Grinding machining method for large-curvature-radius spherical surface of bearing ring

Abstract

The invention discloses a bearing ring large-curvature-radius spherical surface grinding machining method, and relates to the technical field of bearing grinding machining. The problems that the spherical surface diameter difference of an existing bearing ring exceeds the standard, the spherical surface profile tolerance exceeds the standard, and the surface roughness is uneven are solved. The method comprises the steps that the supporting position is adjusted; a workpiece to be machined is clamped; dressing the grinding wheel; and grinding. The method is used for grinding the large-curvature-radius spherical surface of the bearing ring.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bearing grinding processing, in particular to a bearing ring large curvature radius spherical surface grinding processing method. BACKGROUND

[0002] As a kind of bearing core component with special structure, the large curvature spherical surface bearing ring has large spherical curvature radius and special contour, compared with conventional cylindrical or small curvature bearing ring, the key technical problems in grinding process are more prominent.The key points are as follows: on the one hand, the outer diameter of the ring is a non regular spherical surface contour, there is no flat and stable cylindrical surface or end surface that can be used as a reliable positioning reference in traditional grinding process, which makes it difficult to accurately control the space posture of the ring during processing, and positioning deviation is prone to occur; on the other hand, traditional tooling fixtures (such as three jaw chuck, flat mouth tongs, etc.) are designed for regular shaped workpieces, and the rigidity clamping method has poor compatibility with the curved surface structure of the large curvature spherical surface ring - if the clamping force is too large, it is easy to cause local deformation and stress concentration of the spherical surface of the ring, and then cause the diameter difference of the spherical surface after subsequent grinding to exceed the standard; if the clamping force is insufficient, the stability of the ring during processing cannot be guaranteed, which may cause quality defects such as spherical contour tolerance and uneven surface roughness.These problems directly affect the assembly accuracy, rotation flexibility and service life of the bearing, especially under severe working conditions such as heavy load and high speed, which may cause early failure of the bearing, so it has become the core technical pain point in the processing of large curvature spherical surface bearing ring. SUMMARY

[0003] The present application relates to the technical field of bearing grinding processing, in particular to a bearing ring large curvature radius spherical surface grinding processing method.

[0004] The technical solution adopted by the present application to solve the above technical problems is as follows:

[0005] A bearing ring large curvature radius spherical surface grinding processing method, comprising the following steps:

[0006] Step one, adjust the support position: set an off-machine calibration cylinder on one side of the off-machine eccentric adjusting device, use the off-machine calibration cylinder to replace the bearing ring for positioning and calibration, adjust the positions of the lower support assembly and the upper support assembly in the off-machine eccentric adjusting device to realize the support of the outer circumference of the off-machine calibration cylinder;

[0007] Step two, clamp the workpiece to be processed: select a wide surface electromagnetic tire pad to clamp on the grinding machine chuck, adsorb and fix the shaft end surface of the workpiece to be processed on the electromagnetic tire pad, move the off-machine eccentric adjusting device to the grinding machine, and the lower support assembly and the upper support assembly support the outer circumference of the workpiece to be processed;

[0008] Step three, dressing the grinding wheel: select a grinding wheel with large grain size for grinding, and dress the outer shape of the grinding wheel with a natural diamond pen before grinding;

[0009] Step four, grinding processing: clamp the dressed grinding wheel to the grinding machine, and respectively perform rough grinding and fine grinding on the outer circumference of the workpiece to be processed to grind the large curvature radius spherical surface of the bearing ring.

[0010] Further, in step one, the profile of the outer circumferential side wall of the off-machine calibration cylinder is the same as the profile of the bearing ring.

[0011] Further, in step one, the off-machine eccentric adjusting device comprises a support seat, and the lower support assembly and the upper support assembly are clamped on the support seat and the positions of the lower support assembly and the upper support assembly on the support seat are adjustable.

[0012] Further, in step one, the support head of the upper support assembly is a V-shaped floating support head, and the support head of the lower support assembly is an inclined surface support head, and the lower support assembly is arranged on one side directly below the off-machine calibration cylinder, and the upper support assembly is arranged on the other side below the middle of the off-machine calibration cylinder.

[0013] Further, in step one, the position of the upper support assembly on the support seat is adjusted so that the fulcrums of the support heads of the lower support assembly and the upper support assembly are aligned with the spherical center of the off-machine calibration cylinder.

[0014] Further, in step two, when the workpiece to be processed is clamped on the grinding machine chuck, the axis of the workpiece to be processed is arranged eccentrically with the axis of the chuck, and the eccentric angle is 5°~8°.

[0015] Further, in step three, when dressing the grinding wheel, the natural diamond pen is inclined to cut into the dressing grinding wheel to change the straight line on the grinding surface of the grinding wheel into a curved line, and finally the grinding wheel is shaped into a concave working surface by cutting and grinding.

[0016] Further, in step three, after the grinding wheel is dressed, red marks are applied to the contact between the workpiece and the grinding wheel to compare the size of the radius of the grinding wheel.

[0017] Further, in step four, during rough grinding and fine grinding, small feed and multiple grinding are respectively adopted.

[0018] Further, in step four, after rough grinding is completed, the grinding surface of the grinding wheel needs to be dressed again before fine grinding is performed.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] Through the improvement of the bearing ring large curvature radius spherical surface grinding processing method, the machining precision and the qualified rate of the bearing are greatly improved from 65% to more than 98%. Through the research, the grinding processing idea of the large curvature radius spherical surface is expanded, the machining capacity of the bearing is improved, valuable experience is provided for the machining of the future special outer diameter generatrix bearing, and the machining idea and the machining capacity are expanded in the aircraft body bearing machining field. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic view of the eccentric adjusting device outside the machine in the present application;

[0022] Figure 2 is a main view structural schematic view of the lower support assembly in the present application;

[0023] Figure 3 is a side view sectional view of the lower support assembly in the present application;

[0024] Figure 4 is a main view structural schematic view of the upper support assembly support head in the present application;

[0025] Figure 5 is a side view sectional view of the upper support assembly support head in the present application;

[0026] Figure 6 is a main view sectional view of the electromagnetic mattress in the present application;

[0027] Figure 7 is a structural schematic view of the natural diamond pen in the present application;

[0028] Figure 8 is a sectional view of the bearing ring in the present application. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical schemes and beneficial effects solved by the present application more clear and obvious, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0030] Specific embodiment one: in combination with Figures 1 to 8 The present embodiment is described, and the bearing ring large curvature radius spherical surface grinding processing method described in the present embodiment comprises the following steps:

[0031] Step one, adjusting the support position: a machine outside calibration cylinder 4 is arranged on one side of the eccentric adjusting device outside the machine, the machine outside calibration cylinder 4 is used to replace the bearing ring for positioning and calibration, and the positions of the lower support assembly 1 and the upper support assembly 2 in the eccentric adjusting device outside the machine are adjusted to realize the support of the outer circumference of the machine outside calibration cylinder 4;

[0032] Step two, clamping the workpiece to be processed: select the wide electromagnetic cushion 5 clamped on the grinding machine chuck, the shaft end face of the workpiece to be processed is adsorbed and fixed on the electromagnetic cushion 5, the eccentric adjustment device outside the machine is moved to the grinding machine, and the lower support assembly 1 and the upper support assembly 2 support the outer circle of the workpiece to be processed;

[0033] Step three, dressing the grinding wheel: select a grinding wheel with large grain size for grinding, and first dress the shape of the grinding wheel with a natural diamond pencil before grinding;

[0034] Step four, grinding processing: clamp the dressed grinding wheel on the grinding machine, and respectively perform rough grinding and fine grinding on the outer circle of the workpiece to be processed to grind the large curvature radius spherical surface of the bearing ring.

[0035] In this embodiment, by adjusting the processing equipment, designing special tooling, changing the clamping method of the original tooling fixture, and optimizing the grinding wheel profile, the accuracy of the bearing spherical diameter difference is ensured to realize the production and processing of the bearing outer ring under the premise of ensuring product accuracy and pass rate.

[0036] In order to achieve the design requirements of the bearing outer ring large curvature radius spherical surface, according to the characteristics of this type of bearing, SUU130B numerical control bearing ring grinding machine is used for processing. Through the calculation of the outer diameter convexity in the early stage and the adjustment of the equipment, the processing is innovatively improved from the following six aspects:

[0037] 1. Setting of electromagnetic cushion structure

[0038] The electromagnetic cushion directly contacts with the reference surface of the workpiece, and whether the cushion is suitable will directly affect the accuracy and surface quality of the processed workpiece. The original cushion has a small magnetic guide surface, which causes the electromagnetic cushion to be unable to stably adsorb the workpiece. Therefore, a wide electromagnetic cushion is used to increase the magnetic force of the cushion by increasing the area of the magnetic guide surface and improve the rotational stability of the workpiece.

[0039] 2. Selection of grinding wheel and diamond pencil

[0040] The material of the bearing to be processed is Cr4Mo4V steel, which is a high-temperature bearing steel. This steel is different from general bearing steel, and its tensile strength and yield strength are relatively high, and the grinding efficiency is low. Therefore, an imported grinding wheel with good grinding effect is selected. After subsequent tests and continuous comparison, the selected grinding wheel brand is finally determined as 89A220K5V111.63. The grinding wheel has a larger grain size, and the grinding wheel has a shallow grinding process and good surface quality.

[0041] Because the grinding wheel is hard and the surface accuracy of the workpiece is high, the grinding wheel is trimmed in the process of machining by the method of "pre-trimming + intermediate trimming". Because of frequent trimming, the diamond pen is easily worn out. Therefore, natural diamond pen is selected to better control the consumption of diamond pen in the machining process, avoid the rapid consumption of diamond pen in the machining process, and lead to unstable conditions of spherical radius R and spherical diameter difference, and improve the machining precision control.

[0042] 3. Selection of fulcrum

[0043] Because the bearing outer ring is a spherical surface, the surface quality in the machining process should be paid special attention. Although the ordinary circular arc type floating fulcrum supports the workpiece more stably and has small vibration, the contact area with the workpiece is large, the spherical surface is easy to scratch, and the fulcrum head is easy to consume in the grinding process, which has a greater impact on the grinding accuracy. The V-type fulcrum has a small contact area with the workpiece, the surface quality of the workpiece is better, and the cutting residue is not easy to accumulate near the fulcrum, so the machining precision is better. Therefore, the V-type fulcrum is selected in this embodiment.

[0044] The floating fulcrum is adjusted using an external fulcrum disc. The eccentricity range during normal machining is 15°~20°. Considering the special bearing surface type and the high requirement for the edge surface degree, the eccentricity of the workpiece is set to 5°~8° while ensuring that the fulcrum is centered on the spherical surface in this embodiment. Because the smaller the eccentricity, the smaller the centrifugal force when the workpiece rotates, the edge surface degree of the workpiece is better guaranteed. At the same time, when the eccentric shaft is in this angle range, the workpiece eccentricity can also be guaranteed in the third quadrant, so that the workpiece is tightly attached to the fulcrum during rotation, avoiding the occurrence of the crash accident during machining and the subsequent wall thickness out-of-tolerance situation.

[0045] The method for eccentric setting of the bearing sleeve in this embodiment can refer to the eccentric grinding of the bearing sleeve in Chinese invention patent CN201911089220.5.

[0046] 4. Trimming of the grinding wheel profile

[0047] The curvature generatrix of the raceway completely depends on the final trimming shape of the grinding wheel for the raceway. During product machining, the inclination angle a of the grinding wheel trimmer and the running track of the diamond pen on the trimmer are adjusted to trim the grinding wheel, that is, the diamond pen is used to trim the grinding wheel horizontally to trim the grinding wheel obliquely, the straight line on the grinding surface is trimmed to a curved line, and finally the grinding wheel is shaped into a concave working surface, and the grinding is formed by cutting. After the grinding wheel trimming is completed, red marks are applied to the contact between the workpiece and the grinding wheel, so as to compare the size of the grinding wheel R.

[0048] 5. Setting of grinding parameters

[0049] Because of the special shape of the bearing sleeve, the machining parameters need to be explored.

[0050] First, because the spherical radius R is too large, the ball diameter difference precision is high, so the correction value of the equipment parameters needs to be reset. By adjusting the grinding wheel feed amount and measuring the actual grinding amount, the correction amount S = 0.4~0.7 is finally approximately obtained.

[0051] The grinding wheel speed in the grinding process should not be too high to prevent the grinding wheel surface from being blocked and causing slipping. High speed not only cannot better control the size accuracy, but also affects the surface quality of the outer diameter, which is easy to produce strip-shaped grinding marks, and even grinding burn. Different particle sizes of grinding wheels have a completely different impact on the grinding effect.

[0052] To solve the above problems, after repeated experiments, the method of small feed and multiple grinding is adopted, and finally the process parameters are solidified. The size stability is improved, and at the same time the surface quality is also optimized. The outer diameter grinding parameters of NUTR2052 are shown in Table 1.

[0053]

[0054] Table 1 NUTR2052 outer diameter grinding parameters

[0055] 6. Calculation of the outer diameter convexity of the collar

[0056] Since the spherical radius R is measured by a profiler, the theoretical value of the outer diameter convexity needs to be calculated, which will be used as the basis for whether the workpiece meets the process requirements.

[0057] The maximum height difference between the outer diameter spherical generatrix and the outer diameter chamfer edge is the outer diameter convexity. By analogy with the logarithmic curve roller (i.e. the outer diameter generatrix of the roller is a logarithmic curve), the calculation formula of the outer diameter convexity of the collar is obtained:

[0058] R=(D w -2×rp1) 2 / (8×δ)

[0059] Wherein, R is the spherical radius; D w is the nominal diameter of the collar; rp1 is the axial coordinate of the outer diameter chamfer; δ is the generatrix convexity

[0060] According to the calculation, the convexity value is about 2μm.

[0061] Specific implementation method two: combined Figures 1 to 8 To illustrate the present embodiment, in step one of the present embodiment, the profile of the outer circumferential side wall of the off-machine calibration cylinder 4 is the same as the profile of the bearing collar.

[0062] The technical features not disclosed in the present embodiment are the same as those in specific implementation method one.

[0063] Specific implementation method three: combinedFigures 1 to 8 In the step one of the embodiment, the eccentric adjustment device outside the machine comprises a support seat 3, the lower support assembly 1 and the upper support assembly 2 are clamped on the support seat 3, and the positions of the lower support assembly 1 and the upper support assembly 2 on the support seat 3 are adjustable.

[0064] The technical features not disclosed in the embodiment are the same as those in the second embodiment.

[0065] The fourth embodiment is combined with the first embodiment. Figures 1 to 8 In the step one of the embodiment, the support head of the upper support assembly 2 is a V-shaped floating support head, the support head of the lower support assembly 1 is a bevel support head, the lower support assembly 1 is arranged on one side directly below the machine outside calibration cylinder 4, and the upper support assembly 2 is arranged on the other side below the middle of the machine outside calibration cylinder 4.

[0066] The technical features not disclosed in the embodiment are the same as those in the third embodiment.

[0067] The fifth embodiment is combined with the first embodiment. Figures 1 to 8 In the step one of the embodiment, the position of the upper support assembly 2 on the support seat 3 is adjusted, so that the fulcrums of the support heads of the lower support assembly 1 and the upper support assembly 2 are aligned with the spherical center of the machine outside calibration cylinder 4.

[0068] The technical features not disclosed in the embodiment are the same as those in the fourth embodiment.

[0069] The sixth embodiment is combined with the first embodiment. Figures 1 to 8 In the step two of the embodiment, when the workpiece to be machined is clamped on the grinding machine chuck, the axis of the workpiece to be machined is arranged eccentrically with the axis of the chuck, and the eccentric angle is 5°-8°.

[0070] The technical features not disclosed in the embodiment are the same as those in the first embodiment.

[0071] The seventh embodiment is combined with the first embodiment. Figures 1 to 8 In the step three of the embodiment, when the grinding wheel is dressed, the natural diamond pen is tilted to cut into the dressing grinding wheel, the straight line on the grinding wheel grinding surface is dressed into a curved line, and finally the grinding wheel is formed into a concave working surface, which is a cutting type grinding forming.

[0072] The technical features not disclosed in the embodiment are the same as those in the first embodiment.

[0073] The eighth embodiment is combined with the first embodiment. Figures 1 to 8 In the step three of the embodiment, after the grinding wheel is dressed, red marks are used to smear the contact between the workpiece and the grinding wheel, so as to compare the size of the grinding wheel radius.

[0074] The technical features not disclosed in the embodiment are the same as those in Embodiment 1.

[0075] Ninth Embodiment: Combination Figures 1 to 8 In the embodiment, the rough grinding and the fine grinding in Step 4 are performed by the small feed and the multiple grinding, respectively.

[0076] The technical features not disclosed in the embodiment are the same as those in Embodiment 1.

[0077] Tenth Embodiment: Combination Figures 1 to 8 In the embodiment, after the rough grinding is completed, the grinding wheel grinding surface is re-dressed, and then the fine grinding is performed.

[0078] The technical features not disclosed in the embodiment are the same as those in Embodiment 1.

[0079] The basic principles and main features of the present application and the advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for grinding bearing rings with large radius of curvature spherical surfaces, characterized in that: Includes the following steps: Step 1: Adjust the support position: Set an external calibration cylinder (4) on one side of the external eccentric adjustment device. Use the external calibration cylinder (4) to replace the bearing ring for positioning calibration. Adjust the position of the lower support component (1) and the upper support component (2) in the external eccentric adjustment device to support the outer circumference of the external calibration cylinder (4). Step 2, clamping the workpiece to be processed: Select a wide electromagnetic pad (5) and clamp it on the grinding machine chuck. Adsorb and fix the shaft end face of the workpiece to be processed on the electromagnetic pad (5). Move the external eccentric adjustment device to the grinding machine. The lower support assembly (1) and the upper support assembly (2) support the outer circumference of the workpiece to be processed. Step 3: Dressing the grinding wheel: Select a grinding wheel with a large grit size for grinding. Before grinding, use a natural diamond pen to dress the shape of the grinding wheel. Step 4: Grinding: The dressed grinding wheel is clamped onto the grinding machine, and rough grinding and fine grinding are performed on the outer circumference of the workpiece to be processed to grind out the large radius of curvature spherical curve of the bearing ring.

2. The method for grinding a bearing ring with a large radius of curvature spherical surface according to claim 1, characterized in that: In step one, the profile of the outer circumferential sidewall of the external calibration cylinder (4) is the same as the profile of the bearing ring.

3. The method for grinding a bearing ring with a large radius of curvature spherical surface according to claim 2, characterized in that: In step one, the external eccentricity adjustment device includes a support base (3), a lower support assembly (1) and an upper support assembly (2) which are clamped on the support base (3) and their positions on the support base (3) are adjustable.

4. The method for grinding a bearing ring with a large radius of curvature spherical surface according to claim 3, characterized in that: In step one, the support head of the upper support component (2) is a V-shaped floating support head, and the support head of the lower support component (1) is a sloping support head. The lower support component (1) is located on one side directly below the external calibration cylinder (4), and the upper support component (2) is located on the other side below the middle of the external calibration cylinder (4).

5. The method for grinding a bearing ring with a large radius of curvature spherical surface according to claim 4, characterized in that: In step one, the position of the upper support assembly (2) on the support base (3) is adjusted so that the fulcrum of the support head in the lower support assembly (1) and the upper support assembly (2) is aligned with the center of the ball of the external calibration cylinder (4).

6. The method for grinding a bearing ring with a large radius of curvature spherical surface according to claim 1, characterized in that: In step two, when the workpiece to be processed is clamped on the grinding machine chuck, the axis of the workpiece to be processed is set off from the axis of the chuck, and the off-center angle is 5°~8°.

7. The method for grinding a bearing ring with a large radius of curvature spherical surface according to claim 1, characterized in that: In step three, when dressing the grinding wheel, the natural diamond pen is tilted and cuts into the dressing wheel to dress the straight lines on the grinding surface of the grinding wheel into curved lines, and finally the grinding wheel is shaped into a concave working surface, which is formed by in-cut grinding.

8. The method for grinding a bearing ring with a large radius of curvature spherical surface according to claim 1, characterized in that: In step three, after the grinding wheel is dressed, a red mark is applied to the workpiece and then to the grinding wheel to compare the size of the grinding wheel radius.

9. The method for grinding a bearing ring with a large radius of curvature spherical surface according to claim 1, characterized in that: In step four, rough grinding and fine grinding are performed using small feed and multiple grinding operations, respectively.

10. A method for grinding bearing rings with large radius of curvature spherical surfaces according to claim 1, characterized in that: In step four, after the rough grinding is completed, the surface of the grinding wheel needs to be re-dressed before fine grinding is performed.

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