A bearing end face fine grinding tool and a bearing axial runout elimination method

Abstract

This invention relates to the field of bearing assembly technology, and discloses a bearing end face precision grinding fixture and a method for eliminating bearing axial clearance. The fixture includes a positioning mandrel, a positioning sleeve, and an axial preload assembly. The bottom end of the positioning mandrel is mounted on the magnetic table of a grinding machine, and the top end of the positioning mandrel axially supports the inner ring of the bearing. The positioning sleeve is fitted onto the outside of the positioning mandrel, with an axial gap between the inner wall of the positioning sleeve and the outer wall of the positioning mandrel. The axial preload assembly includes a fixing member for fixing to an external pressure application mechanism and a preload member connected to the fixing member. The preload member applies an axial preload force to the outer ring of the bearing. A radial support assembly for radially clamping the outer ring of the bearing is also fixed to the positioning sleeve. When the bearing is in a preloaded state, the inner and outer rings of the bearing are precision ground. After the bearing is assembled to the spindle, there is no height difference between the inner and outer rings in the preloaded state, allowing multiple bearing sets to fit tightly together without the need for measuring and installing spacers, thus reducing the cost of bearing assembly.

Description

Technical Field

[0001] This invention relates to the field of bearing assembly technology, and in particular to a bearing end face precision grinding fixture and a method for eliminating bearing axial clearance. Background Technology

[0002] The spindle is the main transmission device for the vehicle's weight, and it is mounted on the frame via bearings. When installing spindle bearings, if multiple bearings are connected in series, the bearing clearance between the inner ring and outer end face of the bearing must be eliminated to ensure bearing precision.

[0003] Existing multi-bearing tandem assembly structures, such as Figure 1 As shown, the height difference between the inner ring 110 and the outer ring 120 end faces of the bearing 100 needs to be calculated by measurement. Then, spacers 200 are machined and arranged on the inner ring 110 and the outer ring 120 respectively. The spacers 200 are installed between the two bearings 100. The spacers 200 are used to eliminate the gap between the inner ring 110 and the outer ring 120, thereby eliminating the bearing clearance and ensuring the accuracy of the spindle 300.

[0004] However, when using septums to eliminate clearance, it is necessary to measure the height difference between the inner and outer rings of the bearing when the clearance is zero, and to machine the septums for the inner and outer rings separately. After assembly, the position of the septums also needs to be adjusted. The measurement, machining, and assembly process is complex and costly. Summary of the Invention

[0005] The purpose of this invention is to provide a bearing end face precision grinding fixture to solve the problems of complex measurement, machining, and adjustment processes and high costs in the prior art when adjusting bearing clearance with shims; this invention also provides a method for eliminating bearing axial clearance.

[0006] To achieve the above objectives, the present invention provides a bearing end face precision grinding fixture, including a positioning mandrel, a positioning sleeve, and an axial preload assembly. The bottom end of the positioning mandrel is an assembly end for mounting on the magnetic table of a grinding machine, and the top end of the positioning mandrel is a support end for axially supporting the inner ring of the bearing.

[0007] The positioning sleeve is fitted onto the outside of the positioning mandrel, and there is an axial gap between the inner wall of the positioning sleeve and the outer wall of the positioning mandrel for accommodating the outer ring of the bearing.

[0008] The axial preload assembly includes a fastener for fixing to a pressure application mechanism of an external device and a preload member connected to the fastener, the preload member being used to apply an axial preload force to the outer ring of the bearing;

[0009] The positioning sleeve is also fixed with a radial support assembly for radially clamping the outer ring of the bearing. The radial support assembly is used to provide axial preload when the axial preload assembly removes the axial preload.

[0010] Preferably, the positioning sleeve has a plurality of positioning holes evenly distributed around its circumference, and each positioning hole is arranged symmetrically about the center line of the positioning sleeve. The radial support assembly includes locking bolts threaded into each positioning hole.

[0011] Preferably, the radial support assembly further includes a pad, and the positioning hole has an outer threaded section for assembly with the locking bolt and an inner through-hole section, the pad being disposed in the through-hole section.

[0012] Preferably, the preload includes a pressure plate having a downwardly folded flange for axially pressing the outer ring of the bearing.

[0013] Preferably, the fixing member includes a clamping rod, the top end of which is fixedly connected to the pressure applying mechanism, and the bottom end of which is fixedly connected to the clamping plate.

[0014] Preferably, the positioning mandrel is a stepped shaft structure with an increasing outer diameter from top to bottom, and the outer diameter of the assembly end is larger than the outer diameter of the support end.

[0015] Preferably, the positioning sleeve is further radially threaded with a set screw, which is press-fitted with the assembly end.

[0016] This invention also provides a method for eliminating axial clearance in bearings, using the bearing end face precision grinding fixture described in any of the above technical solutions, comprising the following steps: S1, mounting the positioning mandrel and positioning sleeve on the magnetic table of the grinding machine, with the positioning sleeve mounted on the outside of the positioning mandrel, and the positioning mandrel and positioning sleeve magnetically attracted and fixed by the magnetic table; S2, assembling the bearing on top of the positioning mandrel and positioning sleeve, wherein the inner ring of the bearing is supported on the positioning mandrel, and the outer ring of the bearing is located between the positioning sleeve and the positioning mandrel; S3, fixing the fixing part of the axial preload assembly to the pressure application mechanism, pressing the preload part of the axial preload assembly against the outer ring of the bearing, activating the pressure application mechanism and applying an axial preload force to the outer ring of the bearing to eliminate axial clearance; S4, utilizing radial support... S5. The component radially clamps the outer ring of the bearing, and the axial preload component is removed. At this time, the axial preload of the bearing is provided by the radial support component. S6. The grinding machine is started to grind the top of the inner and outer rings of the bearing until the top of the inner and outer rings are flush. S7. The radial clamping force of the radial support component on the outer ring of the bearing is removed, the magnetic force of the magnetic table is turned off, the bearing and the bearing end face fine grinding fixture are removed, and the bearing is flipped over and placed on the magnetic table. S8. The magnetic table is turned on, and the magnetic table fixes the bearing by magnetic attraction until the ground end face is flush with the magnetic table. The grinding machine is started to grind the end face on the other side of the bearing until it is flush.

[0017] Preferably, in step S3, the axial preload applied to the outer ring of the bearing is 5 to 15 kg.

[0018] Preferably, in steps S5 and S7, after grinding the inner and outer rings of the bearing, a height micrometer is used to measure the bearing end face to ensure it is horizontal, so that the bearing outer ring end face is parallel to the grinding table surface with an error of less than 0.05.

[0019] Compared with the prior art, the bearing end face fine grinding fixture and bearing axial clearance elimination method of this invention have the following advantages: When it is necessary to eliminate bearing clearance, the inner ring of the bearing is supported on the positioning mandrel. After the fixing part of the axial preload assembly is connected to the external pressure application mechanism, the axial preload force can be applied to the outer ring of the bearing through the preload component. Then, the radial support assembly arranged on the positioning sleeve provides radial support to the outer ring of the bearing, which can provide continuous preload force. After the axial preload assembly is removed, the bearing is still in the preload state when the inner and outer rings of the bearing are finely ground. That is, the inner and outer rings of the bearing are finely ground in the preload state. After the bearing is assembled to the spindle, there is no height difference between the inner and outer rings in the preload state. Multiple sets of bearings can fit tightly together without the need to measure and install spacers, which reduces the cost of bearing assembly. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an existing multi-bearing series assembly structure;

[0021] Figure 2 This is a schematic diagram of the bearing end face precision grinding fixture of the present invention;

[0022] Figure 3 yes Figure 1 Exploded view of the bearing end face precision grinding fixture;

[0023] Figure 4 This is a cross-sectional view of the bearing end face precision grinding fixture of the present invention after it is assembled on the magnetic table;

[0024] Figure 5 This is a schematic diagram of the bearing assembly structure after the bearing end face precision grinding tool of the present invention has precision ground the bearing.

[0025] In the diagram, 1 is the positioning mandrel, 11 is the assembly end, 12 is the support end, 2 is the positioning sleeve, 3 is the positioning hole, 4 is the locking bolt, 5 is the pad, 6 is the pressure plate, 61 is the flange, 7 is the pressure rod, 8 is the nut, 9 is the set screw, 100 is the bearing, 110 is the inner ring, 120 is the outer ring, 200 is the spacer, and 300 is the main shaft. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0027] A preferred embodiment of the bearing end face precision grinding fixture of the present invention, such as... Figures 2 to 5 As shown, the bearing end face precision grinding fixture includes a positioning mandrel 1, a positioning sleeve 2, an axial preload assembly, and a radial support assembly. The positioning mandrel 1 and the positioning sleeve 2 are arranged on the magnetic table of the grinding machine. The axial preload assembly and the radial support assembly are respectively used to apply axial preload force to the outer ring 120 of the bearing 100.

[0028] The positioning mandrel 1 is used to mount on the magnetic table of the grinding machine and support the assembly bearing 100. The bottom end of the positioning mandrel 1 is the mounting end 11 for mounting on the magnetic table of the grinding machine, and the top end of the positioning mandrel 1 is the support end 12 for axially supporting the inner ring 110 of the bearing 100. When the positioning mandrel 1 is mounted on the magnetic table of the grinding machine, its mounting end 11 can be attracted and fixed to the magnetic table by the magnetic attraction of the magnetic table, ensuring that the positioning mandrel 1 will not move during the fine grinding process.

[0029] The positioning sleeve 2 is fitted on the outside of the positioning mandrel 1. The positioning sleeve 2 and the positioning mandrel 1 are arranged coaxially. There is an axial gap between the inner wall of the top of the positioning sleeve 2 and the outer wall of the positioning mandrel 1. This axial gap is used to accommodate the outer ring 120 of the bearing 100, so that the entire bearing 100 is located inside the positioning sleeve 2. At the same time, when the bearing 100 is subjected to axial force, the outer ring 120 can move axially relative to the inner ring 110, simulating the preload state of the bearing 100 when it is assembled onto the spindle.

[0030] The axial preload assembly applies an axial force to the outer ring 120 of the bearing 100, causing the outer ring 120 to move axially relative to the inner ring 110, thereby eliminating axial clearance in the bearing 100. The axial preload assembly includes a fixing member and a preload member connected to the fixing member. The fixing member is fixedly connected to an external pressure application mechanism. The preload member is used to press against the outer ring 120 of the bearing 100. The pressure application mechanism drives the preload member to move axially along the bearing 100 via the fixing member, and the preload member applies an axial preload force to the outer ring 120 of the bearing 100.

[0031] When the outer ring 120 of the bearing 100 is subjected to axial preload by the axial preload assembly, the inner cavity of the bearing 100 is axially supported by the support end 12 of the positioning spindle 1 and cannot move, thereby causing the inner ring 110 and the outer ring 120 of the bearing 100 to be subjected to opposite forces and move relative to each other, simulating the axial preload of the bearing 100, and the bearing 100 is in a preloaded state that eliminates axial clearance.

[0032] The radial support assembly is used to radially clamp the outer ring 120 of the bearing 100. The radial preload assembly can be arranged on the positioning sleeve 2 or separately fixed on the magnetic table of the grinding machine. After the radial preload assembly radially clamps the outer ring 120 of the bearing 100, a certain axial preload is maintained by the frictional force generated on the cylindrical surface of the outer ring 120 of the bearing 100 by the radial clamping force. At this time, the axial preload applied to the outer ring 120 of the bearing 100 by the axial preload assembly is removed, and the bearing 100 still remains in a preloaded state with zero axial clearance. Then, the bearing 100 can be finely ground in the preloaded state. During the fine grinding process, the radial clamping force of the radial support assembly is always present, that is, the bearing 100 is always in a state of zero clearance during the fine grinding process.

[0033] When it is necessary to eliminate the clearance of bearing 100, the inner ring 110 of bearing 100 is supported on the positioning mandrel 1 of the bearing end face fine grinding fixture. After the fixing part of the axial preload assembly is connected to the external pressure mechanism, the axial preload force can be applied to the outer ring 120 of bearing 100 through the preload assembly. Then, the radial support assembly arranged on the positioning sleeve 2 provides radial support to the outer ring 120 of bearing 100, which can provide a continuous preload force. After the axial preload assembly is removed, the bearing 100 is still in the preload state when the inner ring 110 and outer ring 120 of bearing 100 are finely ground. That is, the inner ring 110 and outer ring 120 of bearing 100 are finely ground in the preload state. After the bearing 100 is assembled to the spindle, there is no height difference between the inner ring 110 and outer ring 120 in the preload state. Multiple sets of bearings 100 can fit tightly together without measuring and installing spacers, which reduces the assembly cost of bearing 100.

[0034] Preferably, the positioning sleeve 2 has a plurality of positioning holes 3 evenly distributed around its circumference, and each positioning hole 3 is arranged symmetrically about the center line of the positioning sleeve 2. The radial support component includes a locking bolt 4 threaded into each positioning hole 3.

[0035] A locking bolt 4 is used as a radial support component, forming a set screw, which simplifies the structure of the radial support component. Several positioning holes 3 are provided on the positioning sleeve 2, and each positioning hole 3 is threaded with a locking bolt 4. Multiple sets of locking bolts 4 can increase the force between the locking bolts 4 and the outer ring 120 of the bearing 100. In addition, since the positioning holes 3 are symmetrically arranged, the radial force of the radial support component on the bearing 100 is symmetrically canceled out. When tightening the locking bolts 4, they can also be tightened in pairs to ensure the force balance of the outer ring 120 of the bearing 100.

[0036] The formula for calculating bolt torque is T = kFd, where F is the preload (approximately axial force), T is the torque, k is the torque coefficient (recommended value in mechanical design manuals is approximately 0.1-0.2), and d is the nominal diameter of the bolt. In this embodiment, an M8 threaded locking bolt 4 is used, and the nominal diameter d of the locking bolt 4 is 8mm. Substituting the data, the axial force of the locking bolt 4 can be obtained.

[0037] In other embodiments, hydraulic cylinders may also be used to form the radial support assembly.

[0038] Preferably, the radial support assembly further includes a pad 5, and the positioning hole 3 has a threaded section on the outer side for assembly with the locking bolt and a through-hole section on the inner side, with the pad 5 arranged in the through-hole section.

[0039] The positioning hole 3 is formed by a threaded section and a through-hole section. A pad 5 is installed in the through-hole section. The pad 5 can increase the interaction area between the radial support assembly and the outer ring 120 of the bearing 100, so that the outer ring 120 of the bearing 100 is subjected to balanced force. In this embodiment, the pad 5 is made of copper, which facilitates the calculation of the coefficient of friction between the pad 5 and the outer ring 120 of the bearing 100, and ensures that the clamping force of the radial support assembly can provide sufficient axial preload.

[0040] Preferably, the preload includes a pressure plate 6 having a downwardly folded flange 61 for engaging with the outer ring 120 of the axially pressing bearing 100.

[0041] The downward-facing flange 61 of the clamping disc 6 presses against the outer ring 120 of the bearing 100, applying an axial preload to the outer ring 120 of the bearing 100 throughout the circumferential direction, thus balancing the forces on the bearing 100. In other embodiments, multiple pressure rods may be used instead of the clamping disc 6.

[0042] Preferably, the fixing component includes a clamping rod 7, the top end of which is fixedly connected to the pressure applying mechanism, and the bottom end of which is fixedly connected to the clamping plate 6.

[0043] The clamping rod 7 forms a fixing component, which simplifies the assembly method between the clamping rod 7 and the pressure applying mechanism and the pressure plate 6. In this embodiment, the clamping rod 7 and the pressure plate 6 are arranged coaxially, and the clamping rod 7 and the pressure plate 6 are fixedly connected by a nut 8.

[0044] Preferably, the positioning mandrel 1 is a stepped shaft structure with an increasing outer diameter from top to bottom, and the outer diameter of the assembly end 11 is larger than the outer diameter of the support end 12.

[0045] The stepped shaft structure can reduce the outer diameter of the support section, forming a space between the positioning mandrel 1 and the positioning sleeve 2 to accommodate the bearing 100, and can also increase the area of ​​the assembly end 11 to ensure the stability of the positioning mandrel 1. The support end 12 also has an insertion section that is axially inserted into the inner ring 110 of the bearing 100. The insertion section is clearance-fitted with the inner ring 110 to radially position the bearing 100 and prevent the bearing 100 from moving.

[0046] Preferably, the positioning sleeve 2 is also radially threaded with a set screw 9, which is press-fitted with the assembly end 11.

[0047] The set screw 9 is pressed and assembled with the assembly end 11, which can fix the positioning sleeve 2 and the positioning mandrel 1 as a whole, and prevent relative movement between the positioning mandrel 1 and the positioning sleeve 2 during grinding.

[0048] The present invention also provides a preferred embodiment of a method for eliminating axial clearance of bearing 100, namely, a method for using the above-mentioned bearing end face precision grinding fixture, comprising the following steps:

[0049] S1, assemble the positioning mandrel 1 and the positioning sleeve 2 on the magnetic table of the grinding machine. The positioning sleeve 2 is fitted on the outside of the positioning mandrel 1, and the positioning mandrel 1 and the positioning sleeve 2 are magnetically attracted and fixed by the magnetic table.

[0050] S2, the bearing 100 is assembled on the top of the positioning mandrel 1 and the positioning sleeve 2, wherein the inner ring 110 of the bearing 100 is supported on the positioning mandrel 1, and the outer ring 120 of the bearing 100 is located between the positioning sleeve 2 and the positioning mandrel 1.

[0051] S3, fix the fixing part of the axial preload assembly to the pressure application mechanism, press the preload part of the axial preload assembly against the outer ring 120 of the bearing 100, start the pressure application mechanism and apply axial preload force to the outer ring 120 of the bearing 100 to eliminate axial clearance.

[0052] S4, the outer ring 120 of the bearing 100 is radially clamped by the radial support assembly, and the axial preload assembly is removed. At this time, the axial preload of the bearing 100 is provided by the radial support assembly.

[0053] S5, start the grinding machine to grind the top of the inner ring 110 and the outer ring 120 of the bearing 100, so that the top of the inner ring 110 and the outer ring 120 are flush.

[0054] S6, remove the radial clamping force of the radial support assembly on the outer ring 120 of the bearing 100, turn off the magnetic force of the magnetic table, remove the bearing 100 and the bearing end face precision grinding fixture, and place the bearing 100 on the magnetic table after flipping it over.

[0055] S7, turn on the magnetic table. The magnetic table uses magnetic force to fix the bearing 100 until the ground end face is flush with the magnetic table. Turn on the grinding machine to grind the other end face of the bearing 100 until it is flush.

[0056] In step S1, before assembling the positioning mandrel 1 and the positioning sleeve 2, the magnetic table surface of the high-precision surface grinder is cleaned to ensure the flatness of the magnetic table surface, which facilitates the assembly of various components of the tooling.

[0057] In step S2, when placing the bearing 100, the orientation of the bearing 100 is determined to ensure that the bearing 100 clearance can be eliminated when the outer ring 120 of the bearing 100 is subjected to a downward axial preload. In this embodiment, taking an angular contact ball bearing 100 as an example, the larger end of the bearing 100 faces downward. This is because when the axial preload of the bearing 100 is applied, the outer ring 120 needs to move downward to eliminate the bearing 100 clearance, ensuring that the clearance elimination direction of the bearing 100 on the tooling is consistent with the actual installation. If the larger end faces upward, the force on the outer ring 120 will damage the bearing 100.

[0058] In step S3, the magnitude of the axial preload force borne by the outer ring 120 of the bearing 100, i.e. the magnitude of the axial force applied by the pressure mechanism, is determined based on the load of the spindle and experience. The axial force applied by the pressure mechanism is equal to the axial load borne by the bearing 100 when it is assembled on the spindle.

[0059] In step S4, when the axial preload assembly uses locking bolts and spacers 5, the locking bolts 4 are preloaded evenly in a diagonal pattern. The torque of the locking bolts 4 is controlled to ensure that the frictional force can provide axial preload to the outer ring 120 of the bearing 100. In this embodiment, the locking bolts 4 are calculated according to the M8 thread specification, and the torque is 10 NM.

[0060] In this embodiment, according to the Mechanical Design Handbook - Connection and Fastening Chapter, the bolt torque calculation formula is T = kFd, where F is the preload, i.e., the approximate axial force, T is the torque, k is the torque coefficient, the Mechanical Design Handbook has a recommended value (approximately 0.1-0.2), and d is the nominal diameter of the bolt (8mm). Substituting the data, the axial force of the bolt can be obtained.

[0061] Based on experience, most of the torque is used to overcome the friction between the threads, and only 10% is used for axial clamping. 10% of 10 Nm is 1 Nm = 0.1 kgm. Therefore, the axial force of the bolt is F = T / kd = 0.1 / (0.2 * 0.008) = 62.5 kg. That is, the pressure of a single locking bolt 4 on the outer ring 120 of the bearing 100 is more than 50 kg.

[0062] The friction coefficient between the pad 5 and the outer ring 120 of the bearing 100 is 0.05-0.1, and we take 0.05. In this embodiment, there are six sets of radial support components. The radial pressure is converted into axial preload through friction. The magnitude of the axial preload is: f = F * μ * K = 50 * 0.05 * 6 (pieces) = 15 kg. That is, the axial preload reaches more than 15 kg, which is sufficient to maintain the zero clearance state of the bearing 100.

[0063] In step S5, when grinding the end face of the bearing 100, the tool (grinding wheel) is fed gently and slowly until both the inner and outer rings 120 of the bearing 100 are ground and the surface is finely ground and flush.

[0064] In step S6, after removing the bearing 100 and the bearing end face precision grinding fixture, the fixture, bearing 100 and the table surface of the magnetic table are cleaned to ensure that the table surface is clean before the flipped bearing 100 is placed on the magnetic table.

[0065] In step S7, after being flipped over, the inner ring 110 and outer ring 120 of the bearing 100 will be in contact with the table surface due to the magnetic force of the magnetic table. Since the inner and outer rings 120 are ground at the same height and flush when the end face of the attracted ring is ground in a zero clearance state, the bearing 100 will also reach a zero clearance state after being attracted to the magnetic table surface and the end face of the inner and outer rings 120 is in contact with the table surface.

[0066] After grinding the two end faces of bearing 100 under axial preload, it is ensured that the inner and outer rings 120 are of equal thickness (equal height) and flush when bearing 100 is in a zero clearance state. When installing on the spindle, it is not necessary to install spacers for the inner and outer rings 120.

[0067] Preferably, in step S3, the axial preload applied to the outer ring 120 of the bearing 100 is 5 to 15 kg.

[0068] Based on experience, after the bearing 100 is assembled with the spindle, the axial force on the spindle during operation is generally between 5 and 15 kg. Therefore, the axial preload applied to the outer ring 120 of the bearing 100 within this range can simulate the zero clearance state of the bearing 100.

[0069] Preferably, in steps S5 and S7, after grinding the inner ring 110 and outer ring 120 of the bearing 100, a height micrometer is used to measure that the end face of the bearing 100 is kept horizontal, so that the end face of the outer ring 120 of the bearing 100 is parallel to the grinding table surface, with an error of less than 0.05.

[0070] After grinding, the end face of bearing 100 is measured with a height micrometer to ensure that the end face of bearing 100 is parallel to the grinding table, so that the inner ring 110 and the outer ring 120 of bearing 100 are at the same height under zero clearance, ensuring that no spacer is needed when assembling bearing 100.

[0071] In summary, this invention provides a bearing end face fine grinding fixture and a method for eliminating bearing axial clearance. When bearing clearance needs to be eliminated, the inner ring of the bearing is supported on a positioning mandrel. After the fixing part of the axial preload assembly is connected to the external pressure mechanism, an axial preload force can be applied to the outer ring of the bearing through the preload assembly. Then, the radial support assembly arranged on the positioning sleeve provides radial support to the outer ring of the bearing, which can provide a continuous preload force. After the axial preload assembly is removed, the bearing is still in the preloaded state when the inner and outer rings are finely ground. That is, the inner and outer rings of the bearing are finely ground while the bearing is in the preloaded state. After the bearing is assembled to the spindle, there is no height difference between the inner and outer rings in the preloaded state. Multiple sets of bearings can fit tightly together without the need to measure and install spacers, thus reducing the cost of bearing assembly.

[0072] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A method for eliminating axial clearance in a bearing, employing a bearing end face precision grinding fixture, the bearing end face precision grinding fixture comprising a positioning mandrel, a positioning sleeve, and an axial preload assembly, wherein the bottom end of the positioning mandrel is an assembly end for mounting on a magnetic table of a grinding machine, and the top end of the positioning mandrel is a support end for axially supporting the inner ring of the bearing; the positioning sleeve is fitted onto the outside of the positioning mandrel, and there is an axial gap between the inner wall of the positioning sleeve and the outer wall of the positioning mandrel for accommodating the outer ring of the bearing; the axial preload assembly comprises a fixing member for fixing to an external pressure application mechanism and a preload member connected to the fixing member, the preload member being used to apply an axial preload force to the outer ring of the bearing; a radial support assembly for radially clamping the outer ring of the bearing is also fixed on the positioning sleeve, the radial support assembly being used to provide an axial preload force when the axial preload force of the axial preload assembly is released, characterized in that... The method for eliminating axial clearance in bearings includes the following steps: S1, mounting the positioning mandrel and positioning sleeve on the magnetic table of the grinding machine, with the positioning sleeve fitted on the outside of the positioning mandrel, and the positioning mandrel and positioning sleeve magnetically attracted and fixed by the magnetic table; S2, assembling the bearing on top of the positioning mandrel and positioning sleeve, wherein the inner ring of the bearing is supported on the positioning mandrel, and the outer ring of the bearing is located between the positioning sleeve and the positioning mandrel; S3, fixing the fixing part of the axial preload assembly to the pressure application mechanism, pressing the preload part of the axial preload assembly against the outer ring of the bearing, activating the pressure application mechanism and applying an axial preload force to the outer ring of the bearing to eliminate axial clearance. S4. Use the radial support assembly to radially clamp the outer ring of the bearing, and remove the axial preload assembly. At this time, the axial preload of the bearing is provided by the radial support assembly. S5. Start the grinding machine to grind the top of the inner and outer rings of the bearing until the tops of the inner and outer rings are flush. S6. Remove the radial clamping force of the radial support assembly on the outer ring of the bearing, turn off the magnetic force of the magnetic table, remove the bearing and the bearing end face fine grinding fixture, and place the bearing on the magnetic table after flipping it over. S7. Turn on the magnetic table. The magnetic table uses magnetic force to attract and fix the bearing until the ground end face is flush with the magnetic table. Turn on the grinding machine to grind the other end face of the bearing until it is flush.

2. The bearing axial clearance elimination method according to claim 1, characterized in that, In step S3, the axial preload applied to the outer ring of the bearing is 5 to 15 kg.

3. The bearing axial clearance elimination method according to claim 1, characterized in that, In steps S5 and S7, after grinding the inner and outer rings of the bearing, a height micrometer is used to measure whether the bearing end face is kept horizontal, so that the bearing outer ring end face is parallel to the grinding table surface, with an error of less than 0.05mm.

4. The method for eliminating axial clearance of a bearing according to any one of claims 1-3, characterized in that, The positioning sleeve has a plurality of positioning holes evenly distributed around its circumference, and each positioning hole is arranged symmetrically about the center line of the positioning sleeve. The radial support assembly includes locking bolts threaded into each positioning hole.

5. The method for eliminating axial clearance of a bearing according to claim 4, characterized in that, The radial support assembly further includes a pad, and the positioning hole has an outer threaded section for assembly with the locking bolt and an inner through-hole section, the pad being disposed in the through-hole section.

6. The method for eliminating axial clearance of a bearing according to any one of claims 1-3, characterized in that, The preload includes a pressure plate having a downwardly folded flange for axially pressing the outer ring of the bearing.

7. The method for eliminating axial clearance of a bearing according to claim 6, characterized in that, The fastener includes a clamping rod, the top end of which is fixedly connected to the pressure applying mechanism, and the bottom end of which is fixedly connected to the clamping plate.

8. The method for eliminating axial clearance of a bearing according to any one of claims 1-3, characterized in that, The positioning mandrel is a stepped shaft structure with an increasing outer diameter from top to bottom, and the outer diameter of the assembly end is larger than the outer diameter of the support end.

9. The method for eliminating axial clearance of a bearing according to claim 8, characterized in that, The positioning sleeve is also radially threaded with a set screw, which is press-fitted with the assembly end.

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