Fan

Abstract

The utility model relates to a fan applied to a dust sensor. The fan comprises a frame; the mute bearing is arranged on the frame, and the mute bearing is arranged on the frame; the rotor comprises a rotating shaft and a fan body, the fan body is connected with the end part of the rotating shaft, the rotating shaft is rotatably arranged in the mute bearing in a penetrating manner, and a lubricant exists between the rotating shaft and the mute bearing; and the driver is arranged on the frame, and the driver is used for driving the rotor to rotate. By arranging the mute bearing, a lubricant exists between the rotating shaft and the mute bearing, so that the frictional resistance between the rotating shaft and the mute bearing can be reduced, and finally the purpose of reducing the noise of the whole fan is achieved. And under the condition that the friction resistance is reduced, the abrasion between the mute bearing and the rotating shaft can be reduced, so that the service life of the fan is prolonged.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a fan. Background Art

[0002] Dust sensors are widely used in cars and homes. They detect the dust content in the air in real time, thereby helping users determine whether there is excessive dust in the environment. Dust sensors include fans. The fans of traditional dust sensors are prone to generate loud noise during operation, which affects the user experience. Summary of the invention

[0003] A technical problem solved by the present application is how to reduce the noise of the fan.

[0004] A fan is applied to a dust sensor, the fan comprising:

[0005] frame;

[0006] A silent bearing, wherein the silent bearing is arranged on the frame;

[0007] A rotor, the rotor comprising a rotating shaft and a sector, the sector being connected to an end of the rotating shaft, the rotating shaft being rotatably disposed in the silent bearing, and a lubricant being present between the rotating shaft and the silent bearing; and

[0008] A driver is arranged on the frame, and is used for driving the rotor to rotate.

[0009] In one embodiment, a mounting cavity is provided on the frame, and the silent bearing is accommodated in the mounting cavity. The silent bearing has a first surface, a second surface and a side circumferential surface. The first surface and the second surface are arranged at intervals along the axial direction of the silent bearing. The first surface is closer to the fan body than the second surface. The side circumferential surface is connected between the first surface and the second surface. The side circumferential surface is recessed to form a ventilation groove extending to the first surface and the second surface to connect the mounting cavity.

[0010] In one embodiment, it also includes a first positioning member, which is fixed in the installation cavity and abuts against the first surface. The first positioning member is provided with a first through hole connected to the installation cavity. The rotating shaft is rotatably matched with the first through hole. A first groove is recessed on the first surface to connect the first through hole and the ventilation groove.

[0011] In one embodiment, a sink groove is provided on the rotating shaft, the sink groove is located in the first through hole, the sink groove extends along the circumference of the rotating shaft and is in a closed loop, and the width of the sink groove gradually decreases along the concave direction of the sink groove.

[0012] In one embodiment, it also includes a second positioning member, which is fixed in the installation cavity and abuts against the second surface. The second positioning member is provided with a second through hole connected to the installation cavity. The rotating shaft is rotatably matched with the second through hole. A second groove is recessed on the second surface to connect the second through hole and the ventilation groove.

[0013] In one embodiment, the second positioning member is further provided with a plurality of through holes penetrating the second positioning member, the through holes being connected to the second through hole, the plurality of through holes being arranged at intervals along the circumference of the second through hole, and the size of the through holes in the circumferential direction of the second through hole increases along the direction pointing from the second through hole to the through hole.

[0014] In one embodiment, the rotating shaft includes a first rotating section, a second rotating section and a boss section, the second rotating section is connected between the first rotating section and the boss section, the first rotating section is inserted into the silent bearing, the second rotating section is inserted into the second through hole, and the cross-sectional dimensions of both the boss section and the first rotating section are larger than the cross-sectional dimension of the second rotating section; the boss section includes a first convex portion and a second convex portion, the first convex portion is connected between the second convex portion and the second rotating section, and in the direction from the first convex portion to the second convex portion, the cross-sectional dimension of the first convex portion is constant, and the cross-sectional dimension of the second convex portion is reduced.

[0015] In one of the embodiments, a gasket is further included. The gasket is disposed in the installation cavity. The end of the rotating shaft away from the sector body contacts the gasket. The surface of the rotating shaft in contact with the gasket is a spherical surface.

[0016] In one embodiment, at least one of the following schemes is also included:

[0017] The installation cavity comprises a first cavity and a second cavity which are coaxially arranged, the caliber of the first cavity is larger than the caliber of the second cavity, the silent bearing is located in the first cavity, and the end of the rotating shaft away from the fan body is located in the second cavity;

[0018] The frame includes a sleeve, a base, a connecting piece and a mounting seat. The sleeve is arranged around the base and the mounting seat. The connecting piece is connected between the sleeve and the base. There are multiple connecting pieces, and the multiple connecting pieces are arranged at intervals along the circumference of the sleeve. The mounting seat is protruded on the base, and the mounting cavity is opened on the mounting seat.

[0019] In one embodiment, at least one of the following schemes is also included:

[0020] The diameter of the mating portion between the rotating shaft and the silent bearing is 0.8 mm to 1.3 mm;

[0021] The silent bearing is made of copper.

[0022] A technical effect of an embodiment of the present application is that by providing a silent bearing, a lubricant is present between the rotating shaft and the silent bearing, thereby reducing the friction resistance between the rotating shaft and the silent bearing, and ultimately achieving the purpose of reducing the noise of the entire fan. When the friction resistance is reduced, the wear between the silent bearing and the rotating shaft can also be reduced, thereby increasing the service life of the fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the three-dimensional structure of a fan provided in an embodiment.

[0024] Figure 2 for Figure 1 The three-dimensional structure schematic diagram of the fan shown in another viewing angle.

[0025] Figure 3 for Figure 1 Schematic diagram of the exploded structure of the fan shown.

[0026] Figure 4 for Figure 1 A schematic diagram of the three-dimensional cross-sectional structure of the frame in the fan shown.

[0027] Figure 5 for Figure 1 A schematic diagram of the three-dimensional structure of the silent bearing in the fan shown.

[0028] Figure 6 for Figure 1 A schematic three-dimensional structural diagram of the second positioning member in the fan shown.

[0029] Figure 7 for Figure 1 A schematic diagram of the three-dimensional cross-sectional structure of the fan shown.

[0030] Figure 8 for Figure 7 Enlarged structural diagram at A in the middle.

[0031] Figure numerals: fan 10, frame 100, sleeve 110, base 120, connector 130, mounting seat 140, mounting cavity 141, first cavity 1411, second cavity 1412, step surface 1413, silent bearing 200, first surface 210, first groove 211, second surface 220, second groove 221, side circumferential surface 230, ventilation groove 231, rotor 300, fan body 310, rotating shaft 320, first rotating section 321, second rotating section 322, boss section 323, first convex portion 3231, second convex portion 3232, spherical surface 3232a, driver 400, first positioning member 510, first through hole 511, second positioning member 520, second through hole 521, through hole 522, gasket 530, label 540. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0033] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0034] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0035] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0036] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0037] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0038] See also Figure 1 , Figure 2 and Figure 3 A fan 10 provided in one embodiment of the present application is applied to a dust sensor. The fan 10 includes a frame 100, a silent bearing 200, a rotor 300 and a driver 400. The silent bearing 200 is arranged on the frame 100. The rotor 300 includes a rotating shaft 320 and a fan body 310. The fan body 310 is connected to the end of the rotating shaft 320. The rotating shaft 320 is rotatably inserted into the silent bearing 200. There is a lubricant between the rotating shaft 320 and the silent bearing 200. The driver 400 is arranged on the frame 100. The driver 400 is used to drive the rotor 300 to rotate. For example, the driver 400 can drive the rotor 300 to rotate by electromagnetic force.

[0039] See also Figure 2 , Figure 3 and Figure 4In some embodiments, the frame 100 includes a sleeve 110, a base 120, a connector 130 and a mounting seat 140. The fan body 310 and the driver 400 can be accommodated in the space surrounded by the sleeve 110. The sleeve 110 is arranged around the base 120 and the mounting seat 140, so that a certain distance is spaced between the sleeve 110 and the base 120. One end of the connector 130 is connected to the inner wall surface of the sleeve 110, and the other end of the connector 130 is connected to the mounting seat 140, that is, the connector 130 is connected between the sleeve 110 and the mounting seat 140. The number of connectors 130 is multiple, and the multiple connectors 130 are arranged at intervals along the circumference of the sleeve 110. For example, the number of connectors 130 can be three, etc. The mounting seat 140 is protrudingly arranged on the base 120, so that the mounting seat 140 is also accommodated in the space surrounded by the sleeve 110. In other embodiments, the frame 100 may also be other structures. For example, the connecting member 130 may be omitted so that the base 120 is directly connected to the sleeve 110 .

[0040] See also Figure 2 , Figure 3 and Figure 4 The mounting seat 140 is provided with a mounting cavity 141, which may include a first cavity 1411 and a second cavity 1412. The first cavity 1411 and the second cavity 1412 may be coaxially arranged, the caliber of the first cavity 1411 is larger than the caliber of the second cavity 1412, and the second cavity 1412 is closer to the base 120 than the first cavity 1411. In this way, the first cavity 1411 and the second cavity 1412 form a stepped hole together, and a stepped surface 1413 is formed at the connection between the first cavity 1411 and the second cavity 1412. Obviously, the stepped surface 1413 is arranged around the second cavity 1412. The silent bearing 200 is located in the first cavity 1411, and the end of the rotating shaft 320 away from the fan body 310 is located in the second cavity 1412.

[0041] See also Figure 3 , Figure 7 and Figure 8 In some embodiments, the fan 10 may further include a label 540 , which is attached to the surface of the base 120 . The label 540 may be used to identify the model of the fan 10 .

[0042] See also Figure 5 , Figure 7 and Figure 8In some embodiments, the silent bearing 200 has a first surface 210, a second surface 220 and a side circumferential surface 230. The first surface 210 and the second surface 220 are arranged at intervals along the axial direction of the silent bearing 200. The first surface 210 and the second surface 220 are respectively two end surfaces of the silent bearing 200 in the axial direction. The side circumferential surface 230 is connected between the first surface 210 and the second surface 220. The side circumferential surface 230 is arranged around the edges of the first surface 210 and the second surface 220 at the same time. A ventilation groove 231 is opened on the side circumferential surface 230. The ventilation groove 231 can be formed by a part of the side circumferential surface 230 being recessed to a set depth. The ventilation groove 231 can extend a certain length along the axial direction of the silent bearing 200, so that the two ends of the ventilation groove 231 extend to the first surface 210 and the second surface 220 respectively. Obviously, the two ends of the ventilation groove 231 will respectively penetrate the first surface 210 and the second surface 220. The number of the ventilation grooves 231 can be one or more. When the silent bearing 200 is matched with the first cavity 1411, the two ends of the ventilation groove 231 can be respectively communicated with the first cavity 1411 and the second cavity 1412. A first groove 211 can be provided on the first surface 210, and the first groove 211 is communicated with one end of the ventilation groove 231, and a second groove 221 can be provided on the second surface 220, and the second groove 221 is communicated with the other end of the ventilation groove 231, so the two ends of the ventilation groove 231 are respectively communicated with the first groove 211 and the second groove 221.

[0043] See also Figure 3 , Figure 6 and Figure 8 In some embodiments, the fan 10 may further include a first positioning member 510 and a second positioning member 520. The first positioning member 510 is fixed in the first cavity 1411. The first positioning member 510 abuts against the first surface 210. The first positioning member 510 can limit the silent bearing 200 along the axial direction of the silent bearing 200 to prevent the silent bearing 200 from axially sliding in the first cavity 1411. The first through hole 511 is provided on the first positioning member 510. The first through hole 511 penetrates the entire first positioning member 510 along the thickness direction of the first positioning member 510. The rotating shaft 320 is penetrated in the first through hole 511 so that the rotating shaft 320 and the first through hole 511 are rotatably matched. The first positioning member 510 may be made of copper. When the first positioning member 510 abuts against the first surface 210, the first groove 211 can be connected to the first cavity 1411 through the first through hole 511.

[0044] See also Figure 3 , Figure 6 and Figure 8The second positioning member 520 is fixed in the first cavity 1411, and the second positioning member 520 is carried on the step surface 1413, and the second positioning member 520 is in contact with the second surface 220 of the silent bearing 200. The second positioning member 520 can limit the silent bearing 200 along the axial direction of the silent bearing 200, so as to prevent the silent bearing 200 from axially sliding in the first cavity 1411. Therefore, by sandwiching the silent bearing 200 between the first positioning member 510 and the second positioning member 520, a good axial positioning effect can be achieved for the silent bearing 200. A second through hole 521 is provided on the second positioning member 520, and the second through hole 521 penetrates the entire second positioning member 520 along the thickness direction of the second positioning member 520, and the rotating shaft 320 is penetrated in the second through hole 521, so that the rotating shaft 320 and the second through hole 521 are rotatably matched. When the second positioning member 520 abuts against the second surface 220 , the second groove 221 may be communicated with the second cavity 1412 through the second through hole 521 .

[0045] During the assembly process, the rotating shaft 320 can first be inserted into the first positioning member 510, the silent bearing 200 and the second positioning member 520 outside the installation cavity 141, and then the first positioning member 510, the silent bearing 200 and the second positioning member 520 can be installed in the first cavity 1411. During the sliding of the first positioning member 510, the silent bearing 200 and the second positioning member 520 in the second cavity 1412, the gas in the first cavity 1411 and the second cavity 1412 can be discharged to the outside through the second through hole 521, the second groove 221, the ventilation groove 231, the first groove 211 and the first through hole 511, thereby reducing the installation resistance of the first positioning member 510, the silent bearing 200 and the second positioning member 520, ensuring the smooth installation of the three to improve the installation accuracy. In other embodiments, without providing the first positioning member 510 and the second positioning member 520 , the first groove 211 and the second groove 221 can be omitted, and during the assembly process of the silent bearing 200 , the gas in the first cavity 1411 and the second cavity 1412 can be directly discharged to the outside through the ventilation groove 231 .

[0046] See also Figure 3 , Figure 6 and Figure 8The second positioning member 520 is also provided with a through hole 522. The number of through holes 522 can be multiple. The multiple through holes 522 are arranged at intervals along the circumference of the second through hole 521. The through holes 522 penetrate the entire second positioning member 520 along the thickness direction of the second positioning member 520. For example, the number of through holes 522 can be three. Along the direction from the second through hole 521 to the through hole 522, the size of the through hole 522 in the circumference of the second through hole 521 increases. For example, the cross-sectional shape of the through hole 522 can be an isosceles trapezoid, the upper base of the trapezoid is arranged close to the second through hole 521, and the lower base of the trapezoid is arranged away from the second through hole 521. By setting the through hole, on the one hand, the gas in the second cavity 1412 can flow into the second groove 221 through the second through hole 521 and the through hole 522 at the same time, thereby increasing the gas flow area and ensuring that the gas in the second cavity 1412 can be quickly discharged. On the other hand, in the process of the rotating shaft 320 passing through the second through hole 521, the setting of the through hole 522 can reasonably increase the deformation of the second positioning member 520, ensuring that the rotating shaft 320 is smoothly passed through the second through hole 521 with less resistance, thereby improving the assembly efficiency and accuracy between the rotating shaft 320 and the second positioning member 520.

[0047] See also Figure 8 In some embodiments, the rotating shaft 320 includes a first rotating section 321, a second rotating section 322 and a boss section 323, one end of the second rotating section 322 is connected to the first rotating section 321, and the other end of the second rotating section 322 is connected to the boss section 323, so that the second rotating section 322 is connected between the first rotating section 321 and the boss section 323. The first rotating section 321 is inserted into the silent bearing 200, and the second rotating section 322 is inserted into the second through hole 521. The cross-sectional dimensions of both the boss section 323 and the first rotating section 321 are greater than the cross-sectional dimension of the second rotating section 322, that is, the cross-sectional dimension of the first rotating section 321 is the smallest, which can be understood as the diameter of the second rotating section 322 is the smallest. The boss section 323 includes a first boss 3231 and a second boss 3232. The first boss 3231 is connected between the second boss 3232 and the second rotating section 322. The direction from the first boss 3231 to the second boss 3232 is constant, and the cross-sectional size of the first boss 3231 is reduced, so that the first boss 3231 is roughly cylindrical, and the second boss 3232 is roughly conical. The outer surface of the second boss 3232 can be a spherical surface 3232a.

[0048] See also Figure 8The cross-sectional dimension of the boss section 323 can be larger than the diameter of the second through hole 521. During the assembly process, since the second convex portion 3232 can be roughly conical, and the outer surface of the second convex portion 3232 can be a spherical surface 3232a, the second convex portion 3232 plays a role similar to a wedge, which can reduce the resistance of the boss section 323 passing through the second through hole 521, thereby reducing the assembly resistance of the shaft 320 and improving the assembly efficiency and accuracy. At the same time, the second positioning member 520 can contact the boss section 323 to produce a positioning effect, preventing the shaft 320 from escaping from the second through hole 521. The second protrusion 3232 can be understood as the end of the rotating shaft 320. When the spherical surface 3232a of the second protrusion 3232 contacts the bottom wall of the second cavity 1412, the spherical surface 3232a can form point contact with the bottom wall of the second cavity 1412. When the rotating shaft 320 rotates, the friction between the second protrusion 3232 and the bottom wall of the second cavity 1412 can be reduced, thereby improving the smoothness of the rotation of the rotating shaft 320.

[0049] See also Figure 8 In some embodiments, the fan 10 may further include a gasket 530, which is disposed in the second cavity 1412 and supported on the bottom wall of the second cavity 1412, so that the gasket 530 forms a point contact relationship with the spherical surface 3232a of the second convex portion 3232, thereby avoiding direct contact between the gasket 530 and the bottom wall of the second cavity 1412. The gasket 530 may be made of a wear-resistant material, thereby reducing the wear of the gasket 530 during the rotation of the shaft 320, thereby reducing the increase in friction resistance caused by wear, and further improving the smoothness of the rotation of the shaft 320.

[0050] In some embodiments, the material of the silent bearing 200 may include copper, which can reduce the friction coefficient of the silent bearing 200, reduce the friction resistance between the rotating shaft 320 and the silent bearing 200, and thus reduce the noise caused by the friction resistance. Since a special lubricant is provided between the silent bearing 200 and the rotating shaft 320, a lubricating film can be formed between the silent bearing 200 and the rotating shaft 320 during the rotation of the rotating shaft 320, thereby further reducing the friction resistance between the rotating shaft 320 and the silent bearing 200, and then reducing the noise. The diameter of the mating part of the rotating shaft 320 and the silent bearing 200 is 0.8mm to 1.3mm, that is, the diameter of the first rotating section 321 can be 0.8mm to 1.3mm. For example, the specific value of the diameter of the first rotating section 321 can be 0.8mm, 1mm, 1.2mm or 1.3mm, etc. On the basis of ensuring the structural strength, the diameter of the first rotating section 321 can be reasonably reduced, thereby reducing the contact area between the silent bearing 200 and the rotating shaft 320, and also reducing the friction resistance and reducing the noise. Therefore, by setting the silent bearing 200, a lubricant is provided between the rotating shaft 320 and the silent bearing 200, so that the friction resistance between the rotating shaft 320 and the silent bearing 200 can be reduced, and finally the purpose of reducing the noise of the entire fan 10 is achieved. Obviously, when the friction resistance is reduced, the wear between the silent bearing 200 and the rotating shaft 320 can also be reduced, thereby increasing the service life of the fan 10.

[0051] See also Figure 8 In some embodiments, a sink groove 324 is provided on the rotating shaft 320. The sink groove 324 is located in the first through hole 511. The sink groove 324 extends along the circumference of the rotating shaft 320 and is in a closed loop. For example, along the concave direction of the sink groove 324, the width of the sink groove 324 gradually decreases. Of course, along the concave direction of the sink groove 324, the width of the sink groove 324 can also remain constant. By providing the sink groove 324, during the rotation of the rotating shaft 320, the sink groove 324 can hinder the lubricant, prevent the lubricant in the silent bearing 200 from leaking along the rotating shaft 320 to the outside of the silent bearing 200, and ensure that the lubricant is kept in the silent bearing 200 as much as possible, thereby improving the lubrication effect of the rotating shaft 320 to reduce friction and further reduce the generation of noise.

[0052] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A fan, applied to a dust sensor, characterized in that: The fan comprises: frame; A silent bearing, wherein the silent bearing is arranged on the frame; A rotor, the rotor comprising a rotating shaft and a sector, the sector being connected to an end of the rotating shaft, the rotating shaft being rotatably disposed in the silent bearing, and a lubricant being present between the rotating shaft and the silent bearing; and A driver is arranged on the frame, and is used for driving the rotor to rotate.

2. The fan according to claim 1, characterized in that The frame is provided with an installation cavity, the silent bearing is accommodated in the installation cavity, the silent bearing has a first surface, a second surface and a side circumferential surface, the first surface and the second surface are arranged at intervals along the axial direction of the silent bearing, the first surface is closer to the fan body than the second surface, the side circumferential surface is connected between the first surface and the second surface, and a ventilation groove is formed in a depression on the side circumferential surface and extends to the first surface and the second surface to connect the installation cavity.

3. The fan according to claim 2, characterized in that: It also includes a first positioning member, which is fixed in the installation cavity and abuts against the first surface. The first positioning member is provided with a first through hole connected to the installation cavity. The rotating shaft is rotatably matched with the first through hole. A first groove is recessed on the first surface to connect the first through hole and the ventilation groove.

4. The fan according to claim 3, characterized in that: The rotating shaft is provided with a sinking groove, the sinking groove is located in the first through hole, the sinking groove extends along the circumference of the rotating shaft and is in a closed loop shape, and the width of the sinking groove gradually decreases along the concave direction of the sinking groove.

5. The fan according to claim 2, characterized in that: It also includes a second positioning member, which is fixed in the installation cavity and abuts against the second surface. The second positioning member is provided with a second through hole connected to the installation cavity. The rotating shaft is rotatably matched with the second through hole. A second groove is recessed on the second surface to connect the second through hole and the ventilation groove.

6. The fan according to claim 5, characterized in that: The second positioning member is also provided with a plurality of through holes penetrating the second positioning member, the through holes being connected to the second through hole, the plurality of through holes being arranged at intervals along the circumference of the second through hole, and the size of the through holes in the circumferential direction of the second through hole increases along the direction pointing from the second through hole to the through hole.

7. The fan according to claim 6, characterized in that: The rotating shaft includes a first rotating section, a second rotating section and a boss section, the second rotating section is connected between the first rotating section and the boss section, the first rotating section is inserted in the silent bearing, the second rotating section is inserted in the second through hole, and the cross-sectional dimensions of the boss section and the first rotating section are both larger than the cross-sectional dimension of the second rotating section; the boss section includes a first convex portion and a second convex portion, the first convex portion is connected between the second convex portion and the second rotating section, and in the direction from the first convex portion to the second convex portion, the cross-sectional dimension of the first convex portion is constant, and the cross-sectional dimension of the second convex portion is reduced.

8. The fan according to claim 2, characterized in that: It also includes a gasket, which is arranged in the installation cavity, and the end of the rotating shaft away from the fan body is in contact with the gasket, and the surface of the rotating shaft in contact with the gasket is a spherical surface.

9. The fan according to claim 2, characterized in that: Also includes at least one of the following options: The installation cavity comprises a first cavity and a second cavity which are coaxially arranged, the caliber of the first cavity is larger than the caliber of the second cavity, the silent bearing is located in the first cavity, and the end of the rotating shaft away from the fan body is located in the second cavity; The frame includes a sleeve, a base, a connecting piece and a mounting seat. The sleeve is arranged around the base and the mounting seat. The connecting piece is connected between the sleeve and the base. There are multiple connecting pieces, and the multiple connecting pieces are arranged at intervals along the circumference of the sleeve. The mounting seat is protruded on the base, and the mounting cavity is opened on the mounting seat.

10. The fan according to claim 1, characterized in that Also includes at least one of the following options: The diameter of the mating portion between the rotating shaft and the silent bearing is 0.8 mm to 1.3 mm; The silent bearing is made of copper.

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