Heat dissipation fan

Abstract

The present design discloses a cooling fan and has a bearing system. The bearing system includes a shaft tube, a bearing, a rotating shaft and a retaining ring. The shaft tube has an accommodating space, and the bearing is disposed therein. The bearing also has a shaft hole, and the rotating shaft passes through the shaft hole. An oil-blocking groove is annularly provided on the outer peripheral surface of the rotating shaft. The retaining ring has an inner hole and is sleeved on the rotating shaft. The position radially close to the inner hole is defined as the oil-blocking portion of the retaining ring. The oil-blocking portion of the retaining ring corresponds to the oil-blocking groove and is located above the bearing. The retaining ring is tightly and fixedly fitted with the open end of the shaft tube. Wherein, the width of the oil-blocking groove gradually decreases from the open end inward along the axial direction of the rotating shaft, and a second inclined surface and a third inclined surface located above the second inclined surface are formed. In the axial direction of the rotating shaft, the oil-blocking portion of the retaining ring is located between the position of the lowest point of the second inclined surface and the position of the highest point of the third inclined surface. The cooperation between the retaining ring and the oil-blocking groove can effectively prevent the lubricating oil from overflowing along the rotating shaft and the retaining ring.

Description

Technical Field

[0001] This design belongs to the technical field of cooling fans. Background Art

[0002] In electronic devices with limited installation space such as laptops, fans are usually installed near electronic components, and the airflow generated by the rotation of the fan blades directly blows on the electronic components or the heat sinks installed on the electronic components to effectively dissipate heat from them.

[0003] During the rotation of the fan, lubricating oil needs to be added between the rotating shaft and the bearing, and between the bearing and the shaft tube in the bearing system of the fan. Generally, the circulating flow effect of the lubricating oil in the existing bearing system is not ideal, and the lubricating oil is also likely to overflow from the joint between the rotating shaft and the retaining ring. After running for a period of time, the lubricating oil will be lost, resulting in a lack of lubricating oil between the bearing and the rotating shaft, and then a large-area contact between the bearing and the rotating shaft, generating a large frictional force, which affects the performance and service life of the bearing.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a cooling fan. Summary of the Invention

[0005] The purpose of this design is to provide a cooling fan that can effectively solve the above technical problems.

[0006] The technical solution provided by this design to solve its technical problems is as follows:

[0007] A cooling fan has a bearing system, and the bearing system includes:

[0008] A shaft tube having a bottom wall and a side wall extending upward along the periphery of the bottom wall, and the bottom wall and the side wall jointly define a receiving space with one end open;

[0009] A bearing disposed in the receiving space, and the bearing has a shaft hole;

[0010] A rotating shaft passing through the shaft hole, and an oil-blocking groove is annularly provided on the outer peripheral surface of the rotating shaft. The width of the oil-blocking groove gradually decreases from the open end inward along the axial direction of the rotating shaft, and forms a second inclined surface and a third inclined surface located above the second inclined surface;

[0011] A retaining ring having an inner hole, and the retaining ring is annularly disposed at a position corresponding to the oil-blocking groove of the rotating shaft through the inner hole and is pressed on the upper side of the bearing, and the retaining ring is tightly fitted and fixed with the open end of the shaft tube;

[0012] The second inclined surface forms a second inclined surface lowest point q2 and a second inclined surface highest point Q2 along the axial direction of the rotating shaft;

[0013] The third inclined surface has a lowest point q3 and a highest point Q3 of the third inclined surface formed in the axial direction of the rotating shaft;

[0014] The position of the pressing ring close to the inner hole in the radial direction is defined as the oil-blocking part of the pressing ring. The oil-blocking part of the pressing ring has a lowest position. In the axial direction of the rotating shaft, the lowest position of the oil-blocking part of the pressing ring is higher than the lowest point q2 of the second inclined surface, and the whole oil-blocking part of the pressing ring is lower than the highest point Q3 of the third inclined surface.

[0015] Preferably, one end of the inner wall surface of the shaft hole of the bearing adjacent to the pressing ring forms a first inclined surface. The first inclined surface has a lowest point q1 and a highest point Q1 of the first inclined surface formed in the axial direction of the rotating shaft. The lowest point q2 of the second inclined surface is not lower than the lowest point q1 of the first inclined surface.

[0016] Preferably, one end of the inner wall surface of the shaft hole of the bearing adjacent to the pressing ring forms a first inclined surface. The projection of the lowest point q2 of the second inclined surface in the radial direction of the rotating shaft is located on the first inclined surface.

[0017] Preferably, the projection of the lowest point q2 of the second inclined surface in the radial direction of the rotating shaft overlaps with the highest point Q1 of the first inclined surface; or the projection of the lowest point q2 of the second inclined surface in the radial direction of the rotating shaft overlaps with the lowest point q1 of the first inclined surface.

[0018] Preferably, in the axial direction of the rotating shaft, the second inclined surface has a maximum height C, and the third inclined surface has a maximum height D. The ratio of the height D to the height C is not less than 0.5 and not greater than 1.

[0019] Preferably, in the axial direction of the rotating shaft, an included angle β is formed between the second inclined surface and the third inclined surface, and the included angle β satisfies 80° ≤ β ≤ 135°.

[0020] Preferably, the oil-blocking groove is a triangular groove recessed inward from the outer peripheral surface of the rotating shaft.

[0021] Preferably, the surface of the pressing ring facing the bearing is thinned at a position adjacent to the rotating shaft to form a thinned surface. The area where the thinned surface is located forms the oil-blocking part of the pressing ring. The space defined by the thinned surface, the first inclined surface and the upper surface of the bearing communicates with the oil-blocking groove to jointly form an oil-blocking space.

[0022] Preferably, one end of the thinned surface adjacent to the inner hole in the radial direction of the rotating shaft is higher than the highest point Q2 of the second inclined surface in the axial direction of the rotating shaft.

[0023] Preferably, a guiding surface is further provided at a position on the second inclined surface close to the lowest point q2 of the second inclined surface and / or at a position on the third inclined surface close to the highest point Q3 of the third inclined surface. The second inclined surface and / or the third inclined surface are transitionally connected to the outer peripheral surface of the rotating shaft through the guiding surface.

[0024] The beneficial effects of this design are as follows:

[0025] Compared with the prior art, in this design, an oil-blocking groove is provided at a position on the rotating shaft corresponding to the pressing ring, and through the cooperative action between the second inclined surface and the third inclined surface in the oil-blocking groove and the pressing ring and the bearing, lubricating oil can be effectively prevented from overflowing along the rotating shaft and the pressing ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following will further illustrate this design in conjunction with the views and embodiments. In the drawings:

[0027] Figure 1 is a schematic structural diagram of a heat dissipation fan disclosed in this design application;

[0028] Figure 2 is Figure 1 a schematic structural diagram of the bearing system shown in;

[0029] Figure 3 is Figure 2 an enlarged schematic diagram of the structure shown in the virtual circle E in;

[0030] Figure 4 is Figure 2 a schematic diagram of another embodiment of the structure shown in the virtual circle E in. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] In order to make the purpose, technical solutions and advantages of this design clearer, the following will further elaborate on this design in detail in conjunction with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this design and are not used to limit this design.

[0032] Please refer to Figure 1 shown. A heat dissipation fan disclosed in this design application can be either a centrifugal fan or an axial flow fan. In this application, a centrifugal fan is taken as an example, but the structure disclosed in this application is not limited to this centrifugal fan.

[0033] The heat dissipation fan 100 includes a fan housing, a stator group, a fan wheel, and a bearing system 90.

[0034] The bearing system 90 has a shaft tube 1, a bearing 2 fixed in the shaft tube 1, a rotating shaft 3 pivotally connected in the bearing 2, and a pressing ring 4 located on top of the bearing 2.

[0035] The fan housing includes a bottom plate, and a bearing system 90 is provided on the bottom plate. Specifically, the shaft tube 1 is fitted onto the bottom plate.

[0036] The stator assembly is disposed within the movable space of the fan housing. In one embodiment, the stator assembly is disposed on the bottom plate and surrounds the periphery of the shaft tube 1. The stator assembly includes a drive circuit board, a silicon steel sheet assembly, and a coil assembly wound around the silicon steel sheet assembly. Among them, the coil assembly is electrically connected to the drive circuit board, and the drive circuit board can be externally connected to a power source through wires, and then controls the coil assembly to generate a magnetic polarity change.

[0037] The fan wheel is rotatably disposed within the movable space of the fan housing. The fan wheel includes a hub 5 and fan blades connected to the hub 5. The fan blades are evenly arranged around the outer peripheral surface of the hub 5. The rotating shaft 3 is fixed to the center of the hub 5 and fixedly connected to the hub 5. The hub 5 further includes a hollow receiving chamber, and an annular magnet is fixed on the inner wall of the receiving chamber. The annular magnet is disposed radially opposite to the stator. A magnetic attraction and repulsion force can be generated between the annular magnet and the stator assembly to drive the fan wheel to rotate.

[0038] Please refer to Figure 2 As shown, it is the bearing system 90 disclosed in the present application. Among them, the shaft tube 1 is generally in a hollow columnar shape, and it has an axially hollow accommodating space S therein to accommodate the bearing 2. The bottom of the accommodating space S is closed and is defined by the bottom wall 11 of the shaft tube 1 and the side wall 12 extending upward along the periphery of the bottom wall 11. A first stepped annular surface 13 and a second stepped annular surface 14 perpendicular to the axis of the shaft tube 1 are sequentially formed on the inner wall of the accommodating space S. The inner diameter of the first stepped annular surface 13 is smaller than the inner diameter of the second stepped annular surface 14.

[0039] The bearing 2 is in a cylindrical shape and is clamped within the accommodating space S of the shaft tube 1. An axial shaft hole 21 is provided through the middle of the bearing 2, and inclined surfaces are formed at both ends of the outer wall surface of the bearing 2 and the inner wall surface of the shaft hole 21. One end of the inner wall surface of the shaft hole 21 of the bearing 2 adjacent to the pressing ring 4 is the first inclined surface L1.

[0040] The bottom surface of the bearing 2 abuts against the first stepped annular surface 13. The outer diameter of the bearing 2 is smaller than the outer diameter of the second stepped annular surface 14, and in the direction away from the bottom of the accommodating space S (i.e., the position of the surface of the bottom wall 11 within the accommodating space S), the top surface of the bearing 2 is higher than the second stepped annular surface 14. Preferably, a retaining piece can also be provided on the first stepped annular surface 13, and the bearing 2 is disposed on the retaining piece.

[0041] The rotating shaft 3 is rotatably disposed within the shaft hole 21 and passes through the bearing 2, and abuts against the surface of the bottom within the accommodating space S. An oil blocking groove 31 is formed by inwardly annularly arranging on the outer peripheral surface of the rotating shaft 3. Preferably, a wear-resistant piece can also be provided on the surface of the bottom within the accommodating space S to increase the wear resistance.

[0042] The width of the oil-blocking groove 31 in the axial direction of the rotating shaft 3 gradually decreases from the open end inward, and has a second inclined surface L2 and a third inclined surface L3 located above the second inclined surface L2. Among them, the second inclined surface L2 has a lowest point q2 and a highest point Q2 of the second inclined surface in the axial direction of the rotating shaft 3; the third inclined surface L3 has a lowest point q3 and a highest point Q3 of the third inclined surface in the axial direction of the rotating shaft 3; the first inclined surface L1 has a lowest point q1 and a highest point Q1 of the first inclined surface in the axial direction of the rotating shaft 3. Among them, the shape of the oil-blocking groove 31 recessed inward from the outer peripheral surface of the rotating shaft 3 can be a triangular groove or a trapezoidal or other polygonal groove, or a groove with a curved surface between the second inclined surface L2 and the third inclined surface L3. In the present application, the projection of the lowest point q2 of the second inclined surface in the axial direction of the rotating shaft 3 overlaps with the highest point Q3 of the third inclined surface, and the lowest point q2 of the second inclined surface is not lower than the lowest point q1 of the first inclined surface.

[0043] Specifically, the projection of the lowest point q2 of the second inclined surface in the radial direction of the rotating shaft 3 is located on the first inclined surface L1, that is, the lowest point q2 of the second inclined surface is located between the lowest point q1 and the highest point Q1 of the first inclined surface in the axial direction of the rotating shaft 3. In the present application, a first flow channel area and a conventional flow channel area for the lubricating oil to flow are defined between the outer surface of the rotating shaft 3 and the inner wall surface of the bearing 2. In the radial direction of the rotating shaft 3, the first flow channel area is the gap area between the surface of the outer peripheral surface of the rotating shaft 3 close to the second inclined surface L2 and the first inclined surface L1 (that is: the surface area of the outer surface of the rotating shaft 3 below the lowest point q2 of the second inclined surface, and the surface area that can be projected onto the first inclined surface L1 in the radial direction is defined as the first flow channel surface, and the gap area between the first flow channel surface and the first inclined surface L1 forms the first flow channel area, and the first flow channel area is formed by the outer surface of the rotating shaft 3 partially standing upright in the axial direction of the rotating shaft 3 and the partial first inclined surface L1 being spaced apart. When the projection of the lowest point q2 of the second inclined surface in the radial direction of the rotating shaft 3 overlaps with the lowest point q1 of the first inclined surface (as Figure 3 shown), there is no such first flow channel area at this time). The conventional flow channel area is the gap area between the outer peripheral surface of the rotating shaft 3 and the surface of the inner wall of the shaft hole 21 excluding the first inclined surface L1 (that is, the gap area between the inner wall surface of the shaft hole 21 of the bearing 2 below the lowest point q1 of the first inclined surface and the outer peripheral surface of the rotating shaft 3).

[0044] Specifically, the first inclined surface L1 has a radial distance in the radial direction of the rotating shaft 3, and this radial distance should be as small as possible so that the capillary spacing of the first flow channel region in the radial direction of the rotating shaft 3 is as close as possible to the capillary spacing of the conventional flow channel region in the radial direction of the rotating shaft 3. This makes the capillary action generated when the lubricating oil in the first flow channel region flows close to the capillary action generated when the lubricating oil in the conventional flow channel region flows. At the same time, when the fan rotates, due to the temperature rise and centrifugal force, the lubricating oil in the conventional flow channel region within the bearing system 90 will move upward along the rotating shaft 3 and enter the first flow channel region. Since the capillary action generated when the lubricating oil in the first flow channel region flows is close to the capillary action generated when the lubricating oil in the conventional flow channel region flows, therefore, the lubricating oil in the first flow channel region will also continue to move upward and overflow from the first flow channel region. In this application, since the second inclined surface L2 is formed in the oil blocking groove 31, the second inclined surface L2 will prevent the overflowing lubricating oil from continuing to move upward, and the overflowing lubricating oil is thrown out under the action of the centrifugal force; at the same time, the first flow channel region can also serve as a buffer region for the lubricating oil in the conventional flow channel region to continue to move upward, so as to reduce the power of the lubricating oil overflowing from the first flow channel region to continue to move upward, and improve the effect of the second inclined surface L2 in blocking the lubricating oil.

[0045] In this embodiment, the oil blocking groove 31 is preferably a triangular groove recessed inward from the outer peripheral surface of the rotating shaft 3, that is, the highest point Q2 of the second inclined surface overlaps with the lowest point q3 of the third inclined surface.

[0046] The pressure ring 4 is pressed against the top surface of the bearing 2 to fix the bearing 2 in the accommodating space S and limit the axial displacement of the bearing 2. The pressure ring 4 includes an inner ring 41 pressed against the top surface of the bearing 2 and an outer ring 42 sleeved on the outer edge of the inner ring 41. An inner hole is formed in the center of the inner ring 41. The pressure ring 4 is sleeved on the rotating shaft 3 through the inner hole and at a position corresponding to the oil-blocking groove 31. Among them, the position of the inner ring 41 close to the inner hole in the radial direction is defined as the pressure ring oil-blocking part. In the axial direction of the rotating shaft 3, the pressure ring oil-blocking part is higher than the lowest point q2 of the second inclined surface and lower than the highest point Q3 of the third inclined surface, so that the pressure ring oil-blocking part and the oil-blocking groove 31 are used in conjunction to prevent the lubricating oil from overflowing from the inner hole 41 of the pressure ring 4; furthermore, the outer edge of the outer ring 42 is tightly pressed against the inner wall surface of the accommodating space S, so that the pressure ring 4 is tightly fitted and fixed to the open end of the shaft tube 1, so that the pressure ring 4 is not easy to escape from the accommodating space S. The lower end surface of the inner ring 41 is thinned to form a thinned surface 411 at a position near the rotating shaft 3, and the space defined by the thinned surface 411, the first inclined surface L1 and the upper surface of the bearing 2 is connected to the oil-blocking groove 31, and together form an oil-blocking space, so that the space between the pressure ring 4 and the bearing 2 can be increased to accommodate more overflowed lubricating oil, so that the lubricating oil can more easily enter the next stage of the circulation channel in the bearing system 90. In the present application, the area where the thinned surface 411 of the pressure ring 4 is located forms the pressure ring oil-blocking part. Preferably, the pressure ring 4 is a closed metal pressure ring. One end of the thinned surface 411 adjacent to the inner hole 41 in the radial direction of the rotating shaft 3 is higher than the highest point Q2 of the second inclined surface in the axial direction of the rotating shaft 3, so that the lubricating oil on the second inclined surface L2 can be completely thrown into the circulation channel between the pressure ring 4 and the bearing 2, promoting the circulation of the lubricating oil; at the same time, when the rotating shaft 3 rotates, the pressure ring 4 will not interfere with the rotating shaft 3.

[0047] Specifically, along the axial direction of the rotating shaft 3, the second inclined surface L2 of the oil-blocking groove 31 near the lowest point q2 of the second inclined surface also includes a guide curved surface, and the second inclined surface L2 is transitionally connected with the outer peripheral surface of the rotating shaft 3 through the guide curved surface. Thus, it is possible to avoid the burrs that may exist at the corners of the rotating shaft 3 from scratching and colliding with the bearing 2, thereby improving the service life of the rotating shaft 3. In the present application, a guide curved surface may also be provided on the third inclined surface L3 of the oil-blocking groove 31 near the highest point Q3 of the third inclined surface, and the third inclined surface L3 is transitionally connected with the outer peripheral surface of the rotating shaft 3 through the guide curved surface.

[0048] Along the axial direction of the rotating shaft 3, the second inclined surface L2 has a maximum height C, the third inclined surface L3 has a maximum height D, and an angle β is formed between the second inclined surface L2 and the third inclined surface L3 (eg Figure 4As shown, this application preferably has: when the included angle β is 80° ≤ β ≤ 135°, and the ratio of D to C is not less than 0.5 and not greater than 1, it should be understood that when the ratio of D to C is not less than 0.5 and not greater than 1, and the range of the included angle β is determined, at this time, it can be determined that the second inclined plane L2 has a larger or equal working area relative to the third inclined plane L3, and the inclination angle of the second inclined plane L2 relative to the radial direction of the rotating shaft 3 is also more appropriate, so that the effect of the second inclined plane L2 hindering the continuous upward movement of the lubricating oil is better, and at the same time, the working area of the third inclined plane L3 is not easily too large, which is also convenient for applying the oil deflector. The structure of the oil blocking groove 31 is simple and convenient to manufacture, and at the same time, the assembly of the fan is also relatively simple.

[0049] In this embodiment, the first inclined plane L1 can also promote the overflowed lubricating oil to enter the oil blocking space; at the same time, the oil blocking groove 31 can also be used to block the oil passage for the lubricating oil to flow between the rotating shaft 3 and the pressing ring 4, so as to prevent the lubricating oil from overflowing along the inner hole 41 of the pressing ring 4.

[0050] Please refer to Figure 4 As shown, different from the above embodiment, the projection of the lowest point q2 of the second inclined plane in the radial direction of the rotating shaft 3 overlaps with the highest point Q1 of the first inclined plane. At this time, the distance of the first flow channel area in the axial direction of the rotating shaft 3 is longer, and the capillary spacing of the first flow channel area in the radial direction of the rotating shaft 3 gradually increases in the axial direction of the rotating shaft 3. The capillary action generated when the lubricating oil located in the first flow channel area flows is poor, but since the lowest point q2 of the second inclined plane is flush with the top surface of the bearing 2 (i.e., the position where the highest point q1 of the first inclined plane is located) in the axial direction of the rotating shaft 3, the second inclined plane L2 is located above the first inclined plane L1. Due to the action of centrifugal force, the lubricating oil located on the second inclined plane L2 (during the rotation of the rotating shaft, the lubricating oil overflowed in the bearing system 90 enters the second inclined plane L2) is more easily thrown out and enters the circulating flow channel between the pressing ring 4 and the bearing 2, so as to promote the circulating flow of the lubricating oil in the bearing system 90.

[0051] The present invention promotes the circulating flow of the lubricating oil in the bearing system by arranging an oil blocking groove at a position corresponding to the pressing ring on the rotating shaft, and the cooperation between the second inclined plane in the oil blocking groove and the first inclined plane of the bearing. At the same time, the cooperation use of the second inclined plane, the third inclined plane and the thinned surface of the pressing ring can also effectively prevent the lubricating oil from overflowing along the rotating shaft and the pressing ring.

[0052] For those skilled in the art, it is obvious that the present design is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present design, the present design can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present design is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present design.

[0053] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementation manners understandable by those skilled in the art.

Claims

1. A cooling fan having a bearing system, characterized in that, The bearing system includes: A shaft tube having a bottom wall and a side wall extending upward along the periphery of the bottom wall, and the bottom wall and the side wall jointly define a receiving space with one end open; A bearing disposed in the receiving space, and the bearing has a shaft hole; A rotating shaft passing through the shaft hole, and an oil-blocking groove is annularly provided on the outer peripheral surface of the rotating shaft. The width of the oil-blocking groove gradually decreases from the open end inward along the axial direction of the rotating shaft, and a second inclined surface and a third inclined surface located above the second inclined surface are formed; A pressing ring having an inner hole, and the pressing ring is annularly disposed at a position corresponding to the oil-blocking groove of the rotating shaft through the inner hole and is pressed above the bearing, and the pressing ring is tightly fitted and fixed to the open end of the shaft tube; The second inclined surface forms a second inclined surface lowest point q2 and a second inclined surface highest point Q2 along the axial direction of the rotating shaft; The third inclined surface forms a third inclined surface lowest point q3 and a third inclined surface highest point Q3 along the axial direction of the rotating shaft; The position of the pressing ring close to the inner hole along the radial direction is defined as the oil-blocking portion of the pressing ring, and the oil-blocking portion of the pressing ring forms a lowest position. In the axial direction of the rotating shaft, the lowest position of the oil-blocking portion of the pressing ring is higher than the second inclined surface lowest point q2, and the whole oil-blocking portion of the pressing ring is lower than the third inclined surface highest point Q3; One end of the inner wall surface of the shaft hole of the bearing adjacent to the pressing ring forms a first inclined surface. The first inclined surface forms a first inclined surface lowest point q1 and a first inclined surface highest point Q1 along the axial direction of the rotating shaft, and the projection of the second inclined surface lowest point q2 in the radial direction of the rotating shaft is located on the first inclined surface.

2. The cooling fan according to claim 1, wherein The projection of the second inclined surface lowest point q2 in the radial direction of the rotating shaft overlaps with the first inclined surface highest point Q1; or, the projection of the second inclined surface lowest point q2 in the radial direction of the rotating shaft overlaps with the first inclined surface lowest point q1.

3. The cooling fan according to claim 1, wherein In the axial direction of the rotating shaft, the second inclined surface has a maximum height C, the third inclined surface has a maximum height D, and the ratio of the height D to the height C is not less than 0.5 and not greater than 1.

4. The cooling fan according to claim 1, wherein In the axial direction of the rotating shaft, an included angle β is formed between the second inclined surface and the third inclined surface, and the included angle β satisfies 80° ≤ β ≤ 135°.

5. The cooling fan according to claim 1, characterized in that, The oil-blocking groove is a triangular groove recessed inward from the outer peripheral surface of the rotating shaft.

6. The cooling fan according to claim 1, wherein The surface of the pressing ring facing the bearing is thinned at a position adjacent to the rotating shaft to form a thinned surface, and the area where the thinned surface is located forms the oil-blocking portion of the pressing ring. The space defined by the thinned surface, the first inclined surface and the upper surface of the bearing communicates with the oil-blocking groove to jointly form an oil-blocking space.

7. The cooling fan according to claim 6, characterized in that One end of the thinned surface adjacent to the inner hole along the radial direction of the rotating shaft is higher than the second inclined surface highest point Q2 in the axial direction of the rotating shaft.

8. The cooling fan according to claim 1, wherein The position on the second inclined surface close to the second inclined surface lowest point q2 and / or the position on the third inclined surface close to the third inclined surface highest point Q3 further includes a guiding curved surface, and the second inclined surface and / or the third inclined surface are transitionally connected to the outer peripheral surface of the rotating shaft through the guiding curved surface.

Images