Electronic expansion valve and assembly process

Abstract

The present application provides an electronic expansion valve and an assembly process. The electronic expansion valve comprises a first connecting tube, a silencing portion, and a valve seat portion and an adapter portion which are connected to each other, wherein the adapter portion is separately connected to the valve seat portion and the first connecting tube, the adapter portion has an accommodating cavity, and the silencing portion is mounted in the accommodating cavity in a position-limited manner. By using the present solution, by means of the adapter portion, an object to be furnace-welded of the first connecting tube is changed from the valve seat portion to the adapter portion; when the adapter portion and the first connecting tube are furnace-welded, the silencing portion located in the accommodating cavity is separated from the first connecting tube by the adapter portion, the first connecting tube does not directly abut against the silencing portion, and solder generated during furnace welding does not permeate to the silencing portion, thereby ensuring the noise reduction effect of the silencing portion and the flow capacity of the electronic expansion valve. In addition, the present solution can realize independent offline installation of the adapter portion and the silencing portion, facilitating reduction of takt time, improvement of part standardization, and avoidance of the risk of part dropping during turnover, thereby improving the processing and installation efficiency of electronic expansion valves.

Description

Electronic expansion valve and assembly process

[0001] This application claims priority to the patent application filed on July 18, 2024, with application number 202410968785.5 and entitled "Electronic Expansion Valve and Assembly Process". Technical Field

[0002] This application relates to the field of electronic expansion valve technology, and more specifically, to an electronic expansion valve and its assembly process. Background Technology

[0003] Currently, electronic expansion valves can be used in series reheat dehumidification systems. Since the electronic expansion valve is located between two indoor heat exchangers in this application, it is necessary to ensure that the pressure drop of the electronic expansion valve at its maximum opening is small enough under normal air conditioning conditions to guarantee the capacity of the air conditioning system. Furthermore, since the electronic expansion valve is located on the indoor side, the noise requirements are also high. Therefore, a perforated silencing part can be installed at the valve port of the electronic expansion valve to reduce the noise of refrigerant flow.

[0004] Electronic expansion valves typically employ a first connecting pipe to directly press the muffler into the valve seat cavity. One end of the first connecting pipe extends into the valve seat cavity and directly abuts against the muffler located within the valve seat cavity. Since the first connecting pipe is usually installed using furnace welding—that is, the first connecting pipe is directly connected to the valve seat via furnace welding—solder can easily seep from the gap between the inner wall of the valve seat cavity and the outer periphery of the first connecting pipe into the muffler during furnace welding. The muffler has a porous structure, and the solder flowing into it can easily adhere to it, causing partial blockage and affecting noise reduction and flow capacity. Furthermore, since the muffler is usually press-fitted into the valve seat, the valve seat needs to be machined to accommodate the muffler. This requires high machining standards and consideration of many factors. On the other hand, there is a risk of parts falling off during the press-fitting process, affecting machining and installation efficiency. Summary of the Invention

[0005] This application provides an electronic expansion valve and its assembly process to solve the problem that the silencing part in the prior art is easily blocked by furnace solder, thus affecting the noise reduction effect, and to improve the processing and installation efficiency of the electronic expansion valve.

[0006] To address the aforementioned problems, according to one aspect of this application, an electronic expansion valve is provided. The electronic expansion valve includes a first connecting pipe, a silencing portion, and a valve seat portion and a transition portion connected to each other. The transition portion is connected to the valve seat portion and the first connecting pipe, and the transition portion has a receiving cavity. The silencing portion is limited and installed in the receiving cavity.

[0007] Furthermore, the silencing part is laser-welded into the receiving cavity, or the silencing part is riveted into the receiving cavity, or the silencing part is press-fitted into the receiving cavity.

[0008] Furthermore, the valve seat also has a limiting cavity, and the transition part includes a mating section. At least part of the mating section is disposed in the limiting cavity. The inner wall of the fixed section and the cavity formed by the mating section are distributed along the axial direction of the transition part, and there is an inner stepped surface between their inner walls. The silencing part abuts against the inner stepped surface.

[0009] Furthermore, the mating section includes a first mating section and a second mating section that are connected to each other. At least a portion of the first mating section extends into the limiting cavity, and at least a portion of the second mating section is located outside the limiting cavity for connecting the first connecting pipe. The outer diameter of the first mating section is larger than the outer diameter of the second mating section, and the inner diameter of the first mating section is larger than the inner diameter of the second mating section.

[0010] Furthermore, there is an outer stepped surface between the outer wall of the first mating section and the outer wall of the second mating section. The outer stepped surface protrudes from the limiting cavity to form a positioning reference surface, or the outer stepped surface is flush with the surface where the opening of the limiting cavity is located and forms a positioning reference surface.

[0011] Furthermore, the adapter has an annular stop protrusion located between the first mating section and the second mating section, and protrudes radially inward in the adapter. The inner diameter of the annular stop protrusion is smaller than the inner diameter of the second mating section. The area surrounded by the annular stop protrusion forms an adapter interface. One end of the first pipe is located in the second mating section and engages with the annular stop protrusion. The adapter interface communicates with the opening of the first pipe.

[0012] Furthermore, the adapter is a straight section with a constant inner diameter along the axial direction of the electronic expansion valve, or the adapter is a first flared mouth, or the adapter has a first flared mouth on the side away from the first connecting pipe, the inner diameter of the first flared mouth gradually increases along the direction from the first connecting pipe toward the adapter, the side with the smaller opening of the first flared mouth is connected to the first connecting pipe and the radial dimension is adapted to the inner diameter of the first connecting pipe, and the opening angle of the first flared mouth is β, 20°≤β≤120°.

[0013] Furthermore, the opening of the receiving cavity has a riveted flange, and the sound-absorbing part is riveted and installed in the receiving cavity through the riveted flange.

[0014] Furthermore, the riveting flange is an annular flange, or there are multiple riveting flanges, which are distributed at intervals along the circumference of the transition part.

[0015] Furthermore, the adapter includes a fixed section, the area surrounded by the fixed section forms a receiving cavity, and in the axial direction of the fixed section, the portion of the fixed section that protrudes from the silencing part on the opening side forms a riveting flange.

[0016] Furthermore, the valve seat portion includes a valve seat and a valve seat core. The valve seat has a mounting cavity, and the valve seat core is disposed within the mounting cavity. The area of ​​the mounting cavity for mounting the valve seat core forms a placement cavity, and the area of ​​the mounting cavity for mounting the adapter forms a limiting cavity.

[0017] Furthermore, the valve seat core and the valve seat are separate, with the valve seat core set inside the placement cavity; or, the valve seat core and the valve seat are an integral structure, with the valve seat core integrally formed inside the placement cavity.

[0018] Furthermore, the valve seat portion has a valve cavity, which is located on the side of the receiving cavity away from the transition portion. The valve cavity is connected to the receiving cavity. The valve cavity includes a valve port section, which is a variable diameter flow regulating section, or the valve port section has a variable diameter flow regulating section on the side away from the receiving cavity.

[0019] Furthermore, the flow regulation section is a second flared opening, and the opening angle of the second flared opening is α, where 1°≤α≤10°.

[0020] Furthermore, the electronic expansion valve also includes a valve needle assembly, which includes a valve head. The valve head engages with the inner wall of the flow regulating section to regulate the flow of the electronic expansion valve. When the electronic expansion valve is fully closed, one end of the valve head extends into the valve port section, and there is a gap between the outer periphery of the valve head and the inner wall of the valve port section.

[0021] Furthermore, the electronic expansion valve also includes a rotor assembly, and the valve needle assembly includes a screw member drivenly connected to the rotor assembly. The inner wall of the valve port section has a first conical section and a first straight section that are interconnected and arranged sequentially along the direction of the valve mouth towards the first connecting pipe. The first conical section is a flow regulating section. When the electronic expansion valve is fully closed, one end of the valve head is located inside the first conical section, and there is a gap between the outer periphery of the valve head and the inner wall of the first conical section. The height of the first conical section is H5, and the distance from the end of the valve head to the connecting surface of the first conical section and the first straight section is H9. The electronic expansion valve has a flow inflection point where the flow slope changes during the valve opening process. B*n*γ / 360+H9=H5; where B is the number of supply pulses required for the valve head to open from the fully closed position to the flow inflection point, n is the screw pitch of the screw member, and γ is the step angle of the rotor assembly.

[0022] Furthermore, the electronic expansion valve also includes a rotor assembly, and the valve needle assembly includes a screw member drivenly connected to the rotor assembly. The inner wall of the valve port section has a first conical section and a first straight-through section that are interconnected and arranged sequentially along the direction of the valve mouth towards the first connecting pipe. The first conical section is a flow regulating section. When the electronic expansion valve is fully closed, one end of the valve head is located in the first straight-through section, and there is a gap between the outer periphery of the valve head and the inner wall of the first straight-through section. The height of the first conical section is H5, and the distance from the end of the valve head to the connecting surface of the first conical section and the first straight-through section is H9. The electronic expansion valve has a flow inflection point where the flow slope changes during the valve opening process. B*n*γ / 360–H9=H5; where B is the number of supply pulses required for the valve head to open from the fully closed position to the flow inflection point, n is the screw pitch of the screw member, and γ is the step angle of the rotor assembly.

[0023] According to another aspect of this application, an assembly process is provided, which is applied to the above-mentioned electronic expansion valve. The electronic expansion valve further includes a second connecting pipe. The assembly process includes: welding one end of the second connecting pipe to the side of the valve seat portion; welding the first connecting pipe to the end of one end of the adapter portion; installing a silencing portion inside the adapter portion; installing a portion of the adapter portion inside the valve seat portion; and welding the adapter portion to the valve seat portion.

[0024] Furthermore, the silencing part includes a first silencing block, a pad block, and a second silencing block that sequentially abut against each other along the installation direction of the silencing part. The process of installing the silencing part in the adapter part includes: sequentially installing the second silencing block, the pad block, and the first silencing block in the adapter part.

[0025] Furthermore, the assembly process also includes: the end of the adapter is the end of the adapter located outside the valve seat, and the first connecting pipe is welded to the end of the adapter located outside the valve seat; the first connecting pipe is first welded to the end of the adapter located outside the valve seat, and then the muffler is installed inside the adapter; or, the muffler is first installed inside the adapter, and then the adapter and the first connecting pipe are welded.

[0026] Furthermore, the electronic expansion valve also includes a nut assembly, a valve needle assembly, and a guide sleeve. The assembly process further includes: sequentially installing the nut assembly and the valve needle assembly on the valve seat; and before sequentially installing the nut assembly and the valve needle assembly on the valve seat, the process of welding one end of the second connecting pipe to the side of the valve seat further includes: pressing the guide sleeve into the valve seat, and then furnace welding the second connecting pipe, the valve seat, and the guide sleeve as a whole, or first furnace welding the second connecting pipe and the valve seat, then pressing the guide sleeve into the valve seat, and then laser welding the guide sleeve and the valve seat.

[0027] Furthermore, the assembly process also includes: laser welding of the connection position between the adapter and the valve seat; and pulse setting of the electronic expansion valve.

[0028] Furthermore, the valve seat portion includes a separate valve seat and a valve seat core, or the valve seat portion includes an integral valve seat and a valve seat core, with a portion of the adapter installed inside the valve seat, one end of the adapter abutting against the valve seat core, or the silencing portion abutting against the valve seat core.

[0029] The present application provides an electronic expansion valve, which includes a first connecting pipe, a silencing part, and a valve seat part and an adapter part connected to each other. The adapter part is connected to the valve seat part and the first connecting pipe, and the adapter part has a receiving cavity. The silencing part is limited and installed in the receiving cavity.

[0030] This solution uses an adapter to change the welding target of the first connecting pipe from the valve seat to the adapter. During furnace welding of the adapter and the first connecting pipe, the silencing part located in the receiving cavity is separated from the first connecting pipe by the adapter, and the first connecting pipe does not directly contact the silencing part. Even if the solder generated during furnace welding penetrates, it will not penetrate into the silencing part. This avoids the situation in the prior art where the first connecting pipe is directly furnace welded to the valve seat, and the solder easily penetrates into the silencing part through the gap between the two, thus affecting the noise reduction effect of the silencing part and the flow capacity of the electronic expansion valve. This ensures the noise reduction effect of the silencing part and the flow capacity of the electronic expansion valve. On the other hand, this solution allows for independent off-line installation of the silencing part through the adapter. The operator only needs to adapt the adapter to the valve seat and the silencing part during processing, and then install the connected adapter and the silencing part together on the valve seat. This setup helps to reduce production cycle time, improve parts standardization, avoid the risk of parts falling during handling, and improve the processing and installation efficiency of the electronic expansion valve. Attached Figure Description

[0031] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0032] Figure 1 shows a schematic diagram of the structure of the electronic expansion valve provided in Embodiment 1 of this application;

[0033] Figure 2 shows an enlarged view of position A in Figure 1;

[0034] Figure 3 shows an enlarged view of position B in Figure 2;

[0035] Figure 4 shows a schematic diagram of the valve seat in Figure 2;

[0036] Figure 5 shows an assembly diagram of the valve seat core, silencer and adapter in Figure 2;

[0037] Figure 6 shows a schematic diagram of the transition section in Figure 2;

[0038] Figure 7 shows a schematic diagram of the electronic expansion valve in Figure 1 when the valve is closed;

[0039] Figure 8 shows an enlarged view of position C in Figure 7;

[0040] Figure 9 shows a schematic diagram of the flow rate in Figure 7;

[0041] Figure 10 shows a partial structural schematic diagram of the valve seat of the electronic expansion valve provided in Embodiment 2 of this application;

[0042] Figure 11 shows an assembly diagram of the valve seat core, silencing part and adapter part of the electronic expansion valve provided in Embodiment 2 of this application;

[0043] Figure 12 shows a partial enlarged view of the electronic expansion valve provided in Embodiment 2 of this application;

[0044] Figure 13 shows a schematic diagram of the electronic expansion valve provided in Embodiment 3 of this application when the valve is closed;

[0045] Figure 14 shows an enlarged view of position D in Figure 13;

[0046] Figure 15 shows a schematic diagram of the flow rate in Figure 13.

[0047] The above-mentioned figures include the following reference numerals: 1. Annular groove; 10. Valve seat portion; 101. Mounting cavity; 1011. Limiting cavity; 1012. Placement cavity; 102. Valve mouth; 1021. Valve port section; 10211. First conical section; 10212. First straight-through section; 10213. Second conical section; 10214. Second straight-through section; 1022. Flared section; 11. Valve seat; 12. Valve seat core; 121. First loose-fit section; 122. First tight-fit section; 20. Transition portion; 201. Receiving cavity; 2011. First limiting cavity section; 2012. Second limiting cavity section; 202. 203 Outer stepped surface; 204 Adapter; 21 Inner stepped surface; 22 First mating section; 23 Second mating section; 24 Annular stop protrusion; 25 Fixed section; 26 Riveted flange; 37 Silencer; 38 First silencing block; 39 Spacer block; 30 Second silencing block; 41 First connecting pipe; 42 Second connecting pipe; 50 Nut assembly; 60 Valve needle assembly; 61 Valve head assembly; 62 Screw assembly; 70 Guide sleeve; 71 First sleeve; 72 Second sleeve; 73 Limiting sleeve; 80 Rotor assembly. Detailed Implementation

[0048] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0049] As shown in Figures 1 to 15, an embodiment of this application provides an electronic expansion valve. The electronic expansion valve includes a first connecting pipe, a silencing part 30, and a valve seat part 10 and a transition part 20 connected to each other. The transition part 20 is connected to the valve seat part 10 and the first connecting pipe 41 respectively. The transition part 20 has a receiving cavity 201, and the silencing part 30 is limited and installed in the receiving cavity 201.

[0050] In some embodiments, the silencing portion 30 may be laser-welded into the receiving cavity 201; or, in other embodiments, the silencing portion 30 may be riveted into the receiving cavity 201; or, in yet another embodiment, the silencing portion 30 may be press-fitted into the receiving cavity 201. The adapter portion 20 in this application includes a fixing section 24, the area surrounded by the fixing section 24 forming the receiving cavity 201.

[0051] In this application, the adapter 20 is connected to the valve seat 10 and the first connecting pipe 41 at both ends along the axial direction of the electronic expansion valve, respectively. The adapter 20 changes the target of the furnace welding of the first connecting pipe 41 from the valve seat 10 to the adapter 20. When the adapter 20 and the first connecting pipe 41 are furnace welded, the silencing part 30 located in the receiving cavity is separated from the first connecting pipe 41 by the adapter 20. The first connecting pipe 41 does not directly contact the silencing part 30. During furnace welding, the molten solder will not penetrate into the silencing part 30. This avoids the situation where the first connecting pipe 41 directly contacts the silencing part 30. When the first connecting pipe 41 is furnace welded to the valve seat 10, the molten solder can easily penetrate from the gap between the two into the silencing part 30, thereby affecting the noise reduction effect of the silencing part 30 and the flow capacity of the electronic expansion valve. This ensures the noise reduction effect of the silencing part 30 and the flow capacity of the electronic expansion valve. On the other hand, this solution allows for independent off-line installation of the muffler 30 via the adapter 20. Operators only need to adapt the adapter 20 to the valve seat 10 and the muffler 30 during processing. Then, the connected adapter 20 and the muffler 30 are installed together on the valve seat 10. This setup helps to reduce production cycle time, improve parts standardization, avoid the risk of parts falling during turnover, and improve the processing and installation efficiency of the electronic expansion valve.

[0052] It should be noted that the adapter 20 can be a drawn part, a precision-machined part, etc. In this application, since multiple steps and flow channels need to be machined inside the adapter 20, and the adapter 20 needs to be press-fitted into the valve seat 10, the dimensional accuracy of the adapter 20 is required to be high. Therefore, the adapter 20 in this application is preferably a precision-machined part. It can be understood that the adapter 20 can be precision-machined as a whole, or it can be stamped first and then precision-machined (the stepped part is precision-machined), or it can be cold-forged first and then precision-machined.

[0053] In Embodiment 1, as shown in Figures 1, 2, 5, and 6, the opening of the receiving cavity 201 has a riveting flange 241, and the silencing part 30 is riveted and installed in the receiving cavity 201 through the riveting flange 241. This arrangement allows for the riveting of the silencing part 30 through the riveting flange 241, which is convenient for design and processing, has a reliable limiting effect, and helps to improve installation efficiency.

[0054] It is understood that in some embodiments, the riveting flange 241 is an annular flange, or in other embodiments, there are multiple riveting flanges 241, which are distributed at intervals along the circumference of the transition portion 20. This arrangement ensures the reliability and stability of the limiting installation of the silencing portion 30.

[0055] In Embodiment 1 shown in Figure 6, the adapter 20 of this application includes a fixing section 24. The area surrounded by the fixing section 24 forms a receiving cavity 201. In the axial direction of the fixing section 24, the portion of the fixing section 24 that protrudes from the silencing part 30 on the open side forms a riveting flange 241. This arrangement facilitates the integral processing and forming of the receiving cavity 201 and the riveting flange 241, which is beneficial to improving processing and installation efficiency.

[0056] The receiving cavity 201 includes a first limiting cavity section 2011 and a second limiting cavity section 2012 that are interconnected. Along the axial direction of the electronic expansion valve, the second limiting cavity section 2012 is located on the side of the receiving cavity 201 away from the first connecting pipe 41, and the first limiting cavity section 2011 is located on the side of the receiving cavity close to the first connecting pipe 41. The radial dimension of the second limiting cavity section 2012 is smaller than the radial dimension of the first limiting cavity section 2011 (as shown in Figure 6, the inner diameter of the first limiting cavity section 2011 is D31, and the inner diameter of the second limiting cavity section 2012 is D32, D31 > D32). Specifically, in Embodiment 1 shown in Figures 2, 5, and 6, the silencing part 30 includes a first silencing block 31, a pad 32, and a second silencing block 33 that sequentially abut against each other along the installation direction of the silencing part 30. The outer diameter of the first silencing block 31 is adapted to the inner diameter of the first limiting cavity 2011, and the first silencing block 31 is disposed within the first limiting cavity 2011 and is limited and engaged with the inner wall of the first limiting cavity 2011. The outer diameter of the second silencing block 33 is adapted to the inner diameter of the second limiting cavity 2012, and the second silencing block 33 is disposed within the second limiting cavity 2012 and is limited and engaged with the inner wall of the second limiting cavity 2012. This arrangement facilitates the differentiation between the first silencing block 31 and the second silencing block 33, avoids incorrect installation sequence, prevents confusion in the installation positions of the two silencing blocks, and improves the installation efficiency of the silencing part 30. The pad 32 in this application has a ring structure.

[0057] It is understood that the installation direction of the silencing part 30 is the direction parallel to the axial direction of the electronic expansion valve in which the silencing part 30 is installed in the receiving cavity 201. In this application, the installation direction is the axial direction of the electronic expansion valve from the first limiting cavity section 2011 toward the second limiting cavity section 2012.

[0058] The first silencing block 31 and the second silencing block 33 are each provided with a flow area and a decomposition area. At least a portion of the flow area provided on the first silencing block 31 corresponds to the decomposition area provided on the second silencing block 33, and at least a portion of the flow area provided on the second silencing block 33 corresponds to the decomposition area provided on the first silencing block 31.

[0059] In Embodiment 1 shown in Figures 2, 5, and 6, the height of the first silencing block 31 is H31, the height of the pad block 32 is H32, and the height of the second silencing block is H33 along the axial direction of the electronic expansion valve. (H31+H32+H33) is the overall height of the silencing part 30 along the axial direction of the electronic expansion valve. The height of the first limiting cavity section 2011 is H62, and the height of the second limiting cavity section 2012 is H61. (H61+H62) is the overall height of the receiving cavity 201 along the axial direction of the electronic expansion valve. Wherein, H61≤H33, that is, along the axial direction of the electronic expansion valve, the second silencing block 33 is not lower than the opening of the second limiting cavity section 2012. Specifically, H61 < H33, meaning the second silencing block 33 protrudes from the opening of the second limiting cavity section 2012; or H61 = H33, meaning the second silencing block 33 is flush with the surface where the opening of the second limiting cavity section 2012 is located, to ensure the contact effect between the pad block 32 and the second silencing block 33. Preferably, H61 < H33, and preferably 0.01mm ≤ (H33 - H61) ≤ 0.7mm. On the other hand, (H31 + H32 + H33) < (H61 + H62) to ensure the forming of the riveting flange 241.

[0060] It is understood that (H61+H62) in this application is the actual height of the fixed section 24 after the riveting flange 241 of the fixed section 24 is riveted to the silencing part 30, which is smaller than the initial height of the fixed section 24 before riveting.

[0061] In this embodiment, the valve seat portion 10 further includes a limiting cavity 1011. The transition portion 20 includes a fixed section 24 and a mating section connected to each other. The fixed section 24 and at least part of the mating section are disposed within the limiting cavity 1011. The inner diameter of the fixed section 24 is larger than the inner diameter of the mating section. The cavity formed by the inner wall of the fixed section 24 and the mating section is distributed along the axial direction of the transition portion 20, and there is an inner stepped surface 204 between their inner walls. The silencing portion 30 abuts against the inner stepped surface 204. This arrangement limits the installation depth of the silencing portion 30 through the inner stepped surface 204, thereby clamping both ends of the silencing portion 30 along the axial direction of the electronic expansion valve between the inner stepped surface 204 and the riveting flange 241. On the other hand, the limiting cavity 1011 facilitates the limiting installation of the transition portion 20, ensuring the reliability of the installation of the transition portion 20.

[0062] As shown in Figures 1 to 15, the valve seat portion 10 in this application includes a valve seat 11 and a valve seat core 12. The valve seat 11 has a mounting cavity 101, and the valve seat core 12 is disposed within the mounting cavity 101. Specifically, the valve seat core 12 is press-fitted into the mounting cavity. The area of ​​the mounting cavity 101 used for mounting the valve seat core 12 forms a placement cavity 1012, and the area of ​​the mounting cavity 101 used for mounting the adapter portion 20 forms a limiting cavity 1011. This arrangement facilitates the division of the limiting cavity 1011 and the installation of the valve seat core 12.

[0063] The valve seat core 12 of the valve seat portion 10 also has a valve cavity 102, which is located on the side of the receiving cavity 201 away from the transition portion 20. The valve cavity 102 is connected to the receiving cavity 201. It should be noted that, since the electronic expansion valve is located between the two indoor heat exchangers in the series reheat dehumidification system, it is determined that under normal air conditioning conditions, the pressure drop of the electronic expansion valve at its large opening should be as small as possible to ensure the energy efficiency of the air conditioning system. In addition, the indoor side has high requirements for noise. Therefore, a silencing structure (corresponding to the silencing portion 30 in this embodiment) needs to be set at the valve port (corresponding to the valve cavity 102 in this embodiment). In order to reduce the throttling of the porous silencing structure, the area of ​​the porous silencing structure can be increased and a large-diameter electronic expansion valve can be used. In related technologies, one end of the connecting pipe (corresponding to the first connecting pipe 41 in this embodiment) extends directly into the valve seat (corresponding to the valve seat 11 in this embodiment) and directly abuts against the silencing part 30. The end of the connecting pipe extending into the valve seat must have a larger outer diameter. Furthermore, in series reheat dehumidification systems, electronic expansion valves are mainly used in 1-3p units. The inner diameter of the corresponding indoor heat exchanger connecting pipe is smaller than that of 3p and above units. The other end of the electronic expansion valve connecting pipe is connected to the indoor heat exchanger connecting pipe, which determines that the inner diameter of the other end of the connecting pipe is smaller. The two ends of the electronic expansion valve connecting pipe have different pipe diameters and a large span. The scheme of using the connecting pipe to abut against the silencing mechanism makes the connecting pipe consist of three or more different pipe diameters. Such connecting pipes are difficult to process and have high costs.

[0064] To address the aforementioned issues, in this embodiment, the mating section includes a first mating section 21 and a second mating section 22 connected to each other. The first mating section 21 is connected to the fixed section 24. At least a portion of the first mating section 21 extends into the limiting cavity 1011, and at least a portion of the second mating section 22 is located outside the limiting cavity 1011 for connecting the first connecting pipe 41. The outer diameter of the first mating section 21 and the outer diameter of the fixed section 24 are both greater than the outer diameter of the second mating section 22. The outer diameter of the first mating section 21 is equal to or slightly larger than the outer diameter of the fixed section 24. The inner diameter of the first mating section 21 is greater than the inner diameter of the second mating section 22. By limiting the dimensions (inner and outer diameters) of the first mating section 21 and the second mating section 22, the adapter 20 can be adapted to valve seat sections 10 of different sizes. At the same time, the reduction in the radial dimension of the second mating section 22 is equivalent to the adapter 20 itself forming a constriction. Therefore, the end of the first connecting pipe 41 connected to the adapter 20 does not need to be modified to adapt to the large-diameter valve seat section 10. It is only necessary to select appropriate raw materials to process the first connecting pipe 41 according to the diameter of the electronic expansion valve, so as to reduce the processing difficulty of the first connecting pipe 41 and improve the processing efficiency.

[0065] It is understandable that the other end of the first connector 41 is connected to the system pipeline. Whether the other end of the first connector 41 and the system pipeline is narrowed, widened, or left untreated depends on the actual situation. Compared with the case in the prior art where the first connector 41 is directly connected to the valve seat 10, the end of the first connector 41 connected to the electronic expansion valve saves at least one widening process through the adapter 20.

[0066] In this configuration, at least a portion of the outer wall of the valve seat core 12 is press-fitted with the inner wall of the placement cavity 1012, and at least a portion of the outer wall of the transition portion 20 extending into the limiting cavity 1011 is press-fitted with the inner wall of the limiting cavity 1011.

[0067] Specifically, in Embodiment 1 shown in Figures 1 to 9, the valve seat core 12 includes a first loose section 121 and a first tight section 122 connected to each other. In this embodiment, the first tight section 122, the fixing section 24, and the first mating section 21 are all straight cylindrical sections. The outer diameter of the first loose section 121 gradually decreases in the direction from the first connecting pipe 41 toward the valve cavity 102. At least part of the first tight section 122 is in an interference fit with the inner wall of the placement cavity 1012. The first mating section 21 extends into the limiting cavity 1011, and part or all of the outer wall of the first mating section 21 is in an interference fit with the inner wall of the limiting cavity 1011. The first loose section 121 facilitates the insertion guidance of the valve seat core 12 during installation and avoids the difficulty of press-fitting due to an excessively long tight section. Furthermore, in this embodiment, the inner diameters of the placement cavity 1012 and the limiting cavity 1011 are the same, which is D1. The outer diameters of the first tight-fit section 122, the fixing section 24 and the first mating section 21 are the same, which is D2. D2 = D1 or D2 is slightly larger than D1 to ensure the interference fit of the first tight-fit section 122 in the mounting cavity 101 and the installation coaxiality requirements. Preferably, D2 is slightly larger than D1.

[0068] As shown in Figures 10 to 12, Embodiment 2 of this application provides an electronic expansion valve. The difference from Embodiment 1 is that, as shown in Figure 10, the inner diameter D11 of the placement cavity 1012 is smaller than the inner diameter D12 of the limiting cavity 1011. As shown in Figure 11, the outer diameter of the first loose section 121 is D21, the outer diameter of the first tight section 122 is D22, the outer diameter of the fixed section 24 is D23, and the outer diameter of the first mating section 21 is D24. D21 is smaller than D11, D23 is smaller than D12, D22 is equal to or slightly larger than D11, and D24 is equal to or slightly larger than D12 to ensure the reliability of the interference fit and the installation coaxiality requirements.

[0069] Understandably, the interference length between the valve seat core 12 or the adapter 20 and the mounting cavity 101 can be adjusted according to the actual situation.

[0070] In this application, the bottom wall of the first mating section 21 is an outer stepped surface 202, which is located between the outer walls of the first mating section 21 and the second mating section 22. In Embodiment 2 shown in FIG12, the outer stepped surface 202 between the outer walls of the first mating section 21 and the second mating section 22 protrudes from the limiting cavity 1011 and forms a positioning reference surface. Alternatively, in Embodiment 1 shown in FIG3, the outer stepped surface 202 between the outer walls of the first mating section 21 and the second mating section 22 is flush with the surface where the opening of the limiting cavity 1011 is located and forms a positioning reference surface. This configuration, compared to directly connecting the valve seat 10 to the first connecting pipe 41 and using the end face of the valve seat 10 facing the first connecting pipe 41 as the positioning reference surface, increases the area of ​​the positioning reference surface. Furthermore, due to the configuration of the adapter 20, the welding ring for furnace welding of the first connecting pipe 41 is placed far away from the positioning reference surface. During furnace welding, the melted solder will not spread on the positioning reference surface, resulting in insufficient positioning reference size or inaccurate positioning. The impact on the positioning reference is almost negligible and will not affect the positioning during subsequent assembly and welding.

[0071] The adapter 20 and the valve seat 10, as well as the adapter 20 and the first connecting pipe 41, can be connected by welding. Specifically, the adapter 20 and the valve seat 10 can be connected by laser welding, and the adapter 20 and the first connecting pipe 41 can be connected by furnace welding, brazing, or other welding methods. In this application, the adapter 20 and the valve seat 10 are connected by laser welding, and the adapter 20 and the first connecting pipe 41 are connected by furnace welding. As shown in Embodiment 1 in FIG3 and Embodiment 2 in FIG12, an annular weld is formed between the bottom of the first mating section 21 and the bottom of the valve seat 11 where the opening of the limiting cavity 1011 is located. This arrangement avoids interference from the second connecting pipe 42 when the laser welding position is formed on the side of the electronic expansion valve.

[0072] The bottom wall of the first mating section 21 can be flush with the bottom wall of the valve seat 11; specifically, in the first embodiment shown in Figures 1 to 9, the silencing part 30 is riveted to the fixed section 24, the valve seat core 12 is pressed onto the bottom wall of the placement cavity 1012, and one end of the fixed section 24 extending into the valve seat 11 abuts against the valve seat core 12. In the axial direction of the electronic expansion valve, the height of the mounting cavity 101 is H1, and the sum of the height of the valve seat core 12, the height of the first mating section 21 of the transition part 20, and the height of the fixed section 24 of the transition part 20 is H2 (wherein, the height of the fixed section 24 is based on the actual height of the silencing part 30 after the riveting flange 241 is riveted, i.e., H61 + H62), H1 = H2, the first mating section 21 The bottom wall of section 1 is flush with the bottom wall of valve seat 11. Furthermore, to avoid excessively high laser weld marks after welding, the bottom wall of the first mating section 21 and / or the bottom wall of valve seat 11 have an annular groove 1 at the annular weld. The area within the annular groove 1 serves as the annular weld. All or most of the laser weld marks formed after welding will be located within the annular groove 1, thus concealing the laser weld marks. This ensures that the laser weld marks formed after laser welding will not protrude from the positioning reference surface, or that any protrusion will have almost no impact on the positioning reference surface's positioning effect, and will not affect the positioning during subsequent assembly and welding, thereby ensuring the reliability of the welding and the positioning reference surface. The cross-sectional shape of the annular groove 1 can be adaptively adjusted according to actual conditions and is not limited to the triangle shown in Embodiment 1.

[0073] The bottom wall of the first mating section 21 can protrude beyond the bottom wall of the valve seat 11, so that the bottom wall of the first mating section 21 and the bottom wall of the valve seat 11 are spaced apart in the axial direction, which facilitates laser welding focusing. Specifically, in the second embodiment shown in Figures 10 to 12, the silencing part 30 is riveted to the fixed section 24, the valve seat core 12 is pressed onto the bottom wall of the placement cavity 1012, and one end of the fixed section 24 extending into the valve seat 11 abuts against the valve seat core 12. In the axial direction of the electronic expansion valve, the height of the mounting cavity 101 is less than the sum of the heights of the valve seat core 12, the first mating section 21 of the transition part 20, and the fixed section 24, that is, the bottom wall of the first mating section 21 protrudes beyond the bottom wall of the valve seat 11. Specifically, the height of the placement cavity 1012 is H11, the height of the limiting cavity 1011 is H12, the height of the mounting cavity 101 is H1, and H1 = H11 + H12. The sum of the height of the valve seat core 12, the height of the first mating section 21 of the transition part 20, and the height of the fixing section 24 of the transition part 20 is H2 (wherein, the height of the fixing section 24 is based on the actual height after the riveting flange 241 is riveted to the silencing part 30, i.e., H61 + H62), and H1 < H2. The bottom wall of the first mating section 21 protrudes from the valve seat 1012. In the case of the bottom wall of section 1, the positioning reference surface is spaced from the weld position, which facilitates the focusing of laser welding at this point. As shown in Figure 12, the height of the bottom wall of the first mating section 21 protruding from the bottom wall of the valve seat 11 is H8, where H8 = H2 - H1, and 0.1mm < H8 < 1mm. By limiting H8, the laser weld marks formed after laser welding will not protrude from the positioning reference surface, or the protruding part will have almost no impact on the positioning reference effect of the positioning reference surface, and will not affect the positioning during subsequent assembly and welding.

[0074] It is understood that the method of fixing the silencing part 30 in the adapter part 20 is not limited to riveting. The silencing part 30 can be directly fixed in the adapter part 20 by laser welding or by the first silencing block 31 of the silencing part 30 protruding from the adapter part 20, with the protruding part of the first silencing block 31 abutting against the valve seat part 10 along the axis of the electronic expansion valve.

[0075] As shown in Figures 1, 2, 5, and 11, the adapter portion 20 in this application has an annular stop protrusion 23. The annular stop protrusion 23 is disposed between the first mating section 21 and the second mating section 22, and protrudes radially inward. The inner diameter of the annular stop protrusion 23 is smaller than the inner diameter of the second mating section 22. The area surrounded by the annular stop protrusion 23 forms an adapter interface 203. One end of the first connector 41 is disposed within the second mating section 22 and engages with the annular stop protrusion 23. The adapter interface 203 communicates with the opening of the first connector 41. In this application, one end of the first connector 41 penetrates into the second mating section 22 and abuts against the annular stop protrusion 23. The annular stop protrusion 23 limits the penetration depth of the first connector 41. The outer diameter of the first connector 41 is adapted to the inner diameter of the second mating section 22.

[0076] The inner diameter of the first connecting pipe 41 is adapted to the radial dimension of the adapter 203, which facilitates the limiting installation of the first connecting pipe 41 and the forming of the adapter 203. At the same time, it realizes the smooth transition of refrigerant flowing through the adapter 203 and the first connecting pipe 41, and reduces the noise of refrigerant flow.

[0077] In some embodiments, the adapter 203 is a straight section with a constant inner diameter along the axis of the electronic expansion valve; in other embodiments, the adapter 203 is a first flared opening; and in still other embodiments, the adapter 203 has a first flared opening on the side opposite to the first connecting pipe 41. The inner diameter of the first flared opening gradually increases along the direction from the first connecting pipe 41 toward the valve cavity 102. The side of the first flared opening with a smaller opening communicates with the first connecting pipe 41, and its radial dimension matches the inner diameter of the first connecting pipe 41. The opening angle of the first flared opening is β, where 20°≤β≤120°. Specifically, in Embodiment 1 shown in FIG. 5 and Embodiment 2 shown in FIG. 11, the adapter 203 includes a first flared opening and a straight section that are interconnected. By setting the first flared opening, on the one hand, it can be ensured that there are no burrs here (the adapter 20 is a precision-machined part, and burrs are easily generated here when the flow is direct); on the other hand, the valve seat 11 of the electronic expansion valve is also connected to the second pipe 42. When the fluid enters from the first pipe 41 and exits from the second pipe 42, the inner diameter of the first flared opening gradually increases along the direction of the first pipe 41 toward the valve mouth 102, which provides a buffer for the fluid entering from the first pipe 41, making it less likely to form eddies, realizing gradual pressure change, reducing flow velocity, reducing the impact of high-speed fluid on the filter screen, that is, reducing the refrigerant flow velocity at the valve port, reducing turbulent kinetic energy, and thus reducing noise.

[0078] In Embodiment 1 shown in Figure 6 and Embodiment 2 shown in Figure 11, the height of the first flared mouth is H7, 0.1mm≤H7≤3mm, and the inner diameter of the small opening of the first flared mouth near the first connecting pipe 41 is as similar as possible to the inner diameter of the first connecting pipe 41, with the difference between the two not exceeding 5%.

[0079] Specifically, the flow curve of the electronic expansion valve provided in this application is designed as a rapidly opening broken line with a flow inflection point. At a small opening, the flow is smooth and the flow value is small to meet the adjustment under dehumidification conditions. At a large opening, the flow is large to meet the flow capacity under normal air conditioning conditions and reduce pressure drop.

[0080] The valve cavity 102 includes a valve port section 1021 and a flared section 1022 that are interconnected. The valve port section 1021 has a flow regulating section, which is connected to the receiving cavity 201 through the flared section 1022. The electronic expansion valve also includes a valve needle assembly 60. The flow regulating section is located at one end of the valve port section 1021 near the valve needle assembly 60. The valve needle assembly 60 includes a valve head 61, which can move closer to or further away from the valve cavity 102 along the axial direction of the electronic expansion valve and cooperate with the flow regulating section to regulate the flow rate of the electronic expansion valve. It should be noted that the electronic expansion valve provided in this application is a fully closed flow-line type. When the entire valve is in the fully closed state, there is a gap between the outer periphery of the valve head 61 and the inner wall of the valve port section 1021. The refrigerant can flow through the gap between the two connecting pipes (the first connecting pipe 41 and the second connecting pipe 42). At this time, the electronic expansion valve has a flow rate, and the flow rate value is greater than the internal leakage rate specified in the industry standard for the corresponding diameter. It is understandable that the flow rate when fully closed is achieved by moving the valve head 61 axially upward after finding the zero point with a fixed pulse, and the flow rate when fully closed is achieved through the gap between the valve head 61 and the valve port section 1021 when fully closed.

[0081] In Embodiment 1, as shown in Figures 6 to 9, the valve needle assembly 60 further includes a screw member 62, and the electronic expansion valve further includes a rotor assembly 80 for driving the screw member 62. The inner wall of the valve port section 1021 of this application has a first conical section 10211 and a first straight-through section 10212 that are interconnected and sequentially arranged along the direction from the valve mouth 102 towards the first connecting pipe 41. The first conical section 10211 is a flow regulating section, and the first straight-through section 10212 is connected to the flared section 1022. The valve head member 61 cooperates with the inner wall of the first conical section 10211 to regulate the flow rate of the electronic expansion valve. The height of the first conical section 10211 is H5, and the electronic expansion valve is fully closed. At that time, the distance from the end of the valve head 61 to the connecting surface of the first conical section 10211 and the first straight section 10212 is H9. The electronic expansion valve has a flow inflection point with a change in flow slope during the valve opening process. The flow inflection point here is the point when the end of the valve head 61 facing the valve cavity 102 just leaves the first conical section 10211; B*n*γ / 360+H9=H5; where B is the number of supply pulses required for the valve head 61 to move from the fully closed position in a direction away from the valve cavity 102 and open the valve until it just leaves the first conical section 10211 (flow inflection point), n is the pitch of the screw 62, and γ is the step angle of the rotor assembly 80. As shown in Figures 7 to 9, in this embodiment, the fully closed position is located on the first conical section 10211. That is, when the electronic expansion valve is in the fully closed position, the end of the valve head 61 facing the valve cavity 102 is located inside the first conical section 10211 and above the first straight section 10212. There is a gap between the valve head 61 and the inner wall of the first conical section 10211. The flow curve has no flat segment after the 0 pulse and rises directly with a slope from the 0 pulse.

[0082] The flow regulation section is shaped like a second flared opening, with the larger opening side of the second flared opening facing away from the first connecting pipe 41. In this application, the first conical section 10211 is the second flared opening, and the opening angle of the second flared opening is α, where 1°≤α≤10°. The slopes of the broken line before and after the flow inflection point are different; before the flow inflection point, the flow curve is gentle, while after the flow inflection point, the slope of the broken line is larger, corresponding to a larger flow rate and a smaller flow resistance when the electronic expansion valve is fully open. The flow rate requirement is relatively small under dehumidification conditions. If this angle is too large, the flow rate will be too large at a small opening, failing to meet the overall dehumidification requirements of the unit. If this angle is too small, it will interfere with the outer diameter of the valve head 61. By limiting the angle α, it is beneficial to ensure the flow rate and stability of the electronic expansion valve at a small opening. Preferably, 1°≤α≤6°. The number of supply pulses required for the valve head 61 to move from the fully closed position to the flow inflection point can be achieved by setting the height H5 of the first conical section 10211. H5 can be customized according to the customer's overall machine requirements (ensuring that the inflection point of the flow curve is between 300P and 400P under normal circumstances). Specifically, 2.5mm≤H5≤7mm.

[0083] Wherein, B is in units of pulses or steps, and the value of B can be customized according to customer requirements. Once the value of B is determined, the height H5 of the corresponding first conical segment 10211 can be determined. It can be understood that, as shown in Embodiment 1 of Figure 7, the maximum diameter of the first conical segment 10211 is D41, and the minimum diameter of the first conical segment 10211 is the same as the diameter of the first straight segment 10212, both being D42. α or H5 can be calculated by tanα / 2=[(D41-D42) / 2] / H5, and the unit of n is mm. γ is related to the number of magnetic pole pairs of the valve body. For example, with 1-2 phase excitation, the rotor has 10 magnetic pole pairs, and the step angle γ=4.5°; with 1-2 phase excitation, the rotor has 12 magnetic pole pairs, and the step angle γ=3.75°; with 2-2 phase excitation, the rotor has 10 magnetic pole pairs, and the step angle γ=9°; with 2-2 phase excitation, the rotor has 12 magnetic pole pairs, and the step angle γ=7.5°. γ / 360 is the number of pulses required for the valve head to rotate one revolution.

[0084] As shown in Figures 13 to 15, Embodiment 3 of this application provides an electronic expansion valve. The difference from Embodiment 1 is that the inner wall of the valve port section 1021 in Embodiment 3 has a first conical section 10211, a first straight-through section 10212, a second conical section 10213, and a second straight-through section 10214 sequentially connected along the direction from the valve mouth 102 towards the first connecting pipe 41. As shown in Figure 13, the maximum diameter of the first conical section 10211 is D43, and the minimum diameter of the first conical section 10211 is the same as the diameter of the first straight-through section 10212, both being D44. The minimum diameter of the valve port section 1021 is also the minimum diameter of the second conical section 10213, and also the minimum diameter of the second straight-through section 10214, which is D45.

[0085] In Embodiment 3, when the electronic expansion valve is in the fully closed state, the end of the valve head 61 is located in the first straight-through section 10212, and there is a gap between the outer periphery of the valve head 61 and the first straight-through section 10212. At this time, the first conical section 10211 plays a role in flow regulation, while the lower second conical section 10213 does not have a flow regulation function. Specifically, the first conical section 10211 is the flow regulation section. In the fully closed position, the end of the valve head 61 facing the valve cavity 102 is located in the first straight-through section 10212. The height of the first conical section 10211 is H5, and the depth of the valve head 61 passing through the first conical section 10211 and extending into the first straight-through section 10212 is H9. Therefore, B*n*γ / 360-H9=H5. As shown in Figures 13 to 15, the fully closed flow rate in Embodiment 3 is achieved through the gap between the valve head 61 and the first straight-through section 10212. The fully closed position is located on the first straight-through section 10212. Since the outer wall of the part of the valve head 61 that extends into the valve cavity 102 in Embodiment 3 is a straight segment, the gap between the outer wall of the valve head 61 and the inner wall of the first straight-through section 10212 remains unchanged as the valve head 61 moves away from the fully closed position towards the direction away from the valve cavity 102. Therefore, the flow rate curve has a flat segment after the 0 pulse. When the end of the valve head 61 facing the valve cavity 102 leaves the first straight-through section 10212 and enters the first conical section 10211, the flow rate curve starts to slope upward again after the flat segment. Since the fully closed position falls on the first straight-through section 10212, the gap between the valve head 61 and the straight section can be controlled to be smaller when fully closed, and the risk of jamming between the valve head 61 and the valve port section 1021 is small, so as to achieve a smaller flow rate adjustment under dehumidification conditions. In embodiment three, the second conical section 10213 is used for the fixed pulse of the electronic expansion valve. That is, during the installation process of the electronic expansion valve, the valve head 61 and the second conical section 10213 are first brought into contact, and then the valve head 61 is moved upward along the axial direction by a certain distance, so that the end face of the valve head 61 facing the valve mouth 102 enters the first straight-through section 10212.

[0086] As shown in Figures 14 and 15, in Embodiment 3, the fully closed flow rate is achieved through the gap between the valve head 61 and the first straight-through section 10212. The fully closed position is located on the first straight-through section 10212. The flow rate curve has a flat section after the 0 pulse, and then starts to slope upward after the flat section.

[0087] In the embodiments of this application, the valve seat 11 and the valve seat core 12 are separately disposed, with the valve seat core 12 press-fitted into the placement cavity 1012 of the valve seat 11. Of course, in other embodiments of this application (not shown in the figures), the valve seat core 12 and the valve seat 11 can also be integrally formed into a valve seat portion 10, with the valve seat core 12 integrally formed in the placement cavity 1012, and the valve mouth 102 located in the integral valve seat portion 10, and the valve mouth 102 having the aforementioned valve port section 1021. Except that the valve seat core 12 and the valve seat 11 are integrally disposed, the other implementation methods and flow curves of the fully closed flow are the same as those in the aforementioned embodiments, and will not be repeated here.

[0088] It is understood that, depending on the position of the end of the valve head 61 when the valve is closed (including but not limited to the first conical section 10211, the first straight section 10212, the second conical section 10213, and the second straight section 10214 in this application), the formula for tanα / 2 and the formula between H5 and H9 can be adapted accordingly, and will not be listed one by one here.

[0089] Specifically, when the electronic expansion valve is in fully open mode, the flow coefficient Cv ≥ 1, where, V represents the maximum flow rate of the electronic expansion valve, G represents the specific gravity of the medium flowing through the electronic expansion valve, P1 represents the pressure on the inflow side of the electronic expansion valve, and P2 represents the pressure on the outflow side of the electronic expansion valve. Cv is the flow coefficient of the electronic expansion valve, representing its flow capacity when fully open. When Cv is less than 1, it indicates insufficient flow capacity in the fluid, meaning the electronic expansion valve will still throttle the flowing fluid even when fully open. This affects the fluid flow between the indoor heat exchangers, thus impacting the overall performance. In this application, by setting Cv ≥ 1, the flow capacity of the electronic expansion valve is guaranteed, ensuring that the valve's flow capacity meets the overall performance requirements when used under normal air conditioning conditions.

[0090] Another embodiment of this application provides an assembly process applied to the aforementioned electronic expansion valve. The electronic expansion valve further includes a second connecting pipe 42, a nut assembly 50, a valve needle assembly 60, and a guide sleeve 70. The assembly process includes: welding one end of the second connecting pipe 42 to a side portion of the valve seat portion 10; welding the first connecting pipe 41 to one end of the adapter portion 20; installing a silencing portion 30 within the adapter portion 20; installing a portion of the adapter portion 20 within the valve seat portion 10; welding the adapter portion 20 to the valve seat portion 10; and [further details about the assembly process are needed for a complete translation]. The process of sequentially installing the nut assembly 50 and the valve needle assembly 60 on the valve seat 10, and welding one end of the second connecting pipe 42 to the side of the valve seat 10 before sequentially installing the nut assembly 50 and the valve needle assembly 60 on the valve seat 10, further includes: first pressing the guide sleeve 70 into the valve seat 10, then furnace welding the second connecting pipe 42, the valve seat 10, and the guide sleeve 70 as a whole; or first furnace welding the second connecting pipe 42 and the valve seat 10, then pressing the guide sleeve 70 into the valve seat 10, and then laser welding the guide sleeve 70 and the valve seat 10 to set the pulse for the electronic expansion valve. This setup allows for independent off-line installation of the adapter 20 and the silencer 30, which helps reduce production cycle time, improve parts standardization, avoid the risk of parts falling during turnover, facilitate the assembly of the electronic expansion valve, and improve assembly efficiency.

[0091] The end of the adapter 20 is located outside the valve seat 10, and the first connecting pipe 41 is welded to the end of the adapter 20 located outside the valve seat 10. The order of the steps "welding one end of the second connecting pipe 42 to the side of the valve seat 10", "welding the first connecting pipe 41 to the end of the adapter 20", and "installing the muffler 30 inside the adapter 20" is not limited.

[0092] Specifically, the silencing part 30 includes a first silencing block 31, a pad block 32 and a second silencing block 33 that abut against each other in the installation direction of the silencing part 30. The process of installing the silencing part 30 in the adapter part 20 includes: installing the second silencing block 33, the pad block 32 and the first silencing block 31 in the adapter part 20 in sequence.

[0093] Similarly, the first connecting pipe 41 is first welded to the end of the adapter 20 located outside the valve seat 10, and then the silencing part 30 is installed inside the adapter 20; or, the silencing part 30 is first installed inside the adapter 20, and then the adapter 20 and the first connecting pipe 41 are welded together.

[0094] Furthermore, in the assembly process provided in this application, the valve seat portion 10 includes a separate valve seat 11 and a valve seat core 12. The assembly process also includes the step of placing the valve seat core 12 inside the valve seat 11, with one end of the adapter 20 extending into the valve seat 11 abutting against the valve seat core 12. It is understood that in another embodiment (not shown in the figures), the valve seat portion 10 includes an integral valve seat 11 and valve seat core 12, in which case the step of installing the valve seat core 12 is unnecessary. Or in yet another embodiment (not shown in the figures), the valve seat portion 10 includes a separate valve seat 11 and valve seat core 12, with the silencing portion 30 abutting against the valve seat core 12.

[0095] The adapter 20 and the valve seat 10 are laser welded together.

[0096] In this embodiment, the guide sleeve 70 is smaller at the top and larger at the bottom. The nut assembly 50 includes a nut component. The guide sleeve 70 includes a first sleeve 71, a limiting sleeve 73, and a second sleeve 72 connected in sequence. The limiting sleeve 73 is used to limit the position of the guide sleeve 70 within the valve seat 11. The outer diameters of the first sleeve 71, the second sleeve 72, and the limiting sleeve 73 increase sequentially. The inner diameters of the first sleeve 71 and the limiting sleeve 73 are the same and larger than the inner diameter of the second sleeve 72. The outer periphery of the second sleeve 72 is interference-fitted with the inner hole of the nut component to ensure their coaxiality. The inner cavity of the first sleeve 71 is used to pass through the valve head component 61 and is clearance-fitted with the outer periphery of the valve head component 61, with a clearance of 0.01mm-0.1mm.

[0097] Since the outer diameter of the main connecting pipe of the indoor heat exchanger of the mainstream household 3P split cabinet air conditioner is mostly Φ9.0 or Φ8.0, taking the outer diameter Φ9.0 as the calculation, the wall thickness is mostly 0.75mm, that is, the inner diameter is Φ7.5. Therefore, the valve port must be >Φ7.5mm to ensure that there is no excessive pressure drop when the valve is fully open, thereby ensuring the performance of the whole machine; 7mm≤ the minimum diameter of valve cavity 102≤9.5mm.

[0098] The above description is merely an optional embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

An electronic expansion valve characterized by The electronic expansion valve comprises a first connecting pipe (41), a sound damping part (30), and a valve seat part (10) and a switching part (20) connected with each other, the switching part (20) is connected with the valve seat part (10) and the first connecting pipe (41) respectively, the switching part (20) has a containing cavity (201), and the sound damping part (30) is limitingly installed in the containing cavity (201). The electronic expansion valve according to claim 1, wherein The sound damping part (30) is laser welded in the containing cavity (201), or the sound damping part (30) is riveted in the containing cavity (201), or the sound damping part (30) is press-fitted in the containing cavity (201). The electronic expansion valve according to claim 1, wherein The valve seat part (10) has a limiting cavity (1011), the switching part (20) comprises a fitting section, at least part of the fitting section is arranged in the limiting cavity (1011), the cavity inner wall of the containing cavity (201) and the cavity formed by the fitting section are distributed along the axial direction of the switching part (20) and have an inner stepped surface (204) between the two inner walls, and the sound damping part (30) abuts against the inner stepped surface (204). The electronic expansion valve according to claim 3, wherein The fitting section comprises a first fitting section (21) and a second fitting section (22) connected with each other, at least part of the first fitting section (21) extends into the limiting cavity (1011), at least part of the second fitting section (22) is located outside the limiting cavity (1011) and is used for switching the first connecting pipe (41), the outer diameter of the first fitting section (21) is greater than the outer diameter of the second fitting section (22), and the inner diameter of the first fitting section (21) is greater than the inner diameter of the second fitting section (22). The electronic expansion valve according to claim 4, wherein An outer stepped surface (202) is formed between the outer wall of the first fitting section (21) and the outer wall of the second fitting section (22), the outer stepped surface (202) protrudes from the limiting cavity (1011) to form a positioning reference surface, or the outer stepped surface (202) is flush with the surface where the opening of the limiting cavity (1011) is located and forms a positioning reference surface. The electronic expansion valve according to claim 4, wherein The switching part (20) has an annular stop protrusion (23) therein, the annular stop protrusion (23) is arranged between the first fitting section (21) and the second fitting section (22) and protrudes inwardly in the radial direction of the switching part (20), the inner diameter of the annular stop protrusion (23) is smaller than the inner diameter of the second fitting section (22), an switching interface (203) is formed around the annular stop protrusion (23), one end of the first connecting pipe (41) is arranged in the second fitting section (22) and is in stop cooperation with the annular stop protrusion (23), and the switching interface (203) is in communication with the opening of the first connecting pipe (41). The electronic expansion valve according to claim 6, wherein The adapter interface (203) is a straight section with a constant inner diameter along the axial direction of the electronic expansion valve, or the adapter interface (203) is a first flared opening, or the adapter interface (203) has a first flared opening on the side away from the first connecting pipe (41), the inner diameter of the first flared opening gradually increases in the direction of the first connecting pipe (41) towards the adapter interface (203), the side with a smaller opening of the first flared opening is in communication with the first connecting pipe (41) and the radial dimension is adapted to the inner diameter of the first connecting pipe (41), the opening angle of the first flared opening is β, 20°≤β≤120°. The electronic expansion valve according to claim 1, wherein The opening of the accommodating cavity (201) has a riveted flange (241), and the sound attenuation part (30) is riveted and installed in the accommodating cavity (201) through the riveted flange (241). The electronic expansion valve according to claim 8, wherein The riveted flange (241) is an annular flange, or the riveted flange (241) is a plurality of riveted flanges (241) distributed along the circumference of the adapter (20). The electronic expansion valve according to claim 8, wherein The adapter (20) includes a fixed section (24), the area surrounded by the fixed section (24) forms the accommodating cavity (201), and on the axial direction of the fixed section (24), the part of the fixed section (24) on the side of the opening protrudes from the sound attenuation part (30) to form the riveted flange (241). The electronic expansion valve according to claim 1, wherein The valve seat part (10) includes a valve seat (11) and a valve seat core (12), the valve seat (11) has a mounting cavity (101), the valve seat core (12) is arranged in the mounting cavity (101), the area of the mounting cavity (101) for mounting the valve seat core (12) forms a placement cavity (1012), and the area of the mounting cavity (101) for mounting the adapter (20) forms a limiting cavity (1011). The electronic expansion valve according to claim 11, wherein The valve seat core (12) is separate from the valve seat (11) and is arranged in the placement cavity (1012), or the valve seat core (12) is an integral structure with the valve seat (11) and is integrally formed in the placement cavity (1012). The electronic expansion valve according to claim 1, wherein The valve seat part (10) has a valve port cavity (102) on the side away from the adapter (20) of the accommodating cavity (201), the valve port cavity (102) is in communication with the accommodating cavity (201), and the valve port cavity (102) includes a valve port section (1021), the valve port section (1021) is a variable-diameter flow regulating section, or the side away from the accommodating cavity (201) of the valve port section (1021) has a variable-diameter flow regulating section for regulating the flow of the electronic expansion valve. The electronic expansion valve according to claim 13, wherein The flow regulating section is a second flared opening, and the opening angle of the second flared opening is α, 1°≤α≤10°. The electronic expansion valve according to claim 13, wherein The electronic expansion valve further comprises a valve needle assembly (60), the valve needle assembly (60) comprises a valve head piece (61), the valve head piece (61) cooperates with the inner wall of the flow regulating section to regulate the flow of the electronic expansion valve, one end of the valve head piece (61) extends into the valve port section (1021) in the full closing state of the electronic expansion valve, and there is a gap between the outer periphery of the valve head piece (61) and the inner wall of the valve port section (1021). The electronic expansion valve according to claim 15, wherein The electronic expansion valve further comprises a rotor assembly (80), the valve needle assembly (60) further comprises a screw piece (62) in driving connection with the rotor assembly (80), the inner wall of the valve port section (1021) has a first tapered section (10211) and a first straight-through section (10212) which are sequentially arranged and communicated in the direction of the valve port cavity (102) towards the first connecting pipe (41), the first tapered section (10211) is the flow regulating section, one end of the valve head piece (61) is located in the first tapered section (10211) in the full closing state of the electronic expansion valve, and there is a gap between the outer periphery of the valve head piece (61) and the inner wall of the first tapered section (10211); the height of the first tapered section (10211) is H5, the distance between the end of the valve head piece (61) and the communication surface of the first tapered section (10211) and the first straight-through section (10212) is H9, and the electronic expansion valve has a flow turning point with a flow rate slope change in the valve opening process; B*n*γ / 360+H9=H5; Wherein, B is the number of supply pulses required for the valve head piece (61) to open from the full closing position to the flow turning point, n is the pitch of the screw piece (62), and γ is the step angle of the rotor assembly (80). The electronic expansion valve according to claim 15, wherein The electronic expansion valve further comprises a rotor assembly (80), the valve needle assembly (60) further comprises a screw piece (62) in driving connection with the rotor assembly (80), the inner wall of the valve port section (1021) has a first tapered section (10211) and a first straight-through section (10212) which are sequentially arranged and communicated in the direction of the valve port cavity (102) towards the first connecting pipe (41), the first tapered section (10211) is the flow regulating section, one end of the valve head piece (61) is located in the first straight-through section (10212) in the full closing state of the electronic expansion valve, and there is a gap between the outer periphery of the valve head piece (61) and the inner wall of the first straight-through section (10212); the height of the first tapered section (10211) is H5, the distance between the end of the valve head piece (61) and the communication surface of the first tapered section (10211) and the first straight-through section (10212) is H9, and the electronic expansion valve has a flow turning point with a flow rate slope change in the valve opening process; B*n*γ / 360-H9=H5; Wherein, B is the number of supply pulses required for the valve head piece (61) to open the valve from the full closed position to the flow turning point, n is the pitch of the screw piece (62), and γ is the step angle of the rotor assembly (80). An assembly process characterized in that, The assembly process is applied to the electronic expansion valve of any one of claims 1 to 17, the electronic expansion valve further comprising a second connecting pipe (42), the assembly process comprising: welding one end of the second connecting pipe (42) to the side of the valve seat portion (10); welding the first connecting pipe (41) to the end of the one end of the adapter portion (20); installing the sound reduction portion (30) in the adapter portion (20), and installing part of the adapter portion (20) in the valve seat portion (10), and welding the adapter portion (20) to the valve seat portion (10). The assembly process of claim 18, wherein The sound reduction portion (30) comprises a first sound reduction block (31), a spacer (32) and a second sound reduction block (33) which abut in sequence along the installation direction of the sound reduction portion (30), and the process of installing the sound reduction portion (30) in the adapter portion (20) comprises: installing the second sound reduction block (33), the spacer (32) and the first sound reduction block (31) in the adapter portion (20) in sequence. The assembly process of claim 18, wherein The assembly process further comprises: the end of the one end of the adapter portion (20) is the end of the adapter portion (20) located outside the valve seat portion (10), and the first connecting pipe (41) is welded to the end of the one end of the adapter portion (20) located outside the valve seat portion (10); first, the first connecting pipe (41) is welded to the end of the one end of the adapter portion (20) located outside the valve seat portion (10), and then the sound reduction portion (30) is installed in the adapter portion (20); or, first, the sound reduction portion (30) is installed in the adapter portion (20), and then the adapter portion (20) and the first connecting pipe (41) are welded. The assembly process of claim 18, wherein The electronic expansion valve further comprises a nut assembly (50), a valve needle assembly (60) and a guide sleeve (70), The assembly process further comprises sequentially installing the nut assembly (50) and the valve needle assembly (60) on the valve seat portion (10); and before sequentially installing the nut assembly (50) and the valve needle assembly (60) on the valve seat portion (10), the process of welding one end of the second connecting pipe (42) to the side of the valve seat portion (10) further comprises: press-fitting the guide sleeve (70) in the valve seat portion (10), integrally furnace welding the second connecting pipe (42), the valve seat portion (10) and the guide sleeve (70), or first furnace welding the second connecting pipe (42) and the valve seat portion (10), and then press-fitting the guide sleeve (70) in the valve seat portion (10), and laser welding the guide sleeve (70) and the valve seat portion (10). The assembly process of claim 18, wherein The assembly process further comprises: laser welding the connection position of the adapter portion (20) and the valve seat portion (10); defining the pulse of the electronic expansion valve. The assembly process of claim 18, wherein The valve seat part (10) comprises a split valve seat (11) and a valve seat core (12), or the valve seat part (10) comprises an integrated valve seat (11) and a valve seat core (12), part of the adapter part (20) is mounted in the valve seat (11), one end of the adapter part (20) abuts the valve seat core (12) or the sound attenuation part (30) abuts the valve seat core (12).

Images