CN216158306U - Electronic expansion valve - Google Patents

Abstract

The utility model provides an electronic expansion valve, comprising: a housing having an opening; the valve seat blocks the opening, the valve seat and the shell form an accommodating cavity, and a valve port is arranged on the valve seat; the guide sleeve is arranged in the accommodating cavity; the valve core assembly is movably arranged in the guide sleeve; the nut sleeve is arranged in the accommodating cavity and is provided with a third guide hole and a threaded hole which are sequentially arranged along the axial direction; the screw rod, the screw rod is connected with the case subassembly, and screw rod drive case subassembly removes in order to shutoff or open the valve port, and the screw rod has direction section and screw thread section, and screw thread section threaded connection is in the screw thread hole, and the direction section is movably worn to establish in the third guiding hole, and the scope in clearance between the lateral wall of direction section and the inner wall of third guiding hole is 0.01mm to 0.04 mm. By adopting the technical scheme, the problems of large valve needle jitter and large noise of the electronic expansion valve in the prior art are solved.

Description

Electronic expansion valve

Technical Field

The utility model relates to the technical field of control valves, in particular to an electronic expansion valve.

Background

The electronic expansion valve is used as an electronic control element, can realize the optimal control of the system due to high precision, and has wide application in a refrigeration system. However, the existing electronic expansion valve has the problems of large valve needle vibration and large mechanical or fluid noise in the working process.

SUMMERY OF THE UTILITY MODEL

The utility model provides an electronic expansion valve, which solves the problems of large valve needle jitter and large noise of the electronic expansion valve in the prior art.

The utility model provides an electronic expansion valve, comprising: a housing having an opening; the valve seat blocks the opening, the valve seat and the shell form an accommodating cavity, and a valve port is arranged on the valve seat; the guide sleeve is arranged in the accommodating cavity; the valve core assembly is movably arranged in the guide sleeve; the nut sleeve is arranged in the accommodating cavity and is provided with a third guide hole and a threaded hole which are sequentially arranged along the axial direction; the screw rod, the screw rod is connected with the case subassembly, and screw rod drive case subassembly removes in order to shutoff or open the valve port, and the screw rod has direction section and screw thread section, and screw thread section threaded connection is in the screw thread hole, and the direction section is movably worn to establish in the third guiding hole, and the scope in clearance between the lateral wall of direction section and the inner wall of third guiding hole is 0.01mm to 0.04 mm. So set up, can guarantee that the axiality between direction section and the third guiding hole is better.

By applying the technical scheme of the utility model, the range of the gap between the outer side wall of the guide section and the inner wall of the third guide hole is set to be 0.01 mm-0.04 mm, so that the good coaxiality between the guide section and the third guide hole can be ensured, the high coaxiality between the valve needle and the valve port can be ensured, and further, the valve needle has small jitter and low fluid or mechanical noise when the electronic expansion valve works. In addition, the arrangement can also make the movement resistance of the screw rod smaller.

Further, the guide sleeve is provided with a first guide hole, the valve core assembly comprises a valve needle, the valve needle is arranged corresponding to the valve port and used for plugging or opening the valve port, the valve needle is arranged in the first guide hole in a penetrating mode, and the range of a gap between the outer side wall of the valve needle and the inner wall of the first guide hole is 0.0075 mm-0.04 mm. The range of the clearance between the outer side wall of the valve needle and the inner wall of the first guide hole is set to be 0.0075mm to 0.04mm, smooth movement of the valve needle is guaranteed, and meanwhile high coaxiality between the valve needle and the valve port is guaranteed, so that the valve needle is small in jitter and low in fluid or mechanical noise when the electronic expansion valve works.

Further, the length of the first guide hole ranges from 2mm to 7 mm. By setting the length range of the first guide hole to be 2mm to 7mm, the volume of the electronic expansion valve can be made smaller while ensuring higher coaxiality of the valve needle and the first guide hole.

Further, the length of the third guide hole ranges from 3mm to 8 mm. The length range of the third guide hole is set to be 3mm to 8mm, the coaxiality between the third guide hole and the screw rod can be ensured, and meanwhile, the size of the electronic expansion valve is small.

Furthermore, the nut sleeve is provided with a cavity, the cavity is located at one end, far away from the third guide hole, of the threaded hole, the top of the guide sleeve extends into the cavity, and the outer side wall of the guide sleeve is in interference fit or transition fit with the inner side wall of the cavity. The outer side wall of the guide sleeve is in interference fit or transition fit with the inner side wall of the cavity, so that the coaxiality between the guide sleeve and the nut sleeve is good, and the guide sleeve can be firmly fixed in the nut sleeve.

Further, the length of the portion of the guide sleeve where the outer side wall is in contact with the inner side wall of the cavity ranges from 1.5mm to 6 mm. The length range of the contact part of the outer side wall of the guide sleeve and the inner side wall of the cavity is set to be 1.5mm to 6mm, so that the coaxiality of the guide sleeve and the nut sleeve can be ensured, and the volume of the electronic expansion valve can be smaller.

Furthermore, a fixing hole is formed in the valve seat, the fixing hole and the valve port are arranged coaxially, and the outer side wall of the guide sleeve is in interference fit or transition fit with the inner wall of the fixing hole. Clearance fit between fixed orifices and the uide bushing, then the axiality between uide bushing and the valve port is relatively poor, consequently, interference fit and transition fit between fixed orifices and the uide bushing can make the uide bushing keep better with the axiality of valve port.

Further, the length range of the contact part of the outer side wall of the guide sleeve and the inner wall of the fixing hole is 3mm to 7 mm. The length range of the contact part of the outer side wall of the guide sleeve and the inner wall of the fixing hole is set to be 3mm to 7mm, so that the coaxiality between the guide sleeve and the fixing hole is better, and the volume of the electronic expansion valve is smaller.

Further, the case assembly further includes: the spring sleeve is provided with a second guide hole, the second guide hole is coaxially arranged with and communicated with the first guide hole, and the spring sleeve is arranged in the second guide hole; the bearing comprises an inner ring and an outer ring, the end part of the screw rod is connected with the inner ring, and the bearing is arranged in the spring sleeve; the gasket is arranged in the spring sleeve, and one end face of the gasket is abutted with the outer ring; and the spring is arranged in the spring sleeve, one end of the spring is abutted against the other end face of the gasket, and the valve needle extends into the other end of the spring. Through setting up the bearing, can make when the screw rod is rotatory relative nut cover, gasket, spring, needle can not rotatory to improve the stability of gasket, spring, needle, improved the axiality of needle and valve port, reduced electronic expansion valve's mechanical noise and fluid noise.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the utility model and, together with the description, serve to explain the utility model and not to limit the utility model. In the drawings:

FIG. 1 is a schematic diagram of an electronic expansion valve provided by the present invention;

FIG. 2 shows an enlarged view at A in FIG. 1;

FIG. 3 shows an enlarged view at B in FIG. 1;

FIG. 4 shows a schematic structural view of a valve seat provided by the present invention;

FIG. 5 shows a schematic structural view of a nut sleeve provided by the present invention;

FIG. 6 is a schematic view showing the structure of a screw provided by the present invention;

fig. 7 shows a schematic structural diagram of a guide sleeve provided by the utility model.

Wherein the figures include the following reference numerals:

10. a housing; 11. an accommodating chamber; 20. a valve seat; 21. a valve port; 22. a fixing hole; 30. a guide sleeve; 31. a first guide hole; 32. a second guide hole; 40. a valve core assembly; 41. a valve needle; 42. a spring housing; 43. a bearing; 44. a gasket; 45. a spring; 50. a nut sleeve; 51. a third guide hole; 52. a threaded hole; 53. a cavity; 60. a screw; 61. a guide section; 62. a threaded segment.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the utility model, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, 2, 5 and 6, an embodiment of the present invention provides an electronic expansion valve, including a housing 10, a valve seat 20, a guide sleeve 30, a valve core assembly 40, a nut sleeve 50 and a screw 60, wherein the housing 10 has an opening; the valve seat 20 blocks the opening, the valve seat 20 and the shell 10 form an accommodating cavity 11, and a valve port 21 is arranged on the valve seat 20; the guide sleeve 30 is arranged in the accommodating cavity 11; the valve core assembly 40 is movably arranged in the guide sleeve 30; the nut sleeve 50 is arranged in the accommodating cavity 11, and the nut sleeve 50 is provided with a third guide hole 51 and a threaded hole 52 which are sequentially arranged along the axial direction; the screw 60 is connected with the valve core assembly 40, the screw 60 drives the valve core assembly 40 to move so as to close or open the valve port 21, the screw 60 is provided with a guide section 61 and a threaded section 62, the threaded section 62 is in threaded connection with the threaded hole 52, the guide section 61 is movably arranged in the third guide hole 51 in a penetrating mode, and the range of a gap between the outer side wall of the guide section 61 and the inner wall of the third guide hole 51 is 0.01 mm-0.04 mm. The screw 60 moves linearly along the nut socket 50 as the screw 60 rotates about the nut socket 50. The screw 60 is connected to the valve core assembly 40, and generally the screw 60 is disposed coaxially with the valve needle 41 and the valve port 21, and the screw 60 drives the valve core assembly 40 to move, so that the valve needle 41 blocks or opens the valve port 21. The guiding section 61 of the screw rod 60 is matched with the third guiding hole 51 of the nut sleeve 50 to guide the screw rod 60, so that the screw rod 60 and the valve port 21 keep high coaxiality, and further the valve needle 41 and the valve port 21 keep high coaxiality.

By applying the technical scheme of the utility model, the range of the gap between the outer side wall of the guide section 61 and the inner wall of the third guide hole 51 is set to be 0.01mm to 0.04mm, so that the good coaxiality between the guide section 61 and the third guide hole 51 can be ensured, the high coaxiality between the valve needle 41 and the valve port 21 can be ensured, and further the valve needle 41 has small vibration and small fluid or mechanical noise when the electronic expansion valve works. Further, this arrangement also enables the movement resistance of the screw 60 to be small.

As shown in fig. 2, the gap between the outer side wall of the guide section 61 and the inner wall of the third guide hole 51 is δ 1. If the clearance between the outer side wall of the guide section 61 and the inner wall of the third guide hole 51 is less than 0.01mm, the requirement on the machining accuracy of the screw 60 and the nut sleeve 50 is high, and the movement resistance of the screw 60 is large when the screw 60 moves linearly along the nut sleeve 50. If the clearance between the outer sidewall of the guide section 61 and the inner wall of the third guide hole 51 is greater than 0.04mm, the screw 60 and the nut sleeve 50 have poor coaxiality, resulting in poor coaxiality between the screw 60 and the valve port 21, and thus poor coaxiality between the valve port 21 and the valve needle 41. Therefore, the clearance between the outer sidewall of the screw 60 and the inner wall of the third guide hole 51 is set to be 0.01mm to 0.04mm, which can ensure high coaxiality between the valve port 21 and the valve needle 41 and also ensure small movement resistance of the screw 60. Specifically, the gap between the outer sidewall of the guide section 61 and the inner wall of the third guide hole 51 may be 0.01mm, 0.02mm, or 0.04 mm.

As shown in fig. 4, in the present embodiment, the guide sleeve 30 has a first guide hole 31, the valve core assembly 40 includes a valve needle 41, the valve needle 41 is disposed corresponding to the valve port 21, the valve needle 41 is used for closing or opening the valve port 21, the valve needle 41 is inserted into the first guide hole 31, and a gap between an outer side wall of the valve needle 41 and an inner wall of the first guide hole 31 ranges from 0.0075mm to 0.04 mm. The coaxiality of the valve needle 41 and the valve port 21 can be improved by limiting the clearance between the outer side wall of the valve needle 41 and the inner wall of the first guide hole 31, so that the fluttering of the valve needle 41 during the operation of the electronic expansion valve can be reduced, and the mechanical or fluid noise can be reduced. When the clearance between the outer sidewall of the valve needle 41 and the inner wall of the first guide hole 31 is less than 0.0075mm, the friction between the valve needle 41 and the first guide hole 31 is large, resulting in a large movement resistance of the valve needle 41. When the clearance between the outer side wall of the valve needle 41 and the inner wall of the first guide hole 31 is greater than 0.04mm, the coaxiality of the valve needle 41 and the valve port 21 is low, which results in large fluttering and mechanical or fluid noise of the valve needle 41. Therefore, the clearance between the outer sidewall of the valve needle 41 and the inner wall of the first guide hole 31 ranges from 0.0075mm to 0.04mm, and the coaxiality of the valve needle 41 and the valve port 21 can be ensured while ensuring smooth movement of the valve needle 41. Specifically, the clearance between the outer side wall of the valve needle 41 and the inner wall of the first guide hole 31 may be 0.0075mm, 0.03mm, or 0.04 mm. As shown in fig. 3, the clearance between the outer side wall of the needle 41 and the inner wall of the first guide hole 31 is δ 2.

As shown in fig. 7, the first guide hole 31 has a length D1. In the present embodiment, the length D1 of the first guide hole 31 ranges from 2mm to 7 mm. When the length of the first guide hole 31 is less than 2mm, the contact area between the first guide hole 31 and the valve needle 41 is small, and the valve needle 41 is prone to shake during movement, so that the coaxiality of the valve needle 41 and the valve port 21 is low. When the length of the first guide hole 31 is greater than 7mm, the length of the guide sleeve 30 is longer, so that the length of the housing 10 or the valve seat 20 is increased, and the volume of the electronic expansion valve is increased. Therefore, the length of the inner wall of the first guide hole 31 ranges from 2mm to 7mm, and the volume of the electronic expansion valve can be reduced while ensuring high coaxiality of the valve needle 41 with the valve port 21. Specifically, the length of the first guide hole 31 may be 2mm, 4mm, 6mm, or 7 mm.

As shown in fig. 5, the third guide hole 51 has a length D2. Specifically, the length D2 of the third guide hole 51 ranges from 3mm to 8 mm. If the length of the third guiding hole 51 is less than 3mm, the contact area between the third guiding hole 51 and the guiding section 61 is small, and the screw 60 is liable to shake relative to the nut sleeve 50, so that the coaxiality between the screw 60 and the valve port 21 is poor, and further the coaxiality between the valve needle 41 and the valve port 21 is poor. If the length of the third guide hole 51 is greater than 8mm, the length of the nut bushing 50 is excessively increased, resulting in a large volume of the electronic expansion valve. Therefore, when the length of the third guiding hole 51 ranges from 3mm to 8mm, the valve needle 41 and the valve port 21 can be ensured to have high coaxiality, and the volume of the electronic expansion valve cannot be too large. Specifically, the length of the third guide hole 51 may be 3mm, 5mm, 6mm, or 8 mm.

In this embodiment, the nut sleeve 50 has a cavity 53, the cavity 53 is located at one end of the threaded hole 52 far away from the third guiding hole 51, the top of the guiding sleeve 30 extends into the cavity 53, and the outer side wall of the guiding sleeve 30 is in interference fit or transition fit with the inner side wall of the cavity 53. The nut sleeve 50, the cavity 53, the guide sleeve 30 and the valve port 21 are coaxially arranged. If the outer sidewall of the guide sleeve 30 is clearance-fitted with the inner sidewall of the cavity 53, the nut sleeve 50 and the guide sleeve 30 have poor coaxiality, resulting in poor coaxiality between the valve needle 41 and the valve port 21. Therefore, the outer side wall of the guide sleeve 30 is in interference fit or transition fit with the inner side wall of the cavity 53, so that the valve needle 41 and the valve port 21 can have high coaxiality.

As shown in fig. 5, specifically, the length of the portion where the outer side wall of the guide sleeve 30 contacts the inner side wall of the cavity 53 ranges from 1.5mm to 6 mm. If the length of the portion of the outer side wall of the guide sleeve 30 contacting the inner side wall of the cavity 53 is less than 1.5mm, the guide sleeve 30 is easily tilted relative to the nut sleeve 50, so that the needle 41 is less coaxial with the valve port 21. If the length of the portion where the outer side wall of the guide sleeve 30 contacts the inner side wall of the cavity 53 is greater than 6mm, the lengths of the nut sleeve 50 and the guide sleeve 30 are long, resulting in a large volume of the electronic expansion valve. Therefore, the length of the contact portion between the outer side wall of the guide sleeve 30 and the inner side wall of the cavity 53 is in the range of 1.5mm to 6mm, which can ensure high coaxiality between the valve needle 41 and the valve port 21 and reduce the volume of the electronic expansion valve. Specifically, the length of the portion of the guide sleeve 30 where the outer side wall contacts the inner side wall of the cavity 53 may be 1.5mm, 3mm, 4.5mm, or 6 mm.

In this embodiment, the valve seat 20 is provided with a fixing hole 22, the fixing hole 22 is coaxially disposed with the valve port 21, and an outer side wall of the guide sleeve 30 is in interference fit or transition fit with an inner wall of the fixing hole 22. The clearance fit between the fixing hole 22 and the guide sleeve 30 results in poor coaxiality between the guide sleeve 30 and the valve port 21, and further results in poor coaxiality between the valve needle 41 and the valve port 21, so that the interference fit and the transition fit between the fixing hole 22 and the guide sleeve 30 can ensure that the valve needle 41 and the valve port 21 have high coaxiality.

Specifically, the length of the portion where the outer sidewall of the guide sleeve 30 contacts the inner wall of the fixing hole 22 ranges from 3mm to 7 mm. When the contact length between the outer side wall of the guide sleeve 30 and the inner wall of the fixing hole 22 is less than 3mm, the contact area between the guide sleeve 30 and the fixing hole 22 is too small, so that the guide sleeve 30 is prone to skew relative to the fixing hole 22. When the contact length between the outer side wall of the guide sleeve 30 and the inner wall of the fixing hole 22 is greater than 7mm, the length between the guide sleeve 30 and the valve seat 20 is greater, so that the volume of the electronic expansion valve is larger. Therefore, the length of the contact portion between the outer side wall of the guide sleeve 30 and the inner wall of the fixing hole 22 ranges from 3mm to 7mm, so that the coaxiality between the valve needle 41 and the valve port 21 can be high, and the volume of the electronic expansion valve can be small. Specifically, the length of the portion where the outer side wall of the guide sleeve 30 contacts the inner wall of the fixing hole 22 is 3mm, 5mm, or 7 mm.

In this embodiment, the valve core assembly 40 further includes a spring sleeve 42, a bearing 43, a spacer 44, and a spring 45. The guide sleeve 30 is provided with a second guide hole 32, the second guide hole 32 is coaxially arranged with and communicated with the first guide hole 31, and the spring sleeve 42 is arranged in the second guide hole 32; the bearing 43 comprises an inner ring and an outer ring, the end part of the screw rod 60 is connected with the inner ring, and the bearing 43 is arranged inside the spring sleeve 42; the gasket 44 is arranged in the spring sleeve 42, and one end face of the gasket 44 is abutted with the outer ring; the spring 45 is disposed in the spring housing 42, one end of the spring 45 abuts against the other end surface of the spacer 44, and the needle 41 extends into the other end of the spring 45. By arranging the bearing 43, when the valve needle 41 abuts against the valve port 21 in the valve closing process, the screw 60 continues to rotate due to the influence of the coil pulse, at this time, the inner ring of the bearing 43 rotates, the outer ring does not move, and the spring sleeve 42, the gasket 44, the spring 45 and the valve needle 41 cannot rotate, so that the abrasion of the valve needle 41 and the valve port 21 is reduced, and the service life of the electronic expansion valve is prolonged.

By applying the technical scheme of the utility model, the range of the gap between the outer side wall of the guide section 61 and the inner wall of the third guide hole 51 is set to be 0.01mm to 0.04mm, so that the good coaxiality between the guide section 61 and the third guide hole 51 can be ensured, and the high coaxiality between the valve needle 41 and the valve port 21 can be ensured, so that the valve needle 41 has small vibration and small fluid or mechanical noise when the electronic expansion valve works; the range of the gap between the outer side wall of the valve needle 41 and the inner wall of the first guide hole 31 is set to be 0.0075mm to 0.04mm, so that the smooth movement of the valve needle 41 is ensured, and simultaneously, the higher coaxiality of the valve needle 41 and the valve port 21 is ensured, so that the valve needle 41 has small vibration and low fluid or mechanical noise when the electronic expansion valve works; the length of the inner wall of the first guide hole 31 ranges from 2mm to 7mm, and the volume of the electronic expansion valve is reduced while ensuring high coaxiality of the valve needle 41 and the valve port 21.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc. are usually based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and in the case of not making a reverse description, these orientation words do not indicate and imply that the device or element being referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore, should not be considered as limiting the scope of the present invention; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (9)

1. An electronic expansion valve, comprising:

a housing (10), the housing (10) having an opening;

the valve seat (20) is used for sealing the opening, the valve seat (20) and the shell (10) form a containing cavity (11), and a valve port (21) is arranged on the valve seat (20);

the guide sleeve (30) is arranged in the accommodating cavity (11);

a valve core assembly (40), wherein the valve core assembly (40) is movably arranged in the guide sleeve (30);

the nut sleeve (50), the nut sleeve (50) is arranged in the accommodating cavity (11), and the nut sleeve (50) is provided with a third guide hole (51) and a threaded hole (52) which are sequentially arranged along the axial direction;

the screw rod (60) is connected with the valve core assembly (40), the screw rod (60) drives the valve core assembly (40) to move so as to close or open the valve port (21), the screw rod (60) is provided with a guide section (61) and a threaded section (62), the threaded section (62) is in threaded connection with the threaded hole (52), the guide section (61) is movably arranged in the third guide hole (51) in a penetrating mode, and the range of a gap between the outer side wall of the guide section (61) and the inner wall of the third guide hole (51) is 0.01 mm-0.04 mm.

2. The electronic expansion valve according to claim 1, wherein the guide sleeve (30) has a first guide hole (31), the valve core assembly (40) comprises a valve needle (41), the valve needle (41) is disposed corresponding to the valve port (21), the valve needle (41) is used for closing or opening the valve port (21), the valve needle (41) is inserted into the first guide hole (31), and a gap between an outer side wall of the valve needle (41) and an inner wall of the first guide hole (31) ranges from 0.0075mm to 0.04 mm.

3. An electronic expansion valve according to claim 2, wherein the length of the first guide hole (31) ranges from 2mm to 7 mm.

4. An electronic expansion valve according to claim 1, wherein the length of the third guiding hole (51) ranges from 3 to 8 mm.

5. An electronic expansion valve according to claim 1, wherein the nut sleeve (50) has a cavity (53), the cavity (53) is located at an end of the threaded hole (52) remote from the third guiding hole (51), a top portion of the guiding sleeve (30) extends into the cavity (53), and an outer side wall of the guiding sleeve is in interference fit or transition fit with an inner side wall of the cavity.

6. An electronic expansion valve according to claim 5, wherein the length of the portion of the guide sleeve (30) where the outer side wall meets the inner side wall of the cavity (53) is in the range of 1.5mm to 6 mm.

7. An electronic expansion valve according to claim 1, wherein a fixing hole (22) is formed in the valve seat (20), the fixing hole (22) is coaxially arranged with the valve port (21), and an outer side wall of the guide sleeve (30) is in interference fit or transition fit with an inner wall of the fixing hole (22).

8. An electronic expansion valve according to claim 7, wherein the length of the outer side wall of the guide sleeve (30) where it meets the inner wall of the fixation hole (22) is in the range of 3mm to 7 mm.

9. The electronic expansion valve of claim 2, wherein the valve cartridge assembly (40) further comprises:

the spring sleeve (42), the guide sleeve (30) is provided with a second guide hole (32), the second guide hole (32) is coaxially arranged with the first guide hole (31) and communicated with the first guide hole, and the spring sleeve (42) is arranged in the second guide hole (32);

the bearing (43) comprises an inner ring and an outer ring, the end part of the screw rod (60) is connected with the inner ring, and the bearing (43) is arranged inside the spring sleeve (42);

a gasket (44) arranged in the spring sleeve (42), wherein one end face of the gasket (44) is abutted with the outer ring;

and the spring (45) is arranged in the spring sleeve (42), one end of the spring (45) is abutted against the other end face of the gasket (44), and the valve needle (41) extends into the other end of the spring (45).

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