seal groove is formed between the plugging member 140 and the guide sleeve 120. With this setting, it is convenient to machine the seal groove on the guide sleeve 120, reducing the machining difficulty of the seal groove, and at the same time, it is also convenient for the installation of the seal member 130.

[0057] In the first embodiment of the present application, referring to Figure 1 as shown, the plugging member 140 is inserted into the installation hole 103. The guide sleeve 120 is further provided with a circulation hole 121, and the circulation hole 121 forms a balance hole. The circulation hole 121 penetrates through the guide sleeve 120 and communicates with the valve cavity, and communicates with the circulation gap through the valve cavity for fluid circulation. The circulation hole 121 can also directly communicate with the circulation gap. At the same time, compared with the prior art, arranging the circulation hole 121 on the guide sleeve 120 can also make the balance channel 400 away from the area where the airflow is disordered after throttling, improving the stability of the internal balance pressure.

[0058] In the second embodiment of the present application, referring to Figure 2 and Figure 3As shown, different from the first embodiment, a connection groove 122 is further provided on the guide sleeve 120. The connection groove 122 is annularly arranged on the end face of the guide sleeve 120. A plugging member 140 is covered on the notch of the connection groove 122. An opening 141 is provided on the plugging member 140. The flow hole 121 and the connection groove 122 form a balance hole, and the balance hole is communicated with the opening 141. In this embodiment, by setting the plugging member 140 to a larger volume, so that the plugging member 140 is covered on the end face of the guide sleeve 120, it is convenient for the processing and forming of the plugging member 140 and also convenient for the installation of the plugging member 140. The setting of the connection groove 122 ensures that when processing the balance hole, there is no need to align the opening 141 with the flow hole 121, which is convenient for the processing of the opening 141 of the plugging member 140.

[0059] In some embodiments of the present application, the solid end of the valve needle assembly 200 near the valve port 101 is directly in sealing cooperation with the valve port 101. The solid end of the valve needle assembly 200 is made of metal, and the valve port 101 is made of metal. A hard seal is directly formed between the solid end of the valve needle assembly 200 and the valve port 101.

[0060] Specifically in the present application, when the sealing groove is provided on the inner wall of the guide sleeve 120, the inner diameter of the sealing ring formed by the sealing area between the sealing member 130 and the valve needle assembly 200 is D1, and the diameter of the sealing ring actually formed by the sealing area between the valve needle assembly 200 and the valve port 101 is D2. 0.005mm ≤ D1 - D2 ≤ 0.02mm, or 0.005mm ≤ D2 - D1 ≤ 0.02mm, and D1 and D2 are approximately equal. When the sealing groove is provided on the valve needle assembly 200, the diameter of the sealing ring formed by the sealing area between the sealing member 130 and the guide sleeve 120 is D3. 0.005mm ≤ D3 - D2 ≤ 0.02mm, or 0.005mm ≤ D3 - D1 ≤ 0.02mm. With such a setting, when the valve needle assembly 200 closes the valve port 101, the fluid force received by the valve needle assembly 200 is close to zero, avoiding the valve needle assembly 200 from moving under the action of the fluid force and causing leakage of the valve port 101.

[0061] In the third embodiment of the present application, refer to Figure 4As shown, when the valve needle assembly 200 is in hard-seal fit with the valve port 101, the valve needle assembly 200 has a body section 210, and there is a seal 130 between the body section 210 and the inner wall of the guide hole 102. To ensure that D1 and D2 are approximately equal, the valve needle assembly 200 further has a protruding section 220. The protruding section 220 is located on the side of the body section 210 close to the valve port 101. The maximum diameter of the protruding section 220 is greater than the diameter of the body section 210. One end of the protruding section 220 facing away from the body section 210 is a seal-fitting section 230. The diameter of the seal-fitting section 230 gradually decreases in the direction close to the valve port 101. The seal-fitting section 230 is in seal fit with the valve port 101 to form an annular sealing ring with a diameter of D2. The maximum outer diameter of the protruding section 220 is greater than D2. The settings of the protruding section 220 and the seal-fitting section 230 are both to facilitate the formation of D2 that is approximately equal to D1.

[0062] Specifically for D2, the valve port 101 has a straight section 1011 and a chamfer section 1012 located at the end of the straight section 1011. The seal-fitting section 230 is in seal fit with the chamfer section 1012 to form an annular sealing ring with a diameter of D2. In this embodiment, the valve needle assembly 200 is in seal fit with the end chamfer section 1012 of the valve port, so D2 is greater than the diameter D3 of the straight section 1011.

[0063] In some embodiments of the present application, the body section 210 is in guiding fit with the inner wall of the guide hole 102, that is, the body section 210 can axially move along the inner wall of the guide hole 102 to prevent the body section 210 from being deflected during movement. The inner diameter of the guide hole 102 is greater than the outer diameter of the protruding section 220 to ensure that the valve needle assembly 200 can be smoothly installed into the guide hole 102.

[0064] Refer to Figure 2 、 Figure 4 and Figure 5 As shown, the valve needle assembly 200 further includes a flow rate adjustment section 240. The body section 210, the protruding section 220, the seal-fitting section 230, and the flow rate adjustment section 240 are arranged in sequence. The diameter of the flow rate adjustment section 240 gradually decreases in the direction away from the protruding section 220. Through the above settings, when the flow rate adjustment section 240 enters the valve port 101, as the valve needle assembly 200 moves relative to the valve port 101, the area for fluid to flow between the outer side wall of the flow rate adjustment section 240 and the inner side wall of the valve port 101 will gradually change, so that the flow rate at the valve port 101 can be adjusted.

[0065] Optionally, the flow rate adjustment section 240 can be provided with a plurality of tapered extension sections with inconsistent tapers, so that the fluid passing through the valve port 101 forms a stepped flow rate curve, improving the service performance of the electronic expansion valve.

[0066] Optionally, a straight extension section may also be provided between multiple tapered sections in the flow regulation section 240 to ensure that the distance between the valve needle assembly 200 and the inner wall of the valve port 101 remains unchanged within a certain pulse range at the straight extension section, so that the flow rate of the valve port 101 remains unchanged within this pulse range, and further improve the applicability of the electronic expansion valve.

[0067] In the fourth embodiment of the present application, referring to Figure 6 As shown, different from the second embodiment: a sealing gasket 201 is sleeved on the valve needle assembly 200. The sealing gasket 201 is used for sealing cooperation with the valve port 101. The hardness of the sealing gasket 201 is less than that of the valve port 101. Through the above settings, the sealing gasket 201 can generate elastic deformation when sealing the valve port 101, realizing soft sealing with the valve port 101, blocking the possible gaps between the valve needle assembly 200 and the valve port 101, reducing the risk of internal leakage of the electronic expansion valve, and ensuring the use effect of the electronic expansion valve.

[0068] Specifically, the valve needle assembly 200 includes a valve needle body 202 and a plug-in part 203. The valve needle body 202 has a plug-in hole, and the plug-in part 203 is in plug-in fit with the plug-in hole. There is an installation interval arranged axially between the end face of the valve needle body 202 and the plug-in part 203, and the sealing gasket 201 is arranged in the installation interval. With such a setting, it is convenient to install the sealing gasket 201, and at the same time, it can also ensure the stability of the sealing gasket 201 installed on the valve needle assembly 200, reducing the risk of the sealing gasket 201 falling off after reciprocatingly sealing with the valve port 101.

[0069] Furthermore, a pressure relief hole 204 is provided on the valve needle body 202, and the plug-in hole can communicate with the back pressure chamber 111 through the pressure relief hole 204. Through the above settings, it can prevent high-pressure air from remaining in the closed space in the plug-in hole after the valve needle body 202 and the plug-in part 203 are press-fitted, ensuring the stable installation of the plug-in part 203.

[0070] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0071] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present utility model. At the same time, it should be understood that for the sake of convenience of description, the sizes of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the description. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0072] In the description of the present utility model, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom", etc. are generally based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description. Without contrary statements, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as limiting the protection scope of the present utility model; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0073] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above" can be used here to describe the spatial positional relationships of one device or feature to other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to cover different orientations in use or operation in addition to the orientation described in the drawings for the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used here.

[0074] In addition, it should be noted that the use of words such as "first", "second", etc. to limit components is only for the convenience of differentiating the corresponding components. Without additional statements, the above words have no special meanings. Therefore, it should not be construed as limiting the protection scope of the present utility model.

[0075] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An electronic expansion valve, characterized in that, The electronic expansion valve includes: A valve seat assembly (100) having a valve cavity and a valve port (101) that communicate with each other; A valve needle assembly (200) movably disposed in the valve cavity to adjust the flow rate of the fluid passing through the valve port (101); A seal (130) is provided between the valve needle assembly (200) and the inner wall of the valve cavity, and the valve cavity on the side of the seal (130) facing away from the valve port (101) is a back pressure cavity (111); The valve seat assembly (100) includes a guide sleeve (120) having a guide hole (102), and the valve needle assembly (200) is in guiding cooperation with the guide hole (102); A balance passage (400) including a balance hole that penetrates the guide sleeve (120), one end of the balance hole communicates with the valve port (101), and the other end of the balance hole communicates with the back pressure cavity (111).

2. The electronic expansion valve according to claim 1, wherein The balance hole axially penetrates the guide sleeve (120) along the valve seat assembly (100).

3. The electronic expansion valve according to claim 1, wherein The inner wall of the guide sleeve (120) has a seal groove, the seal (130) is disposed in the seal groove, and the inner wall of the seal (130) is in sealing cooperation with the outer wall of the valve needle assembly (200), or, The outer wall of the valve needle assembly (200) has a seal groove, the seal (130) is disposed in the seal groove, and the outer wall of the seal (130) is in sealing cooperation with the inner wall of the guide sleeve (120).

4. The electronic expansion valve according to claim 3, wherein, When the seal groove is provided on the inner wall of the guide sleeve (120), the guide sleeve (120) further has a mounting hole (103) that communicates with the guide hole (102), the diameter of the mounting hole (103) is larger than the diameter of the guide hole (102), the valve seat assembly (100) further has a plugging member (140) having an avoidance hole, the valve needle assembly (200) passes through the avoidance hole, and the plugging member (140) and the guide sleeve (120) form the seal groove therebetween.

5. The electronic expansion valve according to claim 4, characterized in that, The guide sleeve (120) is provided with a circulation hole (121) and a connection groove (122), the connection groove (122) is annularly provided on the end surface of the guide sleeve (120), the plugging member (140) covers the notch of the connection groove (122), the plugging member (140) is provided with an opening (141), the circulation hole (121) and the connection groove (122) form the balance hole, and the balance hole communicates with the opening (141).

6. The electronic expansion valve according to claim 3, characterized in that, When the sealing groove is arranged on the inner wall of the guide sleeve (120), the diameter of the sealing ring formed by the sealing area between the sealing member (130) and the valve needle assembly (200) is D1, and the diameter of the sealing ring formed by the sealing area between the valve needle assembly (200) and the valve port (101) is D2, 0.005mm≤D1-D2≤0.02mm, or, 0.005mm≤D2-D1≤0.02mm.

7. The electronic expansion valve according to claim 1, characterized in that, The end portion of the valve needle assembly (200) close to one end of the valve port (101) is directly and sealingly matched with the valve port (101).

8. The electronic expansion valve according to claim 6, characterized in that, The valve needle assembly (200) has a main body section (210) and a protruding section (220) that are connected to each other. The protruding section (220) is located on a side of the main body section (210) close to the valve port (101). The maximum diameter of the protruding section (220) is greater than the diameter of the main body section (210). The end of the protruding section (220) that is away from the main body section (210) is a sealing fitting section (230). The diameter of the sealing fitting section (230) gradually decreases in a direction close to the valve port (101). The diameter of the annular sealing ring formed by the sealing fitting section (230) and the valve port (101) is D2. The maximum outer diameter of the protruding section (220) is greater than D2.

9. The electronic expansion valve according to claim 8, characterized in that, The valve port (101) has a straight section (1011) and a chamfered section (1012) located at the end of the straight section (1011); the diameter of the annular sealing ring formed by the sealing fitting section (230) and the chamfered section (1012) is D2, and D2 is larger than the diameter D3 of the straight section (1011).

10. The electronic expansion valve according to claim 8, characterized in that, The body section (210) is in guiding cooperation with the inner wall of the guide hole (102), and the inner diameter of the guide hole (102) is larger than the maximum diameter of the protruding section (220).

11. The electronic expansion valve according to claim 8, characterized in that, The valve needle assembly (200) further includes a flow regulating section (240), wherein the main body section (210), the protruding section (220), the sealing fitting section (230) and the flow regulating section (240) are arranged in sequence, and the diameter of the flow regulating section (240) gradually decreases in a direction away from the protruding section (220).

12. The electronic expansion valve according to claim 1, wherein, The valve needle assembly (200) is sleeved with a sealing gasket (201), and the sealing gasket (201) is used for sealingly cooperating with the valve port (101).

13. The electronic expansion valve according to claim 12, characterized in that, The valve needle assembly (200) includes a valve needle body (202) and a plug-in connector (203), wherein the valve needle body (202) has a plug-in hole, and the plug-in connector (203) is plugged into the plug-in hole. An axially arranged installation gap is provided between the end face of the valve needle body (202) and the plug-in connector (203), and the sealing gasket (201) is arranged in the installation gap.

14. The electronic expansion valve according to claim 13, characterized in that, The valve needle body (202) is provided with a pressure relief hole (204), the plug hole is communicated with the pressure relief hole (204), and the pressure relief hole (204) is communicated with the back pressure chamber (111).

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