Miniature ball bearings for cooling fans

Abstract

This utility model discloses a miniature ball bearing for a cooling fan, comprising an outer ring, an inner ring, a cage, a dust cover, and rolling elements movably disposed between the outer and inner rings. Both the inner and outer peripheral walls of the outer ring and the inner ring have circumferentially formed grooves for the rolling elements to move. Both ends of the inner peripheral wall of the outer ring have circumferentially formed stepped grooves for installing the dust cover. The connections between the grooves of the inner ring and the outer peripheral wall of the inner ring, and between the grooves of the outer ring and the inner peripheral wall of the outer ring, have chamfered edges. A retaining spring is provided in the stepped groove for an interference fit with the stepped groove. The inner wall of the retaining spring abuts against the outer wall of the dust cover, while the outer peripheral wall of the dust cover has a clearance fit with the inner peripheral wall of the stepped groove. The curvature coefficient of the grooves of the outer ring is greater than that of the grooves of the inner ring. This utility model solves the problems of traditional miniature ball bearings, such as increased bearing ellipticity due to dust cover installation leading to out-of-tolerance bearing ellipticity, and assembly damage during rolling element installation leading to unqualified rolling element vibration during bearing operation.

Description

Technical Field

[0001] This utility model relates to the field of bearing technology, specifically a miniature ball bearing for a cooling fan. Background Technology

[0002] In the field of cooling fans, miniature ball bearings are core components ensuring stable fan operation. Their performance directly determines the cooling efficiency, operating noise, and lifespan of the cooling fan. Existing miniature ball bearings for cooling fans typically consist of an outer ring, inner ring, rolling elements, a cage, and a dust cover. Both the inner and outer circumferential walls of the outer ring have circumferential grooves for the rolling elements to move. The dust cover prevents external dust from entering the bearing and protects the lubrication environment of the rolling elements and grooves; it is an indispensable part of the bearing structure. However, currently, there are still two major technical problems that urgently need to be solved in the production, assembly, and practical application of these miniature ball bearings, which seriously restrict product quality and production efficiency:

[0003] Firstly, the installation of dust covers can easily lead to excessive ellipticity of the outer ring, failing to meet the required precision. Traditional miniature ball bearings often use a straight groove structure on the inner circumferential wall of the outer ring to install dust covers. During assembly, a press-fit process is required to squeeze the dust cover into the straight groove. Because the dust cover exerts uneven radial pressure on the ring body during press-fitting, it easily causes plastic deformation of the bearing outer ring, resulting in a significant increase in ellipticity, typically reaching 5-8 μm. Even with industry-standard adjustments to press-fitting mold parameters, optimization of press-fitting air pressure, or modifications to the straight groove structure, the problem persists. Even with localized improvements, the ellipticity of the outer ring can only be barely controlled within the range of 3-5μm. Some products are still scrapped because the ellipticity exceeds the customer's usage standards. In addition, the diameter of the traditional straight groove is limited by the processing technology, resulting in a large dimensional variation. This means that the dust cover must be matched one by one to the corresponding straight groove for press-fitting, which greatly reduces assembly efficiency. At the same time, the dust cover often deforms due to uneven stress during the press-fitting process, requiring disassembly, prying, and reinstallation, which further increases rework costs and time losses.

[0004] Secondly, rolling element assembly is prone to damage, resulting in a high failure rate of bearing vibration. Traditional miniature ball bearings lack reasonable transition structures at the connection points between the inner ring raceway and the outer ring outer wall, and between the outer ring raceway and the outer ring inner wall. They are mostly right-angled or irregularly shaped designs. During the rolling element assembly process, the hard contact between the rolling element and the raceway edge can easily cause scratches and bumps on the rolling element surface, forming damage marks. This type of damage will cause obvious "rolling element damage sound" during bearing operation, which in turn will lead to abnormal bearing vibration. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a miniature ball bearing for cooling fans. This addresses the problems of traditional miniature ball bearings, such as increased bearing ellipticity due to dust cover installation, leading to out-of-tolerance bearing ellipticity, and assembly damage during rolling element installation causing unqualified rolling element vibration during bearing operation.

[0006] To achieve the above objectives, this utility model provides a miniature ball bearing for a cooling fan, comprising an outer ring, an inner ring, a cage, a dust cover, and rolling elements movably disposed between the outer ring and the inner ring. Both the inner and outer peripheral walls of the outer ring and the inner ring have circumferentially formed grooves for the rolling elements to move. Both ends of the inner peripheral wall of the outer ring have circumferentially formed stepped grooves for the installation of the dust cover. The grooves of the inner ring and the outer peripheral wall of the inner ring, as well as the grooves of the outer ring and the inner peripheral wall of the outer ring, are connected by chamfered edges. A retaining spring is provided in the stepped groove for interference fit with the stepped groove. The inner wall of the retaining spring abuts against the outer wall of the dust cover, and the outer peripheral wall of the dust cover is clearance-fitted with the inner peripheral wall of the stepped groove. The curvature coefficient of the grooves of the outer ring is greater than that of the inner ring.

[0007] The advantages of adopting the above technical solution are as follows: The stepped groove provides a suitable mounting base for the dust cover and retaining ring, avoiding the compression of the outer ring by traditional press-fitting processes, ensuring the stability of the outer ring shape, and solving the problem of excessive ellipticity. The interference fit between the retaining ring and the stepped groove can firmly limit the dust cover, preventing displacement and ensuring a long-lasting seal. The clearance fit between the dust cover and the stepped groove allows for quick installation without the need for optional accessories, simplifying the assembly process and improving assembly efficiency. The chamfered edges of the groove optimize the transition between the groove and the inner and outer ring walls, reducing contact damage during rolling element assembly and lowering the risk of abnormal operation. The design of the outer ring groove curvature coefficient being greater than that of the inner ring optimizes the contact state between the rolling elements and the groove, enhancing the bearing's rotational flexibility and reducing operating resistance. Through the synergistic effect of the above overall structure, the core problems of excessive ellipticity and rolling element assembly damage in traditional bearings are solved, ensuring bearing operational stability and service life, and meeting the precision and reliability requirements of cooling fans.

[0008] The present invention further provides that the chamfer size of the groove edge is 0.1-0.15mm.

[0009] The advantages of adopting the above technical solution are: the specific size of the chamfered groove can be precisely adapted to the assembly scenario of the rolling elements and the inner and outer ring grooves, avoiding the transition being uneven due to the chamfer being too small, preventing damage caused by hard contact between the rolling elements and the groove edge during assembly, and avoiding excessive reduction of the effective contact area of ​​the groove due to the chamfer being too large, thus ensuring the bearing's load-bearing capacity. Moreover, this size is easy to process precisely using existing grinding processes, ensuring the consistency of the chamfer shape and size, reducing assembly differences caused by chamfer deviations, and making the damage protection effect of each bearing unit uniform during the assembly of rolling elements, further improving the bearing's operational stability, reducing the probability of abnormal operation caused by rolling element damage, providing precise dimensional assurance for the overall performance stability of the bearing, and adapting to the precision assembly requirements of miniature ball bearings for cooling fans.

[0010] The present invention further comprises: the channel curvature coefficient of the inner ring is 0.54, and the channel curvature coefficient of the outer ring is 0.56.

[0011] The advantages of adopting the above technical solution are as follows: The specific curvature coefficient combination of the inner and outer ring channels in the above technology precisely optimizes the contact interface between the rolling elements and the channels, making the contact state conform to the operating characteristics of the miniature ball bearing of the cooling fan. The combination of the inner ring curvature coefficient of 0.54 and the outer ring curvature coefficient of 0.56 reduces the contact friction between the rolling elements and the channels, improves the bearing rotational flexibility, reduces operating energy consumption, and at the same time ensures the load-bearing capacity of the contact area, avoids local stress concentration caused by improper curvature coefficients, and extends the service life of the channels and rolling elements. This coefficient combination is easy to achieve through standardized processing technology, ensuring that the curvature accuracy of each bearing unit is consistent, reducing the differences in operating performance caused by curvature deviations, and enabling the bearing to maintain stable rotational performance under different usage scenarios, further adapting to the dual requirements of cooling fans for bearing flexibility and durability.

[0012] The present invention is further provided that the outer diameter of the dust cover is smaller than the diameter of the stepped groove.

[0013] The advantages of adopting the above technical solution are: the design of the dust cover's outer diameter being smaller than the stepped groove's opening diameter creates a reasonable gap between the dust cover and the stepped groove, eliminating the cumbersome process of selecting each dust cover individually during traditional press-fitting, simplifying assembly operations, and improving assembly efficiency. At the same time, this gap prevents the dust cover from being rigidly squeezed against the inner wall of the stepped groove during installation, preventing the dust cover from deforming due to assembly stress, ensuring the integrity of the dust cover's sealing shape, and ensuring its effectiveness in preventing external dust from entering the bearing. In addition, the reasonable gap facilitates quick alignment of the dust cover during assembly, reducing assembly adjustment time, lowering operational difficulty, and avoiding deformation of the stepped groove due to interference fit.

[0014] The present invention is further provided that the combined width of the outer diameter of the dust cover and the outer diameter of the retaining spring is greater than the width of the stepped groove.

[0015] The advantages of adopting the above technical solution are: the design that the combined width of the dust cover and the snap ring is greater than the width of the stepped groove allows the two to form an axial limit within the stepped groove after assembly, preventing the dust cover and snap ring from axially shifting due to vibration during bearing operation, thus ensuring the stability of the sealing structure. This width design eliminates the shaking caused by axial clearance in traditional sealing structures, prevents abnormal noise caused by component displacement during bearing operation, and improves operational quietness. At the same time, the tight axial fit enhances the sealing effect of the dust cover, reduces the probability of external impurities entering the bearing from the axial clearance, and protects the lubrication environment of the raceway and rolling elements.

[0016] The present invention further includes the following features: the groove is formed by grinding with a groove grinding wheel and the chamfer on the groove edge is formed by grinding.

[0017] The advantages of adopting the above technical solution are: In the above technology, the groove and groove chamfer are made by grinding the groove with a grinding wheel. With the high precision characteristics of the grinding process, the surface smoothness and dimensional accuracy of the groove are ensured, the surface roughness defects of the groove are reduced, the frictional resistance when the rolling element contacts the groove is reduced, and the smoothness of bearing rotation is improved. At the same time, the groove chamfer is processed synchronously with the groove grinding, avoiding the dimensional deviation and inconsistency in shape caused by processing the chamfer separately, ensuring a natural transition between the chamfer and the groove, and enhancing the protection effect against damage to the rolling element assembly.

[0018] The present invention further includes: both sides of the outer ring have annular retaining edges bent toward the retaining spring to prevent the retaining spring from coming out of the stepped groove.

[0019] The advantages of adopting the above technical solution are: the annular retaining edge with the outer ring side walls bent towards the retaining ring in the above technology forms radial and axial double protection for the retaining ring in the stepped groove, effectively preventing the retaining ring from falling out of the stepped groove due to vibration, impact and other factors during bearing operation, ensuring the integrity of the sealing structure. At the same time, the annular retaining edge and the outer ring are integrated into the design, eliminating the need for additional assembly of limiting components, simplifying the structural complexity and reducing processing and assembly costs. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the present invention;

[0021] Figure 2 This is a cross-sectional view of the inner ring in this utility model;

[0022] Figure 3 This is a partial cross-sectional view of the outer ring, dust cover, and retaining ring in the present invention, wherein B is the width dimension of the combination of the outer diameter of the retaining ring and the outer diameter of the dust cover, and A is the width dimension of the stepped groove. Detailed Implementation

[0023] This utility model provides a miniature ball bearing for a cooling fan, including an outer ring 1, an inner ring 2, a cage 21, a dust cover 3, and a rolling element 22 movably disposed between the outer ring 1 and the inner ring 2. The inner and outer peripheral walls of the outer ring 1 and the inner ring 2 are both circumferentially formed with grooves 11 for the rolling element 22 to move. Both ends of the inner peripheral wall of the outer ring 1 are circumferentially formed with stepped grooves 12 for the installation of the dust cover 3. The grooves 11 of the inner ring 2 and the outer peripheral wall of the inner ring 2, as well as the grooves 11 of the outer ring 1 and the inner peripheral wall of the outer ring 1, are connected by chamfered edges 111. A retaining spring 31 is provided in the stepped groove 12 for interference fit with the stepped groove 12. The inner wall of the retaining spring 31 abuts against the outer wall of the dust cover 3. The outer ring 1 has a groove 11 with a clearance fit to the inner circumferential wall of the stepped groove 12. The curvature coefficient of the groove 11 of the outer ring 1 is greater than that of the groove 11 of the inner ring 2. The chamfer 111 of the groove edge has a size of 0.1-0.15mm. The curvature coefficient of the groove 11 of the inner ring 2 is 0.54, and the curvature coefficient of the groove 11 of the outer ring 1 is 0.56. The outer diameter of the dust cover 3 is smaller than the diameter of the stepped groove 12. The combined width of the outer diameter of the dust cover 3 and the outer diameter of the retaining spring 31 is greater than the width of the stepped groove 12. The groove 11 is formed by groove grinding with a groove grinding wheel, and the chamfer 111 of the groove edge is formed by grinding. Both sides of the outer ring 1 have annular retaining edges 32 bent towards the retaining spring 31 to prevent the retaining spring 31 from falling out of the stepped groove 12.

[0024] In the above-mentioned technology, the curvature coefficient of the inner ring in the traditional standard is 0.515, while the curvature coefficient of the outer ring in the standard is 0.525. Compared with the curvature coefficient of the traditional standard, the curvature coefficient set in this technology reduces the contact area between the rolling element and the raceway by 40% under the same radial load, thereby improving the flexibility of the bearing, meeting the flexibility requirements of customers, and thus improving its practicality and applicability.

[0025] The foregoing has shown and described the basic principles and main features of this utility model, as well as its advantages. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications may be made to this utility model without departing from its spirit and scope. All such changes and modifications fall within the scope of protection of this utility model as defined by the appended claims and their equivalents.

Claims

1. A miniature ball bearing for a cooling fan, comprising an outer ring, an inner ring, a cage, a dust cover, and rolling elements movably disposed between the outer ring and the inner ring, wherein the inner peripheral wall of the outer ring and the outer peripheral wall of the inner ring are both provided with circumferentially circumferentially grooved for the movement of the rolling elements, and both ends of the inner peripheral wall of the outer ring are provided with stepped grooves for the installation of the dust cover, characterized in that: The grooves of the inner ring and the outer peripheral wall of the inner ring, as well as the grooves of the outer ring and the inner peripheral wall of the outer ring, are connected by chamfered edges. A retaining spring is provided in the stepped groove for interference fit with the stepped groove. The inner wall of the retaining spring is abutted against the outer wall of the dust cover. The outer peripheral wall of the dust cover is clearance fitted to the inner peripheral wall of the stepped groove. The curvature coefficient of the groove of the outer ring is greater than that of the groove of the inner ring.

2. The miniature ball bearing for a cooling fan according to claim 1, characterized in that: The chamfer size of the groove edge is 0.1-0.15mm.

3. A miniature ball bearing for a cooling fan according to claim 1, characterized in that: The inner ring has a channel curvature coefficient of 0.54, and the outer ring has a channel curvature coefficient of 0.

56.

4. A miniature ball bearing for a cooling fan according to claim 1, characterized in that: The outer diameter of the dust cover is smaller than the diameter of the stepped groove.

5. A miniature ball bearing for a cooling fan according to claim 1, characterized in that: The combined width of the outer diameter of the dust cover and the outer diameter of the retaining ring is greater than the width of the stepped groove.

6. A miniature ball bearing for a cooling fan according to claim 1, characterized in that: The groove is formed by grinding with a groove grinding wheel, and the chamfered edges of the groove are formed by grinding.

7. A miniature ball bearing for a cooling fan according to claim 1, characterized in that: Both sides of the outer ring have annular retaining edges bent towards the retaining spring to prevent the retaining spring from coming out of the stepped groove.

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