Electronic expansion valve, refrigeration equipment and positioning and assembling process of electronic expansion valve

Abstract

According to the technical scheme, the electronic expansion valve comprises a connecting base and a nut assembly, the outer wall of a first matching section of a nut is in clearance fit with the inner wall of a first containing cavity of the connecting base, and a first annular groove is formed; the outer wall of the second matching section is in clearance fit with the inner wall of the second containing cavity of the connecting base, and a second annular groove is formed. When the fixing piece and the connecting seat are welded, heat generated by welding is not directly transmitted to the nut from the connecting seat but is dissipated from the first ring groove and the second ring groove, so that the influence of the heat generated by welding the fixing piece and the connecting seat on the nut is reduced, burning and aging acceleration of the nut are avoided, and the service life of the electronic expansion valve is prolonged. And meanwhile, the risk that foreign matter generated after nut material melting and re-solidification is brought into a refrigerating system, and consequently the system is stuck is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid control components, and in particular to an electronic expansion valve, a refrigeration device and a positioning and assembling process of the electronic expansion valve. Background Art

[0002] The nut of the electronic expansion valve is welded to the connection seat, and the fixing piece that is integrally molded with the nut is welded to the connection seat. In the prior art, the nut includes a guide section and a positioning section, wherein the positioning section is interference-fitted with the connection seat to prevent the nut and the connection seat from being displaced, thus playing a positioning role. However, a large amount of heat generated when welding the fixing piece to the connection seat is easily transferred directly to the nut through the connection seat, causing the nut to burn, and even generating foreign matter from the nut material that melts and solidifies, which is brought into the refrigeration system, causing the system to jam. Summary of the invention

[0003] The main purpose of the present invention is to provide an electronic expansion valve, aiming to reduce the influence of heat generated during welding of a fixing member and a connecting seat on a nut.

[0004] The technical solution of the present invention provides an electronic expansion valve, comprising:

[0005] A connecting seat, comprising a first connecting section and a second connecting section, wherein the first connecting section is provided with a first accommodating cavity, and the second connecting section is provided with a second accommodating cavity, wherein the second accommodating cavity is provided at the cavity bottom of the first accommodating cavity and communicates with the first accommodating cavity;

[0006] A nut assembly includes a nut and a fixing member, wherein the nut includes a first mating section and a second mating section, wherein the first mating section is at least partially disposed in the first accommodating cavity and is mated with the inner wall clearance of the first accommodating cavity to form a first annular groove, and the second mating section is at least partially disposed in the second accommodating cavity and is mated with the inner wall clearance of the second accommodating cavity to form a second annular groove; the fixing member is disposed at one end of the first accommodating cavity away from the second accommodating cavity and connects the nut and the connecting seat.

[0007] In one embodiment, the distance between the first accommodating cavity and the first matching segment is greater than the distance between the second accommodating cavity and the second matching segment.

[0008] In one embodiment, a diameter of the second accommodating cavity is smaller than a diameter of the first accommodating cavity.

[0009] In one embodiment, a diameter of the second mating segment is smaller than a diameter of the first mating segment.

[0010] In one embodiment, part of the second mating section is disposed in the second accommodating cavity, and the other part is disposed in the first accommodating cavity, and the second mating section and the inner wall of the first accommodating cavity form a third annular groove, and the third annular groove connects the first annular groove and the second annular groove.

[0011] In one embodiment, a receiving groove is formed at one end of the first receiving cavity away from the second receiving cavity, the bottom of the receiving groove is connected to the inner wall of the first receiving cavity, and the fixing member is disposed in the receiving groove and abuts against the bottom of the receiving groove.

[0012] In one embodiment, the second connecting section is provided with a plurality of balancing channels, the balancing channels penetrate the second connecting section along the axial direction of the connecting seat and are connected to the first annular groove; the fixing member is provided with a plurality of balancing through holes, the balancing through holes are connected to the first annular groove, and the plurality of balancing through holes are arranged at intervals along the circumference of the fixing member.

[0013] In one embodiment, the nut is provided with a guide through hole along its axial direction, and the electronic expansion valve is further provided with a valve needle assembly passing through the through hole, the valve needle assembly can move along the axial direction of the guide through hole, and the valve needle assembly is clearance-matched with the inner wall of the guide through hole.

[0014] In one embodiment, a gap between the valve needle assembly and an inner wall of the guide through hole is not greater than 0.10 mm and not less than 0.05 mm.

[0015] In one embodiment, the fixing member and the nut are integrally formed by injection molding.

[0016] In one embodiment, the fixing member is welded to the connecting seat.

[0017] The present invention also provides a refrigeration device, comprising the aforementioned electronic expansion valve.

[0018] The present invention also provides a positioning and assembling process of an electronic expansion valve, the electronic expansion valve comprises a connecting seat and a nut assembly, the connecting seat comprises a first connecting section and a second connecting section, the first connecting section is provided with a first accommodating cavity, the second connecting section is provided with a second accommodating cavity, the second accommodating cavity is provided at the cavity bottom of the first accommodating cavity and communicates with the first accommodating cavity; the nut assembly comprises a nut and a fixing member provided at the outer periphery of the nut, the nut comprises a first matching section and a second matching section, the nut is provided with a guide through hole along its axial direction, and the positioning and assembling process of the electronic expansion valve comprises the following steps:

[0019] Step 1, passing the positioning shaft through the guide through hole to install the nut assembly on the outer periphery of the positioning shaft;

[0020] Step 2: Pass the assembled nut assembly and the positioning shaft through the first accommodating cavity, so that the first matching section and the inner wall of the first accommodating cavity form a first annular groove, and the second matching section and the inner wall of the second accommodating cavity form a second annular groove;

[0021] Step 3, welding the fixing member to the connecting seat;

[0022] Step 4: Take out the positioning shaft.

[0023] In one embodiment, in step 1, the guide through hole includes a first guide through hole and a second guide through hole, the positioning shaft includes a first positioning segment, a second positioning segment and a third positioning segment arranged in sequence along its axial direction, the diameter of the second positioning segment is larger than the first positioning segment and smaller than the third positioning segment, and a portion of the third positioning segment protruding from the second positioning segment is formed with a step surface; the first positioning segment is passed through the first guide through hole, the second positioning segment is arranged in the second guide through hole, and the end face of the nut abuts against the step surface.

[0024] In one embodiment, a gap between the first positioning section and the first guide hole is L1, which is not greater than 0.02 mm and not less than 0.005 mm; a gap between the second positioning section and the second guide hole is L2, which is not greater than 0.005 mm and greater than 0 mm.

[0025] In one embodiment, the diameter of the first accommodating cavity is larger than the diameter of the second accommodating cavity, and the diameter of the first mating section is larger than the diameter of the second mating section; in step 2, the second mating section and the inner wall of the first accommodating cavity form a third annular groove, and the third annular groove connects the first annular groove and the second annular groove.

[0026] In one embodiment, in step 2, the third positioning section passes through the second accommodating cavity, and a gap between the third positioning section and the second accommodating cavity is L3, and L3 is not greater than 0.02 mm and not less than 0.005 mm.

[0027] In one embodiment, the first connecting section is further provided with a receiving groove, and the receiving groove is provided at one end of the first receiving cavity away from the second receiving cavity. In the step 2, the fixing member overlaps the bottom of the receiving groove, and there is a gap L4 between the fixing member and the groove wall of the receiving groove, and L4 is not greater than 0.1 mm and not less than 0.02 mm.

[0028] The technical solution of the present invention is that the outer wall of the first matching section of the nut is loosely matched with the inner wall of the first accommodating cavity of the connecting seat to form a first annular groove, and the outer wall of the second matching section is loosely matched with the inner wall of the second accommodating cavity of the connecting seat to form a second annular groove. When welding the fixing member and the connecting seat, the heat generated by welding will not be directly transferred from the connecting seat to the nut, but will be dissipated from the first annular groove and the second annular groove, thereby reducing the influence of the heat generated when the fixing member and the connecting seat are welded on the nut, avoiding the nut from being burned and aging faster, and extending the service life of the electronic expansion valve. At the same time, it reduces the risk of foreign matter melted and then solidified by the nut material being brought into the refrigeration system, causing the system to get stuck. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of the structure of an electronic expansion valve according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the assembly of a nut assembly, a connecting seat and a positioning shaft in one embodiment;

[0032] Figure 3 for Figure 1 A schematic diagram of the structure of the nut assembly;

[0033] Figure 4 for Figure 1 A schematic diagram of the structure of the middle connecting seat;

[0034] Figure 5 for Figure 2 Schematic diagram of the structure of the central positioning axis;

[0035] Figure 6 for Figure 2 A partial enlarged view of the middle A;

[0036] Figure 7 for Figure 2 A partial enlarged view of point B in the middle;

[0037] Figure 8 for Figure 2 A partial enlarged view of point C in the middle;

[0038] Fig. 9 This is a partial schematic diagram before welding the fixing part and the connecting seat.

[0039] Description of Figure Numbers:

[0040] Label name Label name 10 Electronic expansion valve 110 First connection section 100 Nut assembly 120 Second connecting section 200 Connector 111 The first accommodating chamber 300 Valve needle assembly 112 Receiving slot 410 First ring groove 121 Second accommodating chamber 420 Second ring groove 122 Balanced Channel 430 The third ring groove 210 Nuts 20 Positioning axis 220 Fixings 21 First positioning section 221 Balanced vias 22 Second positioning section 211 The first matching section 23 The third positioning section 212 The second matching section 24 Step surface 2131 First guide hole 213 Guide hole 2132 The second guide hole

[0041] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0044] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if the meaning of "and / or" appearing in the full text is to include three parallel schemes, taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0045] The electronic expansion valve proposed by the present invention is an important component in a refrigeration system, and mainly plays the role of throttling, reducing pressure and regulating flow. The existing electronic expansion valve includes a valve seat assembly, a shell, a rotor assembly, a nut assembly and a valve core assembly, the nut assembly has a nut, the nut has a thread, the valve core assembly has a valve stem, the valve stem has a thread, the nut is threadedly connected to the valve stem, the rotor assembly is fixedly connected to the valve stem, the valve seat assembly has a valve port, the valve core assembly has a valve needle, the magnetic rotor drives the valve stem, and the valve stem drives the valve needle to approach or move away from the valve port to achieve flow regulation.

[0046] The electronic expansion valve proposed in the present invention can be applied to an air-conditioning system, and the fluid medium flowing through the electronic expansion valve is a refrigerant used for heat exchange in the air-conditioning system. At this time, the electronic expansion valve is installed at the inlet of the evaporator of the air-conditioning system. The electronic expansion valve serves as a dividing element between the high-pressure side and the low-pressure side of the air-conditioning system, throttling and reducing the pressure of the high-pressure liquid refrigerant from the liquid storage dryer and other devices, thereby adjusting and controlling the dosage of the liquid refrigerant entering the evaporator, so that the dosage of the liquid refrigerant can meet the requirements of the external refrigeration load. Alternatively, the electronic expansion valve is applied to other types of refrigeration equipment, and the fluid medium flowing through the electronic expansion valve can also be other fluid media besides the refrigerant, as long as the electronic expansion valve can achieve throttling and reducing the pressure of the fluid medium, and there is no specific limitation on this.

[0047] Please refer to Figures 1 to 5 The present invention provides an electronic expansion valve 10, including a connection seat 200 and a nut assembly 100, the connection seat 200 includes a first connection section 110 and a second connection section 120, the first connection section 110 is provided with a first accommodating cavity 111, the second connection section 120 is provided with a second accommodating cavity 121, the second accommodating cavity 121 is provided at the bottom of the first accommodating cavity 111, and is connected to the first accommodating cavity 111; the nut assembly 100 includes a nut 210 and a fixing member 220, the nut 210 includes a first matching section 211 and a second matching section 212, the first matching section 211 is at least partially disposed in the first accommodating cavity 111, and is matched with the inner wall clearance of the first accommodating cavity 111 to form a first annular groove 410, the second matching section 212 is at least partially disposed in the second accommodating cavity 121, and is matched with the inner wall clearance of the second accommodating cavity 121 to form a second annular groove 420; the fixing member 220 is disposed at one end of the first accommodating cavity 111 away from the second accommodating cavity 121, and is connected to the nut 210 and the connecting seat 200.

[0048] Specifically, an electronic expansion valve 10 includes a connection seat 200 and a nut assembly 100, wherein the connection seat 200 is used to connect the nut assembly 100 to the valve seat. The connection seat 200 is provided with a first accommodating chamber 111 and a second accommodating chamber 121, wherein the second accommodating chamber 121 is arranged at the bottom of the first accommodating chamber 111 and communicates with the first accommodating chamber 111. The diameter of the first accommodating chamber 111 may be greater than the diameter of the second accommodating chamber 121, or may be the same as the diameter of the second accommodating chamber 121. The nut assembly 100 includes a nut 210 and a fixing member 220, wherein the nut 210 includes a first matching section 211 and a second matching section 212, wherein the first matching section 211 is at least partially arranged in the first accommodating chamber 111, and the second matching section 212 is at least partially arranged in the second accommodating chamber 121. The fixing member 220 is fixedly connected to the nut 210, and the fixing member 220 is made of metal, preferably SUS303 or SUS304. The fixing member 220 and the nut 210 can be welded or integrally injection molded. The fixing member 220 is arranged on the outer wall of the first matching section 211, and the outer wall of the fixing member 220 and the connecting seat 200 are laser welded, so that the fixing member 220 and the connecting seat 200 are fixedly connected together, so that the nut assembly 100 and the connecting seat 200 are fixedly connected. Soldering or ultrasonic metal welding can also be used between the fixing member 220 and the connecting seat 200.

[0049] Nut 210 can be made of PPS (polyphenylene sulfide), which is a new high-performance thermoplastic resin with the advantages of high mechanical strength, high temperature resistance, chemical resistance, flame retardancy, good thermal stability, and excellent electrical properties. By making nut 210 of engineering plastic, it can be processed by injection molding, and the quality of the thread can be guaranteed by the mold. Injection molding is not only efficient, but also has better thread quality stability. However, the thermal deformation temperature of PPS is generally greater than 260°C, and it can only be used in the temperature range of 180-220°C. When the fixing part 220 is welded to the connecting seat 200, the high temperature generated by the welding of the fixing part 220 and the connecting seat 200 is easy to burn the nut 210, causing the nut 210 to age, deform or burn, reducing the strength of the nut 210 and affecting its normal use. It may even produce foreign matter from the melted and solidified material of the nut 210, which is brought into the refrigeration system and causes the system to jam.

[0050] Therefore, the first matching section 211 is matched with the inner wall clearance of the first accommodating chamber 111, so that a first annular groove 410 is formed between the first matching section 211 and the inner wall of the first accommodating chamber 111, and the second matching section 212 is matched with the inner wall clearance of the second accommodating chamber 121, so that a second annular groove 420 is formed between the second matching section 212 and the inner wall of the second accommodating chamber 121. The first annular groove 410 and the second annular groove 420 have the function of a heat-insulating cavity. When welding the fixing member 220 and the connecting seat 200, the heat generated by welding will not be directly transferred from the connecting seat 200 to the nut 210, but will be dissipated from the first annular groove 410 and the second annular groove 420, thereby reducing the influence of the heat generated when the fixing member 220 and the connecting seat 200 are welded on the nut 210, avoiding the burn and accelerated aging of the nut 210, and extending the service life of the electronic expansion valve 10. At the same time, it reduces the risk of foreign matter melted and resolidified by the nut 210 material being brought into the refrigeration system, causing the system to be stuck.

[0051] It should be noted that there is a gap between the fixing member 220 and the connecting seat 200 before welding. In order to facilitate the welding operation of the fixing member 220 and the connecting seat 200 and ensure the coaxiality of the installation of the nut 210, the connecting seat 200 and the nut assembly 100 are press-fitted using the positioning shaft 20 before welding the fixing member 220 and the connecting seat 200. The positioning shaft 20 includes a first positioning section 21, a second positioning section 22 and a third positioning section 23 arranged in sequence along its axial direction, wherein the diameter of the second positioning section 22 is larger than the first positioning section 21, and the diameter of the second positioning section 22 is smaller than the third positioning section 23, so that the portion of the third positioning section 23 protruding from the second positioning section 22 forms a step surface 24 toward the second positioning section 22. The first positioning section 21 and the second positioning section 22 are passed through the guide through hole 213 of the nut 210, so that the end face of one end of the nut 210 abuts against the step surface 24 of the third positioning section 23.

[0052] Then, the assembled nut assembly 100 and the positioning shaft 20 are passed through the first accommodating cavity 111 and the second accommodating cavity 121 of the connecting seat 200, so that the nut assembly 100 and the connecting seat 200 are installed on the positioning shaft 20. At this time, the third positioning section 23 is at least partially arranged in the second accommodating cavity 121, and is gap-matched with the second accommodating cavity 121. Moreover, a first annular groove 410 is formed between the first matching section 211 and the inner wall of the first accommodating cavity 111, and a second annular groove 420 is formed between the second matching section 212 and the inner wall of the second accommodating cavity 121. The first annular groove 410 and the second annular groove 420 have the function of heat-insulating cavities. When the fixing member 220 and the connecting seat 200 are welded, the heat generated by welding will not be directly transferred from the connecting seat 200 to the nut 210. There is a gap between the outer wall of the fixing member 220 and the connecting seat 200 before welding, and the welding stress between the outer wall of the fixing member 220 and the connecting seat 200 is small, which can reduce the influence of large coaxiality deviation. After the fixing member 220 and the connecting seat 200 are welded, the positioning shaft 20 is taken out, thereby realizing a reliable connection between the nut assembly 100 and the connecting seat 200 and ensuring the coaxiality of the nut 210 and the connecting seat 200 .

[0053] By using the positioning shaft 20 to position and install the connection seat 200 and the nut assembly 100, not only can the reliable connection between the nut assembly 100 and the connection seat 200 be achieved, but also the coaxiality of the nut 210 and the connection seat 200 can be ensured. In addition, the first matching section 211 of the nut 210 and the first accommodating cavity 111 of the connection seat 200 are clearance-matched, and the second matching section 212 and the second accommodating cavity 121 of the connection seat 200 are clearance-matched, so that the plastic material of the nut 210 is far away from the welding position, and the welding heat of the fixing part 220 and the connection seat 200 is not directly transferred to the nut 210 through the connection seat 200, causing the nut 210 to burn and melt. In addition, the material consumption of the nut 210 is reduced, and the requirements for the dimensional process accuracy of the nut 210 are reduced, thereby reducing the process cost.

[0054] In one embodiment, the distance between the first accommodating cavity 111 and the first matching segment 211 is greater than the distance between the second accommodating cavity 121 and the second matching segment 212 .

[0055] Please refer to Figure 2 The fixing member 220 is disposed at one end of the first matching section 211 away from the second matching section 212. When the fixing member 220 and the connecting seat 200 are welded, the heat generated is mainly concentrated near the first annular groove 410. The first matching section 211 is more affected by the heat and is more likely to be burned. The distance between the first accommodating cavity 111 and the first matching section 211 is greater than the distance between the second accommodating cavity 121 and the second matching section 212, so that the heat insulation effect of the first annular groove 410 is better, so as to reduce the influence of heat on the first matching section 211.

[0056] In one embodiment, the diameter of the second accommodating cavity 121 is smaller than the diameter of the first accommodating cavity 111 .

[0057] Please refer to Figure 4 , the nut 210 is a standard part, the size of its guide through hole 213 is constant, and the thickness of the first matching section 211 is constant. When the diameter of the second accommodating chamber 121 is larger than the diameter of the first accommodating chamber 111, in order to ensure that the distance between the first accommodating chamber 111 and the first matching section 211 is greater than the distance between the second accommodating chamber 121 and the second matching section 212, it is necessary to increase the diameter of the first accommodating chamber 111 and the second accommodating chamber 121, resulting in an increase in the volume of the connecting seat 200. The size of the second matching section 212 also needs to be increased along with the second accommodating chamber 121, which not only wastes materials but also increases the difficulty of processing. The diameter of the first accommodating chamber 111 is larger than the diameter of the second accommodating chamber 121, so that the positioning shaft 20 and the nut 210 can pass through the first accommodating chamber 111 more easily, thereby reducing the difficulty of assembling the positioning shaft 20 and the connecting seat 200. In other embodiments, the diameter of the second accommodating cavity 121 may be substantially the same as the diameter of the first accommodating cavity 111, and the diameter of the first mating segment 211 may be smaller than the diameter of the second mating segment 212, so that the distance between the first accommodating cavity 111 and the first mating segment 211 is greater than the distance between the second accommodating cavity 121 and the second mating segment 212.

[0058] In one embodiment, the diameter of the second matching segment 212 is smaller than the diameter of the first matching segment 211 .

[0059] Please refer to Figure 3 The fixing member 220 is generally a metal sheet with a small thickness. When the width of the fixing member 220 is large, the strength of the fixing member 220 is reduced, which is not conducive to the stability of the connection between the nut assembly 100 and the connecting seat 200. In addition, under the impact of the refrigerant, the fixing member 220 is subjected to a large impact force and is easily damaged and vibrated. The diameter of the first accommodating cavity 111 is larger than the diameter of the second accommodating cavity 121, and the diameter of the first matching section 211 is larger than the diameter of the second matching section 212, so as to avoid the distance between the first accommodating cavity 111 and the first matching section 211 being too large, thereby avoiding the width of the fixing member 220 being too large, which is more conducive to the stability of the connection between the nut assembly 100 and the connecting seat 200.

[0060] In one embodiment, part of the second mating section 212 is disposed in the second accommodating cavity 121 , and the other part is disposed in the first accommodating cavity 111 . The second mating section 212 and the inner wall of the first accommodating cavity 111 form a third annular groove 430 , which connects the first annular groove 410 and the second annular groove 420 .

[0061] Please refer to Figure 2The second mating section 212 and the inner wall of the first accommodating cavity 111 form a third annular groove 430. On the one hand, the heat generated when the fixing piece 220 and the connecting seat 200 are welded can be dissipated from the second annular groove 420 through the third annular groove 430, further accelerating the heat transfer to the air and reducing the influence of the heat on the nut 210; on the other hand, since the second mating section 212 and the inner wall of the first accommodating cavity 111 form the third annular groove 430, direct contact between the bottom surface of the first mating section 211 and the end surface of the second connecting section 120 (i.e., the bottom of the first accommodating cavity 111) is avoided, thereby avoiding direct heat transfer from the first connecting section 110 to burn the first mating section 211.

[0062] In one embodiment, a receiving groove 112 is formed at one end of the first receiving cavity 111 away from the second receiving cavity 121 , the bottom of the receiving groove 112 is connected to the inner wall of the first receiving cavity 111 , and the fixing member 220 is disposed in the receiving groove 112 and abuts against the bottom of the receiving groove 112 .

[0063] Please refer to Figure 2 and Figure 4 , the diameter of the receiving groove 112 is greater than the diameter of the first receiving cavity 111, the groove bottom of the receiving groove 112 is connected to the inner side wall of the first receiving cavity 111, the fixing member 220 is arranged in the receiving groove 112, the groove bottom of the receiving groove 112 serves as a positioning surface, the bottom wall of the fixing member 220 abuts against the positioning surface, and the positioning surface realizes axial positioning for the installation of the nut 210. The groove bottom of the receiving groove 112 is welded to the bottom wall of the fixing member 220 to realize the fixed connection between the nut assembly 100 and the connecting seat 200. The peripheral wall of the fixing member 220 can abut against the groove wall of the receiving groove 112 to increase the stability of the connection between the fixing member 220 and the connecting seat 200. In other embodiments, the peripheral wall of the fixing member 220 can also have a gap with the groove wall of the receiving groove 112. In other embodiments, the fixing member 220 may also be welded to the end surface of the first connecting section 110 away from the second connecting section 120, so that the fixing member 220 and the connecting seat 200 are fixedly connected together, thereby the nut assembly 100 is fixedly connected to the connecting seat 200. The fixing member 220 is arranged outside the connecting seat 200, which reduces the axial dimension of the connecting seat 200, facilitates processing and reduces costs.

[0064] In one embodiment, the second connecting section 120 is provided with a plurality of balancing channels 122, which penetrate the second connecting section 120 along the axial direction of the connecting seat 200 and are connected to the first annular groove 410; the fixing member 220 is provided with a plurality of balancing through holes 221, which are connected to the first annular groove 410, and the plurality of balancing through holes 221 are arranged at circumferential intervals along the fixing member 220.

[0065] Please refer to Figure 2 and Figure 4, the balancing through hole 221 and the balancing through hole 221 play the role of guiding the refrigerant and balancing the pressure on both sides of the axial direction of the connecting seat 200. The refrigerant flows through the balancing channel 122, the third annular groove 430, the first annular groove 410 and the balancing through hole 221 in sequence, thereby guiding the external refrigerant into the valve shell, so that the electronic expansion valve 10 is filled with refrigerant, and the pressure on both sides of the axial direction of the balancing connecting seat 200 is balanced, which is convenient for the reliability of the movement of the valve needle assembly 300. The balancing channel 122 is arranged in the second connecting section 120, and the length of the balancing channel 122 is small, which reduces the damage of the balancing channel 122 to the structure of the connecting seat 200. Multiple balancing channels 122 are arranged at intervals along the circumference of the connecting seat 200, and multiple balancing through holes 221 are arranged at intervals along the circumference of the fixing member 220. The balancing channels 122 and the balancing through holes 221 can be arranged correspondingly or staggered, and their numbers can be the same or different. The number of the balancing channels 122 and the balancing through holes 221 can be two, three, four or more.

[0066] In one embodiment, the nut 210 is provided with a guide through hole 213 along its axial direction, and the electronic expansion valve 10 is further provided with a valve needle assembly 300 passing through the through hole. The valve needle assembly 300 can move along the axial direction of the guide through hole 213, and the valve needle assembly 300 is matched with the inner wall clearance of the guide through hole 213.

[0067] Please refer to Figure 1 The valve needle assembly 300 passes through the guide through hole 213 and can move along the axial direction of the guide through hole 213. The valve needle assembly 300 is matched with the inner wall clearance of the guide through hole 213 to avoid interference between the valve needle assembly 300 and the inner wall of the guide through hole 213, affecting the movement of the valve needle assembly 300 and reducing the reliability and accuracy of the electronic expansion valve 10.

[0068] In one embodiment, the gap between the valve needle assembly 300 and the inner wall of the guide through hole 213 is not greater than 0.10 mm and not less than 0.05 mm.

[0069] When the gap between the valve needle assembly 300 and the inner wall of the guide through hole 213 is less than 0.05 mm, the valve needle assembly 300 is likely to interfere with the inner wall of the guide through hole 213, which not only easily affects the movement of the valve needle assembly 300, but also easily increases the wear of the valve needle assembly 300 and the nut 210. When the gap between the valve needle assembly 300 and the inner wall of the guide through hole 213 is greater than 0.10 mm, it will cause the thickness of the nut 210 to decrease, reduce the strength of the nut 210; or increase the volume of the nut 210, which is not conducive to the miniaturization of the electronic expansion valve 10. The gap between the valve needle assembly 300 and the inner wall of the guide through hole 213 can be any value between 0.05 mm and 0.10 mm, such as 0.06 mm, 0.08 mm, 0.09 mm, etc.

[0070] In one embodiment, the fixing member 220 and the nut 210 are integrally formed by injection molding. The nut 210 is injection molded, and the material of the fixing member 220 is metal. The fixing member 220 and the nut 210 are integrally molded by injection molding, and the fit between the two is tighter, and the connection stability is good, so that the fixing member 220 and the nut 210 are fixedly connected. Due to the use of injection molding, the coaxiality of the nut 210 and the fixing member 220 is guaranteed. The fixing member 220 is fixedly connected to the connecting seat 200, and further, the connecting seat 200 can well control the coaxiality of the installation of the nut 210. The nut 210 can be made of a low-priced plastic material, thereby reducing costs.

[0071] In one embodiment, the fixing member 220 and the connecting base 200 are welded.

[0072] The fixing member 220 is disposed on the outer wall of the first matching section 211, and the outer wall of the fixing member 220 and the connecting seat 200 are laser welded, so that the fixing member 220 and the connecting seat 200 are fixedly connected together, making the combination between the fixing member 220 and the connecting seat 200 more firm, thereby achieving a fixed connection between the nut assembly 100 and the connecting seat 200. Soldering or ultrasonic metal welding can also be used between the fixing member 220 and the connecting seat 200.

[0073] The present invention also proposes a refrigeration device, which includes an electronic expansion valve 10. The specific structure of the electronic expansion valve 10 refers to the above embodiment. Since the refrigeration device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here one by one.

[0074] Please refer to Figures 2 to 5 The present invention further proposes a positioning and assembling process of an electronic expansion valve 10. The electronic expansion valve 10 includes a connecting seat 200 and a nut assembly 100. The connecting seat 200 includes a first connecting section 110 and a second connecting section 120. The first connecting section 110 is provided with a first accommodating chamber 111. The second connecting section 120 is provided with a second accommodating chamber 121. The second accommodating chamber 121 is provided at the bottom of the first accommodating chamber 111 and communicates with the first accommodating chamber 111. The nut assembly 100 includes a nut 210 and a fixing member 220 provided at the periphery of the nut 210. The nut 210 includes a first matching section 211 and a second matching section 212. The nut 210 is provided with a guide through hole 213 along its axial direction. The positioning and assembling process of the electronic expansion valve 10 includes the following steps:

[0075] Step 1: Pass the positioning shaft 20 through the guide through hole 213 to install the nut assembly 100 on the outer periphery of the positioning shaft 20;

[0076] Step 2: Pass the assembled nut assembly 100 and the positioning shaft 20 through the first accommodating cavity 111 , so that the first matching section 211 and the inner wall of the first accommodating cavity 111 form a first annular groove 410 , and the second matching section 212 and the inner wall of the second accommodating cavity 121 form a second annular groove 420 ;

[0077] Step 3, welding the fixing member 220 to the connecting seat 200;

[0078] Step 4: Take out the positioning shaft 20.

[0079] Specifically, a positioning assembly process of an electronic expansion valve 10 is provided, wherein the positioning shaft 20 is first passed through the guide through hole 213 of the nut assembly 100, and then the assembled nut assembly 100 and the positioning shaft 20 are passed through the first accommodating chamber 111, so that the connecting seat 200 is sleeved on the outer periphery of the nut assembly 100 and the positioning shaft 20. The connecting seat 200 and the nut assembly 100 are installed on the positioning shaft 20 and assembled together through the positioning shaft 20. By using the positioning shaft 20 to position and install the connecting seat 200 and the nut assembly 100, not only can the reliable connection between the nut assembly 100 and the connecting seat 200 be achieved, but also the shaking between the nut assembly 100 and the connecting seat 200 can be reduced when the fixing member 220 is welded to the connecting seat 200, thereby reducing the difficulty of welding; and because the positioning shaft 20 passes through the nut 210 and the connecting seat 200, the axes of the positioning shaft 20, the nut 210 and the connecting seat 200 are on substantially the same straight line, and the coaxiality of the nut 210 and the connecting seat 200 can also be ensured. After the connection seat 200 and the nut assembly 100 are installed on the positioning shaft 20, the first matching section 211 and the inner wall of the first accommodating cavity 111 form a first annular groove 410, and the second matching section 212 and the inner wall of the second accommodating cavity 121 form a second annular groove 420. The first annular groove 410 and the second annular groove 420 have the function of a heat-insulating cavity. When welding the fixing member 220 and the connection seat 200, it is possible to prevent the heat generated by welding from being directly transferred from the connection seat 200 to the nut 210, causing the nut 210 to age or burn out faster. Then, the assembled connection seat 200 and the fixing member 220 are welded to fix the connection seat 200 and the nut assembly 100. The fixing member 220 and the connection seat 200 are made of metal material, and SUS303 or SUS304 material can be selected. The fixing member 220 and the connection seat 200 can be laser welded, and the fixing member 220 and the connection seat 200 are fixedly connected together, so that the nut assembly 100 and the connection seat 200 are fixedly connected. Soldering or ultrasonic metal welding can also be used between the fixing member 220 and the connecting seat 200. Due to the presence of the first annular groove 410 and the second annular groove 420, the heat generated by welding will not burn the nut 210. Since the connecting seat 200 and the nut assembly 100 are both stably mounted on the positioning shaft 20, good stability and coaxiality can be maintained during the welding process, thereby reducing the difficulty of welding and improving product quality. Finally, the positioning shaft 20 is taken out to obtain the welded connecting seat 200 and the nut assembly 100, which are used to be assembled with other components of the electronic expansion valve 10.

[0080] The positioning and assembly process of the electronic expansion valve 10 proposed by the present invention can not only realize the reliable connection between the nut assembly 100 and the connection seat 200, but also ensure the coaxiality between the nut 210 and the connection seat 200 by using the positioning shaft 20 to position and install the connection seat 200 and the nut assembly 100. In addition, the first matching section 211 of the nut 210 and the first accommodating cavity 111 of the connection seat 200 are clearance-matched, and the second matching section 212 and the second accommodating cavity 121 of the connection seat 200 are clearance-matched, so that the plastic material of the nut 210 is far away from the welding position, and the welding heat of the fixing member 220 and the connection seat 200 will not be directly transferred to the nut 210 through the connection seat 200, causing the nut 210 to burn and melt. In addition, the material consumption of the nut 210 is reduced, the requirements for the dimensional process accuracy of the nut 210 are reduced, and the process cost is reduced. In addition, after the nut assembly 100 and the fixing member 220 are assembled, the positioning shaft 20 is taken out and can be recycled, which saves resources and reduces production costs.

[0081] In one embodiment, in step 1, the guide through hole 213 includes a first guide through hole 2131 and a second guide through hole 2132, and the positioning shaft 20 includes a first positioning segment 21, a second positioning segment 22 and a third positioning segment 23 arranged in sequence along its axial direction, the diameter of the second positioning segment 22 is larger than the first positioning segment 21 and smaller than the third positioning segment 23, and a portion of the third positioning segment 23 protruding from the second positioning segment 22 is formed with a step surface 24; the first positioning segment 21 is passed through the first guide through hole 2131, the second positioning segment 22 is arranged in the second guide through hole 2132, and the end face of the nut 210 abuts against the step surface 24.

[0082] Please refer to Figures 2 to 5 The guide hole 213 includes a first guide hole 2131 and a second guide hole 2132. The first guide hole 2131 is used for the valve stem to pass through, and the second guide hole 2132 is used for the valve needle to move. The first guide hole 2131 and the second guide hole 2132 are connected to each other, and the diameter of the first guide hole 2131 is smaller than the diameter of the second guide hole 2132. In step 1, the positioning shaft 20 passes through the guide hole 213, so that the first positioning section 21 is partially disposed in the first guide hole 2131, that is, the first positioning section 21 can pass through the end of the first guide hole 2131 away from the second guide hole 2132, or not; the first positioning section 21 can also be partially disposed in the second guide hole 2132. The second positioning section 22 is disposed in the second guide through hole 2132 , and the end face of the second mating section 212 away from the first mating section 211 abuts against the step surface 24 , and the step surface 24 plays a role in positioning and supporting, thereby installing the nut assembly 100 on the positioning shaft 20 .

[0083] In one embodiment, the gap between the first positioning section 21 and the first guide hole 2131 is L1, which is not greater than 0.02 mm and not less than 0.005 mm; the gap between the second positioning section 22 and the second guide hole 2132 is L2, which is not greater than 0.005 mm and greater than 0 mm.

[0084] Please refer to Figure 2 , Figure 6 and Figure 7 The guide hole 213 of the nut 210 includes a first guide hole 2131 and a second guide hole 2132. The first positioning section 21 and the first guide hole 2131 are clearance-matched, and the spacing L1 of the clearance is not greater than 0.02mm and not less than 0.005mm. There is a clearance between the first positioning section 21 and the first guide hole 2131, and the first positioning section 21 can smoothly pass through the first guide hole 2131 without interfering with each other, which makes it difficult to install the nut assembly 100 and the positioning shaft 20, thereby facilitating the second positioning section 22 to penetrate into the second guide hole 2132; and the first positioning section 21 can also be smoothly removed from the first guide hole 2131 after the connection seat 200 and the fixing member 220 are welded. The gap between the first positioning section 21 and the first guide through hole 2131 is not greater than 0.02mm, and the first positioning section 21 will not produce a large shake in the first guide through hole 2131, so as to ensure the coaxiality of the installation of the nut 210, and avoid the valve stem and the rotor installation inside it being tilted due to the poor coaxiality of the nut 210, which may cause the rotor to get stuck when rotating, thereby reducing the difficulty of installing the nut 210. The second positioning section 22 and the second guide through hole 2132 are clearance-matched, and the spacing L2 of the gap is not greater than 0.005mm, and greater than 0mm. Similarly, there is a gap between the second positioning section 22 and the second guide through hole 2132, and the gap can not only ensure that the second positioning section 22 can smoothly penetrate into the second guide through hole 2132, but also ensure that the nut assembly 100 and the connecting seat 200 have good coaxiality after assembly.

[0085] In one embodiment, the diameter of the first accommodating cavity 111 is greater than the diameter of the second accommodating cavity 121, and the diameter of the first mating segment 211 is greater than the diameter of the second mating segment 212; in step 2, the second mating segment 212 and the inner wall of the first accommodating cavity 111 form a third annular groove 430, and the third annular groove 430 connects the first annular groove 410 and the second annular groove 420.

[0086] Please refer to Figures 2 to 4, the connecting seat 200 is used as a connecting piece, and its first connecting section 110 is used to connect the valve shell and the valve seat, and the second connecting section 120 is used to connect the valve port. When the connecting seat 200 occupies a certain space as a whole, the diameter of the first accommodating cavity 111 is greater than the diameter of the second accommodating cavity 121, which can reduce the volume of the valve port, thereby reducing the overall weight of the electronic expansion valve 10. The fixing member 220 is arranged in the first matching section 211, and the first matching section 211 needs to have a certain thickness to ensure the stability and structural strength of the connection between the fixing member 220 and the first matching section 211. At the same time, the fixing member 220 is generally a metal sheet with a small thickness. When the width of the fixing member 220 is large, the strength of the fixing member 220 is reduced, which is not conducive to the stability of the connection between the nut assembly 100 and the connecting seat 200. In addition, under the impact of the refrigerant, the fixing member 220 is subjected to a large impact force and is easily damaged and vibrated. The diameter of the first accommodating cavity 111 is greater than the diameter of the second accommodating cavity 121, and the diameter of the first mating segment 211 is greater than the diameter of the second mating segment 212, so as to avoid the distance between the first accommodating cavity 111 and the first mating segment 211 being too large, thereby avoiding the width of the fixing member 220 being too large, which is more conducive to the stability of the connection between the nut assembly 100 and the connecting seat 200.

[0087] Part of the second mating section 212 is disposed in the second accommodating cavity 121, and the other part is disposed in the first accommodating cavity 111, wherein the second mating section 212 and the inner wall of the first accommodating cavity 111 form a third annular groove 430, the third annular groove 430 is formed between the first annular groove 410 and the second annular groove 420, and is connected to the first annular groove 410 and the second annular groove 420, and the width of the third annular groove 430 is greater than the width of the first annular groove 410 and the second annular groove 420. On the one hand, the heat generated when the fixing member 220 and the connecting seat 200 are welded can be dissipated from the second annular groove 420 through the third annular groove 430, further accelerating the heat transfer to the air and reducing the influence of the heat on the nut 210; on the other hand, since the second mating section 212 and the inner wall of the first accommodating cavity 111 form the third annular groove 430, direct contact between the bottom surface of the first mating section 211 and the end surface of the second connecting section 120 (i.e., the bottom of the first accommodating cavity 111) is avoided, thereby avoiding direct heat transfer from the first connecting section 110 and burning the first mating section 211.

[0088] In one embodiment, in step 2, the third positioning section 23 passes through the second accommodating cavity 121, and a gap L3 is provided between the third positioning section 23 and the second accommodating cavity 121, and L3 is not greater than 0.02 mm and not less than 0.005 mm.

[0089] Please refer to Figure 2 and Figure 8There is a gap between the third positioning section 23 and the second accommodating cavity 121, and the third positioning section 23 can smoothly pass through the second accommodating cavity 121. After the connection seat 200 and the fixing member 220 are welded, it is also convenient to remove the third positioning section 23 from the second accommodating cavity 121 without interfering with each other. The gap between the third positioning section 23 and the second accommodating cavity 121 is not greater than 0.02mm, and the third positioning section 23 will not cause a large shake in the second accommodating cavity 121 to ensure the coaxiality of the connection seat 200 and the nut assembly 100, and the connection seat 200 can be stably installed on the positioning shaft 20, so as to facilitate the welding operation of the connection seat 200 and the fixing member 220.

[0090] In one embodiment, the first connecting section 110 is further provided with a receiving groove 112, which is provided at one end of the first receiving cavity 111 away from the second receiving cavity 121. In step 2, the fixing member 220 is overlapped on the bottom of the receiving groove 112, and there is a gap L4 between the fixing member 220 and the groove wall of the receiving groove 112, and L4 is not greater than 0.1 mm and not less than 0.02 mm.

[0091] Please refer to Fig. 9 , the receiving groove 112 is arranged at one end of the first receiving cavity 111 away from the second receiving cavity 121, and the receiving groove 112 plays the role of accommodating the fixing member 220 and positioning the nut assembly 100. In step 2, the nut assembly 100 and the positioning shaft 20 pass through the first receiving cavity 111 together until the fixing member 220 abuts against the bottom of the groove of the receiving groove 112, so as to realize the axial positioning of the nut assembly 100 by the connecting seat 200. There is a gap between the fixing member 220 and the groove wall of the receiving groove 112, and the welding stress between the outer wall of the fixing member 220 and the groove wall of the receiving groove 112 is small, which can reduce the influence of large coaxiality deviation. After the fixing member 220 and the connecting seat 200 are welded, the gap between the fixing member 220 and the groove wall of the receiving groove 112 is at least partially filled, so as to realize the fixed connection between the connecting seat 200 and the fixing member 220.

[0092] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. An electronic expansion valve, characterized in that: include: A connecting seat, comprising a first connecting section and a second connecting section, wherein the first connecting section is provided with a first accommodating cavity, and the second connecting section is provided with a second accommodating cavity, wherein the second accommodating cavity is provided at the cavity bottom of the first accommodating cavity and communicates with the first accommodating cavity; A nut assembly includes a nut and a fixing member, wherein the nut includes a first mating section and a second mating section, wherein the first mating section is at least partially disposed in the first accommodating cavity and is mated with the inner wall clearance of the first accommodating cavity to form a first annular groove, and the second mating section is at least partially disposed in the second accommodating cavity and is mated with the inner wall clearance of the second accommodating cavity to form a second annular groove; the fixing member is disposed at one end of the first accommodating cavity away from the second accommodating cavity and connects the nut and the connecting seat.

2. The electronic expansion valve according to claim 1, characterized in that: The distance between the first accommodating cavity and the first matching section is greater than the distance between the second accommodating cavity and the second matching section.

3. The electronic expansion valve according to claim 2, characterized in that: The diameter of the second accommodating cavity is smaller than the diameter of the first accommodating cavity.

4. The electronic expansion valve according to claim 3, characterized in that: The diameter of the second fitting segment is smaller than the diameter of the first fitting segment.

5. The electronic expansion valve according to claim 4, characterized in that: Part of the second matching section is disposed in the second accommodating cavity, and the other part is disposed in the first accommodating cavity. The second matching section and the inner wall of the first accommodating cavity form a third annular groove, and the third annular groove connects the first annular groove and the second annular groove.

6. The electronic expansion valve according to claim 1, characterized in that: An accommodating groove is formed at one end of the first accommodating cavity away from the second accommodating cavity, the bottom of the accommodating groove is connected to the inner side wall of the first accommodating cavity, and the fixing member is arranged in the accommodating groove and abuts against the bottom of the accommodating groove.

7. The electronic expansion valve according to claim 6, characterized in that: The second connecting section is provided with a plurality of balancing channels, which penetrate the second connecting section along the axial direction of the connecting seat and are connected to the first annular groove; the fixing member is provided with a plurality of balancing through holes, which are connected to the first annular groove, and the plurality of balancing through holes are arranged at intervals along the circumference of the fixing member.

8. The electronic expansion valve according to claim 1, characterized in that: The nut is provided with a guide through hole along its axial direction, and the electronic expansion valve is also provided with a valve needle assembly penetrating the through hole. The valve needle assembly can move along the axial direction of the guide through hole, and the valve needle assembly is clearance-matched with the inner wall of the guide through hole.

9. The electronic expansion valve according to claim 8, characterized in that: The gap between the valve needle assembly and the inner wall of the guide through hole is not greater than 0.10 mm and not less than 0.05 mm.

10. The electronic expansion valve according to claim 1, characterized in that: The fixing piece and the nut are integrally formed by injection molding.

11. The electronic expansion valve according to claim 1, characterized in that: The fixing piece is welded to the connecting seat.

12. A refrigeration device, characterized in that: Comprising the electronic expansion valve as described in any one of claims 1-11.

13. A positioning and assembly process for an electronic expansion valve, characterized in that: The electronic expansion valve comprises a connection seat and a nut assembly, wherein the connection seat comprises a first connection section and a second connection section, wherein the first connection section is provided with a first accommodating cavity, wherein the second connection section is provided with a second accommodating cavity, wherein the second accommodating cavity is provided at the cavity bottom of the first accommodating cavity and communicates with the first accommodating cavity; wherein the nut assembly comprises a nut and a fixing member provided at the outer periphery of the nut, wherein the nut comprises a first matching section and a second matching section, wherein the nut is provided with a guide through hole along its axial direction, and wherein the positioning assembly process of the electronic expansion valve comprises the following steps: Step 1, passing the positioning shaft through the guide through hole to install the nut assembly on the outer periphery of the positioning shaft; Step 2: Pass the assembled nut assembly and the positioning shaft through the first accommodating cavity, so that the first matching section and the inner wall of the first accommodating cavity form a first annular groove, and the second matching section and the inner wall of the second accommodating cavity form a second annular groove; Step 3, welding the fixing member to the connecting seat; Step 4: Take out the positioning shaft.

14. The positioning and assembling process of the electronic expansion valve according to claim 13, characterized in that: In step 1, the guide through hole includes a first guide through hole and a second guide through hole, the positioning shaft includes a first positioning segment, a second positioning segment and a third positioning segment arranged in sequence along its axial direction, the diameter of the second positioning segment is larger than the first positioning segment and smaller than the third positioning segment, and a portion of the third positioning segment protruding from the second positioning segment forms a step surface; the first positioning segment is passed through the first guide through hole, the second positioning segment is arranged in the second guide through hole, and the end face of the nut abuts against the step surface.

15. The positioning and assembling process of the electronic expansion valve according to claim 14, characterized in that: The gap between the first positioning section and the first guide hole is L1, which is not greater than 0.02 mm and not less than 0.005 mm; the gap between the second positioning section and the second guide hole is L2, which is not greater than 0.005 mm and greater than 0 mm.

16. The positioning and assembling process of the electronic expansion valve according to claim 14, characterized in that: The diameter of the first accommodating cavity is larger than the diameter of the second accommodating cavity, and the diameter of the first mating section is larger than the diameter of the second mating section; in step 2, the second mating section and the inner wall of the first accommodating cavity form a third annular groove, and the third annular groove connects the first annular groove and the second annular groove.

17. The positioning and assembling process of the electronic expansion valve according to claim 14, characterized in that: In step 2, the third positioning section passes through the second accommodating cavity, and a gap L3 is provided between the third positioning section and the second accommodating cavity, and L3 is not greater than 0.02 mm and not less than 0.005 mm.

18. The positioning and assembling process of the electronic expansion valve according to claim 14, characterized in that: The first connecting section is also provided with a receiving groove, which is provided at one end of the first receiving cavity away from the second receiving cavity. In the step 2, the fixing member overlaps the bottom of the receiving groove, and there is a gap L4 between the fixing member and the groove wall of the receiving groove, and L4 is not greater than 0.1 mm and not less than 0.02 mm.

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