Electronic expansion valve

Abstract

The electronic expansion valve comprises a valve body and a coil component, the valve body comprises a valve seat, a valve needle, a first connecting pipe and a second connecting pipe, the valve seat is provided with a first inner hole and a second inner hole, a valve port is formed in the upper end of the second inner hole, the valve needle penetrates through the first inner hole to be matched with the valve port, and the coil component is arranged on the valve seat. The valve seat is provided with a first connector and a second connector, the first connecting pipe and the valve seat are welded and fixed at the first connector, the second connecting pipe and the valve seat are welded and fixed at the second connector, the valve seat and the valve needle are made of stainless steel materials, and the first connecting pipe and the second connecting pipe are made of copper materials. A first copper plating layer is arranged on the inner surface, used for being welded to the first connecting pipe, of the first connector, and a second copper plating layer is arranged on the inner surface, used for being welded to the second connecting pipe, of the second connector. The welding manufacturability and the sealing effect of the valve seat and the connecting pipe are improved, meanwhile, the economical efficiency of welding flux selection is improved, and the effect of improving the leakage performance of the valve body at low cost is achieved.

Description

Technical Field

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

[0002] An electronic expansion valve adjusts the liquid supply amount of an evaporator according to a preset program. Since it belongs to an electronic adjustment mode, it is called an electronic expansion valve. It meets the development requirements of refrigeration mechatronics, has excellent characteristics that a thermal expansion valve cannot match, provides conditions for the intelligent control of a refrigeration system, and is a very commonly used automatic control and energy-saving component.

[0003] According to different driving methods, electronic expansion valves can be divided into direct-acting electronic expansion valves and reduction-type electronic expansion valves. Taking the direct-acting electronic expansion valve as an example, it mainly consists of a valve seat component, a valve needle component, a nut, a rotor component, a stopper, etc. During operation, the coil is excited to drive the rotor component to rotate. The screw thread pair between the lead screw and the nut in the rotor component converts the rotational motion into the up-and-down motion of the valve needle component, and jointly controls the refrigerant flow rate passing through the valve port with the valve port of the valve seat component.

[0004] Since the valve seat is made of brass, and the valve seat and the valve port are of an integral structure, and the valve port part is also brass, with a relatively soft texture, it is not only easy to accumulate impurities, but also, in the fully closed state, is easily damaged by the relatively large pressure exerted by the stainless steel valve needle. Summary of the Invention

[0005] The purpose of the present invention is to provide an electronic expansion valve to solve the above technical problems.

[0006] To achieve the above purpose, the present invention provides an electronic expansion valve, including a valve body and a coil component. The valve body includes a valve seat, a valve needle, a first connection pipe, and a second connection pipe. A flow guiding cavity is provided inside the valve seat. A first inner hole is provided in the upper part of the flow guiding cavity, and a second inner hole is provided in the lower part of the flow guiding cavity. The upper end of the second inner hole forms a valve port. The valve needle passes through the first inner hole and cooperates with the valve port. The valve seat is provided with a first interface and a second interface. The first connection pipe is fixedly welded to the valve seat at the first interface, and the second connection pipe is fixedly welded to the valve seat at the second interface. The valve seat, the first connection pipe, and the second connection pipe are made of copper, the valve needle is made of stainless steel, and a stainless steel coating is provided on the surface of the valve port that cooperates with the valve needle. In the fully closed state, the sealing part of the valve needle abuts against the stainless steel coating of the valve port.

[0007] Optionally, the second inner hole of the valve seat includes a large hole part and a small hole part. The upper end of the small hole part forms the valve port; there is a step surface between the large hole part and the small hole part; the outer surface of the insertion end of the first connection pipe is welded to the inner wall of the large hole part, and the end surface of the insertion end of the first connection pipe is welded to the step surface.

[0008] Optionally, the stainless steel coating covers the valve port, the peripheral area of the valve port, and at least a part of the inner wall of the second inner hole.

[0009] Optionally, the pressure-bearing part of the valve port is provided with an inner conical surface, the sealing part of the valve needle is provided with an outer conical surface corresponding to the inner conical surface, and the stainless steel coating covers the inner conical surface of the valve port.

[0010] Optionally, the thickness of the stainless steel coating is 2 μm - 3 μm.

[0011] Optionally, the valve needle and the inner wall of the first inner hole are in sliding fit along the axial direction to guide the valve needle.

[0012] Optionally, it is a direct-acting electronic expansion valve, and the coil component includes an exciting coil, a nut, a rotor component, and a stopper.

[0013] Optionally, it is a reduction-type electronic expansion valve, and the coil component includes a permanent magnet stepping motor and a gear reduction mechanism. The power output end of the gear reduction mechanism is in transmission connection with the valve needle to drive the valve needle to move up and down.

[0014] Optionally, the upper end of the valve needle is connected to a valve rod, and a bellows is sleeved outside the valve rod.

[0015] Optionally, the first connecting pipe and the second connecting pipe are made of red copper or brass.

[0016] For the electronic expansion valve provided by the present invention, its valve seat and valve core are of an integral structure, the valve port is directly formed inside the valve seat, and the valve seat, the first connecting pipe, and the second connecting pipe are made of copper, the valve needle is made of stainless steel, the first connecting pipe is welded to the first interface, and the second connecting pipe is welded to the second interface. Due to the same material, according to the characteristic that the closer the materials are, the relatively better the weldability is, the welding difficulty between the valve seat and the first connecting pipe and the second connecting pipe can be reduced. In terms of solder selection, the solder with a reduced or eliminated silver content in the solder can be used, thereby improving the welding economy between the valve seat and the first connecting pipe and the second connecting pipe. In terms of welding effect, the solder filling of the entire welding surface is made denser, reducing the risk of leakage and optimizing the sealing performance of the electronic expansion valve; moreover, the surface where the valve port and the valve needle cooperate is provided with a stainless steel coating, and the hardness is significantly improved. In the fully closed state, the sealing part of the valve needle abuts against the stainless steel coating of the valve port, making the valve port not easily damaged by the extrusion of the valve needle. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of an electronic expansion valve provided by the first embodiment of the present invention;

[0018] Figure 2 is Figure 1Partial enlarged view of part I;

[0019] Figure 3 This is a partial enlarged view of an electronic expansion valve provided by the second embodiment of the present invention;

[0020] Figure 4 This is a partial enlarged view of an electronic expansion valve provided by the third embodiment of the present invention.

[0021] In the figure:

[0022] 10. Valve body 11. Valve seat 111. First inner hole 112. Second inner hole 1121. Large hole part 1122. Small hole part 1123. Step surface 113. First interface 114. Second interface 115. Stainless steel coating 13. Valve needle 15. First connecting pipe 16. Second connecting pipe 20. Coil component 21. Excitation coil 22. Nut 23. Screw rod 24. Rotor component 25. Stopper 26. Spring Detailed implementation manners

[0023] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0024] In this article, terms such as "upper, lower, inner, outer" are established based on the positional relationship shown in the drawings. Depending on the different drawings, the corresponding positional relationship may also change accordingly. Therefore, it cannot be understood as an absolute limitation of the protection scope; moreover, relational terms such as "first" and "second" are only used to distinguish one component with the same name from another, and do not necessarily require or imply any such actual relationship or order between these components.

[0025] Please refer to Figure 1 、 Figure 2 , Figure 1 This is a structural schematic diagram of an electronic expansion valve provided by the first embodiment of the present invention; Figure 2 is Figure 1 a partial enlarged view of part I.

[0026] In a specific embodiment, the electronic expansion valve provided by the present invention is a direct-acting electronic expansion valve, which can be widely applied to refrigeration and heating devices or equipment such as air conditioners, heat pump water heaters, chillers, vending machines, ice makers, supermarket freezers, refrigerators, etc.

[0027] This direct-acting electronic expansion valve mainly consists of two major parts: a valve body 10 and a coil assembly 20. The valve body 10 is used to regulate the flow rate, and the coil assembly 20 is used to drive the valve body 10 to perform the action of regulating the flow rate. Among them, the valve body 10 has core components such as a valve seat 11, a valve needle 13, a first connecting pipe 15, and a second connecting pipe 16. The coil assembly 20 has an exciting coil 21, a nut 22, a screw rod 23, a rotor assembly 24, and a stopper 25, etc.

[0028] During operation, the exciting coil 21 is electrically connected to the control circuit. When energized, the exciting coil 21 drives the rotor assembly 24 to rotate, and further drives the valve needle 13 to act through a screw transmission mechanism. When the rotor assembly 24 rotates, due to the action of the thread structure, the screw rod 23 rotates and moves up and down relative to the nut 22 under the drive of the rotor assembly 24. Since the valve needle 13 is relatively fixed to the screw rod 23, the valve needle 13 moves up and down with the screw rod 23.

[0029] A spring 26 is provided between the valve needle 13 and the screw rod 23. In the axial direction and the radial direction, there can be a certain relative displacement between the valve needle 13 and the screw rod 23 to play an elastic buffering role.

[0030] The valve seat 11 is made of brass material, and a flow guiding cavity is provided inside it. A first inner hole 111 is provided in the upper part of the flow guiding cavity, and a second inner hole 112 is provided in the lower part of the flow guiding cavity. The first inner hole 111 and the second inner hole 112 are located on the same axis. The upper end of the second inner hole 112 forms a valve port. The valve needle 13 is made of stainless steel material, and it passes through the first inner hole 111 from top to bottom and can slide axially along the inner wall of the first inner hole 111 to guide the valve needle 13. When the valve needle 13 moves up and down, the flow rate regulation function is realized through cooperation with the valve port.

[0031] When the valve needle 13 moves downward, the valve port gradually decreases until it is fully closed. When the valve needle 13 moves upward, the valve port assembly increases until it is fully open.

[0032] The valve seat 11 is provided with a first interface 113 and a second interface 114. The first connecting pipe 15 and the second connecting pipe 16 are made of copper material. The surface of the valve port in contact with the valve needle 13 is provided with a stainless steel coating 115. In the fully closed state, the sealing part of the valve needle 13 abuts against the stainless steel coating 115 of the valve port.

[0033] The second inner hole 112 of the valve seat 11 includes a large hole part 1121 and a small hole part 1122. The upper end of the small hole part 1122 forms a valve port; there is a step surface 1123 between the large hole part 1121 and the small hole part 1122; the outer surface of the inserted end of the first connecting pipe 15 is welded to the inner wall of the large hole part 1121, and the end surface of the inserted end of the first connecting pipe 15 is welded to the step surface 1123.

[0034] In this embodiment, the stainless steel coating 115 covers the valve port, the peripheral area of the valve port, and the wall of the second inner hole, and the thickness of the stainless steel coating is 2μm - 3μm.

[0035] The pressure-bearing part of the valve port is provided with an inner conical surface, and the stainless steel coating 115 covers the inner conical surface of the valve port. The sealing part of the valve needle 13 is provided with an outer conical surface corresponding to the inner conical surface. In the fully closed state, the outer conical surface of the valve needle 13 fits with the inner conical surface of the valve port provided with the stainless steel coating 115.

[0036] The valve seat 11 can be plated with stainless steel at the valve port by means of electroplating or electroless plating, etc. Before plating steel, surface treatment work on the copper body needs to be carried out, including removing oil stains, oxide scales, and copper rust, etc. After the valve seat 11, the first connecting pipe 15, and the second connecting pipe 16 are assembled, tunnel furnace or flame brazing is carried out.

[0037] Since the closer the materials are, the relatively better the weldability is. Therefore, after adopting the above technical solution, the welding difficulty between the valve seat 11 and the first connecting pipe 15 and the second connecting pipe 16 can be reduced. In terms of solder selection, the solder with a reduced or eliminated silver content in the solder can be used, thereby improving the welding economy between the valve seat 11 and the first connecting pipe 15 and the second connecting pipe 16. In terms of welding effect, the solder filling of the entire welding surface is made denser, reducing the risk of leakage and optimizing the sealing performance of the electronic expansion valve; moreover, the surface where the valve port cooperates with the valve needle 13 is provided with a stainless steel coating 115 (see the bold line), and the hardness is significantly improved. In the fully closed state, the sealing part of the valve needle 13 abuts against the stainless steel coating 115 of the valve port, making the valve port not easily damaged by the extrusion of the valve needle 13.

[0038] The above embodiments are only the preferred solutions of the present invention, and are not specifically limited thereto. On this basis, targeted adjustments can be made according to actual needs to obtain different implementation manners.

[0039] For example, the above structure is not only applicable to the direct-acting electronic expansion valve, but also applicable to the step-down electronic expansion valve. If it is a step-down electronic expansion valve, the coil component has a permanent magnet stepper motor, a gear reduction mechanism with a speed reduction function, and a screw pair structure for converting the rotational motion of the motor into the vertical motion of the screw rod, etc.

[0040] Since there are many possible implementation manners, they will not be exemplified one by one here.

[0041] The present invention uses a valve seat 11 made of copper material and designs a stainless steel coating 115 on the surface of the valve port of the valve seat 11, which improves the welding processability, sealing effect, and solder selection economy between the valve seat 11 and the first connecting pipe 15 and the second connecting pipe 16. At the same time, the valve port is not easily damaged by the extrusion of the valve needle 13, achieving the effect of improving the leakage performance of the valve body at low cost.

[0042] The above has introduced the electronic expansion valve provided by the present invention in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. Electronic expansion valve, comprising a valve body (10) and a coil component (20), characterized in that, The valve body (10) comprises a valve seat (11), a valve needle (13), a first connecting pipe (15) and a second connecting pipe (16); a flow guide cavity is provided inside the valve seat (11); a first inner hole (111) is provided at the upper part of the flow guide cavity; a second inner hole (112) is provided at the lower part of the flow guide cavity; a valve port is formed at the upper end of the second inner hole (112); the valve needle (13) passes through the first inner hole (111) and matches with the valve port; the valve seat (11) is provided with a first interface (113) and a second interface (114) The first connecting pipe (15) is welded and fixed to the valve seat (11) at the first interface (113), and the second connecting pipe (16) is welded and fixed to the valve seat (11) at the second interface (114). The valve seat (11), the first connecting pipe (15) and the second connecting pipe (16) are made of copper, and the valve needle (13) is made of stainless steel. The surfaces of the valve port and the valve needle (13) that match each other are provided with a stainless steel coating (115). In the fully closed state, the sealing portion of the valve needle (13) abuts against the stainless steel coating (115) of the valve port.

2. The electronic expansion valve according to claim 1, wherein, The second inner hole (112) of the valve seat (11) includes a large hole portion (1121) and a small hole portion (1122), and the upper end of the small hole portion (1122) forms the valve port; a step surface (1123) is provided between the large hole portion (1121) and the small hole portion (1122); the outer surface of the insertion end of the first connecting pipe (15) is welded to the inner wall of the large hole portion (1121), and the end surface of the insertion end of the first connecting pipe (15) is welded to the step surface (1123).

3. The electronic expansion valve according to claim 2, wherein The stainless steel coating (115) covers the valve port, the peripheral area of ​​the valve port, and at least a portion of the inner wall of the second inner hole (112).

4. The electronic expansion valve according to claim 3, characterized in that, The pressure-bearing portion of the valve port is provided with an inner conical surface, the sealing portion of the valve needle (13) is provided with an outer conical surface corresponding to the inner conical surface, and the stainless steel coating (115) covers the inner conical surface of the valve port.

5. The electronic expansion valve according to claim 1, wherein The thickness of the stainless steel coating (115) is 2 μm-3 μm.

6. The electronic expansion valve according to claim 1, characterized in that, The valve needle (13) is slidably matched with the inner wall of the first inner hole (111) in the axial direction to guide the valve needle (13).

7. The electronic expansion valve according to claim 1, characterized in that, The invention is a direct-acting electronic expansion valve, wherein the coil component (20) comprises an excitation coil (21), a nut (22), a rotor component (24) and a stopper (25).

8. The electronic expansion valve according to claim 1, wherein The invention is a deceleration type electronic expansion valve, wherein the coil component (20) comprises a permanent magnet stepping motor and a gear reduction mechanism, and the power output end of the gear reduction mechanism is drivingly connected to the valve needle (13) to drive the valve needle (13) to move up and down.

9. The electronic expansion valve according to claim 8, wherein, The upper end of the valve needle (13) is connected to a valve stem, and a bellows is sleeved on the outside of the valve stem.

10. The electronic expansion valve according to any one of claims 1 to 9, characterized in that, The first connecting pipe (15) and the second connecting pipe (16) are made of copper or brass.

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