JP6517105B2 - Superfinishing method of roller bearing rolling surface - Google Patents

Description

  The present invention relates to a superfinishing method for processing the rolling contact surface of a tapered roller bearing or a cylindrical roller bearing, and in particular, the superfinishing method of a composite crowning surface in which the cross sectional shape of the rolling contact surface is a shape of a plurality of arcs. It relates to a finishing method.

  The rolling surface of the inner ring or the outer ring of the roller bearing has a straight surface in the axial direction, or a single crowning surface in which the cross section is a single arc shape, or a composite in which the cross sections are connected in a plurality of arc shapes. It has a crowning surface, or a logarithmic crowning surface whose cross section is a logarithmic curve.

  Conventionally, as a method of superfinishing (mirror finishing) of these surfaces, using a square grinding wheel disposed perpendicularly to a conical surface or a cylindrical surface, the fine vibration operation is performed in parallel to the conical surface or the cylindrical surface. There is a method of giving and pressing the grindstone (Patent Document 1). Furthermore, there has been a method in which a traverse operation (reciprocation operation) and a micro-vibration operation are given to the grinding stone in parallel with a conical surface or a cylindrical surface, and the grinding wheel is pressurized (Patent Document 2).

Japanese Patent Laid-Open No. 2002-326153 JP 2007-260829 A

  For example, FIG. 10 shows the case where the rolling contact surface 1 of the bearing ring (outer ring) 5 of the roller bearing is in contact with the grindstone 2 pressurized by the pressure source 6 of the pressure means. In this case, the outer ring 5 is supported by the support mechanism 7. The support mechanism 7 includes a backing plate 8 which rotates the outer ring 5 about its axis L in contact with the end face of the outer ring 5 and a pusher roll 9 which presses the outer ring 5 against the backing plate 8. Further, as shown in FIGS. 11 (a) and 11 (b), in general, a compound having a large diameter circular arc portion 1a at the center in the axial direction and a small diameter circular arc portion 1b at the axial end. It is crowning. For this reason, as described in Patent Document 1, when processing is performed without traverse operation by only the fine vibration operation, the grindstone 2 is in the shape of the large diameter arc portion 1a and the small diameter arc portions 1b and 1b. It has a polished surface.

  However, as described above, since the cross-sectional shape of the rolling contact surface 1 has arcs of different diameters and the arcs at both axial end portions have a small diameter, the axial direction of the grinding surface of the grindstone 2 is shown in FIG. Although processing is possible at the end corresponding portion, as shown in FIG. 11 (b), the axial end corresponding portion of the grinding surface of the grindstone 2 can not correspond to the small diameter arc portion 1b at the axial end, There are cases where this small diameter arc portion 1b can not be processed. That is, FIG. 11 (a) shows the case where the crowning height of the composite crowning is low, and FIG. 11 (b) shows the case where the crowning height of the composite crowning is high.

  Moreover, in the case of the patent document 2, as shown in FIG. 12, the traverse action (reciprocal movement) is performed in which the grinding stone 3 suppresses the turning movement in the vibration action / normal direction. As described above, when processing the composite crowning by normal pressure processing, the processing efficiency is poor compared to the processing of only the fine vibration, so the processing time becomes long. If the entire axial direction is to be machined at one time, the grinding surface 3a has a concave surface as shown in FIG. 13 when machining the central large diameter circular arc portion 1a after the grindstone 3 conforms to the small diameter circular arc portions 1b at both ends. The grinding surface 3a of the grindstone 3 may not uniformly contact the large diameter arc portion (machined surface) 1a, and the crowning shape may be broken, and a uniform finished surface roughness may not be obtained.

  Therefore, it is possible to provide a method of superfinishing a roller bearing rolling surface which can obtain a uniform finished surface roughness without losing the shape of the crowning shape and can improve the machining efficiency.

  The method for superfinishing a roller bearing rolling surface according to the present invention is a superfinishing method for machining a rolling bearing surface of a roller bearing, wherein the rolling bearing surface is a large diameter arc portion in the axial center and an axial direction A compound crowning surface having a small diameter circular arc at the end, and after machining the entire axial direction of the rolling surface, separate machining of only the large diameter circular arc at the axial center of the rolling surface is there.

  According to the method of superfinishing the roller bearing rolling surface of the present invention, after machining the entire axial direction of the rolling surface, separate machining of only the large diameter arc portion of the axial center portion of the rolling surface is performed. Therefore, uniform finished surface roughness can be obtained in the large diameter arc portion at the axial center portion. Moreover, even in the small diameter arc portion at the axial end of the rolling surface, the entire axial direction of the rolling surface is processed before separate machining of only the large diameter arc portion, so even finishing in the small diameter arc portion Surface roughness can be obtained. Here, separate processing may be performed in the case of processing with another facility or in the case of processing with the same facility, as long as there is another processing step.

  The machining of the entire axial direction of the rolling surface is a traverse operation of the grinding wheel, and it is preferable to stop the traverse movement of the grinding wheel for a predetermined time at an end position of the small diameter arc portion. In this way, by configuring, machining insufficiency at the end of the small diameter arc portion can be resolved.

  Machining in the entire axial direction may include roughing and finishing. As described above, by setting the number of processes to two, high-precision processing can be achieved.

  The roller bearings may be tapered roller bearings or cylindrical roller bearings.

  The rolling contact surface may be a rolling contact surface formed on the outer diameter surface of the inner ring, or may be a rolling contact surface formed on the outer diameter surface of the outer ring.

  In the present invention, uniform finished surface roughness can be obtained in the large diameter arc portion at the axial center, uniform finish surface roughness can be obtained even in the small diameter arc portion, and a highly accurate rolling surface can be obtained. You can get it.

By stopping the traversing motion of the grinding wheel at the end position of the small diameter arc portion for a predetermined time,
It is possible to reduce the number of traverses of the small diameter arc portion, improve the processing efficiency, and achieve shortening of the processing time as a whole.

It is a schematic plan view which shows the relationship between the outer ring | wheel as a bearing ring of a roller bearing, and a grindstone in the processing method of this invention. The superfinishing method of the roller bearing rolling surface of the present invention is shown, wherein (a) is a simplified view during roughing of the entire axial direction, and (b) is a simplified view during the finishing of the entire axial direction. It is a figure and (c) is a simple figure of another processing of only a large diameter circular arc part of an axial direction central part of a rolling contact side. It is a simplification figure in traverse operation stop. The surface roughness of the axial center portion is shown, and (a) is a graph when the axial central portion is not separately processed, and (b) is the graph when the axial central portion is separately processed. FIG. The result of processing with no tally time in the method of superfinishing a roller bearing rolling surface according to the present invention is shown, (a) is a simplified view of the sectional shape of the rolling surface, (b) is a rolling surface It is a graph of the surface roughness of. The results of machining with tally time in the method of superfinishing a roller bearing rolling surface according to the present invention are shown, (a) is a simplified view of the sectional shape of the rolling surface, (b) is a rolling surface FIG. 6 is a graph of the surface roughness of FIG. It is a sectional view of a tapered roller bearing. It is a sectional view of a cylindrical roller bearing. It is sectional drawing of another cylindrical roller bearing. It is a schematic plan view which shows the relationship between the outer ring | wheel as a bearing ring of a roller bearing, and a grindstone in the process of the conventional fine vibration operation | movement. (A) is a simplified view showing the relationship between the grinding wheel and the rolling contact surface when the crowning is low, and (b) is a grinding wheel and the rolling contact surface when the crowning is high. Is a simplified diagram showing the relationship between It is a simplification figure showing the processing method which performs conventional traverse operation and micro-vibration operation. FIG. 12 is a simplified view showing problems of the processing method shown in FIG. 11;

  Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 9. FIG. 7 shows a tapered roller bearing, which, as shown in FIG. 7, comprises an inner ring 11 having a conical rolling surface 10 on the outer peripheral surface and a conical rolling surface 12 on the inner peripheral surface. The plurality of tapered rollers 14 rollably interposed between the outer ring 13 having the rolling contact surface 10 of the inner ring 11 and the rolling contact surface 12 of the outer ring 13 and the plurality of tapered rollers 14 at predetermined intervals in the bearing circumferential direction And a retainer 15 for holding the components apart. Further, the inner ring 11 forms a small ridge 16 on the small diameter side of the raceway surface 10 and a large ridge 17 on the large diameter side.

  The cage 15 has a plurality of column portions 15c between the small diameter ring portion 15a and the large diameter ring portion 15b, and a pocket 18 for holding the tapered roller 14 is formed between the column portions 15c. . Then, the tapered roller 14 is disposed in the pocket 18.

  FIG. 8 shows a cylindrical roller bearing, which comprises an inner ring 21 having a rolling surface 20 on the outer periphery, an outer ring 23 having a rolling surface 22 on the inner periphery, a rolling surface 20 of the inner ring 21 and an outer ring A plurality of cylindrical rollers 24 rotatably disposed between the rolling surfaces 23 and 23 and a cage 25 for holding the cylindrical rollers 24 at predetermined circumferential intervals are provided. Collars 26 and 27 are provided on both sides of the inner ring 21, respectively.

  At the corners where the ridge surfaces 26 and 27 of the inner ring 21 and the rolling surface 20 cross each other, relief grooves 28 are provided. These relief grooves 28 are mainly provided as relief grooves when grinding the rolling contact surface 20 and the heel surface.

  The cylindrical roller bearing shown in FIG. 9 includes an inner ring 31 having a rolling surface 30 on the outer periphery, an outer ring 33 having a rolling surface 32 on the inner circumference, a rolling surface 30 of the inner ring 31 and a rolling surface 32 of the outer ring 33. And a cage 35 for holding the cylindrical rollers 34 at a predetermined circumferential distance. Collars 36 and 37 are provided on both sides of the outer ring 33, respectively. At the corners where the ridge surfaces of the ridges 36 and 37 of the outer ring 33 and the rolling surface 32 intersect, a recess groove 38 is provided.

  In the superfinishing method of the present invention, the rolling contact surfaces 10 and 12 of tapered roller bearings shown in FIGS. 7 to 9 and the rolling contact surfaces 20, 22 and 30, 32 of cylindrical roller bearings are as shown in FIG. Processing is performed by the processing method. The rolling surface R (10, 12, 20, 22, 30, 32) shown in FIG. 2 is a composite crowning having a large diameter arc portion 40 at the axial center and small diameter arc portions 41a and 41b at the axial end. It is a face. Here, the large diameter circular arc portion 40 at the axial central portion of the rolling contact surface R (10, 12, 20, 22, 30, 32) is about R 500 to 2000 mm, and the small diameter circular arc portions 41a and 41 b at the axial end It is about R 30-100 mm, and the rolling surface R in FIG. 2 and FIG. 11 is exaggerated.

  This superfinishing method is performed by supporting the outer ring 13 of a bearing of a roller bearing (a conical bearing in the illustrated example) by a support mechanism 51 as shown in FIG. It has a backing plate 52 that rotates the outer ring 13 about its axis L in contact, and a pusher roll 53 that presses the outer ring 13 toward the backing plate 52. In this case, the rolling surface R of the outer ring 13 of the roller bearing and pressure The case where the grinding wheel 50 pressed by the pressure source 54 of the means is brought into contact with the outer ring 23, 33 of the cylindrical roller bearing is omitted because it becomes the superfinishing method by the same supporting mechanism. In addition, since the superfinishing method is the same as in the inner ring 11 of the tapered roller bearing and the inner rings 21 and 21 of the cylindrical roller bearing, the description thereof will be omitted.

  Moreover, as shown in FIG. 2 (a), this superfinishing method includes first step machining for roughing the entire axial direction of the rolling contact surface R, and as shown in FIG. 2 (b), rolling. Second step machining for finishing the entire surface in the axial direction of the surface R, and third machining for finishing only the large-diameter circular arc portion 40 at the axially central portion of the rolling surface R, as shown in FIG. It is equipped with step processing.

  That is, in the first step machining, the grindstone 50 (rough grindstone 50A) is traversed along the entire axial direction (full length) of the rolling surface R. In this case, the traverse can be, for example, one reciprocation of 5 seconds. In the second step machining, the grindstone 50 (finishing grindstone 50B) is traversed along the entire axial direction (full length) of the rolling surface R. The traverse can be, for example, one reciprocation of 5 seconds. In the third step machining, only the large diameter arc portion 40 of the rolling surface R is traversed by the grindstone 50 (the grinding stone 50C for finishing the large diameter arc portion 40). The traverse can be, for example, 15 round trips of 7 seconds. Further, in each step machining, a minute vibration operation is given to the grinding stone 50 (50A, 50B, 50C) in parallel to the rolling surface R.

  The grain size of the roughing grindstone 50A is, for example, about # 1000 to # 1500, and the grain size of the finishing grindstones 50B and 50C is, for example, about # 1500 to # 3000. The same grindstone 50 may be used from roughing to finishing. As the particle size in this case, for example, about # 1500 to # 2500 is used.

  In this method of superfinishing the rolling surface of the roller bearing, after machining the entire axial direction of the rolling surface R, separately machining only the large-diameter circular arc portion 40 at the central portion in the axial direction of the rolling surface R become. For this reason, in the large-diameter circular arc portion 40 at the axially central portion, uniform finished surface roughness can be obtained. Moreover, even in the small diameter arc portions 41a and 41b at the axial end of the rolling surface R, the entire axial direction of the rolling surface R is processed before separately processing only the large diameter arc portion 40. Even in the arc portions 41a and 41b, uniform finished surface roughness can be obtained. That is, uniform finished surface roughness can be obtained in the large diameter arc portion 40 at the central portion in the axial direction, uniform finish surface roughness can be obtained even in the small diameter arc portions 41a and 41b, and highly accurate rolling The face R can be obtained.

  Further, in this method of superfinishing the rolling surface of the roller bearing, as shown in FIG. 3, in machining the entire axial direction of the rolling surface R (in the second step machining), the end portions of the small diameter arc portions 41a and 41b It is preferable to stop the traverse operation of the grindstone 50B for a predetermined time (for example, one second) at each end position of the small diameter arc portion at the position. Even during this stop, a minute vibration operation is given to the grinding stone 50 (50B) in parallel to the rolling surface R.

  By stopping the traverse movement of the grinding stone at the end position of the small diameter arc portions 41a and 41b for a predetermined time, the number of traverses of the small diameter arc portions 41a and 41b can be reduced, thereby improving processing efficiency, The reduction of the processing time as a whole can be achieved.

  As a roller bearing processed by the processing method shown in FIG. 2, it may be a tapered roller bearing or a cylindrical roller bearing, and as the raceway surface R, on the outer diameter surface of the inner rings 11, 21, 31 The rolling contact surfaces 10, 20, 30 may be formed, or the rolling contact surfaces 12, 22, 32 formed on the inner diameter surfaces of the outer rings 13, 23, 33. For this reason, this processing method is excellent in versatility.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment and can be variously modified. The first step machining, the second step machining, the third step machining traverse The number of round trips can be set arbitrarily. Moreover, it is also arbitrary as processing time of each process. Furthermore, the stop time can be arbitrarily set as the stop time when the traverse operation of the grinding stone is stopped at the end position of the small diameter arc portions 41a and 41b.

  The grindstones 50A, 50B, and 50C used in the first step processing, the second step processing, and the third step processing can be variously adopted depending on the material, hardness, and the like of the rolling contact surface R. Grains and abrasive grains of silicon carbide can be used.

Example 1
Surface roughness in the case where only overall processing (processing of the entire rolling surface), overall processing (processing of the entire rolling surface) and central processing (processing of the large diameter arc portion of the rolling surface) are performed The processing time etc. were compared. In this case, an outer ring of a tapered roller bearing having an outer diameter of 50 to 80 mm, a rolling surface angle of 27 ° and a rolling surface width of 14 mm was used. FIG. 4 (a) shows the surface roughness of the axially central portion of each rolling surface in the case of overall processing and FIG. 4 (b) in the case of overall processing and central portion processing.

  In FIG. 4A, two reciprocations (26 seconds) were performed as a processing time. In this case, the surface roughness Ra of the central portion (large diameter arc portion) was 0.13 μm. Further, in FIG. 4B, the entire processing was performed for 13 seconds in one reciprocation, and the central processing was performed for a total of 23 seconds in 21 reciprocations (10 seconds). In this case, the surface roughness Ra of the central portion was 0.075 μm.

  At least two reciprocations (26 seconds) have to be added in order to obtain surface roughness comparable to that of the central part of FIG. 4 (b) by only the overall processing, and the overall processing time was 52 seconds. For this reason, if (whole processing + center part processing) is performed, it will be 29 seconds (52 seconds-23 seconds) shortening as processing time.

Example 2
In the processing of (whole processing + central part processing), the surface roughness and the processing time etc. were compared with no tally time and with tally time. The outer ring of a tapered roller bearing having an outer diameter size of 50 to 80 mm, a taper angle of 44 °, and a rolling surface width of 13 mm was used. Here, the tally time is a time during which the traverse operation of the grinding stone 50 is stopped at the end position of the small-diameter circular arc portions 41a and 41b during machining of the entire axial direction of the rolling surface R; In this case, there is no time to stop, and with tally time, there is a time to stop.

  When there is no tally time, the first step machining (rough machining in the entire axial direction) is performed one reciprocation (5 seconds), and the second step machining (finishing in the entire axial direction) is performed one reciprocation (5 seconds). Step work (finishing of the large diameter arc portion) was carried out 15 cycles (7 seconds). That is, the entire processing time was 17 seconds. In this case, the surface roughness Ra of the central large diameter arc portion 40 is 0.114 μm, the surface roughness Ra of 0.136 μm of the one small diameter arc portion 41a, and the surface roughness Ra of 0.153 μm of the other small diameter arc portion 41b. there were.

  When the tally time is present, the grindstone 50 is stopped for one second at the end of each of the small diameter arc portions 41a and 41b during the second step processing (finishing in the entire axial direction) without the tally time. For this reason, the processing time was 19 seconds as a whole. In this case, the surface roughness Ra of the central large diameter arc portion 40 is 0.083 μm, the surface roughness Ra of 0.102 μm of the one small diameter arc portion 41a, and the surface roughness Ra of 0.109 μm of the other small diameter arc portion 41b. there were.

  In order to obtain the same level of surface roughness as processing with tally time, it required 22 seconds of processing with no tally time processing. It is necessary to add one reciprocation (5 seconds) of the second step processing, and in the processing with tally time, the processing time as a whole can be shortened by 3 seconds (22 seconds-19 seconds).

R (10, 12, 20, 22, 30, 32) Rolling surface 11, 21, 31 Inner ring 13, 23, 33 Outer ring 40 Large diameter arc portion 41a, 41b Small diameter arc portion 50 (50A, 50B, 50C)

Claims (7)

A superfinishing method for processing the rolling surface of a roller bearing,
The rolling surface is a composite crowning surface having a large diameter arc portion at the axial center and a small diameter circular portion at the axial end, and after processing the entire rolling surface in the axial direction, the rolling surface A superfinishing method characterized by performing separate machining of only the large diameter arc portion at the central portion in the axial direction of the above.   2. The superfinishing method according to claim 1, wherein the machining of the entire axial direction of the rolling surface is a traverse operation of the grinding wheel, and the traverse movement of the grinding wheel is stopped for a predetermined time at an end position of the small diameter arc portion. .   The superfinishing method according to claim 1 or 2, wherein machining in the entire axial direction includes roughing and finishing.   The superfinishing method according to any one of claims 1 to 3, wherein the roller bearing is a tapered roller bearing.   The superfinishing method according to any one of claims 1 to 3, wherein the roller bearing is a cylindrical roller bearing.   The superfinishing method according to any one of claims 1 to 5, wherein the rolling contact surface is a rolling contact surface formed on the outer diameter surface of the inner ring.   The superfinishing method according to any one of claims 1 to 5, wherein the rolling contact surface is a rolling contact surface formed on an inner diameter surface of an outer ring.