Electronic expansion valve

Abstract

The application provides an electronic expansion valve, which comprises a coil assembly, a sleeve assembly, a valve body assembly, a magnetic rotor, a rotating nut, a screw rod, a valve needle assembly and a stop assembly; the rotating nut is fixed in the magnetic rotor and rotates synchronously with the magnetic rotor; the rotating nut comprises a first accommodating cavity and a threaded hole; the screw rod has a threaded part matched with the threaded hole; the screw rod drives the valve needle assembly to move up and down to adjust the opening size of a valve port; the stop assembly limits the total stroke of the valve needle moving up and down; the stop assembly comprises a spring guide rail and a sliding ring; when the sliding ring moves up and down by rotating the spring guide rail, the sliding ring abuts against the limiting structure on the spring guide rail to limit the total stroke of the valve needle moving up and down. The electronic expansion valve improves the defects of the existing stop structure, realizes the ingenious design of the stop structure, guarantees that the electronic expansion valve can realize stop limiting and adjust the maximum and minimum opening of the valve port, and reduces the overall size and weight of the valve structure.

Description

Technical Field

[0001] This invention relates to a thermal management system, and more particularly to an electronic expansion valve. Background Technology

[0002] In thermal management systems, electronic expansion valves play a crucial role in throttling, pressure reduction, and flow regulation. Existing electronic expansion valves primarily consist of a rotor assembly, a nut assembly, a valve needle assembly threaded to the nut, and a valve seat assembly. A drive device moves the valve needle assembly axially along the nut to adjust the valve opening, thereby controlling the flow rate. In these types of electronic expansion valves, a stop structure is typically required to limit the maximum range of the valve needle's vertical travel, thus defining the maximum and minimum valve opening, or preventing damage to the valve port from excessive needle movement. Related technologies typically employ a stop structure in electronic expansion valves, including a stop rod, a nut, a threaded guide rail, a slip ring, and a stop point. The stop rod is fixed to the rotor connecting plate and rotates with the magnetic rotor. The nut has a guide rail groove or a guide rail spring. The stop rod drives the slip ring to move along the preset guide rail along the axial direction of the nut seat until the stop point is reached. However, this structure results in a complex electronic expansion valve design, difficult component assembly, large overall size, and high cost.

[0003] Therefore, it is necessary to provide an electronic expansion valve to overcome the defects mentioned above. Summary of the Invention

[0004] The purpose of this invention is to provide an electronic expansion valve that improves upon the shortcomings of existing stop structures. While ensuring that the electronic expansion valve can achieve stop limiting and adjust the maximum and minimum opening of the valve port, it reduces the overall size and weight of the valve structure, thereby reducing the cost of the product.

[0005] According to one aspect of the present invention, an electronic expansion valve is provided, comprising a coil assembly, a sleeve assembly, a valve body assembly, a magnetic rotor, a rotating nut, a lead screw, a valve needle assembly, and a stop assembly. The coil assembly is at least partially sleeved outside the sleeve assembly. The valve body assembly is fixed to the lower end of the sleeve assembly, and the lower end of the valve body assembly includes a valve port for flowing a fluid medium. The magnetic rotor is placed inside the sleeve assembly and is driven to rotate by the coil assembly. The rotating nut is fixed inside the magnetic rotor and rotates synchronously with the magnetic rotor. The rotating nut includes a first receiving cavity opening towards the end away from the valve port, and a connection between the first receiving cavity and the valve body assembly. A threaded hole is provided, and a lead screw passes through the first receiving cavity and the threaded hole. The lead screw has a threaded part that mates with the threaded hole. The lead screw moves up and down by rotating the nut. The valve needle assembly is connected to the lower end of the lead screw. The lead screw drives the valve needle assembly to move up and down to adjust the opening of the valve port. A stop assembly is placed in the first receiving cavity to limit the total stroke of the valve needle. The stop assembly includes a spring guide rail that rotates synchronously with the rotating nut and a slip ring sleeved on the lead screw and limited by the spring guide rail. When the spring guide rail rotates and drives the slip ring to move up and down, it abuts against the limiting structure on the spring guide rail to limit the total stroke of the valve needle.

[0006] The above solution provides an electronic expansion valve with a simple stop mechanism, which improves the shortcomings of the existing stop structure and achieves a clever design of the stop structure. While ensuring that the electronic expansion valve can achieve stop limit and adjust the maximum and minimum opening of the valve port, the overall size and weight of the valve structure are reduced, thereby reducing the cost of the product.

[0007] Preferably, it further includes a nut retainer ring sleeved on the rotating nut, the nut retainer ring being fixed to the valve body assembly to limit the movement of the rotating nut along the axial direction of the rotating nut.

[0008] Preferably, the rotating nut includes a main body, a stepped portion located at the lower end of the main body near the valve port, a first receiving cavity located in the main body, a threaded hole located at the lower end of the main body with a diameter smaller than that of the first receiving cavity, the stepped portion located inside the valve body assembly, and a nut retaining ring located at the upper end of the stepped portion with a gap between it and the stepped portion.

[0009] Preferably, the valve body assembly includes a valve seat and a valve base that at least partially passes through the valve seat. The valve seat has a first valve seat cavity and a second valve seat cavity located at the lower end of the first valve seat cavity and having a diameter smaller than that of the first valve seat cavity. A stepped portion is located in the first valve seat cavity, and the lower end of the stepped portion abuts against the lower end face of the first valve seat cavity. A nut retaining ring is interference-fitted into the first valve seat cavity.

[0010] Preferably, the outer wall of the stepped portion has multiple friction-reducing grooves coaxial with the stepped portion, and these grooves are arranged in a ring shape and spaced apart. This design reduces the contact area between the rotating nut and the valve seat, thereby reducing friction.

[0011] Preferably, the sleeve assembly includes a sleeve fixed to the valve body assembly and an end cap fixed to the upper end of the sleeve. The end cap includes a body portion, a crimping portion protruding from the body portion toward the rotating nut, a boss protruding cylindrically from the lower end face of the crimping portion toward the rotating nut, a mounting hole formed on the end face of the boss and coaxial with the boss, and an annular groove disposed on the end face of the boss and coaxial with the mounting hole, the annular groove surrounding the mounting hole. This design better ensures the limited degrees of freedom of the lead screw movement while restricting excess degrees of freedom, and also provides limiting space for the stop structure.

[0012] Preferably, it further includes an anti-rotation sleeve interference-fitted into the mounting hole, the anti-rotation sleeve having a limiting hole including at least one limiting plane along the axial direction; the upper end of the lead screw is placed in the limiting hole and can move relative to the rotor along the axial direction, and the side wall of the lead screw has a limiting tangent that makes limiting contact with the plane of the limiting hole. This solution helps to ensure that the up-and-down movement of the lead screw is simultaneously limited by limiting its rotation, and the torque of the nut is converted into the linear motion force of the lead screw through the meshing force of the threaded engagement, thereby achieving the adjustment of the valve opening.

[0013] Preferably, the lead screw includes a limiting part located at the upper end of the threaded portion, and the upper end of the limiting part is located inside the limiting hole.

[0014] Preferably, the cross-sectional shape of the limiting hole of the anti-rotation sleeve is the same as the cross-sectional profile of the upper end of the lead screw.

[0015] Preferably, the spring guide rail includes a helical section, a first vertical section extending vertically from the upper end of the helical section toward the end away from the valve port, and a second vertical section extending vertically from the lower end of the helical section toward the end near the valve port. The first vertical section is at least partially slidably disposed within an annular groove, and the second vertical section is connected to a rotating nut. This design helps to stop the expansion valve while reducing the overall structural space, thus contributing to product miniaturization and reducing structural complexity.

[0016] Preferably, the slip ring includes a main ring body, a first ear protruding radially along the outer side wall of the main ring body, and a second ear protruding radially along the other outer side wall of the main ring body that is relatively far from the first ear. The first ear is closer to the valve port than the second ear. The rotation of the magnetic rotor drives the rotating nut to rotate, and the lead screw and slip ring move up and down along the rotation axis of the magnetic rotor. When the first ear abuts against the second vertical section, it is in the lower stop position, and when the second ear abuts against the first vertical section, it is in the upper stop position.

[0017] Preferably, the cross-section of the inner hole of the slip ring is the same as the profile of the upper end cross-section of the lead screw.

[0018] Preferably, the bottom of the first receiving cavity has a positioning hole, and the second vertical section is placed inside the positioning hole.

[0019] Preferably, the rotating nut further includes a second receiving cavity located on the stepped portion and opening towards the valve port, and a balance hole located at the bottom of the first receiving cavity and connecting the first receiving cavity and the second receiving cavity. The second receiving cavity and the second valve seat cavity form a space for receiving the fluid medium.

[0020] Preferably, the valve base has a valve cavity, the valve port is located at the lower end of the valve base and communicates with the valve cavity, and the valve needle assembly is located in the valve cavity.

[0021] Preferably, the valve base further includes a flow channel hole disposed on the side wall and communicating with the valve cavity and valve port.

[0022] Preferably, the valve needle assembly includes a valve needle and a valve needle spring. The valve needle includes a valve needle cavity that opens toward the rotating nut and a riveted portion located at the upper end of the valve needle cavity. The lead screw also includes a connecting portion located at the lower end of the threaded portion and a ring portion arranged radially from the connecting portion. The ring portion is located inside the valve needle cavity. The upper end of the valve needle spring abuts against the ring portion, and the lower end of the valve needle spring abuts against the bottom of the valve needle cavity. The riveted portion is pressed against the upper end of the ring portion to prevent the lead screw from disengaging from the valve needle.

[0023] The electronic expansion valve provided by this invention improves upon the shortcomings of existing stop structures by designing structures such as coil assembly, sleeve assembly, valve body assembly, magnetic rotor, rotating nut, lead screw, valve needle assembly, and stop assembly. It achieves a clever design of the stop structure, ensuring that the electronic expansion valve can achieve stop limit and adjust the maximum and minimum opening of the valve port, while reducing the overall size and weight of the valve structure, thereby reducing the cost of the product. Attached Figure Description

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a schematic diagram of the electronic expansion valve. Figure 2 This is a partial structural diagram of an electronic expansion valve; Figure 3 for Figure 2 Top view; Figure 4 For along Figure 3 A cross-sectional view at position AA in the middle; Figure 5 for Figure 4 A magnified view of the area at position 'a'; Figure 6 This is a schematic diagram of the end cap; Figure 7 A schematic diagram showing the process of switching to a fixed position; Figure 8 This is a schematic diagram of the lead screw and valve needle assembly; Figure 9 This is a schematic diagram of rotating the nut; Figure 10This is a cross-sectional view of the rotating nut; Figure 11 for Figure 4 A magnified view of the area at position b in the middle; Figure 12 A sectional view of the stop component; Figure 13 This is a schematic diagram of a spring guide rail; Figure 14 This is a schematic diagram of a slip ring.

[0025] Explanation of icon numbers: 10. Coil assembly; 20. Sleeve assembly; 21. End cap; 211. Body part; 212. Crimping part; 213. Boss; 214. Mounting hole; 215. Annular groove; 22. Sleeve; 30. Anti-rotation sleeve; 301. Limiting hole; 302. First anti-rotation part; 303. Second anti-rotation part; 40. Lead screw; 401. Limiting part; 402. Threaded part; 403. Connecting part; 404. Ring part; 50. Magnetic rotor; 60. Rotating nut; 601. Body part; 602. First receiving cavity; 603. Threaded hole; 604. Stepped part; 6041. Anti-friction groove; 605. Positioning hole; 606. Balance hole; 607. Second receiving cavity; 70, stop assembly; 71, spring guide rail; 711, first vertical section; 712, spiral section; 713, second vertical section; 72, slip ring; 721, first ear; 722, main ring body; 723, second ear; 724, inner hole; 80, valve body assembly; 81, valve seat; 82, valve base; 811, first valve seat cavity; 812, second valve seat cavity; 821, valve cavity; 822, flow channel hole; 90, valve needle assembly; 91, valve needle; 911, riveting part; 912, valve needle cavity; 92, valve needle spring; S1, limiting plane; S2, limiting section; K, valve port; H, nut retaining ring; X, limiting structure. Detailed Implementation

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] To keep the drawings concise, only the parts relevant to the invention are shown schematically in each figure, and they do not represent the actual structure of the product. Furthermore, for ease of understanding, in some figures, only one of components with the same structure or function is shown schematically, or only one is labeled. In this document, "one" can mean not only "only one" but also "more than one".

[0028] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0029] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0032] See Figures 1 to 14 As shown, this embodiment provides an electronic expansion valve, including a coil assembly 10, a sleeve assembly 20, a valve body assembly 80, a magnetic rotor 50, a rotating nut 60, a lead screw 40, a valve needle assembly 90, a stop assembly 70, an anti-rotation sleeve 30, and a nut retaining ring H. The coil assembly 10 is at least partially sleeved outside the sleeve assembly 20. The valve body assembly 80 is fixed to the lower end of the sleeve assembly 20. The lower end of the valve body assembly 80 includes a valve port K for the flow of fluid medium. The magnetic rotor 50 is placed inside the sleeve assembly 20 and is driven to rotate by the coil assembly 10. The rotating nut 60 is fixed inside the magnetic rotor 50 and rotates synchronously with the magnetic rotor 50. The magnetic rotor 50 can be fixed by injection molding it onto the rotating nut 60.

[0033] See Figure 4 and Figure 6As shown, the sleeve assembly 20 includes a sleeve 22 fixed to the valve body assembly 80 and an end cap 21 fixed to the upper end of the sleeve 22. The end cap 21 includes a body portion 211, a crimping portion 212 protruding from the body portion 211 toward the rotating nut 60, a boss 213 protruding in a cylindrical shape from the lower end face of the crimping portion 212 toward the rotating nut 60, a mounting hole 214 opened on the end face of the boss 213 and coaxial with the boss 213, and an annular groove 215 disposed on the end face of the boss 213 and coaxial with the mounting hole 214. The annular groove 215 surrounds the mounting hole 214.

[0034] See Figure 3 and Figure 7 As shown, the electronic expansion valve also includes an anti-rotation sleeve 30 that is interference-fitted into the mounting hole 214. The anti-rotation sleeve 30 is provided with a limiting hole 301 along the axial direction, which includes at least one limiting plane S1. The anti-rotation sleeve 30 includes a first anti-rotation part 302 and a second anti-rotation part 303 with a diameter larger than the first anti-rotation part 302. The first anti-rotation part 302 serves as a guide to facilitate the installation of the anti-rotation sleeve 30. The second anti-rotation part 303 is interference-fitted into the mounting hole 214. The limiting hole 301 passes through the upper and lower ends of the anti-rotation sleeve 30.

[0035] See Figure 3 and Figure 8 As shown, the upper end of the lead screw 40 is placed inside the limiting hole 301 and can move up and down relative to the rotor axis. The side wall of the lead screw 40 has a limiting cross-section S2 that contacts the plane of the limiting hole 301. The lead screw 40 includes a threaded portion 402, a limiting portion 401 placed at the upper end of the threaded portion 402, a connecting portion 403 placed at the lower end of the threaded portion 402, and a ring portion 404 radially arranged from the connecting portion 403. The upper end of the limiting portion 401 is placed inside the limiting hole 301. The limiting portion 401 has a limiting cross-section S2 that contacts the plane of the limiting hole 301. More specifically, the cross-sectional shape of the limiting hole 301 of the anti-rotation sleeve 30 is the same as the cross-sectional profile of the upper end of the lead screw 40, i.e., the limiting portion 401.

[0036] The valve needle assembly 90 is connected to the lower end of the lead screw 40. The valve needle assembly 90 includes a valve needle 91 and a valve needle spring 92. The valve needle 91 includes a valve needle cavity 912 that opens toward the rotating nut 60 and a riveting part 911 placed at the upper end of the valve needle cavity 912. The upper end of the valve needle spring 92 abuts against the ring part 404, and the lower end of the valve needle spring 92 abuts against the bottom of the valve needle cavity 912. The riveting part 911 is pressed against the upper end of the ring part 404 to prevent the lead screw 40 from disengaging from the valve needle 91. The lead screw 40 drives the valve needle assembly 90 to move up and down to adjust the opening of the valve port K.

[0037] See Figure 4 , Figure 9 and Figure 10As shown, the rotating nut 60 includes a first receiving cavity 602 opening towards the end away from the valve port K, a threaded hole 603 connecting the first receiving cavity 602 and the valve body assembly 80, and a positioning hole 605 at the bottom of the first receiving cavity 602. Furthermore, the rotating nut 60 includes a main body 601, a stepped portion 604 located at the lower end of the main body 601 near the valve port K, a second receiving cavity 607 located on the stepped portion 604 opening towards the valve port K, and a balancing hole 606 located at the bottom of the first receiving cavity 602 and connecting the first receiving cavity 602 and the second receiving cavity 607. The stepped portion 604 is located within the valve body assembly 80, the first receiving cavity 602 is located within the main body 601, and the threaded hole 603... 03 is placed at the lower end of the main body 601. The diameter of the threaded hole 603 is smaller than the diameter of the first receiving cavity 602. The lead screw 40 passes through the first receiving cavity 602 and the threaded hole 603. The torque of the nut is converted into the linear motion force of the lead screw 40 through the meshing force of the threaded engagement, thereby realizing the adjustment of the valve port K opening degree. The lead screw 40 has a threaded part 402 that mates with the threaded hole 603. By rotating the nut 60, the lead screw 40 moves up and down. The outer wall of the stepped part 604 is provided with multiple anti-friction grooves 6041 that are coaxial with the stepped part 604. The multiple anti-friction grooves 6041 are arranged in a ring and spaced apart to reduce the contact area between the rotating nut 60 and the valve body assembly 80 or the valve seat 81, thereby reducing friction.

[0038] See Figure 4 and Figure 11 As shown, the valve body assembly 80 includes a valve seat 81 and a valve base 82 that at least partially passes through the valve seat 81. The valve seat 81 has a first valve seat cavity 811 and a second valve seat cavity 812 located at the lower end of the first valve seat cavity 811 and having a diameter smaller than the first valve seat cavity 811. The second receiving cavity 607 and the second valve seat cavity 812 form a space for containing a fluid medium. A step portion 604 is located in the first valve seat cavity 811, and the lower end of the step portion 604 abuts against the lower end face of the first valve seat cavity 811. The valve base 82 has a valve cavity 821, and a valve port K is located at the lower end of the valve base 82 and communicates with the valve cavity 821. A valve needle assembly 90 is located in the valve cavity 821. The valve base 82 also includes a flow channel hole 822 located on the side wall and communicating with the valve cavity 821 and the valve port K. The fluid medium flows in or out through the flow channel hole.

[0039] The electronic expansion valve also includes a nut retainer H sleeved on the rotating nut 60. The nut retainer H is fixed to the valve body assembly 80 to limit the movement of the rotating nut 60 along the axial direction. More specifically, the nut retainer H is interference-fitted into the first valve seat cavity 811, and the nut retainer H is positioned at the upper end of the step portion 604 with a gap between it and the step portion 604.

[0040] See Figure 4 and Figure 12As shown, the stop assembly 70 is placed in the first receiving cavity 602 to limit the total stroke of the valve needle 91 moving up and down. The stop assembly 70 includes a spring guide rail 71 that rotates synchronously with the rotating nut 60 and a slip ring 72 that is sleeved on the lead screw 40 and limited to the spring guide rail 71. When the spring guide rail 71 rotates and drives the slip ring 72 to move up and down, it abuts against the limiting structure X on the spring guide rail 71 to limit the total stroke of the valve needle 91 moving up and down.

[0041] See Figure 13 As shown, the spring guide rail 71 includes a helical section 712, a first vertical section 711 extending vertically from the upper end of the helical section 712 toward the end away from the valve port K, and a second vertical section 713 extending vertically from the lower end of the helical section 712 toward the end close to the valve port K. The first vertical section 711 is at least partially slidably disposed in the annular groove 215, and the second vertical section 713 is connected to the rotating nut 60. More specifically, the second vertical section 713 is placed in the positioning hole 605, which realizes the stop of the expansion valve and reduces the space occupied by the overall structure, which helps to realize the miniaturization of the product and reduce the complexity of the structure.

[0042] See Figure 4 , Figure 12 , Figure 14 As shown, the slip ring 72 includes a main ring body 722, a first ear 721 protruding radially along the outer side wall of the main ring body 722, a second ear 723 protruding radially along the other outer side wall of the main ring body 722 that is relatively far from the first ear 721, and an inner hole 724 placed in the main ring body 722. The first ear 721 is closer to the valve port K than the second ear 723. The rotation of the magnetic rotor 50 drives the rotating nut 60 to rotate, and the lead screw 40 and the slip ring 72 move up and down along the rotation axis of the magnetic rotor 50. When the first ear 721 abuts against the second vertical section 713, it is in the lower stop position. When the second ear 723 abuts against the first vertical section 711, it is in the upper stop position. The cross section of the inner hole 724 of the slip ring 72 is the same as the upper end cross section profile of the lead screw 40. The limiting structure X in the stop assembly 70 is composed of the first ear 721, the second ear 723, the first vertical section 711, and the second vertical section 713.

[0043] The working principle of this embodiment is illustrated by way of example: the coil assembly 10 drives the magnetic rotor 50 to rotate (rotating around its own central axis), and the rotating nut 60 rotates synchronously. Since the lead screw 40 is threadedly engaged with the threaded hole 603 on the rotating nut 60 through the threaded part 402, and since the upper end of the lead screw 40 is placed in the anti-rotation sleeve 30 with the limiting plane S1, its rotational freedom is restricted. When the rotating nut 60 rotates, the meshing force of the threaded engagement converts the torque of the nut into the linear motion force of the lead screw 40, causing the lead screw 40 to move up and down in the vertical direction, thereby driving the valve needle assembly 90 to move up and down. This allows for the adjustment of the valve port K opening degree (including the open and closed state of valve port K). During the adjustment of the valve port K opening degree, the spring guide rail 71 rotates, causing the slip ring 72 to move up and down and abut against the limiting structure X on the spring guide rail 71, limiting the total stroke of the valve needle 91's up and down movement. Specifically, when the electronic expansion valve changes from a closed state to an open state or to the maximum opening degree, the rotating nut 60 rotates, and the lead screw 40 moves upward, gradually driving the valve needle assembly 90 to open the valve port K and gradually adjust the valve port K to become larger. The second vertical section 713 at the lower end of the spring guide rail 71 is inserted into the positioning hole 605 of the rotating nut 60, therefore... The spring guide rail 71 rotates synchronously with the rotating nut 60. The first ear 721 and the second ear 723 of the slip ring 72 are positioned between the gaps of the spiral section 712 of the spring guide rail 71, forming a limit, causing the slip ring 72 to move upward. When the second ear 723 (i.e., the ear at the upper end of the slip ring 72) abuts against the first vertical section 711 on the spring guide rail 71, it reaches the upper stop position, and the valve needle assembly 90 stops moving upward, and the valve port K opens to its maximum. When the electronic expansion valve is adjusted from the maximum opening state to the reduced opening state or the closed state, the rotating nut 60 rotates, and the lead screw 40 moves downward, gradually driving the valve needle assembly 90. As the valve port K gradually decreases, the second vertical section 713 at the lower end of the spring guide rail 71 is inserted into the positioning hole 605 of the rotating nut 60. Therefore, the spring guide rail 71 rotates synchronously with the rotating nut 60. The first ear 721 and the second ear 723 of the slip ring 72 are positioned between the gaps of the spiral section 712 of the spring guide rail 71, forming a limit, which causes the slip ring 72 to move downward. When the first ear 721 (i.e., the ear at the lower end of the slip ring 72) abuts against the second vertical section 713 on the spring guide rail 71, it reaches the lower stop position, the valve needle assembly 90 stops moving downward, and the valve port K is adjusted to the minimum or closed state.

[0044] The electronic expansion valve provided by this invention improves upon the shortcomings of existing stop structures by designing structures such as coil assembly, sleeve assembly, valve body assembly, magnetic rotor, rotating nut, lead screw, valve needle assembly, and stop assembly. It achieves a clever design of the stop structure, ensuring that the electronic expansion valve can achieve stop limit and adjust the maximum and minimum opening of the valve port, while reducing the overall size and weight of the valve structure, thereby reducing the cost of the product.

[0045] It will be apparent to those skilled in the art that various modifications and variations can be made to the exemplary embodiments described above without departing from the spirit and scope of the invention. Therefore, it is intended that this invention cover modifications and variations falling within the scope of the appended claims and their equivalents.

Claims

1. An electronic expansion valve, characterized in that, include: Coil assembly; A sleeve assembly, wherein the coil assembly is at least partially sleeved on the outside of the sleeve assembly; A valve body assembly, the valve body assembly being fixed to the lower end of the sleeve assembly, the lower end of the valve body assembly including a valve port for the flow of a fluid medium; A magnetic rotor, which is placed inside the sleeve assembly and driven to rotate by a coil assembly; A rotating nut is fixed inside the magnetic rotor and rotates synchronously with the magnetic rotor. The rotating nut includes a first receiving cavity that opens toward the end away from the valve port and a threaded hole that connects the first receiving cavity to the valve body assembly. A lead screw passes through the first receiving cavity and the threaded hole. The lead screw has a threaded portion that mates with the threaded hole. The lead screw moves up and down by rotating the rotating nut. A valve needle assembly is connected to the lower end of the lead screw, and the lead screw drives the valve needle assembly to move up and down to adjust the opening of the valve port. A stop assembly is provided, which is placed in the first receiving cavity to limit the total stroke of the valve needle moving up and down. The stop assembly includes a spring guide rail that rotates synchronously with the rotating nut and a slip ring sleeved on the lead screw and limited by the spring guide rail. When the spring guide rail rotates and drives the slip ring to move up and down, it abuts against the limiting structure on the spring guide rail to limit the total stroke of the valve needle moving up and down.

2. The electronic expansion valve as described in claim 1, characterized in that, It also includes a nut retainer ring sleeved on the rotating nut, the nut retainer ring being fixed to the valve body assembly to limit the movement of the rotating nut along the axial direction of the rotating nut.

3. The electronic expansion valve as described in claim 2, characterized in that, The rotating nut includes a main body and a stepped portion located at the lower end of the main body near the valve port. The first receiving cavity is located in the main body. The threaded hole is located at the lower end of the main body. The diameter of the threaded hole is smaller than the diameter of the first receiving cavity. The stepped portion is located inside the valve body assembly. The nut retaining ring is located at the upper end of the stepped portion and has a gap with the stepped portion.

4. The electronic expansion valve as described in claim 3, characterized in that, The valve body assembly includes a valve seat and a valve base that passes through the valve seat at least partially. The valve seat has a first valve seat cavity and a second valve seat cavity located at the lower end of the first valve seat cavity with a diameter smaller than that of the first valve seat cavity. The stepped portion is located in the first valve seat cavity, and the lower end of the stepped portion abuts against the lower end face of the first valve seat cavity. The nut retaining ring is interference-fitted into the first valve seat cavity.

5. The electronic expansion valve as described in claim 4, characterized in that, The outer wall of the stepped portion is provided with a plurality of wear-reducing grooves coaxial with the stepped portion, and the plurality of wear-reducing grooves are arranged in a ring shape and spaced apart.

6. The electronic expansion valve as described in claim 5, characterized in that, The sleeve assembly includes a sleeve fixed to the valve body assembly and an end cap fixed to the upper end of the sleeve. The end cap includes a body portion, a crimping portion protruding from the body portion toward the rotating nut, a boss protruding in a cylindrical shape from the lower end face of the crimping portion toward the rotating nut, a mounting hole formed on the end face of the boss and coaxial with the boss, and an annular groove disposed on the end face of the boss and coaxial with the mounting hole. The annular groove surrounds the mounting hole.

7. The electronic expansion valve as described in claim 6, characterized in that, It also includes an anti-rotation sleeve that is interference-fitted into the mounting hole, the anti-rotation sleeve having a limiting hole including at least one limiting plane along the axial direction; the upper end of the lead screw is placed in the limiting hole and can move relative to the rotor along the axial direction, and the side wall of the lead screw has a limiting cross-section that makes limiting contact with the plane of the limiting hole.

8. The electronic expansion valve as described in claim 7, characterized in that, The spring guide rail includes a helical section, a first vertical section extending vertically from the upper end of the helical section toward the end away from the valve port, and a second vertical section extending vertically from the lower end of the helical section toward the end close to the valve port. The first vertical section is at least partially slidably disposed within the annular groove, and the second vertical section is connected to the rotating nut.

9. The electronic expansion valve as described in claim 8, characterized in that, The slip ring includes a main ring body, a first ear protruding radially along the outer side wall of the main ring body, and a second ear protruding radially along the other outer side wall of the main ring body that is relatively far from the first ear. The first ear is closer to the valve port than the second ear. The rotation of the magnetic rotor drives the rotating nut to rotate. The lead screw and the slip ring move up and down along the rotation axis of the magnetic rotor. When the first ear abuts against the second vertical section, it is in the lower stop position. When the second ear abuts against the first vertical section, it is in the upper stop position.

10. The electronic expansion valve as described in claim 9, characterized in that, The bottom of the first receiving cavity has a positioning hole, and the second vertical section is placed inside the positioning hole.

11. The electronic expansion valve as described in claim 10, characterized in that, The rotating nut also includes a second receiving cavity located on the stepped portion and opening towards the valve port side, and a balance hole located at the bottom of the first receiving cavity and connecting the first receiving cavity and the second receiving cavity. The second receiving cavity and the second valve seat cavity form a space for receiving fluid fluid medium.

12. The electronic expansion valve as described in claim 11, characterized in that, The valve base has a valve cavity, the valve port is located at the lower end of the valve base and communicates with the valve cavity, and the valve needle assembly is located in the valve cavity.

13. The electronic expansion valve as described in claim 12, characterized in that, The valve needle assembly includes a valve needle and a valve needle spring. The valve needle includes a valve needle cavity that opens toward the rotating nut and a riveted portion located at the upper end of the valve needle cavity. The lead screw also includes a connecting portion located at the lower end of the threaded portion and a ring portion arranged radially from the connecting portion. The ring portion is located inside the valve needle cavity. The upper end of the valve needle spring abuts against the ring portion, and the lower end of the valve needle spring abuts against the bottom of the valve needle cavity. The riveted portion is pressed against the upper end of the ring portion to prevent the lead screw from disengaging from the valve needle.

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