Low stress multi-ball bearing seat and method of designing same

Abstract

The application discloses a low-stress multi-ball bearing seat and a design method thereof, and relates to the technical field of multi-ball bearing seats, wherein the multi-ball bearing seat comprises an upper thrust plate, a lower thrust plate, a plurality of steel balls arranged between the upper thrust plate and the lower thrust plate, and a retainer assembly for limiting the steel balls; the first bearing surface of the upper thrust plate in contact with the steel balls and the second bearing surface of the lower thrust plate in contact with the steel balls are both planes; and the design method comprises the following steps: determining the grouping number N of the steel balls according to the size of the upper thrust plate and / or the lower thrust plate, wherein N is greater than or equal to 3. On the basis that the bearing surfaces of the upper thrust plate and the lower thrust plate are planes, the contact stress of each radial group of steel balls is balanced by grouping and diameter adjustment of the steel balls at different radial positions, so that the local high stress is reduced, and the load uniformity and working reliability of the multi-ball bearing seat are improved.

Description

Technical Field

[0001] This invention relates to the field of multi-ball bearing housing technology, specifically to a low-stress multi-ball bearing housing and its design method. Background Technology

[0002] Chinese patent CN107211580B discloses a multi-ball bearing housing, which consists of a housing, a top cover, a pressure block, a retaining ring, an upper pressure plate, a lower pressure plate, rolling elements, a locating pin, a locating bolt, a fastening pressure block, bolts, and nuts.

[0003] The key components of a multi-ball bearing housing are the upper thrust plate (also known as the upper pressure plate), the lower thrust plate (also known as the lower pressure plate), the rolling balls, and the cage assembly. The rolling balls are positioned between the upper and lower thrust plates, and the cage assembly separates them to prevent friction and guides their movement. The middle rolling balls are responsible for transmitting the load from the upper thrust plate and ensuring smooth operation. However, in practical applications, this design has a significant drawback: when the multi-ball bearing housing bears a load from the upper structure, the load is not evenly distributed on the upper thrust plate, but concentrated in the middle (at the axis of the upper thrust plate). This results in the rolling balls closer to the axis of the upper and lower thrust plates experiencing greater forces, leading to higher contact stress, while the rolling balls farther from the axis experience less force. This uneven stress distribution not only limits the overall performance of the bearing but may also accelerate the wear of the middle rolling balls and the corresponding thrust plate area, shortening the bearing's service life and affecting the reliability of the entire system.

[0004] Multi-ball bearing housings are commonly used in the chemical, metallurgical, and power industries, as well as various engineering projects, especially for supporting heavy-load equipment and facilities. With the rapid development of industry and the continuous increase in equipment size, higher demands are placed on the load-bearing capacity of multi-ball bearing housings, requiring them to withstand higher loads within the same dimensions. Therefore, new design methods are urgently needed to overcome these shortcomings and improve the service life of multi-ball bearing housings. Summary of the Invention

[0005] The purpose of this invention is to propose a low-stress multi-ball bearing housing and its design method. By keeping the bearing surfaces of the upper and lower thrust plates as planes, the contact stress of the steel balls in different radial positions is made more uniform by grouping and adjusting the diameter of the steel balls, thereby reducing local high stress and improving the load uniformity and operational reliability of the multi-ball bearing housing.

[0006] The technical solution adopted in this invention is: a design method for a low-stress multi-ball bearing housing, wherein the multi-ball bearing housing includes an upper thrust plate, a lower thrust plate, a plurality of steel balls disposed between the upper thrust plate and the lower thrust plate, and a cage assembly for limiting the position of the steel balls. The first bearing surface of the upper thrust plate in contact with the steel balls and the second bearing surface of the lower thrust plate in contact with the steel balls are both planar. The design method includes the following steps: The number of groups N of steel balls is determined based on the dimensions of the upper thrust plate and / or the lower thrust plate, where N≥3. Using the axis of the upper and lower thrust plates as a reference, the steel balls are divided into N groups from the inside out according to their radial distance from the axis. The radial group closest to the axis is the first group, and the radial group farthest from the axis is the Nth group. The initial diameter D1 of the first group of steel balls and the initial diameter increment between adjacent radial groups of steel balls are set. The diameter of each radial group of steel balls is gradually increased from the first group to the Nth group. A finite element model of the multi-ball bearing housing is established, and an axial load is applied to the multi-ball bearing housing to obtain the contact stress of each radial group of steel balls. The diameter increment between adjacent radial groups of steel balls is adjusted according to the deviation between the contact stresses of each radial group of steel balls, and the diameter of each radial group of steel balls is determined based on the adjusted diameter increments, so that the steel balls at different radial positions compensate for the load distribution of the multi-ball bearing housing through diameter differences.

[0007] As a preferred option, the first The diameter of the steel balls satisfies:

[0008] in, For the first The diameter of the steel balls. For the first The diameter of the steel balls. For the first Group of steel balls and the first The diameter increment between groups of steel balls This is the group number for the steel ball group. =2,3,...,N.

[0009] As a preferred embodiment, the contact stress of each radial group of steel balls corresponding to different diameter increment configurations is obtained through the finite element model, and the diameter increment between adjacent radial group steel balls is adjusted according to the deviation between the contact stresses of each radial group of steel balls until the deviation between the contact stresses is not greater than a preset stress deviation threshold.

[0010] As a preferred embodiment, the contact stress of the steel balls in each radial group is the average value of the contact stress of each steel ball in the corresponding radial group.

[0011] As a preferred embodiment, the preset stress deviation threshold is 10%.

[0012] As a preferred embodiment, the N groups of steel balls respectively form N concentric layers centered on the axis, with each group of steel balls corresponding to one concentric layer, and the center-to-center distance between steel balls in adjacent concentric layers located in the same radial direction is equal.

[0013] A low-stress multi-ball bearing housing, wherein the diameter configuration of the steel balls is determined according to the low-stress design method and assembled accordingly, the multi-ball bearing housing includes an upper thrust plate, a lower thrust plate, a plurality of steel balls disposed between the upper thrust plate and the lower thrust plate, and a cage assembly for limiting the position of the steel balls, wherein the first bearing surface of the upper thrust plate in contact with the steel balls and the second bearing surface of the lower thrust plate in contact with the steel balls are both planar; The plurality of steel balls are divided into at least three groups from the inside out based on the axis of the upper thrust plate and the lower thrust plate, according to the radial distance from the axis. The steel balls in the same group have the same diameter, the steel balls in different groups have different diameters, and the diameter of the steel balls in each radial group increases with the increase of their radial distance from the axis.

[0014] As a preferred embodiment, the plurality of steel balls form a plurality of concentric layers with the axis as the center, the center-to-center distance between steel balls in adjacent concentric layers located in the same radial direction is equal, and the steel balls in each concentric layer adopt a hexagonal close-packed structure.

[0015] As a preferred option, the innermost layer has 6 steel balls. For each additional layer from the inside out, the number of steel balls in that layer increases by 6. Except for the steel balls in the innermost and outermost layers, each steel ball is surrounded by 6 adjacent steel balls at equal intervals.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention, while maintaining the planar bearing surfaces of the upper and lower thrust plates, achieves different bearing characteristics for steel balls at different radial positions by setting a gradually increasing diameter gradient of steel balls from the inside out. Compared to a structure using steel balls of the same diameter at all positions, this is beneficial for reducing the load difference between the inner and outer steel balls and improving the contact stress distribution of the multi-ball bearing housing.

[0017] 2. This invention divides the steel balls into multiple radial groups according to their radial distance from the thrust plate axis, and uses the contact stress of the steel balls in each radial group as the basis for diameter increment adjustment. The steel ball diameter gradient is determined through finite element analysis. This allows the steel ball diameter configuration to match the actual radial load-bearing state of the multi-ball bearing housing, improving the pertinence and repeatability of the steel ball size design.

[0018] 3. This invention can further employ a concentric layered arrangement centered on the axes of the upper and lower thrust plates, and increase the number of steel balls in the outer layer compared to the inner layer. This improves the load transfer state from both the diameter and arrangement of the steel balls. Within the same load-bearing area, this facilitates the formation of a more stable load-bearing network and enhances the overall load-bearing capacity of the multi-ball bearing housing.

[0019] 4. By controlling the average contact stress of each radial group of steel balls within a predetermined deviation range, concentrated wear and fatigue damage caused by excessive local contact stress of the steel balls can be reduced. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is an axial sectional view of the multi-ball bearing housing in this invention; Figure 2 This is a top view of the steel ball layout in this invention; Figure 3 This is a side view of the steel ball layout in this invention.

[0022] Reference numerals: 1. Upper thrust plate, 2. Steel ball, 3. Cage assembly, 4. Lower thrust plate. Detailed Implementation

[0023] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0024] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," or "the," etc., used in the specification and claims of this patent application do not express a limitation on quantity, but rather indicate the presence of at least one; the terms "first," "second," and "third," as used herein, should not be considered as a limitation on the order of components, but are merely for distinguishing different components; the terms "comprising" or "including," etc., indicate that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function.

[0025] like Figures 1 to 3 As shown, this embodiment provides a low-stress multi-ball bearing housing and its design method. The multi-ball bearing housing includes an upper thrust plate 1, a lower thrust plate 4, a plurality of steel balls 2 disposed between the upper thrust plate 1 and the lower thrust plate 4, and a cage assembly 3 for limiting the movement of the steel balls 2. The first bearing surface of the upper thrust plate 1 in contact with the steel balls 2 and the second bearing surface of the lower thrust plate 4 in contact with the steel balls 2 are both planar. The steel balls 2 are disposed between the upper thrust plate 1 and the lower thrust plate 4, and the cage assembly 3 separates the steel balls 2 from each other to prevent friction between the steel balls 2 and limits the movement of the steel balls 2.

[0026] This embodiment employs a steel ball grouping and diameter gradient design. The number N of steel ball 2 groups is determined based on the dimensions of the upper thrust plate 1 and / or the lower thrust plate 4, where N ≥ 3. Using the axis of the upper thrust plate 1 and the lower thrust plate 4 (hereinafter referred to as the axis) as a reference, the steel balls 2 are divided into N groups from the inside out according to the radial distance of each steel ball 2 from the axis. The radial group closest to the axis is the first group, and the radial group farthest from the axis is the Nth group. The number of groups is determined based on the external dimensions of the multi-ball bearing housing; larger housings can be divided into more groups.

[0027] Let the initial diameter D1 of the first group of steel balls 2 and the initial diameter increment between each adjacent radial group of steel balls 2 be set, so that the diameter of each radial group of steel balls 2 increases progressively from the first group to the Nth group. The diameter of the i-th group of steel balls 2 satisfies:

[0028] in, For the first The diameter of the steel balls. For the first The diameter of the steel balls. For the first Group of steel balls and the first The diameter increment between groups of steel balls can be the same or different between adjacent radial groups of steel balls 2. Generally, however... ; This is the group number for the steel ball group. =2,3,...,N.

[0029] A finite element model of the multi-ball bearing housing was established, and an axial load was applied to the housing to obtain the contact stress of each radial group of steel balls 2. The contact stress of each radial group of steel balls 2 corresponding to different diameter increment configurations was obtained through finite element analysis. Based on the deviation between the contact stresses of each radial group of steel balls 2, the diameter increment between adjacent radial groups of steel balls 2 was adjusted. Based on the adjusted diameter increments Determine the diameter of each radial group of steel balls 2. Finite element analysis can be performed using software such as ANSYS or ABAQUS.

[0030] The contact stress of each radial group of steel balls 2 is the average value of the contact stress of each steel ball 2 within the corresponding radial group. In one embodiment, a preset stress deviation threshold of 10% is used, and the diameter increment between adjacent radial groups of steel balls 2 is adjusted based on the finite element analysis results. The process continues until the deviation between the contact stresses of the steel balls 2 in each radial group is no greater than 10%. The load distribution of the multi-ball bearing housing is compensated by the difference in diameter of the steel balls 2 at different radial positions, making the load distribution more balanced.

[0031] like Figure 2 and Figure 3 As shown, N groups of steel balls 2 form concentric layers centered on the axes of N or more thrust plates 1 and lower thrust plate 4. Each group of steel balls 2 corresponds to one concentric layer, and the center-to-center distance between steel balls 2 in adjacent concentric layers located in the same radial direction is equal. Each layer of steel balls 2 adopts a hexagonal close-packed structure. Except for the innermost and outermost layers of steel balls 2, each steel ball 2 is surrounded by 6 adjacent steel balls 2 at equal intervals, forming a stable force transmission network. The innermost layer has 6 steel balls 2. With each additional layer from the inside out, the number of steel balls 2 in that layer increases by 6, that is, the second layer has 12 steel balls 2, and so on.

[0032] In this embodiment, the number of groups N for the steel balls 2 is determined to be 10 based on the dimensions of the upper thrust plate and / or lower thrust plate. Centered on the axes of the upper thrust plate 1 and lower thrust plate 4, the steel balls 2 are divided into 10 groups according to radial distance, from the innermost layer to the outermost layer: Group 1, Group 2, Group 3, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, and Group 10. Each group of steel balls 2 corresponds to a concentric layer. The diameter of the steel balls 2 increases progressively from the innermost layer to the outermost layer.

[0033] During the steel ball size design process, after determining the number of groups of steel balls 2 based on the dimensions of the upper thrust plate and / or lower thrust plate, the initial diameter D1 of the first group of steel balls 2 and the initial diameter increment between each adjacent radial group of steel balls 2 are set. ,according to The initial diameter of each radial group of steel balls 2 is determined. Then, the load distribution is simulated through finite element analysis, and the diameter increment between adjacent radial groups of steel balls 2 is adjusted according to the deviation between the contact stresses of each radial group of steel balls 2. The diameter of each radial group of steel balls 2 is determined until the deviation between the contact stresses of each radial group of steel balls 2 is not greater than the preset stress deviation threshold.

[0034] In a specific diameter gradient setting method, the initial diameter D1 of the first group of steel balls 2 is 20.0 mm, the diameter D2 of the second group of steel balls 2 is 20.005 mm, and the diameter D3 of the third group of steel balls 2 is 20.010 mm. Correspondingly, the diameter increment between the first group of steel balls 2 and the second group of steel balls 2 is... The diameter increment between the second group of steel balls 2 and the third group of steel balls 2 is 5μm. The diameter increment is 5 μm. In this configuration, the same diameter increment is used between adjacent radial groups; in other embodiments, the diameter increment between each adjacent radial group can be adjusted according to the contact stress distribution obtained from finite element analysis.

[0035] During the steel ball assembly process, the first group of 6 steel balls 2 are installed in the innermost layer, and the positions of the hexagonal vertices are fixed using a special fixture. Then, the remaining radial groups of steel balls 2 are placed sequentially, ensuring that the center-to-center distance between two steel balls 2 in the same radial direction in adjacent concentric layers is equal. The concentricity of the steel balls 2 is calibrated using a laser positioning instrument, and the radial runout is controlled within ±0.05mm.

[0036] After assembling steel balls 2, stress tests are performed on the multi-ball bearing housing. A rated load, such as 2000 kN, is applied to the upward thrust plate 1. The deformation of each radial group of steel balls 2 is measured using strain gauges, and the stress of the steel balls 2 is calculated based on the measured deformation. The test data is recorded, the average stress value of each group of steel balls 2 is determined, and it is verified that the deviation between the average stress values ​​of each radial group of steel balls 2 is not greater than 10%.

[0037] Through the aforementioned diameter gradient design, the middle layer uses steel balls 2 with smaller diameters, while the outer layer uses steel balls 2 with larger diameters. This allows the steel balls 2 at different radial positions to compensate for load distribution through diameter differences. Simultaneously, the steel balls 2 employ a hexagonal close-packed structure, allowing for more steel balls 2 to be placed within the same area. This improves overall rigidity while reducing stress and increasing service life.

[0038] Tests showed that the middle layer steel ball 2, due to its smaller diameter, flexibly absorbing the impact load, while the outer layer steel ball 2 provided rigid support, resulting in a 42% reduction in the overall stress distribution standard deviation. Bench tests, in accordance with ISO 281 standards, increased the rated life of the bearing housing from 10,000 hours to 15,000 hours.

[0039] Based on the actual dimensions and working conditions of the multi-ball bearing housing, the number of groups of steel balls 2, the diameter increment between adjacent radial groups of steel balls 2, and the layout density can be adjusted. The contact stress of each radial group of steel balls 2 under different diameter increment configurations can be compared through finite element analysis, and the diameter of each radial group of steel balls 2 can be determined accordingly, thereby achieving further optimization of stress distribution.

[0040] It should be noted that although the present invention has been described through the above embodiments, the present invention may have many other embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art can obviously make various corresponding changes and modifications to the present invention, but all such changes and modifications should fall within the scope of protection of the appended claims and their equivalents.

Claims

1. A design method for a low-stress multi-ball bearing housing, the multi-ball bearing housing comprising an upper thrust plate, a lower thrust plate, a plurality of steel balls disposed between the upper thrust plate and the lower thrust plate, and a cage assembly for limiting the position of the steel balls, wherein a first bearing surface of the upper thrust plate in contact with the steel balls and a second bearing surface of the lower thrust plate in contact with the steel balls are both planar, characterized in that, The design method includes the following steps: The number of groups N of steel balls is determined according to the size of the upper thrust plate and / or the lower thrust plate, where N≥3. Based on the axis of the upper thrust plate and the lower thrust plate, the steel balls are divided into N groups from the inside to the outside according to the radial distance of each steel ball from the axis. The radial group closest to the axis is the first group, and the radial group farthest from the axis is the Nth group. Set the initial diameter of the first group of steel balls and the initial diameter increment between each adjacent radial group of steel balls, so that the diameter of each radial group of steel balls increases from the first group to the Nth group; A finite element model of the multi-ball bearing housing is established, and an axial load is applied to the multi-ball bearing housing to obtain the contact stress of each radial group of steel balls; The diameter increment between adjacent radial groups of steel balls is adjusted according to the deviation between the contact stresses of each radial group of steel balls, and the diameter of each radial group of steel balls is determined based on the adjusted diameter increments, so that the steel balls at different radial positions can compensate for the load distribution of the multi-ball bearing housing through diameter differences.

2. The design method according to claim 1, characterized in that: No. The diameter of the steel balls satisfies: in, For the first The diameter of the steel balls. For the first The diameter of the steel balls. For the first Group of steel balls and the first The diameter increment between groups of steel balls This is the group number for the steel ball group. =2,3,...,N.

3. The design method according to claim 2, characterized in that: The contact stress of each radial group of steel balls corresponding to different diameter increment configurations is obtained through the finite element model, and the diameter increment between adjacent radial groups of steel balls is adjusted according to the deviation between the contact stresses of each radial group of steel balls until the deviation between the contact stresses is not greater than a preset stress deviation threshold.

4. The design method according to claim 3, characterized in that: The contact stress of the steel balls in each radial group is the average value of the contact stress of each steel ball in the corresponding radial group.

5. The design method according to claim 3, characterized in that: The preset stress deviation threshold is 10%.

6. The design method according to claim 1, characterized in that: The N groups of steel balls form N concentric layers centered on the axis. Each group of steel balls corresponds to one concentric layer, and the distance between the centers of steel balls in adjacent concentric layers located in the same radial direction is equal.

7. A low-stress multi-ball bearing housing, wherein the diameter configuration of the steel balls is determined and assembled according to the design method of any one of claims 1 to 6, the multi-ball bearing housing comprising an upper thrust plate, a lower thrust plate, a plurality of steel balls disposed between the upper thrust plate and the lower thrust plate, and a cage assembly for limiting the position of the steel balls, wherein a first bearing surface of the upper thrust plate in contact with the steel balls and a second bearing surface of the lower thrust plate in contact with the steel balls are both planar, characterized in that: The plurality of steel balls are divided into at least three groups from the inside out based on the axis of the upper thrust plate and the lower thrust plate, according to the radial distance from the axis. The steel balls in the same group have the same diameter, the steel balls in different groups have different diameters, and the diameter of the steel balls in each radial group increases with the increase of their radial distance from the axis.

8. The low-stress multi-ball bearing housing according to claim 7, characterized in that: The plurality of steel balls form multiple concentric layers with the axis as the center. The distance between the centers of the steel balls in adjacent concentric layers that are located in the same radial direction is equal. The steel balls in each concentric layer adopt a hexagonal close-packed structure.

9. The low-stress multi-ball bearing housing according to claim 8, characterized in that: The innermost layer has 6 steel balls. With each additional layer from the inside out, the number of steel balls in that layer increases by 6. Except for the steel balls in the innermost and outermost layers, each steel ball is surrounded by 6 adjacent steel balls at equal intervals.

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