Electronic expansion valve

Abstract

The electronic expansion valve comprises a valve seat assembly, a valve element assembly, a screw rod and a second elastic piece. The valve seat assembly is provided with a valve cavity, and the cavity wall of the valve cavity is provided with a first valve port and a second valve port which are arranged at intervals in the axial direction of the electronic expansion valve. The valve element assembly is at least partially arranged in the valve cavity and comprises a first valve element, a second valve element and a first elastic piece, the first valve element can move between a first position for blocking the first valve port and a second position for blocking the second valve port, and the second valve element is used for driving the first valve element to move; the first elastic piece is connected to the first valve element and the second valve element and used for applying first pre-tightening force for blocking the first valve port to the first valve element. The screw is used for driving the second valve element to move in the axial direction of the electronic expansion valve. The second elastic piece is connected to the second valve element and the screw and used for applying second pre-tightening force for blocking the second valve port to the first valve element through the second valve element.

Description

Technical Field

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

[0002] An electronic expansion valve is a device used to control the refrigerant flow rate in a refrigeration cycle, and is commonly used in refrigeration and air conditioning systems. It is an expansion valve that adjusts the refrigerant flow rate through an electronic control method to ensure the normal operation and high efficiency of the refrigeration system.

[0003] In related technologies, an electronic expansion valve often has multiple valve ports, and the spool assembly can be switched between different valve ports to achieve the switching of different flow paths. However, the sealing performance between the spool assembly and the valve port in related technologies is poor, which may lead to fluid leakage in the electronic expansion valve. Summary of the Utility Model

[0004] Embodiments of the present application provide an electronic expansion valve to solve the problem of poor sealing performance between the spool assembly and the valve port in related technologies, which may lead to easy fluid leakage.

[0005] The electronic expansion valve according to the embodiments of the present application includes:

[0006] A valve seat assembly having a valve cavity, and the cavity wall of the valve cavity has a first valve port and a second valve port arranged at intervals along the axial direction of the electronic expansion valve;

[0007] A spool assembly, at least a part of which is disposed in the valve cavity, and includes a first spool, a second spool and a first elastic member. The first spool is movable between a first position blocking the first valve port and a second position blocking the second valve port. The second spool is used to drive the first spool to move; the first elastic member is connected between the first spool and the second spool; after the first spool is in the first position, the second spool can move relative to the first spool in a direction close to the first valve port, so that the compression amount of the first elastic member increases and is used to apply a first pre-tightening force for blocking the first valve port to the first spool;

[0008] A screw rod for driving the second spool to move along the axial direction of the electronic expansion valve; and

[0009] A second elastic member connected between the second spool and the screw rod. After the first spool is in the second position, the screw rod can move relative to the first spool in a direction away from the second valve port, so that the compression amount of the second elastic member increases and is used to apply a second pre-tightening force for blocking the second valve port to the first spool through the second spool.

[0010] According to some embodiments of the present application, the first valve core includes:

[0011] A valve needle for blocking the first valve port or the second valve port;

[0012] A first valve sleeve fixedly connected to the valve needle;

[0013] Wherein, the first valve sleeve is in limit connection with the second valve core so that the first valve core moves from the first position to the second position.

[0014] According to some embodiments of the present application, the part of the valve needle surrounded by the first valve sleeve has an end face;

[0015] A first stop portion is convexly provided on the inner peripheral surface of the first valve sleeve, and the first stop portion and the end face are arranged at an interval along the axial direction of the electronic expansion valve;

[0016] A flange is provided on the part of the second valve core extending into the first valve sleeve, and the flange moves between the first stop portion and the end face to compress the first elastic member; the flange pulls the first stop portion so that the first valve core moves from the first position to the second position.

[0017] According to some embodiments of the present application, the valve needle has a receiving groove which is recessed from the end face along the axial direction of the electronic expansion valve away from the second valve core;

[0018] The first elastic member is accommodated in the receiving groove, one end of the first elastic member abuts against the bottom surface of the receiving groove, and the other end abuts against the second valve core.

[0019] According to some embodiments of the present application, the valve needle and the first valve sleeve are in interference fit.

[0020] According to some embodiments of the present application, the outer periphery of the part of the valve needle surrounded by the first valve sleeve has a first fitting section and a second fitting section, the first fitting section and the second fitting section are arranged along the axial direction of the electronic expansion valve, and the first fitting section is closer to the second valve core than the second fitting section;

[0021] The first fitting section is in clearance fit with the inner peripheral surface of the first valve sleeve, and the second fitting section is in interference fit with the inner peripheral surface of the first valve sleeve.

[0022] According to some embodiments of the present application, the valve seat assembly includes a first valve seat and a second valve seat, the first valve seat and the second valve seat are fixedly connected and enclose at least part of the valve cavity;

[0023] The inner circumferential surface of one of the first valve seat and the second valve seat is in guiding cooperation with the outer circumferential surface of the first valve sleeve, and there is a first gap between the inner circumferential surface and the outer circumferential surface, and there is a second gap between the inner circumferential surface of the other and the outer circumferential surface of the first valve sleeve; the first gap is smaller than the second gap.

[0024] According to some embodiments of the present application, the second valve core includes:

[0025] A valve core seat, at least part of the valve core seat is arranged in the first valve core, and is used to pull the first valve core to move from the first position to the second position; and

[0026] A second valve sleeve, the second valve sleeve is fixedly connected to the valve core seat; one end of the second elastic member and the screw rod is arranged in the second valve sleeve.

[0027] According to some embodiments of the present application, the inner circumferential surface of the second valve sleeve has a second stop portion;

[0028] The screw rod includes a rod portion and a third stop portion, the third stop portion is connected to one end of the rod portion, and is located in the second valve sleeve and is movable between the second stop portion and the valve core seat;

[0029] One end of the second elastic member abuts against the second stop portion, and the other end abuts against the third stop portion.

[0030] According to some embodiments of the present application, the third stop portion includes:

[0031] A bearing, the inner ring of the bearing is sleeved on the outer circumference of the rod portion and is fixedly connected to the rod portion; and

[0032] A protection piece is arranged on the side of the bearing facing the second stop portion, and the other end of the second elastic member abuts against the protection piece.

[0033] According to some embodiments of the present application, a first inner sealing ring is further arranged between the valve core assembly and the cavity wall of the valve cavity, the first valve core is in movable sealing cooperation with the cavity wall of the valve cavity through the first inner sealing ring, and a first sealing ring is formed at the sealing position between the first valve core and the cavity wall of the valve cavity;

[0034] A second sealing ring is formed at the position where the first valve core seals with the first valve port, and a third sealing ring is formed at the position where the first valve core seals with the second valve port;

[0035] The diameter of the second sealing ring is larger than the diameter of the first sealing ring, and the diameter of the third sealing ring is larger than the diameter of the first sealing ring.

[0036] According to some embodiments of the present application, the valve seat assembly further includes a first opening, a second opening, and a third opening that communicate with the valve cavity; along the axial direction of the electronic expansion valve, the first opening, the second valve port, the second opening, the first valve port, and the third opening are arranged in sequence; the first opening and the second opening are respectively located on both sides of the first valve port, the second opening and the third opening are respectively located on both sides of the second valve port, and the second opening is located between the first valve port and the second valve port;

[0037] The first pre-tightening force F1 satisfies: (π×D2 2 ÷4 - π×D1 2 ÷4)×ΔP1 < F1;

[0038] Wherein, D2 is the diameter of the second sealing ring, D1 is the diameter of the first sealing ring, and ΔP1 is the fluid pressure difference between the third opening and the second opening when the electronic expansion valve is filled with fluid;

[0039] The second pre-tightening force F2 satisfies: (π×D3 2 ÷4 - π×D1 2 ÷4)×ΔP2 < F2;

[0040] Wherein, D3 is the diameter of the third sealing ring, D1 is the diameter of the first sealing ring, and ΔP2 is the fluid pressure difference between the first opening and the second opening when the electronic expansion valve is filled with fluid.

[0041] One embodiment of the above application has at least the following advantages or beneficial effects:

[0042] The electronic expansion valve of the embodiment of the present application includes a first elastic member and a second elastic member. The first elastic member can apply a first pre-tightening force to the first valve core to block the first valve port, and the second elastic member can apply a second pre-tightening force to the first valve core to block the second valve port. In this way, the sealing performance of the first valve core blocking the first valve port or the second valve port is significantly improved, preventing fluid leakage of the electronic expansion valve and improving the working reliability. In addition, in the electronic expansion valve of the embodiment of the present application, the screw drives the first valve core to move between the first position and the second position through the second valve core. Moreover, the first pre-tightening force provided by the first elastic member acts on the first valve core and the second valve core respectively, and the second pre-tightening force provided by the second elastic member acts on the screw and the second valve core respectively, so that the first pre-tightening force and the second pre-tightening force do not affect each other, ensuring that the first pre-tightening force and the second pre-tightening force are large enough, and further improving the sealing performance when the first valve core blocks the first valve port and the second valve port. Description of the Drawings

[0043] Figure 1 The figure shows a side view schematic diagram of the electronic expansion valve of the first embodiment of the present application.

[0044] Figure 2 Shown is a perspective schematic view of an electronic expansion valve according to the first embodiment of the present application.

[0045] Figure 3 Shown is along Figure 1 Cross-sectional view taken along the A-A cutting line of

[0046] Figure 4 Shown is a schematic view when the first valve core and the second valve core are not installed in place.

[0047] Figure 5 Shown is Figure 4 Exploded schematic view of

[0048] Figure 6 Shown is along Figure 4 Cross-sectional view taken along the B-B cutting line of

[0049] Figure 7 Shown is a cross-sectional view of an electronic expansion valve according to the second embodiment of the present application.

[0050] Figure 8 Shown is Figure 7 Perspective schematic view of the guiding portion in

[0051] Figure 9 Shown is a cross-sectional view of an electronic expansion valve according to the third embodiment of the present application.

[0052] Figure 10 Shown is Figure 9 Perspective schematic view of the second guiding rod in

[0053] Figure 11 Shown is a cross-sectional view of an electronic expansion valve according to the fourth embodiment of the present application.

[0054] Figure 12 Shown is Figure 11 Perspective schematic view of the second guiding rod in

[0055] Figure 13 Shown is a cross-sectional view of an electronic expansion valve according to the fifth embodiment of the present application.

[0056] Figure 14 Shown is a cross-sectional view of an electronic expansion valve according to the sixth embodiment of the present application.

[0057] Figure 15 Shown is a cross-sectional view of an electronic expansion valve according to the seventh embodiment of the present application. Detailed implementation manners

[0058] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. Like reference numerals in the figures denote like or similar structures, and thus their detailed description will be omitted.

[0059] It will be understood that the terms "comprising" and "having" and any variations thereof in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or components inherent to these processes, methods, products or devices.

[0060] As Figures 1 to 3 shown, the electronic expansion valve of the first embodiment of this application includes a valve seat assembly 100, a valve core assembly 200, a rotor assembly 810, an outer cover 820, a nut seat 830 and a screw 300.

[0061] The valve seat assembly 100 has a valve cavity 110. At least a part of the valve core assembly 200 is disposed in the valve cavity 110 and is axially movable relative to the valve seat assembly 100 along the electronic expansion valve. The outer cover 820 is fixedly connected to the valve seat assembly 100, for example, by welding, but not limited thereto. The rotor assembly 810 is movably disposed in the outer cover 820 and is used for coupling with a coil assembly (not shown in the figure) sleeved on the outer periphery of the outer cover 820. The nut seat 830 is fixedly connected to the valve seat assembly 100 and is disposed in the outer cover 820. The screw 300 is disposed in the outer cover 820, is connected to the rotor assembly 810, and is screwed with the nut seat 830.

[0062] When the electronic expansion valve works, by applying a pulse signal to the coil assembly, the rotor assembly 810 can be driven to drive the screw 300 to rotate. Since the nut seat 830 is fixed and screwed with the screw 300, the screw 300 can reciprocate axially along the electronic expansion valve, thereby driving the valve core assembly 200 to move in the valve cavity 110 relative to the valve seat assembly 100.

[0063] The valve seat assembly 100 may include a first valve seat 120, a second valve seat 130 and a third valve seat 150. Along the axial direction of the electronic expansion valve, the first valve seat 120, the second valve seat 130 and the third valve seat 150 are connected in sequence and jointly enclose the valve cavity 110.

[0064] The valve seat assembly 100 has a first opening 103, a second opening 104, and a third opening 105 that communicate with the valve cavity 110. The first opening 103, the second opening 104, and the third opening 105 are arranged in sequence along the axial direction of the electronic expansion valve. The wall of the valve cavity 110 has a valve port 110a. It can be understood that the number of valve ports 110a can be one or more. When the number of valve ports 110a is two, the two valve ports 110a are respectively defined as the first valve port 101 and the second valve port 102. Among them, the first valve port 101 is located between the second opening 104 and the third opening 105, and the second valve port 102 is located between the second opening 104 and the first opening 103.

[0065] In the embodiment of the present application, the second valve seat 130 has the first opening 103, the second opening 104, and the second valve port 102, and the third valve seat 150 has the third opening 105 and the first valve port 101, but it is not limited thereto.

[0066] As Figures 3 to 6 shown, the valve core assembly 200 includes a first valve core 210, a second valve core 220, and a first elastic member 230. The first valve core 210 is movable between a first position blocking the first valve port 101 and a second position blocking the second valve port 102. The second valve core 220 is used to drive the first valve core 210 to move; the first elastic member 230 is connected between the first valve core 210 and the second valve core 220; after the first valve core 210 is in the first position, the second valve core 220 can move relative to the first valve core 210 in a direction close to the first valve port 101, so that the compression amount of the first elastic member 230 increases and is used to apply a first pre-tightening force for blocking the first valve port 101 to the first valve core 210. The screw 300 is used to drive the second valve core 220 to move along the axial direction of the electronic expansion valve.

[0067] The electronic expansion valve further includes a second elastic member 500. The second elastic member 500 is connected between the second valve core 220 and the screw 300. After the first valve core 210 is in the second position, the screw can move relative to the first valve core 210 in a direction away from the second valve port 102, so that the compression amount of the second elastic member 500 increases and is used to apply a second pre-tightening force for blocking the second valve port 102 to the first valve core 210 through the second valve core 220.

[0068] The electronic expansion valve according to the embodiment of the present application includes a first elastic member 230 and a second elastic member 500. The first elastic member 230 can apply a first pre-tightening force to the first valve core 210 to block the first valve port 101, and the second elastic member 500 can apply a second pre-tightening force to the first valve core 210 to block the second valve port 102. In this way, the sealing performance of the first valve core 210 for blocking the first valve port 101 or the second valve port 102 is significantly improved, preventing fluid leakage of the electronic expansion valve and improving the working reliability. In addition, in the electronic expansion valve according to the embodiment of the present application, the screw 300 drives the first valve core 210 to move between a first position and a second position through the second valve core 220. Moreover, the first pre-tightening force provided by the first elastic member 230 acts on the first valve core 210 and the second valve core 220 respectively, and the second pre-tightening force provided by the second elastic member 500 acts on the screw 300 and the second valve core 220 respectively, so that the first pre-tightening force and the second pre-tightening force do not affect each other, ensuring that the first pre-tightening force and the second pre-tightening force are large enough, and further improving the sealing performance of the first valve core 210 when blocking the first valve port 101 and the second valve port 102.

[0069] In one embodiment, the first elastic member 230 and the second elastic member 500 can be compression springs, but not limited thereto. For example, the first elastic member 230 and the second elastic member 500 can also be rubber parts or other components that can provide elastic force when compressed.

[0070] As Figure 3 、 Figure 5 and Figure 6 shown, the first valve core 210 includes a first component and a second component, and the first component and the second component are connected with interference fit. In the embodiment of the present application, the first component is a valve needle 211, and the second component is a first valve sleeve 212. The valve needle 211 is used to block the first valve port 101 or the second valve port 102. At least a part of the first valve sleeve 212 is sleeved on the outer periphery of the valve needle 211 and is fixedly connected with the valve needle 211; wherein, the first valve sleeve 212 is connected with the second valve core 220 in a limiting manner so that the first valve core 210 moves from the first position to the second position.

[0071] One end face 2111 is provided on the part of the valve needle 211 surrounded by the first valve sleeve 212. A first stop portion 2121 is convexly provided on the inner peripheral surface of the first valve sleeve 212, and the first stop portion 2121 and the end face 2111 are arranged at intervals along the axial direction of the electronic expansion valve. A flange 2211 is provided on the part of the second valve core 220 extending into the first valve sleeve 212, and the flange 2211 can move between the first stop portion 2121 and the end face 2111 to compress the first elastic member 230; the flange 2211 can also pull the first stop portion 2121 so that the first valve core 210 moves from the first position to the second position.

[0072] The second valve core 220 includes a valve core seat 221 and a second valve sleeve 222. One axial end of the second valve sleeve 222 is fixedly connected to the valve core seat 221, such as by welding, screwing, interference fit, etc. At least part of the valve core seat 221 is disposed inside the first valve core 210 and is used to pull the first valve core 210 to move from the first position to the second position, or to compress the first elastic member 230. One end of the second elastic member 500 and the screw 300 are disposed inside the second valve sleeve 222. Wherein, the valve core seat 221 has a flange 2211, and the flange 2211 can move between the first stop portion 2121 and the end face 2111. When the flange 2211 moves towards the direction close to the first valve port 101, it can compress the first elastic member 230. When the flange 2211 moves away from the first valve port 101, it can pull the first stop portion 2121 to make the first valve core 210 move from the first position to the second position.

[0073] The inner peripheral surface of the second valve sleeve 222 has a second stop portion 2221. The screw 300 includes a rod portion 310 and a third stop portion 320. The rod portion 310 is screwed to the nut seat 830. The third stop portion 320 is connected to one end of the rod portion 310, is located inside the second valve sleeve 222, and is movable between the second stop portion 2221 and the valve core seat 221; one end of the second elastic member 500 abuts against the second stop portion 2221, and the other end abuts against the third stop portion 320.

[0074] As Figure 3 and Figure 6 shown, the third stop portion 320 includes a bearing 321 and a protective sheet 322. The inner ring of the bearing 321 is sleeved on the outer periphery of the rod portion 310 and is fixedly connected to the rod portion 310; the protective sheet 322 is disposed on the side of the bearing 321 facing the second stop portion 2221, and the other end of the second elastic member 500 abuts against the protective sheet 322.

[0075] In the embodiment of the present application, the protective sheet 322 can play a role in protecting the bearing 321 and prevent the second elastic member 500 from directly abutting on the bearing 321 and causing deformation of the bearing 321.

[0076] The valve needle 211 has a receiving groove 2112, and the receiving groove 2112 is recessed from the end face 2111 along the axial direction of the electronic expansion valve towards the direction away from the second valve core 220; the first elastic member 230 is accommodated in the receiving groove 2112, one end of the first elastic member 230 abuts against the groove bottom surface of the receiving groove 2112, and the other end abuts against the second valve core 220.

[0077] In the embodiment of the present application, the receiving groove 2112 can play a role in limiting the first elastic member 230 and prevent the elastic preloading force provided by the first elastic member 230 from being affected due to the change in the position of the first elastic member 230.

[0078] In one embodiment, the valve needle 211 is in interference fit with the first valve sleeve 212. For example, the portion of the valve needle 211 surrounded by the first valve sleeve 212 has a first fitting section 2113 and a second fitting section 2114. The first fitting section 2113 and the second fitting section 2114 are arranged along the axial direction of the electronic expansion valve, and the first fitting section 2113 is closer to the second valve core 220 than the second fitting section 2114. The first fitting section 2113 is in clearance fit with the inner peripheral surface of the first valve sleeve 212, and the second fitting section 2114 is in interference fit with the inner peripheral surface of the first valve sleeve 212.

[0079] Of course, in other embodiments, the valve needle 211 and the first valve sleeve 212 can also be connected by welding, screwing or other means.

[0080] The following will Figure 3 describe in detail the movement process of the valve core assembly 200, and how the first elastic member 230 and the second elastic member 500 provide elastic pre-tightening force.

[0081] The process of the first valve core 210 blocking the first valve port 101: The rotor assembly 810 drives the screw 300 to rotate. Under the thread fit of the screw 300 and the nut seat 830, the screw 300 moves downward as a whole. During the downward movement of the screw 300, the bearing 321 of the screw 300 presses against the valve core seat 221, causing the valve needle 211 to move in the direction of blocking the first valve port 101. When the valve needle 211 blocks the first valve port 101 (the first position), the valve needle 211 stops moving, and at this time the valve core seat 221 continues to move downward. The first elastic member 230 is compressed by the valve core seat 221 and the compression amount increases to provide the first pre-tightening force. Under the action of the first pre-tightening force, the valve needle 211 can tightly block the first valve port 101, improving the sealing performance of the valve needle 211 blocking the first valve port 101.

[0082] The process of the first valve core 210 blocking the second valve port 102: The rotor assembly 810 drives the screw 300 to rotate in the reverse direction. Under the screw-thread fit between the screw 300 and the nut seat 830, the screw 300 drives the second valve core 220 to move upward through the second elastic member 500. During the upward movement of the second valve core 220, the flange 2211 contacts the first stop portion 2121 of the first valve sleeve 212. Then, the second valve core 220 can drive the first valve core 210 to move to the second position. When the first valve core 210 moves to the second position, the first valve core 210 cannot continue to move upward. Under the action of the first stop portion 2121 blocking the flange 2211, the second valve core 220 also cannot continue to move upward. At this time, the screw 300 can continue to move upward under the drive of the rotor assembly 810. During the continuous movement of the screw 300, the third stop portion 320 of the screw 300 presses the second elastic member 500, causing the compression amount of the second elastic member 500 to increase and generating a second pre-tightening force. The second pre-tightening force can continuously abut against the second stop portion 2221 of the second valve sleeve 222, so that the second valve core 220 continuously provides an upward pulling force for the first valve core 210 to maintain the state of the first valve core 210 blocking the second valve port 102. It can be seen that under the action of the second pre-tightening force, the valve needle 211 can tightly block the second valve port 102, improving the sealing performance of the valve needle 211 blocking the second valve port 102.

[0083] As Figure 3 shown, there is a movable gap between the end face 2111 of the valve core seat 221 and the valve needle 211 along the axial direction of the electronic expansion valve. This movable gap is used to adjust the opening valve pulse number of the electronic expansion valve. Specifically, by setting the size of this movable gap, the opening valve pulse number of the device can be adjusted according to the actual situation.

[0084] As Figure 3 shown, a first inner sealing ring 140 is further provided between the valve core assembly 200 and the cavity wall of the valve cavity 110. The first valve sleeve 212 of the first valve core 210 is movably and sealingly fitted with the cavity wall of the valve cavity 110 through the first inner sealing ring 140, and a first sealing ring is formed at the sealing position between the first valve core 210 and the cavity wall of the valve cavity 110. The first valve core 210 has a second inner sealing ring 213. A second sealing ring is formed at the sealing position between the second inner sealing ring 213 and the first valve port 101, and a third sealing ring is formed at the sealing position between the second inner sealing ring 213 and the second valve port 102. The diameter D2 of the second sealing ring is greater than the diameter D1 of the first sealing ring, and the diameter D3 of the third sealing ring is greater than the diameter D1 of the first sealing ring.

[0085] It can be understood that by designing the diameter D2 of the second sealing ring to be greater than the diameter D1 of the first sealing ring and the diameter D3 of the third sealing ring to be greater than the diameter D1 of the first sealing ring, it is convenient to install the valve core assembly 200 into the valve cavity 110 from the bottom of the valve seat assembly 100.

[0086] However, such a design causes the electronic expansion valve as a whole to no longer maintain internal balance, that is, the valve core assembly 200 is no longer balanced under the action of the fluid.

[0087] For this reason, in the electronic expansion valve according to the embodiment of the present application, the relationship between the first pre-tightening force F1 and D2, D1 satisfies the following inequality (π×D2 2 ÷4 - π×D1 2 ÷4)×ΔP1 < F1; where D2 is the diameter of the second sealing ring, D1 is the diameter of the first sealing ring, and ΔP1 is the fluid pressure difference between the third opening 105 and the second opening 104 when the electronic expansion valve is filled with fluid.

[0088] The second pre-tightening force F2 and D3, D1 satisfy the following inequality: (π×D3 2 ÷4 - π×D1 2 ÷4)×ΔP2 < F2; where D3 is the diameter of the third sealing ring, D1 is the diameter of the first sealing ring, and ΔP2 is the fluid pressure difference between the first opening 103 and the second opening 104 when the electronic expansion valve is filled with fluid.

[0089] In the embodiment of the present application, F1, D1 and D2 satisfy (π×D2 2 ÷4 - π×D1 2 ÷4)×ΔP1 < F1, which can prevent fluid leakage caused by the valve needle 211 being pushed open by the reverse acting force of the fluid; similarly, F2, D1 and D3 satisfy (π×D3 2 ÷4 - π×D1 2 ÷4)×ΔP2 < F2, which can prevent fluid leakage caused by the valve needle 211 being pushed open by the reverse acting force of the fluid.

[0090] Specifically, it is set that the second opening 104 of the valve seat assembly 100 is the fluid inlet, and the first opening 103 and the third opening 105 are the fluid outlets. When the valve needle 211 blocks the first valve port 101, the fluid enters from the second opening 104 and flows out from the first opening 103. At this time, the upper space of the second inner sealing ring 213 (i.e., the chamber corresponding to the second opening 104 and the first opening 103) is the high-pressure chamber, and the lower space of the second inner sealing ring 213 (i.e., the chamber corresponding to the third opening 105) is the low-pressure chamber. Under normal circumstances, the fluid enters from the second opening 104 and flows out from the first opening 103. At this time, the valve needle 211 is subjected to a downward fluid pressure, and the valve needle 211 will not be pushed open by the fluid. However, in abnormal circumstances, if the fluid suddenly enters from the third opening 105, the pressure formed by the fluid is (π×D2 2 ÷4 - π×D1 2 ÷4)×ΔP1, and the direction of the pressure is upward.

[0091] It can be seen that the first pre-tightening force F1 provided by the first elastic member 230 in the embodiment of the present application is greater than (π×D2 2 ÷4 - π×D1 2 ÷4)×ΔP1, which can effectively prevent the fluid pressure from pushing open the valve needle 211 and ensure the sealing performance of the valve needle 211 blocking the first valve port 101.

[0092] Similarly, when the valve needle 211 blocks the second valve port 102, the fluid enters from the second opening 104 and flows out from the third opening 105. At this time, the upper space of the second inner sealing ring 213 (i.e., the chamber corresponding to the first opening 103) is a low-pressure chamber, and the lower space of the second inner sealing ring 213 (i.e., the chambers corresponding to the second opening 104 and the third opening 105) is a high-pressure chamber. Under normal circumstances, the fluid enters from the second opening 104 and flows out from the third opening 105. At this time, the valve needle 211 is subjected to an upward fluid pressure, and the valve needle 211 will not be pushed open by the fluid. However, in abnormal circumstances, if the fluid suddenly enters from the first opening 103, the pressure formed by the fluid is (π×D3 2 ÷4 - π×D1 2 ÷4)×ΔP2, and the direction of the pressure is downward.

[0093] It can be seen that the second pre-tightening force F2 provided by the second elastic member 500 in the embodiment of the present application is greater than (π×D3 2 ÷4 - π×D1 2 ÷4)×ΔP2, which can effectively prevent the fluid pressure from pushing open the valve needle 211 and ensure the sealing performance of the valve needle 211 blocking the second valve port 102.

[0094] As Figure 3 shown, the first inner sealing ring 140 includes an outer sealing ring 141 and an inner sealing ring 142. The inner sealing ring 142 is sleeved on the outer periphery of the first valve sleeve 212. The outer sealing ring 141 surrounds the outer periphery of the inner sealing ring 142 and applies an elastic pre-tightening force towards the first valve sleeve 212 to the inner sealing ring 142. The combined sealing structure of the outer sealing ring 141 and the inner sealing ring 142 can improve the high-pressure resistance and wear resistance of the dynamic seal.

[0095] In one embodiment, the material of the inner sealing ring 142 can be polytetrafluoroethylene, but not limited thereto.

[0096] It can be understood that the diameter D1 of the first sealing ring is the outer diameter dimension of the first valve sleeve 212. The diameter D2 of the second sealing ring is the diameter of the circle formed by the tangent points between the R corner at the edge of the first valve port 101 and the lower inclined surface of the second inner sealing ring 213. The diameter D3 of the third sealing ring is the diameter of the circle formed by the tangent points between the R corner at the edge of the second valve port 102 and the upper inclined surface of the second inner sealing ring 213.

[0097] Further, in order to reduce the difference between D2 and D1, as well as the difference between D3 and D1, so that the electronic expansion valve can be as close as possible to the internal balance, it can be achieved by reducing the R angle at the edge of the first valve port 101, increasing the taper of the lower inclined surface of the second inner sealing ring 213, reducing the R angle at the edge of the second valve port 102, and increasing the taper of the upper inclined surface of the second inner sealing ring 213.

[0098] In an embodiment, the second inner sealing ring 213 is made of a flexible sealing material, such as rubber, polymer, plastic, etc. In this way, the sealing performance of the second inner sealing ring 213 when blocking the first valve port 101 or the second valve port 102 can be improved, and leakage can be prevented.

[0099] When the first valve port 101 is closed, at least part of the lower inclined surface of the second inner sealing ring 213 is located inside the first valve port 101, which can ensure that when the valve core assembly 200 is skewed, the valve core assembly 200 can be corrected through the lower inclined surface of the second inner sealing ring 213. When the second valve port 102 is closed, at least part of the upper inclined surface of the second inner sealing ring 213 is located inside the second valve port 102, which can ensure that when the valve core assembly 200 is skewed, the valve core assembly 200 can be corrected through the upper inclined surface of the second inner sealing ring 213.

[0100] As Figure 3 shown, the inner peripheral surface of one of the first valve seat 120 and the second valve seat 130 is in guiding fit with the outer peripheral surface of the first valve sleeve 212, and there is a first gap between the inner peripheral surface and the outer peripheral surface; there is a second gap between the inner peripheral surface of the other and the outer peripheral surface of the first valve sleeve 212; the first gap is smaller than the second gap.

[0101] For example, the inner peripheral surface of the first valve seat 120 is in clearance fit with the outer peripheral surface of the first valve sleeve 212, and there is a second gap between the inner peripheral surface and the outer peripheral surface; the inner peripheral surface of the second valve seat 130 is in guiding fit with the outer peripheral surface of the first valve sleeve 212, and there is a first gap between the inner peripheral surface and the outer peripheral surface.

[0102] Of course, in other embodiments, it can also be that: the inner peripheral surface of the first valve seat 120 is in guiding fit with the outer peripheral surface of the first valve sleeve 212, and the inner peripheral surface of the second valve seat 130 is in clearance fit with the outer peripheral surface of the first valve sleeve 212.

[0103] It can be seen that only one valve seat in the valve seat assembly 100 has a small-gap guiding fit between its inner peripheral surface and the outer peripheral surface of the first valve sleeve 212, and the remaining valve seats maintain a large clearance fit. In this way, it can be avoided that the valve core assembly 200 gets stuck during movement due to the inner peripheral surfaces of the valve seat assembly 100 being all designed as guiding fits.

[0104] As Figure 6As shown, one of the valve needle 211 and the first valve sleeve 212 has a connection hole 212a, and the other has a connection shaft 211a for inserting into the connection hole 212a. At least a part of the first elastic member 230 is located in the connection hole 212a and can be abutted by the connection shaft 211a. When the axial dimension of the connection shaft 211a inserted into the connection hole 212a is less than or equal to the first target value, the first elastic member 230 is in its original length state.

[0105] When assembling the valve core assembly 200 according to the embodiment of the present application, first insert the second valve core 220 and the screw 300 into the first valve sleeve 212, then install the first elastic member 230 into the first valve sleeve 212, and finally connect the valve needle 211 and the first valve sleeve 212 to enclose the first elastic member 230 in the first valve sleeve 212. When connecting the valve needle 211 and the first valve sleeve 212, first insert the connection shaft 211a into the connection hole 212a. When the axial dimension of the part of the connection shaft 211a inserted into the connection hole 212a is less than or equal to the first target value, the first elastic member 230 is in its original length state. On the one hand, the inner wall surface of the connection hole 212a can play a guiding role to guide the connection shaft 211a to insert into the connection hole 212a; on the other hand, since the first elastic member 230 is in its original length state when the axial dimension of the connection shaft 211a inserted into the connection hole 212a is less than or equal to the first target value, at this time the first elastic member 230 does not generate elastic force, that is to say, in the initial stage of inserting the connection shaft 211a into the connection hole 212a, the connection shaft 211a will not be subjected to the reaction force provided by the first elastic force, improving the smoothness of inserting the connection shaft 211a into the connection hole 212a, and thus improving the assembly efficiency.

[0106] In one embodiment, the first target value is greater than or equal to 0.5 mm, but not limited thereto.

[0107] When the connection shaft 211a and the connection hole 212a are in interference fit, one end of the first elastic member 230 abuts against the second valve core 220, and the other end abuts against the connection shaft 211a.

[0108] In one embodiment, the valve needle 211 has a connection shaft 211a, and the first valve sleeve 212 has a connection hole 212a. Of course, in other embodiments, the valve needle 211 has a connection hole 212a, and the first valve sleeve 212 has a connection shaft 211a.

[0109] Next, an example will be given with the valve needle 211 having a connection shaft 211a and the first valve sleeve 212 having a connection hole 212a.

[0110] As Figure 6 shown, one of the outer peripheral surface of the connection shaft 211a and the inner wall surface of the connection hole 212a has a stepped surface, and the other has a surface that is in clearance fit or interference fit with the stepped surface.

[0111] In one embodiment, the connecting shaft 211a has a first mating section 2113 and a second mating section 2114. The first mating section 2113 and the second mating section 2114 are arranged along the axial direction of the connecting shaft 211a and form a stepped surface. The first mating section 2113 is used for clearance fit with the inner wall surface of the connecting hole 212a, and the second mating section 2114 is used for interference fit with the inner wall surface of the connecting hole 212a.

[0112] Wherein, when the axial dimension of the connecting shaft 211a inserted into the connecting hole 212a is less than or equal to a first target value, at least a part of the first mating section 2113 is located in the connecting hole 212a, and the first mating section 2113 has a clearance fit with the inner wall of the connecting hole 212a. When the axial dimension of the connecting shaft 211a inserted into the connecting hole 212a is greater than the first target value, the entire first mating section 2113 is located in the connecting hole 212a, the first mating section 2113 has a clearance fit with the inner wall of the connecting hole 212a, at least a part of the second mating section 2114 is located in the connecting hole 212a, and the second mating section 2114 has an interference fit with the inner wall of the connecting hole 212a.

[0113] In another embodiment, the inner wall surface of the connecting hole 212a has a stepped surface, and the outer peripheral surface of the connecting shaft 211a has a surface that first has a clearance fit and then an interference fit with the stepped surface.

[0114] As Figure 6 shown, the valve needle 211 further has a fourth stop portion 2115, which is used to stop the other one of the first component and the second component when the connecting shaft 211a and the connecting hole 212a are in interference fit and the axial dimension of the part of the connecting shaft 211a inserted into the connecting hole 212a reaches a second target value; wherein, the second target value is greater than the first target value. By providing the fourth stop portion 2115 on the valve needle 211, it is possible to prevent the dimension of the connecting shaft 211a inserted into the connecting hole 212a from being too long during the assembly of the valve needle 211 and the first valve sleeve 212, resulting in inconvenient disassembly.

[0115] Of course, in other embodiments, when the valve needle 211 has a connecting hole 212a and the first valve sleeve 212 has a connecting shaft 211a, the fourth stop portion 2115 can be provided on the first valve sleeve 212.

[0116] In one embodiment, the fourth stop portion 2115 is an annular protrusion that surrounds the outer peripheral surface of the connecting shaft 211a and is used to abut against the periphery of the connecting hole 212a.

[0117] In other embodiments, the fourth stop portion 2115 may include a plurality of sub-protrusions and is arranged circumferentially along the connecting shaft 211a.

[0118] As Figure 2 and Figure 3As shown, the top of the valve cavity 110 has a back pressure cavity 111, and the valve core assembly 200 has a first balance channel 201 communicating with the back pressure cavity 111 and the valve port 110a. The electronic expansion valve according to the embodiment of the present application further includes a guiding structure 600 for guiding the movement of the valve core assembly 200 relative to the valve seat assembly 100; the guiding structure 600 has a second balance channel 601 communicating with the first balance channel 201 and the valve port 110a.

[0119] In the embodiment of the present application, the electronic expansion valve includes a guiding structure 600 for guiding the movement of the valve core assembly 200. The guiding structure 600 can effectively avoid the problem that the valve core assembly 200 is prone to tilt and cannot be aligned with the valve port after being affected by the fluid impact force. In addition, the valve core assembly 200 has a first balance channel 201 communicating with the back pressure cavity 111 and the valve port 110a, and the guiding structure 600 has a second balance channel 601 communicating with the first balance channel 201 and the valve port 110a, so that the electronic expansion valve is an internal balance valve as a whole, improving the ability to open and close the valve.

[0120] Wherein, in the embodiment of the present application, the valve needle 211 and the valve core seat 221 of the valve core assembly 200 have mutually communicating channels, and the valve core seat 221 has an opening communicating with the channel of the valve core seat 221. Each channel and opening together constitute the first balance channel 201.

[0121] Such as Figure 2 and Figure 3 As shown, the guiding structure 600 includes a connecting portion 610 and a guiding portion 620. The connecting portion 610 is connected to the cavity wall of the valve cavity 110 and has a second balance channel 601; the guiding portion 620 is connected to one of the connecting portion 610 and the valve core assembly 200 and is in guiding cooperation with the other. In one embodiment, the connecting portion 610 has a plurality of second balance channels 601, and the plurality of second balance channels 601 are arranged along the circumferential direction of the guiding portion 620.

[0122] The guiding portion 620 is a guiding hole 621, and the guiding hole 621 axially penetrates the connecting portion 610 along the electronic expansion valve; the valve needle 211 of the valve seat assembly 100 is inserted into the guiding hole 621, and the outer peripheral surface of the valve needle 211 of the valve seat assembly 100 is in guiding cooperation with the hole wall of the guiding hole 621.

[0123] Such as Figure 7 and Figure 8 As shown, the same parts of the second embodiment of the present application and the first embodiment will not be described in detail. The differences are as follows:

[0124] The guiding part 620 includes a first guiding rod 622 and a guiding column 623. One end of the first guiding rod 622 is connected to the connecting part 610, and the other end is connected to the guiding column 623. The guiding column 623 extends into the first balance channel 201, and the outer peripheral surface of the guiding column 623 is in guiding cooperation with the inner wall surface of the first balance channel 201.

[0125] The outer periphery of the guiding column 623 has a first cutting surface 623a. The first cutting surface 623a penetrates through two first end surfaces 623b of the guiding column 623. The first cutting surface 623a and the inner wall surface of the first balance channel 201 enclose a third balance channel 602, and the first balance channel 201 is communicated with the valve port through the third balance channel 602.

[0126] In another embodiment, the guiding part 620 includes a first guiding rod 622 and a guiding column 623. One end of the guiding column 623 extends into the first balance channel 201 and is connected to the valve core assembly 200, and the other end is connected to the first guiding rod 622. The connecting part 610 also has a guiding hole 621 axially penetrating therethrough, and the outer peripheral surface of the first guiding rod 622 is in guiding cooperation with the hole wall of the guiding hole 621.

[0127] As Figure 9 and Figure 10 shown, the same parts of the third embodiment and the first embodiment of the present application will not be described in detail. The differences are as follows:

[0128] The guiding part 620 includes a second guiding rod 624. One end is connected to the connecting part 610, and the other end extends into the first balance channel 201. The outer peripheral surface of the second guiding rod 624 is in guiding cooperation with the inner wall surface of the first balance channel 201.

[0129] The outer periphery of the second guiding rod 624 has a second cutting surface 624a. One end of the second cutting surface 624a extends to the second end surface 624b of the second guiding rod 624 located in the first balance channel 201. The second cutting surface 624a and the inner wall surface of the first balance channel 201 enclose a fourth balance channel 603, and the first balance channel 201 is communicated with the valve port through the fourth balance channel 603.

[0130] In one embodiment, the number of the second cutting surfaces 624a is multiple, and the multiple second cutting surfaces 624a are arranged along the circumferential direction of the second guiding rod 624. Of course, in other embodiments, the number of the second cutting surfaces 624a can also be one.

[0131] In another embodiment, the guiding part 620 includes a second guiding rod 624, and the connecting part 610 also has a guiding hole 621 axially penetrating therethrough. One end of the second guiding rod 624 extends into the first balance channel 201 and is connected to the valve core assembly 200, and the other end is in guiding cooperation with the hole wall of the guiding hole 621.

[0132] AsFigure 11 and Figure 12 As shown, the same parts of the fourth embodiment of the present application and the first embodiment will not be described in detail. The differences are as follows:

[0133] The second guide rod 624 has a fifth balance channel 604 inside, and the fifth balance channel 604 penetrates through the two second end faces 624b of the second guide rod 624; the first balance channel 201 is communicated with the second balance channel 601 through the fifth balance channel 604.

[0134] As Figure 13 shown, the same parts of the fifth embodiment of the present application and the fourth embodiment will not be described in detail. The differences are as follows:

[0135] The electronic expansion valve of the embodiment of the present application further includes a mounting seat 700. The mounting seat 700 has a mounting cavity 704, and at least part of the valve seat assembly 100 is inserted into the mounting cavity 704.

[0136] The mounting seat 700 further has an inlet 701, a first outlet 702 and a second outlet 703 communicated with the mounting cavity 704. The inlet 701 is communicated with the second opening 104 of the valve seat assembly 100, the first outlet 702 is communicated with the first opening 103 of the valve seat assembly 100, and the second outlet 703 is communicated with the third opening 105 of the valve seat assembly 100. Among them, the third opening 105 is opened at the bottom of the third valve seat 150.

[0137] As Figure 14 shown, the same parts of the sixth embodiment of the present application and the fifth embodiment will not be described in detail. The differences are as follows:

[0138] The length of the third valve seat 150 of the embodiment of the present application along the axial direction of the electronic expansion valve is greater than the axial length of the third valve seat 150 of the fifth embodiment, and the third opening 105 is opened at the side of the third valve seat 150.

[0139] As Figure 15 shown, the same parts of the seventh embodiment of the present application and the fifth embodiment will not be described in detail. The differences are as follows:

[0140] The electronic expansion valve does not have a guide structure 600.

[0141] It can be understood that the electronic expansion valve of the first to fourth embodiments of the present application may not be provided with a mounting seat 700, but the first opening 103, the second opening 104 and the third opening 105 are directly connected to the external connecting pipe.

[0142] In summary, the electronic expansion valve of the embodiment of the present application has at least the following advantages and beneficial effects:

[0143] The electronic expansion valve according to the embodiment of the present application includes a first elastic member 230 and a second elastic member 500. The first elastic member 230 can apply a first pre-tightening force to the first valve core 210 to block the first valve port 101, and the second elastic member 500 can apply a second pre-tightening force to the first valve core 210 to block the second valve port 102. In this way, the sealing performance of the first valve core 210 for blocking the first valve port 101 or the second valve port 102 is significantly improved, preventing fluid leakage of the electronic expansion valve and improving the working reliability. In addition, in the electronic expansion valve according to the embodiment of the present application, the screw 300 drives the first valve core 210 to move between a first position and a second position through the second valve core 220. Moreover, the first pre-tightening force provided by the first elastic member 230 acts on the first valve core 210 and the second valve core 220 respectively, and the second pre-tightening force provided by the second elastic member 500 acts on the screw 300 and the second valve core 220 respectively, so that the first pre-tightening force and the second pre-tightening force do not affect each other, ensuring that the first pre-tightening force and the second pre-tightening force are large enough, and further improving the sealing performance when the first valve core 210 blocks the first valve port 101 and the second valve port 102.

[0144] In the clearance fit state, when the axial dimension of the part of the connecting shaft 211a inserted into the connecting hole 212a is less than or equal to the first target value, the first elastic member 230 is in the original length state. On the one hand, the connecting shaft 211a and the connecting hole 212a are in the clearance fit state, and the inner wall surface of the connecting hole 212a can play a guiding role to guide the connecting shaft 211a to insert into the connecting hole 212a. On the other hand, since the first elastic member 230 is in the original length state when the axial dimension of the part of the connecting shaft 211a inserted into the connecting hole 212a is less than or equal to the first target value, the first elastic member 230 does not generate an elastic force at this time. That is to say, in the initial stage when the connecting shaft 211a is inserted into the connecting hole 212a, the connecting shaft 211a will not be subjected to the reaction force provided by the first elastic force, improving the smoothness of the connecting shaft 211a being inserted into the connecting hole 212a, and thus improving the assembly efficiency.

[0145] The electronic expansion valve according to the embodiment of the present application includes a guiding structure 600 for guiding the movement of the valve core assembly 200. The guiding structure 600 can effectively avoid the problem that the valve core assembly 200 is prone to tilt and cannot align with the valve port after being subjected to the fluid impact force. In addition, the valve core assembly 200 has a first balance channel 201 communicating with the back pressure chamber 111 and the valve port 110a, and the guiding structure 600 has a second balance channel 601 communicating with the first balance channel 201 and the valve port 110a, making the electronic expansion valve an internal balance valve as a whole and improving the ability to open and close the valve.

[0146] It can be understood that the various embodiments / implementation manners provided in the present application can be combined with each other without conflict, and no further examples will be given here.

[0147] In the application embodiments, the terms "first", "second", and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "plural" means two or more, unless otherwise clearly defined. Terms such as "installed", "connected", "joined", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "joined" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the application embodiments can be understood according to specific circumstances.

[0148] In the description of the application embodiments, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the application embodiments and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the application embodiments.

[0149] In the description of this specification, the description of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the application embodiments. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0150] The above are only the preferred embodiments of the application embodiments and are not used to limit the application embodiments. For those skilled in the art, the application embodiments can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application embodiments shall be included in the protection scope of the application embodiments.

Claims

1. An electronic expansion valve, characterized in that: include: A valve seat assembly, comprising a valve cavity, a cavity wall of the valve cavity comprising a first valve port and a second valve port spaced apart along the axial direction of the electronic expansion valve; A valve core assembly, wherein at least a portion of the valve core assembly is disposed in the valve cavity, and comprises a first valve core, a second valve core and a first elastic member, wherein the first valve core is movable between a first position for blocking the first valve port and a second position for blocking the second valve port, and the second valve core is used to drive the first valve core to move; the first elastic member is connected to the first valve core and the second valve core; after the first valve core is located at the first position, the second valve core can move relative to the first valve core in a direction close to the first valve port, so that the compression amount of the first elastic member is increased and used to apply a first pre-tightening force to the first valve core to block the first valve port; A screw, used for driving the second valve core to move along the axial direction of the electronic expansion valve; as well as A second elastic member is connected to the second valve core and the screw. After the first valve core is located at the second position, the screw can move relative to the first valve core in a direction away from the second valve port, so that the compression of the second elastic member is increased and is used to apply a second pre-tightening force to the first valve core through the second valve core to block the second valve port.

2. The electronic expansion valve according to claim 1, characterized in that: The first valve core comprises: a valve needle, used for blocking the first valve port or the second valve port; A first valve sleeve, fixedly connected to the valve needle; Wherein, the first valve sleeve is limitedly connected to the second valve core so that the first valve core moves from the first position to the second position.

3. The electronic expansion valve according to claim 2, characterized in that: The portion of the valve needle surrounded by the first valve sleeve has an end surface; A first stopper is convexly provided on the inner circumferential surface of the first valve sleeve, and the first stopper and the end surface are spaced apart from each other along the axial direction of the electronic expansion valve; The portion of the second valve core extending into the first valve sleeve is provided with a flange, and the flange moves between the first stopper and the end surface to compress the first elastic member; the flange pulls the first stopper to move the first valve core from the first position to the second position.

4. The electronic expansion valve according to claim 3, characterized in that: The valve needle has a receiving groove, and the receiving groove is recessed from the end surface along the axial direction of the electronic expansion valve in a direction away from the second valve core; The first elastic member is accommodated in the accommodating groove, one end of the first elastic member abuts against the groove bottom surface of the accommodating groove, and the other end of the first elastic member abuts against the second valve core.

5. The electronic expansion valve according to claim 2, characterized in that: The valve needle is interference fit with the first valve sleeve.

6. The electronic expansion valve according to claim 5, characterized in that: The portion of the valve needle surrounded by the first valve sleeve comprises a first matching section and a second matching section, the first matching section and the second matching section are arranged along the axial direction of the electronic expansion valve, and the first matching section is closer to the second valve core than the second matching section; The first matching section is clearance-matched with the inner circumferential surface of the first valve sleeve, and the second matching section is interference-matched with the inner circumferential surface of the first valve sleeve.

7. The electronic expansion valve according to claim 2, characterized in that: The valve seat assembly comprises a first valve seat and a second valve seat, wherein the first valve seat and the second valve seat are fixedly connected and enclose at least a portion of the valve cavity; The inner circumference of one of the first valve seat and the second valve seat is guided and matched with the outer circumference of the first valve sleeve, and a first gap is provided between the inner circumference and the outer circumference, and a second gap is provided between the inner circumference of the other valve seat and the outer circumference of the first valve sleeve; the first gap is smaller than the second gap.

8. The electronic expansion valve according to any one of claims 1 to 7, characterized in that: The second valve core comprises: a valve core seat, at least a portion of which is disposed in the first valve core and is used to pull the first valve core to move from the first position to the second position; and A second valve sleeve, wherein the second valve sleeve is fixedly connected to the valve core seat; the second elastic member and one end of the screw rod are arranged in the second valve sleeve.

9. The electronic expansion valve according to claim 8, characterized in that: The inner circumferential surface of the second valve sleeve has a second stopper; The screw comprises a rod portion and a third stop portion, wherein the third stop portion is connected to one end of the rod portion, is located in the second valve sleeve, and is movable between the second stop portion and the valve core seat; One end of the second elastic member abuts against the second stop portion, and the other end abuts against the third stop portion.

10. The electronic expansion valve according to claim 9, characterized in that: The third stopper comprises: A bearing, wherein an inner ring of the bearing is sleeved on the outer periphery of the rod and fixedly connected to the rod; and A protection sheet is arranged on a side of the bearing facing the second stopper, and the other end of the second elastic member abuts against the protection sheet.

11. The electronic expansion valve according to claim 1, characterized in that: A first inner sealing ring is further provided between the valve core assembly and the cavity wall of the valve cavity, the first valve core is movably sealed with the cavity wall of the valve cavity through the first inner sealing ring, and a first sealing ring is formed at the sealing position between the first valve core and the cavity wall of the valve cavity; The position where the first valve core is sealed with the first valve port forms a second sealing ring, and the position where the first valve core is sealed with the second valve port forms a third sealing ring; The diameter of the second sealing ring is greater than that of the first sealing ring, and the diameter of the third sealing ring is greater than that of the first sealing ring.

12. The electronic expansion valve according to claim 11, characterized in that: The valve seat assembly further comprises a first opening, a second opening and a third opening which are in communication with the valve cavity; along the axial direction of the electronic expansion valve, the first opening, the second valve port, the second opening, the first valve port and the third opening are arranged in sequence; the first opening and the second opening are respectively located on both sides of the first valve port, the second opening and the third opening are respectively located on both sides of the second valve port, and the second opening is located between the first valve port and the second valve port; The first preload force F1 satisfies: (π×D2 2 ÷4-π×D1 2 ÷4)×ΔP1 <F1; Wherein, D2 is the diameter of the second sealing ring, D1 is the diameter of the first sealing ring, and ΔP1 is the fluid pressure difference between the third opening and the second opening when the fluid is passed into the electronic expansion valve; The second preload force F2 satisfies: (π×D3 2 ÷4-π×D1 2 ÷4)×ΔP2 <F2; Wherein, D3 is the diameter of the third sealing ring, D1 is the diameter of the first sealing ring, and ΔP2 is the fluid pressure difference between the first opening and the second opening when the fluid is passed into the electronic expansion valve.

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