Piston assembly and its electronic expansion valve

Abstract

The utility model relates to fluid control technical field especially is related to a piston assembly and electronic expansion valve thereof. A kind of piston assembly, including positioning cylinder and positioning sheet, one end of positioning cylinder is equipped with installation slot, and in the radial direction of positioning cylinder, the slot wall of installation slot is equipped with the positioning slot of through arrangement, and the outer periphery of positioning sheet is provided with protrusion;In the axial direction of positioning cylinder, installation slot includes first portion second portion, and first portion is located above second portion, and positioning slot includes the first slot and second slot of intercommunication, positioning sheet is contained in installation slot, and positioning sheet is fixedly connected with second portion, and riveting with first portion, and in the circumferential direction of positioning cylinder, protrusion and the slot wall of second slot limit cooperation;Wherein, the width of first slot is L3, the width of second slot is L4, L3 and L4 satisfy, L3>L4.The application can improve the service life and reliability of protrusion and positioning cylinder circumferential limit.

Description

Technical Field

[0001] This utility model relates to the field of fluid control technology, and in particular to a piston assembly and its electronic expansion valve. Background Technology

[0002] Electronic expansion valves are commonly used in refrigeration systems as throttling elements. They consist of a piston assembly, a drive assembly, and a guide sleeve. The drive assembly moves the piston assembly along the axis of the guide sleeve. The working principle of an electronic expansion valve is as follows: the drive assembly first drives a screw to rotate. The screw engages with a positioning cylinder via a thread. Because the positioning cylinder is circumferentially limited, the circumferential motion is converted into axial motion along the guide sleeve.

[0003] In related technologies, a positioning plate is provided on the positioning cylinder, and a protrusion is provided on the positioning plate. The protrusion engages with the groove of the positioning cylinder to achieve circumferential limiting of the positioning plate. Then, the guide sleeve engages with the circumferential limiting of the positioning plate to achieve circumferential limiting of the positioning cylinder. Due to the large rotational torque, the sidewall of the groove can easily cut off the protrusion, causing the circumferential limiting to fail. Utility Model Content

[0004] In view of this, it is necessary to provide a piston assembly and its electronic expansion valve that can improve the service life and reliability of the circumferential limiting of the protrusion and positioning cylinder.

[0005] This utility model provides a piston assembly for use in an electronic expansion valve. The piston assembly includes a positioning cylinder and a positioning plate. One end of the positioning cylinder has an installation groove, and a through positioning groove is formed on the wall of the installation groove in the radial direction of the positioning cylinder. The outer periphery of the positioning plate has a protrusion. In the axial direction of the positioning cylinder, the installation groove includes a first part and a second part, and the first part is located at the end of the positioning cylinder and connected to the second part. The positioning groove includes a first groove and a second groove that communicate with each other. The positioning plate is received in the installation groove and fixedly connected to the first part. In the circumferential direction of the positioning cylinder, the protrusion is in limiting fit with the groove wall of the second groove. The width of the first groove is L3, and the width of the second groove is L4, where L3 > L4.

[0006] In one embodiment, L3 and L4 satisfy L3 > 1.5L4; and / or, in the radial direction of the positioning cylinder, the thickness of the groove wall of the first groove is L1, the thickness of the groove wall of the second groove is L2, and L1 and L2 satisfy L2 > L1.

[0007] In one embodiment, in the axial direction of the positioning cylinder, the depth of the mounting groove is h, the depth of the first groove is h1, the depth of the second groove is h2, and the depth of the positioning groove is h3, where h, h1, h2, and h3 satisfy: h = h3 = h1 + h2.

[0008] In one embodiment, the thickness of the positioning piece is h4, and h, h1, and h4 satisfy: h4≤h-h1.

[0009] In one embodiment, the second groove has a first groove wall in the circumferential direction of the positioning cylinder, and the mounting groove has a second groove wall. In the circumferential direction of the positioning cylinder, the first groove wall and the second groove wall are connected by a first surface. The protrusion and the positioning piece are connected by a second surface, and the first surface and the second surface can cooperate with each other.

[0010] In one embodiment, both the first surface and the second surface are curved; and / or, the first surface and the second surface can fit together.

[0011] In one embodiment, in the axial direction of the positioning cylinder, the positioning piece is interference-fitted with the second part and riveted to the first part.

[0012] In one embodiment, the number of protrusions is configured to be multiple, and the multiple protrusions are equally spaced along the circumference of the positioning piece on the outer periphery of the positioning piece, and the positioning groove is configured to correspond one-to-one with the protrusion.

[0013] In one embodiment, the number of protrusions is configured to be three, and the three protrusions are arranged in a triangle.

[0014] This utility model also provides the following technical solution:

[0015] An electronic expansion valve includes a valve seat, a drive assembly, a valve body assembly, and a piston assembly. The valve seat has a valve port. The valve body assembly is mounted on the valve seat. The drive assembly is mounted on the valve body assembly and provides rotational driving force. The piston assembly is movably mounted on the valve body assembly and connected to the drive assembly to move along the axial direction of the valve seat under the drive of the drive assembly, and to open / close the valve port. The drive assembly includes a sleeve, a coil, a rotor unit, and a gear unit. The valve body assembly includes a guide sleeve, a connecting piece, and multiple stop rods. The piston assembly includes a screw, a positioning cylinder, and a positioning plate. The sleeve is fixed to the guide sleeve. The sleeve is set around the circumference of the sleeve, the rotor unit is rotatably set inside the sleeve, the gear unit is installed inside the guide sleeve and connected to the rotor unit and the screw respectively, the connecting piece is fixedly installed inside the guide sleeve, each stop rod extends along the axial direction of the guide sleeve and is connected to the connecting piece; one end of the positioning cylinder is slidably connected to the guide sleeve, and the other end is used to open and close the valve port, the positioning plate is fixed to the positioning cylinder and has an anti-rotation hole, one end of the screw is connected to the drive assembly, the other end passes through the positioning plate and is threadedly connected to the positioning cylinder, one end of multiple stop rods is fixedly connected to the connecting piece, and the other end passes through the anti-rotation hole so that the stop rods are limited and matched with the positioning plate in the circumference of the positioning cylinder.

[0016] The piston assembly and its electronic expansion valve provided by this utility model can achieve circumferential positioning of the positioning piece 43 by the cooperation of the protrusion with the groove wall of the second groove, and L3>L4; this allows the positioning piece to be housed in the mounting groove and fixedly connected to the first part, so that the protrusion does not contact or reduces contact with the first part in the circumferential direction of the positioning cylinder, thereby avoiding the first part from being cut off by the excessive rotational torque of the positioning cylinder. That is, the above setting can improve the service life and reliability of the circumferential positioning of the protrusion and the positioning cylinder. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A three-dimensional structural diagram of the electronic expansion valve provided by this utility model.

[0019] Figure 2 for Figure 1 A sectional view.

[0020] Figure 3 for Figure 2 A cross-sectional view omitting the valve seat and connecting pipe.

[0021] Figure 4This is an exploded view of the guide sleeve and drive assembly in cross-section.

[0022] Figure 5 Sectional view of the connector installed in the guide sleeve.

[0023] Figure 6 This is a three-dimensional structural diagram of the connection component and the stop bar.

[0024] Figure 7 This is a three-dimensional structural diagram of the stop lever.

[0025] Figure 8 for Figure 2 A cross-sectional view of Embodiment 1, omitting the valve seat and connecting pipe.

[0026] Figure 9 for Figure 8 A magnified view of a portion of point A in the middle.

[0027] Figure 10 A three-dimensional structural diagram of the assembly of the positioning cylinder and positioning plate.

[0028] Figure 11 for Figure 10 A top-down view.

[0029] Figure 12 This is a schematic diagram of the three-dimensional structure of the positioning piece.

[0030] Figure 13 This is a cross-sectional view of the piston assembly in its mating state with the guide sleeve.

[0031] Figure 14 This is a schematic diagram of the three-dimensional structure of the positioning cylinder.

[0032] Figure 15 for Figure 14 A magnified view of a section at point B in the middle.

[0033] Figure 16 This is an exploded diagram of the positioning cylinder and positioning plate.

[0034] Figure 17 This is a cross-sectional view of the positioning cylinder.

[0035] Figure 18 This is a side view of the positioning cylinder, labeled L3 and L4.

[0036] Figure 19 This is a side view of the positioning cylinder, labeled h, h1, h2, and h3.

[0037] The labels for each figure are as follows:

[0038] 100. Electronic expansion valve; 10. Valve seat; 11. Valve port; 12. Valve chamber; 13. First port; 14. Second port; 15. Connecting pipe; 20. Drive assembly; 21. Sleeve; 22. Coil; 23. Rotor unit; 231. Connecting post; 2311. First connecting section; 2312. Second connecting section; 2313. First step; 2314. Second step; 232. Rotor; 233. Shaft; 234. Bearing; 235. Gasket; 24. Gear unit; 241. First gear; 242. Second gear; 243. Third gear; 30. Valve body assembly; 31. Guide sleeve; 311. Mounting hole 312. Receiving groove; 313. Connecting cover; 314. Third step; 315. Guide cavity; 316. Sealing ring; 317. Annular groove; 32. Connecting piece; 33. Stop rod; 40. Piston assembly; 41. Screw; 42. Positioning cylinder; 421. Mounting groove; 4211. First part; 4212. Second part; 4213. Second groove wall; 422. Positioning groove; 4221. First groove; 4222. Second groove; 4223. First groove wall; 4224. First surface; 423. Nut seat; 424. Valve head; 43. Positioning piece; 431. Anti-rotation hole; 432. Protrusion; 433. Second surface. Detailed Implementation

[0039] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0040] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this specification are for illustrative purposes only and do not represent the only possible implementation.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this specification belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0044] Please see Figure 1 and Figure 2 This utility model provides an electronic expansion valve 100, particularly a large-size electronic expansion valve. The electronic expansion valve 100 includes a valve seat 10, a drive assembly 20, a valve body assembly 30, and a piston assembly 40. The valve seat 10 has a valve port 11. The valve body assembly 30 is mounted on the valve seat 10. The drive assembly 20 is mounted on the valve body assembly 30 and provides rotational driving force. The piston assembly 40 is movably mounted on the valve body assembly 30 and connected to the drive assembly 20, so that it moves along the axial direction X (refer to the reference axis) of the valve seat 10 under the drive of the drive assembly 20. Figure 2 ) Movement, and opening / closing valve port 11.

[0045] Please see Figure 2 , Figures 5 to 7The valve body assembly 30 includes a guide sleeve 31, a connector 32, and multiple stop rods 33. The piston assembly 40 includes a screw 41, a positioning cylinder 42, and a positioning plate 43. The connector 32 is fixedly installed inside the guide sleeve 31. Each stop rod 33 extends along the axial direction X of the guide sleeve 31 and is connected to the connector 32. One end of the positioning cylinder 42 is slidably connected to the guide sleeve 31, and the other end is used to open and close the valve port 11. The positioning plate 43 is fixed to the positioning cylinder 42 and has an anti-rotation hole 431. One end of the screw 41 is connected to the drive assembly 20, and the other end passes through the positioning plate 43 and is threadedly connected to the positioning cylinder 42, so as to drive the positioning cylinder 42 to slide relative to the guide sleeve 31 and open and close the valve port 11. Among them, one end of the multiple stop rods 33 is fixedly connected to the connector 32, and the other end passes through the anti-rotation hole 431, so that the stop rods 33 are limited and matched with the positioning plate 43 in the circumferential direction of the positioning cylinder 42.

[0046] In this embodiment, one end of each of the multiple stop rods 33 is integrally formed with the connector 32. By making the multiple stop rods 33 and the connector 32 an integral structure, and with the connector 32 fixedly connected to the guide sleeve 31, the parallelism between the multiple stop rods 33 and the parallelism between the stop rods 33 and the central axis of the positioning cylinder 42 can be improved. This effectively prevents the positioning cylinder 42 from jamming during movement due to the stop rods 33 being misaligned relative to the anti-rotation hole 431. In other words, this design improves the smoothness of the movement of the positioning cylinder 42; simultaneously, this design reduces processing steps and lowers the overall valve height.

[0047] In one embodiment, please continue to refer to Figure 2 The valve seat 10 is made of stainless steel. Of course, it is not limited to this; the valve seat can also be made of copper.

[0048] A valve seat 10 contains a valve cavity 12, and the valve seat 10 also has a first port 13 and a second port 14. A valve port 11 is located within the valve cavity 12, and the axis of the valve cavity 12 is inclined relative to the axis of the first port 13. The end of the positioning cylinder 42 furthest from the drive assembly 20 extends into the valve cavity 12. The first port 13 and the second port 14 are respectively used to connect to the connecting pipe 15. Opening and closing the valve port 11 controls the connection and disconnection between the first port 13 and the second port 14.

[0049] In one embodiment, the central axes of the first port 13 and the second port 14 are parallel and coaxial, that is, the first port 13 and the second port 14 are located on the same horizontal line. This not only reduces flow losses during the medium flow process but also lowers the overall height of the electronic expansion valve 100. In other embodiments, the first port 13 and the second port 14 may also be parallel but not coaxial.

[0050] Please see Figure 3 and Figure 4The drive assembly 20 includes a sleeve 21, a coil 22, a rotor unit 23, and a gear unit 24. The sleeve 21 is fixed to the guide sleeve 31. The sleeve 21 and the guide sleeve 31 can be connected by welding. The coil 22 is sleeved around the circumference of the sleeve 21. The rotor unit 23 is rotatably disposed inside the sleeve 21. The gear unit 24 is installed inside the guide sleeve 31 and is connected to the rotor unit 23 and the screw 41 respectively, for transmitting the rotational force of the rotor unit 23 to the screw 41. When the coil 22 is energized, the rotor unit 23 is driven to rotate by the coil 22, and then drives the gear unit 24 to move, thereby driving the screw 41 to move. Because the guide sleeve 31 is fixed, the stop rod 33 is circumferentially limited by the anti-rotation hole 431, causing the positioning cylinder 42 to be unable to rotate circumferentially. At this time, the circumferential rotation of the screw 41 is converted into the axial movement of the positioning cylinder 42, thereby controlling the opening degree or opening and closing of the valve port 11.

[0051] Specifically, the rotor unit 23 includes a connecting post 231, a rotor 232, and a rotating shaft 233. The connecting post 231 is fixed to the guide sleeve 31, and the sleeve 21 is fixed to the connecting post 231. That is, the sleeve 21 and the guide sleeve 31 are connected through the connecting post 231. The rotor 232 is located inside the sleeve 21. One end of the rotating shaft 233 is connected to the rotor 232 (i.e., the rotor 232 is installed on the rotating shaft 233), and the other end of the rotating shaft 233 passes through the connecting post 231 and is then connected to the gear unit 24. In other words, by using the connecting post 231, the rotor 232 and the rotating shaft 233 can be formed as a whole before subsequent installation. This makes installation more convenient; and by using the connecting post 231, the concentricity of the entire rotor unit 23 is also better.

[0052] Preferably, please refer to Figure 4 One end of the connecting post 231 is provided with a first connecting section 2311, and the other end is provided with a second connecting section 2312. A first step 2313 is formed between the first connecting section 2311 and the connecting post 231, and a second step 2314 is formed between the second connecting section 2312 and the connecting post 231. The sleeve 21 is fitted onto the first connecting section 2311 and abuts against the first step 2313; the guide sleeve 31 has a mounting hole 311, the second connecting section 2312 extends into the mounting hole 311, and the second step 2314 abuts against the surface of the guide sleeve 31.

[0053] Furthermore, the first connecting section 2311 and the sleeve 21 are interference-fitted, and the second connecting section 2312 and the mounting hole 311 are also interference-fitted. In addition, the first connecting section 2311 and the sleeve 21 are connected by welding, and the second connecting section 2312 and the guide sleeve 31 are also welded together. This ensures the connection strength among the guide sleeve 31, the sleeve 21, and the connecting post 231. Here, the welding method can be laser welding, argon arc welding, etc.

[0054] In one embodiment, please continue to refer to Figure 4 The rotor unit 23 also includes a bearing 234, which is sleeved on the rotating shaft 233 and fixed on the connecting column 231. In this way, the bearing 234 can improve the smoothness and coaxiality of the rotating shaft 233.

[0055] Here, the bearing 234 can be fixed by a shim 235. The shim 235 and the connecting column 231 are laser welded or argon arc welded to ensure the connection strength.

[0056] Preferably, the number of bearings 234 can be set to multiple. This improves the concentricity of the shaft 233 and the gear unit 24. In this embodiment, the number of bearings 234 is set to two. However, it is not limited to this; the number of bearings 234 can also be set to three.

[0057] In one embodiment, please refer to Figure 3 and Figure 4 A rear receiving groove 312 is provided at the end of the guide sleeve 31 away from the valve port 11, and the gear unit 24 is housed in the receiving groove 312. Here, the gear unit 24 includes a first gear 241, a second gear 242, and a third gear 243. The first gear 241 is fixed to the end of the rotating shaft 233 away from the rotor 232. The second gear 242 is rotatably mounted on the guide sleeve 31 and meshes with the first gear 241. The third gear 243 is fixed to the end of the screw 41 away from the valve port 11 and meshes with the second gear 242. Thus, the rotating shaft 233 rotates and drives the first gear 241 to rotate, the second gear 242 rotates accordingly and drives the third gear 243 to rotate, thereby driving the screw 41 to rotate.

[0058] In this embodiment, during the assembly of the drive assembly 20, the lower bearing 234 is first pressed into the connecting post 231, and the lower gasket is installed and then laser-welded. Then, the rotating shaft 233 is placed into the connecting post 231. The rotating shaft 233 is provided with double steps, which cooperate with the double bearings 234 for positioning. Then, the upper bearing 234 and the gasket are placed in, and the bottom of the upper bearing 234 just contacts the step on the rotating shaft 233. After the upper gasket is laser-welded, the first gear 241 is pressed flat with the bottom surface of the rotating shaft 233 by interference fit, and the two are laser-welded. Then, the entire structure of the connecting post 231 is interference-fitted with the guide sleeve 31 and laser-welded. Finally, the top of the rotating shaft 233 is connected to the rotor 232, and the sleeve 21 is pressed in to complete the installation of the entire drive assembly.

[0059] In one embodiment, please refer to Figure 4 A connecting cover 313 is provided at the end of the guide sleeve 31 away from the valve port 11. The connecting cover 313 covers the guide sleeve 31, thereby forming a receiving groove 312 between the connecting cover 313 and the guide sleeve 31. The mounting hole 311 is formed on the connecting cover 313.

[0060] Preferably, the guide sleeve 31 has a third step 314 at the end away from the valve port 11, and the connecting cover 313 is fitted over the end of the guide sleeve 31. The end of the connecting cover 313 facing downward towards the valve port 11 abuts against the third step 314 and is welded to the guide sleeve 31. This improves the strength of the connection between the guide sleeve 31 and the connecting cover 313.

[0061] Here, the guide sleeve 31 and the connecting cover 313 are interference-fitted, and the guide sleeve 31 and the connecting cover 313 are welded by laser welding or argon arc welding.

[0062] like Figure 3 As shown, the guide sleeve 31 has a guide cavity 315 at one end facing the valve port 11, and a sealing ring 316 is provided in the guide cavity 315. The end of the positioning cylinder 42 away from the valve port 11 extends into the guide cavity 315 and is sealed and connected with the sealing ring 316. Thus, the positioning cylinder 42 moves under the guidance of the guide cavity 315.

[0063] In one embodiment, an annular groove 317 is provided inside the guide sleeve 31, and the connector 32 is annular in shape. The connector 32 is installed in the annular groove 317 and is either interference-fitted with the annular groove 317 or welded to it. In this embodiment, the connector 32 and the guide sleeve 31 are connected by furnace welding or submerged arc welding.

[0064] Further, please refer to Figure 3 , Figure 5 as well as Figure 7 Along the axial direction X of the guide sleeve 31, the depth of the annular groove 317 is t, and the height of the connector 32 is t1, where t and t1 satisfy: t1-t≥1.5mm. This arrangement ensures sufficient fit between the connector 32 and the annular groove, improving the connection strength between the connector 32 and the guide sleeve 31.

[0065] Here, the value of t1-t can be 1.5mm, 2mm, 2.5mm, etc.

[0066] In one embodiment, such as Figure 5 and Figure 7 As shown, the connector 32 is annular, with an inner diameter of d1 and an outer diameter of d2, where d2-d1≥3mm. This ensures that the connector 32 has sufficient thickness in the radial direction of the guide sleeve 31 to guarantee its structural strength.

[0067] Here, the values ​​of d2-d1 can be 3mm, 4mm, 5mm, etc. In this embodiment, d2-d1 can be set to 3mm.

[0068] Please see Figure 6The number of stop bars 33 can be set to two, three, or four. In this embodiment, the number of stop bars 33 is two. Correspondingly, the number of anti-rotation holes 431 is also set to two.

[0069] Further, please refer to Figure 7 The width of the stop rod 33 is *a*, and its height along the axial direction X of the guide sleeve 31 is *t2*, where *a* ≥ 1 / 8(t1 + t2). It is understandable that as the positioning cylinder 42 moves along its axial direction X, the distance between the stop rod 33 and the positioning plate 43 also moves closer or further away. Specifically, the distance between the stop rod 33 and the positioning plate 43 is greatest when the valve port 11 is closed. Conversely, the distance between the stop rod 33 and the positioning plate 43 is closest when the valve port 11 is fully open. Therefore, when the valve port 11 needs to be opened, the torque on the stop rod 33 is the greatest, so the stop rod 33 needs to have sufficient width to resist the torque and prevent deformation. Therefore, *a* ≥ 1 / 8(t1 + t2).

[0070] Here, the value of a can be 1 / 8(t1+t2), 2 / 8(t1+t2), 1 / 7(t1+t2), etc.

[0071] Please see Figure 8 In one embodiment, the end of the positioning cylinder 42 furthest from the valve port 11 has a mounting groove 421, and a positioning groove 422 is formed on the wall of the mounting groove 421 in the radial direction of the positioning cylinder 42. A protrusion 432 is provided on the outer periphery of the positioning piece 43. The positioning piece 43 is fixed to the mounting groove 421, and the protrusion 432 and the positioning groove 422 are mutually limiting and engaged in the circumferential direction of the positioning cylinder 42. This arrangement, through the circumferential limiting and engaged relationship between the protrusion 432 and the mounting groove 421, prevents the positioning piece 43 from circumferentially moving. Combined with the engagement of the stop rod 33 and the anti-rotation hole 431, the entire positioning cylinder 42 can be made to remain circumferentially stationary.

[0072] Furthermore, a nut seat 423 is fixedly installed inside the positioning cylinder 42, and the end of the screw 41 away from the drive assembly 20 is threadedly connected to the nut seat 423. In this way, by using the fixing of the nut seat 423, the rotation of the screw 41 is converted into the axial movement of the positioning cylinder 42.

[0073] Please refer to section 8. A valve head 424 is provided at one end of the positioning cylinder 42 near the valve port 11. The valve head 424 is used to seal the valve port 11. Here, the valve head 424 and the positioning cylinder 42 are threaded together for easy installation.

[0074] In one embodiment, please refer to Figures 8 to 11 Please see Figure 1In the radial direction of the positioning cylinder 42, the positioning groove 422 penetrates the groove wall of the mounting groove 421, and the protrusion 432 extends radially out of the positioning groove 422 of the valve seat 10 and abuts against the inner wall surface of the guide sleeve 31. This arrangement, with the protrusion 432 abutting against the inner wall surface of the guide sleeve 31 in the radial direction of the valve seat 10, enables dual guidance of the positioning cylinder 42, reducing swaying during movement and thus improving the stability of the positioning cylinder 42's movement. Simultaneously, the abutment between the protrusion 432 and the guide sleeve 31 reduces the risk of contact between the guide sleeve 31 and the positioning cylinder 42.

[0075] Optionally, the guide sleeve 31 is configured as a stainless steel part, the positioning cylinder 42 is configured as a copper part, and / or the protrusion 432 is made of PTFE. Here, copper is generally less hard than stainless steel. When copper and stainless steel come into contact, the lower hardness of copper makes it easier for the stainless steel to scratch. Simultaneously, a chemical reaction may occur between copper and stainless steel, causing changes to the surfaces of both materials. For example, copper may turn dark yellow due to oxidation, while stainless steel may rust, become dirty, or develop marks. In this application, the protrusion 432 abuts against the inner wall of the guide sleeve 31, further reducing the risk of contact between the guide sleeve 31 and the positioning cylinder 42.

[0076] Here, the positioning cylinder 42 can be made of brass or copper.

[0077] Further, please refer to Figure 12 Multiple protrusions 432 are provided. The farthest distance between the protrusion 432 and the central axis of the positioning piece 43 is R3. The inner diameter of the guide sleeve 31 is d4 (that is, the inner diameter of the guide cavity 315). R3 and d4 satisfy: 0≤d4-2R3≤0.2mm. Here, 2R3 means twice R3. It can be understood that d4-2R3 is the gap value between the protrusion 432 and the inner wall of the guide sleeve 31. This gap value cannot be too large. If it is too large, the protrusion 432 will expand at high temperature, which will increase the friction between the protrusion 432 and the guide sleeve 31 during movement, posing a risk of jamming and preventing normal valve opening; at the same time, it reduces the swing of the positioning cylinder.

[0078] Here, the value of d4-2R3 can be 0, 0.1mm, 0.2mm, etc.

[0079] Preferably, the protrusion 432 is arc-shaped, R3 represents the radius of the arc-shaped protrusion 432, and 2R3 can also represent the diameter of the arc-shaped protrusion 432.

[0080] In one embodiment, please continue to refer to Figure 12Multiple protrusions 432 are provided. The farthest distance between the protrusion 432 and the central axis of the positioning piece 43 is R3. The outer diameter of the positioning cylinder 42 is d5. R3 and d5 satisfy: 0 ≤ 2R3 - d5 ≤ 0.8 mm. Here, 2R3 means twice R3. It can be understood that the value of 2R3 - d5 represents the size by which the protrusion 432 protrudes from the positioning cylinder 42 in the radial direction of the guide sleeve 31. By limiting 2R3 - d5, the amount of wear between the protrusion 432 and the inner wall surface of the guide sleeve 31 can be guaranteed.

[0081] Here, the value of 2R3-d5 can be 0, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, etc.

[0082] Preferably, the protrusion 432 is arc-shaped, R3 represents the radius of the arc-shaped protrusion 432, and 2R3 can also represent the diameter of the arc-shaped protrusion 432.

[0083] In one embodiment, the positioning piece 43 is made of PTFE. This reduces the overall weight of the electronic expansion valve 100 and provides a low coefficient of friction and strong corrosion resistance. Simultaneously, the PTFE material also possesses a degree of flexibility, reducing wear between it and the guide sleeve 31. For example, the positioning piece 43 can be made of polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE).

[0084] In this embodiment, the material of the positioning piece 43 is preferably polytetrafluoroethylene.

[0085] Furthermore, such as Figure 11 As shown, multiple protrusions 432 are circumferentially spaced on the positioning plate 43 of the valve cavity 12, and the number of positioning grooves 422 corresponds one-to-one with the number of protrusions 432. This arrangement can effectively improve the reliability of circumferential limiting.

[0086] In this embodiment, the number of protrusions 432 is configured to be three. However, this is not a limitation; the number of protrusions 432 can also be set to two, four, or five. The specific number of protrusions 432 can be set according to actual needs.

[0087] Furthermore, such as Figure 11 As shown, the three protrusions 432 are arranged in an equilateral triangle. This arrangement ensures that the force is evenly distributed among the protrusions 432, increasing the stability of the positioning cylinder 42 in the X-axis direction of the valve seat 10.

[0088] In another embodiment, please refer to Figures 13 to 19In the axial direction X of the positioning cylinder 42, the groove wall of the mounting groove 421 includes a first part 4211 and a second part 4212, with the first part 4211 located at the end of the positioning cylinder 42 and connected to the second part 4212. In this embodiment, the first part 4211 is located above the second part 4212. See also... Figure 17 Using the dotted line as the boundary, in the axial direction X of the positioning cylinder 42, the part located above is the first part 4211, and the part located below is the second part 4212.

[0089] The positioning groove 422 includes a first groove 4221 and a second groove 4222 that are interconnected. The positioning piece 43 is housed in the mounting groove 421 and fixedly connected to the first part 4211. In the circumferential direction of the positioning cylinder 42, the protrusion 432 engages with the wall of the second groove 4222 for limiting. The width of the first groove 4221 is L3, and the width of the second groove 4222 is L4, where L3 > L4. This configuration allows for circumferential limiting of the positioning piece 43 through the engagement of the protrusion 432 with the wall of the second groove 4222, with L3 > L4. This ensures that after the positioning piece 43 is housed in the mounting groove 421 and fixedly connected to the first part 4211, the protrusion 432 does not contact or has reduced contact with the first part 4211, thus preventing excessive rotational torque of the positioning cylinder 42 from cutting off the protrusion 432. In other words, this configuration improves the service life and reliability of the circumferential limiting of the protrusion 432 and the positioning cylinder 42.

[0090] Preferably, L3 and L4 satisfy L3≥1.5L4. In this way, in the circumferential direction of the positioning cylinder 42, there is a sufficient distance between the protrusion 432 and the first part 4211, so that the protrusion 432 and the first part 4211 do not contact each other in the circumferential direction of the positioning cylinder 42 as much as possible, and the influence of the first part 4211 on the protrusion 432 is avoided.

[0091] Here, the relationship between L3 and L4 can be L3=1.5L4, L3=1.55L4, L3=1.6L4.

[0092] In one embodiment, the positioning piece 43 and the second part 4212 of the mounting groove 421 are interference fit to achieve positioning of the positioning piece 43. The first part 4211 is used to achieve riveting with the positioning piece 43, that is, the first part 4211 bends and deforms under the action of external force, thereby abutting against the surface of the positioning piece 43 in its axial direction X.

[0093] In one embodiment, a first groove 4221 is formed in a first portion 4211, and a second groove 4222 is formed in a second portion 4212. In the radial direction of the positioning cylinder 42, the thickness of the groove wall of the first groove 4221 is L1, and the thickness of the groove wall of the second groove 4222 is L2. L1 and L2 satisfy that L2 > L1. Thus, during the riveting process, the first portion 4211 is more likely to deform, thereby achieving riveting fixation.

[0094] Furthermore, considering that L3 > L4, the radial direction of the positioning cylinder 42 ensures that the wall of the first groove 4221 does not contact or has minimal contact with the protrusion 432. Because the wall of the first groove 4221 is relatively thin, it would be easier to cut off the protrusion 432 if contact were made.

[0095] In one embodiment, please refer to Figure 19 Along the axial direction X of the positioning cylinder 42, the depth of the mounting groove 421 is h, the depth of the first groove 4221 is h1, the depth of the second groove 4222 is h2, and the depth of the positioning groove 422 is h3. h, h1, h2 and h3 satisfy: h=h3=h1+h2.

[0096] Furthermore, the thickness of the positioning piece 43 is h4, where h, h1, and h4 satisfy: h4 ≤ h - h1. It can be understood that the value of h - h1 represents h2, and h4 ≤ h - h1 means that the depth of the second groove 4222 is greater than or equal to the thickness of the positioning piece 43. Thus, in the axial direction X of the positioning cylinder 42, the side of the positioning piece 43 furthest from the valve port is at least located within the second groove 4222, meaning the positioning piece 43 is completely contained within the second groove 4222. This prevents the first part 4211 (i.e., the riveted part) from contacting the positioning piece in the circumferential direction of the positioning cylinder 42, further effectively preventing the connector from being cut.

[0097] In one embodiment, see Figures 14 to 16 The second groove 4222 has a first groove wall 4223 along its circumferential direction in the positioning cylinder 42, and the mounting groove 421 has a second groove wall 4213 along its circumferential direction. The first groove wall 4223 and the second groove wall 4213 are connected by a first surface 4224. The protrusion 432 and the positioning piece 43 are connected by a second surface 433, and the first surface 4224 and the second surface 433 can cooperate with each other. This arrangement increases the contact area between the protrusion 432 and the groove wall of the mounting groove 421 after the positioning piece 43 is installed, thereby further improving the reliability of the limiting mechanism.

[0098] Furthermore, the first surface 4224 and the second surface 433 can fit together. This further increases the contact area between the protrusion 432 and the groove wall of the mounting groove 421.

[0099] Optionally, please refer to Figure 15Both the first surface 4224 and the second surface 433 are set as curved surfaces. The curved surface design increases the contact area between the first surface 4224 and the second surface 433. Of course, this is not the only option; the first surface 4224 and the second surface 433 can also be set as arc surfaces or straight inclined surfaces, etc.

[0100] In one embodiment, such as Figure 16 As shown, multiple protrusions 432 are configured, and these protrusions 432 are equidistantly spaced along the circumference of the positioning piece 43 on its outer periphery. Positioning grooves 422 correspond one-to-one with the protrusions 432. This configuration ensures multiple limiting engagements between the positioning piece 43 and the positioning cylinder 42 in the circumference of the valve seat 10, thereby improving the reliability of the circumferential limiting between the positioning piece 43 and the positioning cylinder 42.

[0101] Preferably, the number of protrusions 432 is configured to be three. Of course, this is not a limitation; the number of protrusions 432 can also be set to two, four, or five. The specific number of protrusions 432 can be set according to actual needs.

[0102] Furthermore, the three protrusions 432 are arranged in a triangle. This arrangement makes the circumferential positioning between the positioning piece 43 and the positioning cylinder 42 more reliable.

[0103] Preferably, the three protrusions 432 are distributed in an equilateral triangle. This arrangement ensures that the circumferential limiting force between the positioning piece 43 and the positioning cylinder 42 is uniform.

[0104] In one embodiment, the protrusion 432 and the positioning piece 43 are configured as an integral structure. This configuration can improve the structural strength of the protrusion 432 and extend its lifespan.

[0105] The positioning plate 43 is made of PTFE. This reduces the overall weight of the electronic expansion valve 100 and provides a low coefficient of friction and strong corrosion resistance. PTFE also offers some flexibility, reducing wear between the positioning plate and the guide sleeve 31. For example, the positioning plate 43 can be made of polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE).

[0106] In this embodiment, the material of the positioning piece 43 is preferably polytetrafluoroethylene.

[0107] The working principle of this electronic expansion valve is as follows:

[0108] When coil 22 is energized, rotor 232 is driven to rotate by coil 22, which in turn drives shaft 233 to rotate. Shaft 233 drives screw 41 to rotate through gear unit 24. Because screw 41 is threadedly connected to nut seat 423, and stop rod 33 is axially limited by anti-rotation hole 431, the circumferential movement of positioning cylinder 42 is limited by protrusion 432 and positioning groove 422, meaning positioning cylinder 42 cannot rotate circumferentially. At the same time, nut seat 423 cannot rotate circumferentially. Nut seat 423 converts circumferential movement into axial movement, thereby driving positioning cylinder 42 to move axially and controlling the opening of valve port 11.

[0109] In this application, it should be noted that the axial direction of the valve seat 10, the axial direction of the positioning plate 43, the axial direction of the positioning cylinder 42, and the axial direction of the guide sleeve 31 are all represented by X, and the radial direction is the direction perpendicular to the axial direction X.

[0110] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0111] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present utility model and are not intended to limit the present utility model. Any appropriate changes and variations made to the above embodiments within the scope of the essential spirit of the present utility model shall fall within the scope of protection claimed by the present utility model.

Claims

1. A piston assembly for use in an electronic expansion valve, the piston assembly comprising a positioning cylinder (42) and a positioning plate (43), wherein one end of the positioning cylinder (42) is provided with a mounting groove (421), and in the radial direction of the positioning cylinder (42), a through positioning groove (422) is provided on the groove wall of the mounting groove (421), and a protrusion (432) is provided on the outer periphery of the positioning plate (43). Its features are, In the axial direction of the positioning cylinder (42), the mounting groove (421) includes a first part (4211) and a second part (4212), and the first part (4211) is located at the end of the positioning cylinder (42) and connected to the second part (4212). The positioning groove (422) includes a first groove (4221) and a second groove (4222) that are interconnected. The positioning piece (43) is received in the mounting groove (421) and can be fixedly connected to the first part (4211). In the circumferential direction of the positioning cylinder (42), the protrusion (432) is limited and engaged with the groove wall of the second groove (4222). The width of the first groove (4221) is L3, and the width of the second groove (4222) is L4. L3 and L4 satisfy L3 > L4.

2. The piston assembly according to claim 1, characterized in that, L3 and L4 satisfy the condition that L3 > 1.5L4; And / or, in the radial direction of the positioning cylinder (42), the thickness of the groove wall of the first groove (4221) is L1, and the thickness of the groove wall of the second groove (4222) is L2, where L1 and L2 satisfy L2 > L1.

3. The piston assembly according to claim 1, characterized in that, In the axial direction of the positioning cylinder (42), the depth of the mounting groove (421) is h, the depth of the first groove (4221) is h1, the depth of the second groove (4222) is h2, and the depth of the positioning groove (422) is h3. h, h1, h2 and h3 satisfy: h=h3=h1+h2.

4. The piston assembly according to claim 3, characterized in that, The thickness of the positioning piece (43) is h4, and h, h1 and h4 satisfy: h4≤h-h1.

5. The piston assembly according to claim 1, characterized in that, The second groove (4222) has its groove wall in the circumferential direction of the positioning cylinder (42) set as the first groove (4221) wall, and the groove wall of the mounting groove (421) is set as the second groove wall (4213). In the circumferential direction of the positioning cylinder (42), the first groove (4221) wall and the second groove wall (4213) are connected by a first surface (4224). The protrusion (432) and the positioning piece (43) are connected by a second surface (433), and the first surface (4224) and the second surface (433) can cooperate with each other.

6. The piston assembly according to claim 5, characterized in that, Both the first surface (4224) and the second surface (433) are set as curved surfaces; And / or, the first surface (4224) and the second surface (433) are fitted together.

7. The piston assembly according to claim 1, characterized in that, In the axial direction of the positioning cylinder (42), the positioning piece (43) is interference-fitted with the second part (4212) and riveted to the first part (4211).

8. The piston assembly according to claim 1, characterized in that, The number of protrusions (432) is configured to be multiple, and the multiple protrusions (432) are equally spaced along the circumference of the positioning piece (43) on the outer periphery of the positioning piece (43). The positioning groove (422) is provided in a one-to-one correspondence with the protrusions (432).

9. The piston assembly according to claim 8, characterized in that, The number of protrusions (432) is configured to be three, and the three protrusions (432) are arranged in a triangle.

10. An electronic expansion valve, characterized in that, The electronic expansion valve includes a valve seat (10), a drive assembly (20), a valve body assembly (30), and a piston assembly (40) as described in any one of claims 1-9; the valve seat (10) has a valve port (11), the valve body assembly (30) is mounted on the valve seat (10), the drive assembly (20) is mounted on the valve body assembly (30) and is used to provide rotational driving force, and the piston assembly (40) is movably mounted on the valve body assembly (30) and connected to the drive assembly (20) to move along the axial direction of the valve seat (10) under the drive of the drive assembly (20) and open / close the valve port (11). The drive assembly (20) includes a sleeve (21), a coil (22), a rotor unit (23), and a gear unit (24); the valve body assembly (30) includes a guide sleeve (31), a connector (32), and multiple stop rods (33); and the piston assembly (40) includes a screw (41), a positioning cylinder (42), and a positioning plate (43). The sleeve (21) is fixed on the guide sleeve (31), the coil (22) is sleeved around the circumference of the sleeve (21), the rotor unit (23) is rotatably disposed inside the sleeve (21), the gear unit (24) is installed inside the guide sleeve (31) and is connected to the rotor unit (23) and the screw (41) respectively, the connector (32) is fixedly installed inside the guide sleeve (31), each stop rod (33) extends along the axial direction of the guide sleeve (31) and is connected to the connector (32); one end of the positioning cylinder (42) is connected to The guide sleeve (31) is slidably connected, and the other end is used to open and close the valve port (11). The positioning plate (43) is fixed to the positioning cylinder (42) and has an anti-rotation hole (431). One end of the screw (41) is connected to the drive assembly (20), and the other end passes through the positioning plate (43) and is threadedly connected to the positioning cylinder (42). One end of the multiple stop rods (33) is fixedly connected to the connector (32), and the other end passes through the anti-rotation hole (431) so that the stop rods (33) are limited to the positioning plate (43) in the circumference of the positioning cylinder (42).

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