JP5056189B2 - Method for manufacturing rolling ring bearing ring - Google Patents

Description

The present invention relates to an improvement in a method of manufacturing a bearing ring for a rolling bearing for manufacturing an outer ring and an inner ring constituting a rolling bearing such as a radial ball bearing from a single material.

  A radial ball bearing 1 as shown in FIG. 4 is incorporated in a rotation support portion of various rotating devices. This radial ball bearing 1 is of a single-row deep groove type, and has a plurality of balls 4, 4 installed between an outer ring 2 and an inner ring 3 arranged concentrically with each other. Of these, a deep groove type outer ring raceway 5 is formed on the axially intermediate portion of the inner peripheral surface of the outer ring 2, and a deep groove type inner ring raceway 6 is formed on the entire outer periphery of the inner ring 3. doing. The balls 4 and 4 are arranged so as to be able to roll between the outer ring raceway 5 and the inner ring raceway 6 while being held by a cage 7. With this configuration, the outer ring 2 and the inner ring 3 can freely rotate relative to each other. In the example shown in FIG. 4, a metal corrugated cage is used as the cage 7, but a synthetic resin crown-shaped cage is often used. Further, in many cases, a structure in which the outer peripheral edge of the sealing plate is locked in the locking grooves formed on the inner peripheral surfaces of both ends of the outer ring 2 is employed. In this case, the inner peripheral edges of the both sealing plates are slidably contacted or closely opposed to the outer peripheral surfaces of both end portions of the inner ring 3 over the entire periphery.

  By the way, as a manufacturing method for manufacturing the outer ring 2 and the inner ring 3 constituting the radial ball bearing 1 as described above, for example, as described in Patent Documents 1 and 2, a single material is used in a multistage manner. A technique of manufacturing using hot forging using a feed type forging machine (former) is known. FIG. 5 shows the processing steps of the outer ring 2 and the inner ring 3 described in Patent Documents 1 and 2. In the illustrated example, from the step (cutting step) for obtaining the cylindrical material 8 shown in (A), the step for obtaining the outer ring intermediate material 24 and the inner ring intermediate material 25 shown in (D). Up to (separation and punching step) is continuously processed hot using a multi-feed forging machine. And the process (diameter expansion and raceway surface formation process) for obtaining the outer ring | wheel 2 and the inner ring | wheel 3 shown to (E) is performed cold with a roll former.

  In the case of the prior art, first, as a cutting process, a metal wire or bar such as high carbon chromium bearing steel (SUJ2) is cut into a predetermined length, and a cylindrical shape as shown in FIG. A material (billet) 8 is obtained. After that, as an upsetting process, the cylindrical material 8 is subjected to upsetting which is compressed in the axial direction by free forging, and a flat (disc-shaped) first intermediate material 9 as shown in FIG. And

Next, as a forming step, die forging is performed on the first intermediate material 9 using a die 10 as a receiving die and a punch 11 as a pressing die, as shown in FIG. Specifically, as shown in FIG. 6B, as the die 10, the inner peripheral surface side large diameter portion 12 located on the opening side and the inner peripheral surface side small diameter portion 13 located on the bottom side are arranged on the inner side. What has the step-shaped shaping | molding hole 15 made to continue by the level | step-difference part 14 is used. Further, as the punch 11, the outer peripheral surface side small diameter portion 16 is disposed on the distal end side, the outer peripheral surface side large diameter portion 17 is disposed on the proximal end side, and the outer peripheral surface side small diameter portion 16 and the outer peripheral surface side large diameter portion 17 are disposed between these punches 11. A stepped shape having each of the medium diameter portions 18 is used. And the axial direction one end surface of the said 1st intermediate material 9 (Axial one end points to the right end side of FIGS. 1-3, 5 and 6, and the other axial direction other end points to the left end side. In the state in which the portion closer to the outer diameter is in contact with the inner stepped portion 14 formed on the inner peripheral surface of the molding hole 15 from the other end side in the axial direction by the punch 11. . Thereby, the outer peripheral surface shape of the first intermediate material 9 is formed by the molding hole 15 and the inner peripheral surface shape is also formed by the punch 11. Then, as shown in FIG. 5 and FIG. 6C, a stepped bottomed cylindrical second intermediate material 19 having step portions at the axial intermediate portions of the inner and outer peripheral surfaces is obtained. The second intermediate material 19 includes a large-diameter cylindrical portion 20 on the other axial end side, a small-diameter cylindrical portion 21 on one axial end side, and a bottom portion 22 that closes the axial one-end opening of the small-diameter cylindrical portion 21. It consists of.
In the illustrated example, the bottom surface 23 of the molding hole 15 is formed integrally with the die 10. However, in the actual case, the bottom surface 23 constitutes a receiving mold. In some cases, the intermediate material 19 may be constituted by a tip surface such as a counter sleeve or a counter punch for extracting the intermediate material 19 from the molding hole 15.

  Next, as the separation / punching step, the second intermediate material 19 is transferred to the large diameter side cylindrical portion 20 and the small diameter side cylindrical portion 21 at the boundary position between the large diameter side cylindrical portion 20 and the small diameter side cylindrical portion 21. While separating, the bottom 22 of the second intermediate material 19 is punched out. As a result, as shown in FIG. 5D, the outer ring intermediate material 24 is obtained from the large-diameter side cylinder part 20, and the inner ring intermediate material 25 is obtained from the small-diameter side cylinder part 21.

  Then, after the outer ring intermediate material 24 and the inner ring intermediate material 25 are taken out from the forging machine, a cold rolling process using a roll former is applied as a diameter expansion and raceway surface forming process to constitute the radial ball bearing 1. The outer ring 2 and the inner ring 3 are used. Specifically, the diameter of the intermediate material 24 for the outer ring and the intermediate material 25 for the inner ring is enlarged using a molding roll and a mandrel (not shown), and the inner portion in the axial direction of the intermediate material 24 for the outer ring is expanded. An outer ring raceway 5 having a circular arc cross section is formed on the peripheral surface, and an inner ring raceway 6 having a circular arc cross section is formed on the outer peripheral surface of the intermediate portion 25 in the axial direction of the inner ring intermediate material 25. As a result, the outer ring 2 and the inner ring 3 as shown in FIG. In addition, after performing such a cold rolling process, in order to remove the oxidized layer and decarburized layer on the surface caused by hot forging (and annealing), a turning process using a general cutting tool or the like is performed, Finish the entire surface. A locking groove for locking the outer peripheral edge of the sealing plate may be formed simultaneously on the inner peripheral surface of the outer ring intermediate material 24 by the cold rolling process.

  In the case of the prior art having the processing steps as described above, there is a possibility that a defect portion is generated on the outer peripheral surface of the inner ring 3 due to burrs. In this way, the defective portion generated on the outer peripheral surface of the inner ring 3 is the axial direction of the cylindrical material 8 generated when the metal wire or bar is cut to obtain the cylindrical material 8. Caused by burrs on the outer edge of the edge. And, when such a defective portion occurs in the inner ring raceway 6 portion or the boundary portion 26 between the inner ring raceway 6 and the cylindrical surface portion adjacent to the inner ring raceway 6 in the outer peripheral surface of the inner ring 3, Since the radial ball bearing 1 is assembled, it causes a decrease in rolling accuracy and durability.

For this reason, conventionally, during the turning process performed after the cold rolling process, the defective part generated in the inner ring raceway 6 part or the boundary part 26 has been removed (scraped) simultaneously with the oxide layer or the like. However, the turning process performed on the outer peripheral surface of the inner ring 3 is performed using a general-purpose cutting tool having a complicated cutting edge shape in which the cutting edge surface matches the generatrix shape of the outer peripheral surface of the inner ring 3. For this reason, when the defective part which arose in the said inner ring track | orbit 6 part or the said boundary part 26 was scraped off, the problem that it became easy to lose | delete a cutting edge occurred. In addition, the burr | flash which generate | occur | produces in the axial direction edge part outer periphery of the said column-shaped raw material 8 is hot with a horizontal (multistage feed type) forging machine compared with the case where a cutting process is performed cold with a vertical forging machine. If you do it, you will get bigger. This is because the hardness of the material (metal wire or bar) is lowered and the ductility is increased, and the depth of the defect portion due to the squeezing is increased, and the cutting edge is likely to be damaged early. In addition, the time required for the turning process becomes longer, and it is necessary to prepare a plurality of alternative tools, which causes a decrease in processing efficiency and an increase in processing cost.
Hereinafter, a process in which burrs generated on the outer peripheral edge of the columnar material 8 in the axial direction end will appear as defects in the boundary portion 26 by swallowing the burrs will be described with reference to FIGS. Will be described. Of the black circle portions attached to these drawings, the black circle portions shown in FIG. 5A indicate burrs, and the other black circle portions indicate the positions of defective portions based on the burrs.

The burrs generated on the outer peripheral edge of the cylindrical material 8 in the axial direction are crushed by the subsequent upsetting process, and as shown in FIGS. 5B and 6A, the first intermediate A defect portion appears in the radial intermediate portion of the axial end surfaces of the material 9. The defect portion appearing on the end surface in the axial direction of the first intermediate material 9 has an annular shape, and its diameter d ₉ is the same as or slightly larger than the outer diameter D ₈ of the cylindrical material 8 (d ₉ ≧ D ₈ ). Further, the molding hole 15 of the die 10 to be used for subsequent molding step, smaller than the inner diameter _{r 13} of the inner peripheral surface side small-diameter portion _{13 (d 9 <r 13)} .

  For this reason, in the molding process, the defect portion that appears on one end surface in the axial direction of the first intermediate material 9 is not supported by the inner stepped portion 14 provided on the inner peripheral surface of the molding hole 15. As shown in FIG. 6B, as the molding process proceeds, the inner surface side small diameter portion 13 is pushed into the inner diameter side and contacts the inner peripheral surface of the inner peripheral surface side small diameter portion 13. At the time of hot forging, the friction coefficient of the contact portion between the die (die 10) and the workpiece (first intermediate material 9) becomes considerably high. Therefore, until the molding process is completed, the amount of relative displacement of the defective portion in contact with the inner peripheral surface of the inner peripheral surface side small-diameter portion 13 with respect to the inner peripheral surface is small. For this reason, the second intermediate material 19 is made from the first intermediate material 9 in a state where the defective portion is kept in contact with the inner peripheral surface of the inner peripheral surface side small diameter portion 13. Therefore, as shown in FIG. 5 and FIG. 6C, the small diameter side cylinder which is a portion corresponding to the inner peripheral surface of the inner peripheral surface side small diameter portion 13 in the second intermediate material 19. A defective portion appears in the axially intermediate portion of the outer peripheral surface of the portion 21. As a result, after the subsequent separation / punching step and diameter-expansion / track surface forming step, as shown in FIG. 5 (E), the boundary portion 26 to the inner ring track 6 of the outer peripheral surface of the inner ring 3 are formed. , Defects appear due to engulfing burrs.

  On the other hand, with respect to the defective portion appearing on the other axial end surface of the first intermediate material 9, the outer peripheral surface side small diameter portion 16 of the punch 11 is pushed into the inner diameter side during the forming step. With the progress, the outer peripheral surface side small diameter portion 16 and the medium diameter portion 18 of the punch 11 are brought into contact with a continuous step surface. For this reason, in the second intermediate material 19 obtained after the molding step, the small-diameter side cylinder portion 21, which is a portion corresponding to the stepped surface where the outer peripheral surface side small-diameter portion 16 and the medium-diameter portion 18 of the punch 11 are continuous. A defect appears on the other axial end surface. As a result, a defect portion appears on the other end surface in the axial direction of the inner ring 3 as shown in FIG. In this way, the defective portion appearing on the other axial end surface of the inner ring 3 can be easily removed using a single-edged cutting tool or the like having a flat blade edge shape during the turning process performed after the cold rolling process. . For this reason, the problem of a chip | tip defect | deletion as mentioned above does not arise. Moreover, regarding the other end surface in the axial direction, even if a defective portion remains, it is unlikely to cause a deterioration in rolling accuracy and durability. As described above, only the defective portion generated in the inner ring raceway 6 portion or the boundary portion 26 of the inner ring 3 is problematic among the two types of defective portions appearing on the surface of the inner ring 3.

  Incidentally, in order to prevent a defective part from appearing in the inner ring raceway 6 part or the boundary part 26 due to burrs, for example, the axial end face of the cylindrical material 8 obtained by the cutting process is turned. It is also conceivable to remove burrs generated on the outer peripheral edge of the axial end of the columnar material 8 in advance. However, in this case, a new process only for removing burrs will be interrupted between the shearing process and the upsetting process, and the flow of the entire processing process will be worsened (the cycle time will be longer). ), Which reduces processing efficiency, and is not preferable.

JP-A-11-257357 Japanese Patent Laid-Open No. 11-244983

In view of the circumstances as described above, the present invention is to allow a defect portion based on a burr generated on an outer peripheral edge of an axial end portion of a cylindrical material to exist only on an axial end surface of an inner ring or an outer ring that can be easily removed. This invention was invented to realize a method for manufacturing a bearing ring for a rolling bearing.

The present invention includes an outer ring having an outer ring raceway formed over the entire circumference in the axially intermediate portion of the inner peripheral surface, an inner ring formed with an inner ring track extending over the entire circumference in the axially intermediate portion of the outer peripheral surface, Rolling bearing track comprising a single material for the outer ring and the inner ring, constituting a rolling bearing comprising a plurality of rolling elements provided between the inner ring raceway and the outer ring raceway. The wheel manufacturing method includes a cutting process, an upsetting process, a molding process, and a separation / punching process.
In these cutting processes, a metal wire or bar is cut into a predetermined length to obtain a cylindrical material.
In the upsetting step, the columnar material is compressed in the axial direction to form a disk-shaped first intermediate material.
In the molding step, the first intermediate material is formed in a receiving mold, and an inner circumferential surface side large diameter portion located on the opening side and an inner circumferential surface side small diameter portion located on the bottom side are formed as inner step portions. In the molding hole that is continuous with the outer peripheral surface side small diameter portion on the distal end side, the outer peripheral surface side large diameter portion on the proximal end side, and the intermediate diameter between the outer peripheral surface side small diameter portion and the outer peripheral surface side large diameter portion. This is a hot forging process in which the respective parts are pushed in the axial direction by a pressing die having the respective parts. As a result, the stepped bottomed cylindrical shape has stepped portions at the axially intermediate portions of both the inner and outer peripheral surfaces, with one axial side as the large-diameter side cylindrical portion and the other side as the small-diameter side cylindrical portion. Two intermediate materials.
In the separation / punching step, the second intermediate material is separated into the large diameter side cylindrical portion and the small diameter side cylindrical portion at the boundary position between the large diameter side cylindrical portion and the small diameter side cylindrical portion, The bottom of the second intermediate material is punched out. Separation and punching may be performed simultaneously or before and after. In any case, the portion obtained from the large-diameter side cylindrical portion is used as the intermediate material for the outer ring, and the portion obtained from the small-diameter side cylindrical portion is used as the intermediate material for the inner ring.

In particular, in the method for manufacturing a bearing ring for a rolling bearing according to claim 1, the diameter of the portion corresponding to the outer peripheral edge of the cylindrical material in the axial direction of the axial end surface of the first intermediate material. Is made smaller than the inner diameter of the inner peripheral surface side small diameter portion of the molding hole of the receiving mold.
Then, a molding process for making the second intermediate material from the first intermediate material, a portion corresponding to the axial end outer peripheral edge of the cylindrical material within the axial end surface of the first intermediate material, Defects based on burrs generated on the outer circumferential edge of the cylindrical material in the axial direction of the cylindrical material, while making contact with the bottom surface of the molding hole, the axial direction of the small-diameter side cylindrical portion constituting the second intermediate material Located on the end face.

Moreover, in the manufacturing method of the bearing ring for rolling bearings described in claim 3, the diameter of the portion corresponding to the outer peripheral edge of the cylindrical material in the axial direction of the axial end surface of the first intermediate material. Is made larger than the inner diameter of the inner peripheral surface side small diameter portion of the receiving mold forming hole and smaller than the inner diameter of the inner peripheral surface side large diameter portion.
Then, a molding process for making the second intermediate material from the first intermediate material, a portion corresponding to the axial end outer peripheral edge of the cylindrical material within the axial end surface of the first intermediate material, Defects based on burrs generated on the outer peripheral edge of the columnar material in the axial direction are carried out while abutting against the inner stepped portion provided on the inner peripheral surface of the molding hole , and the second intermediate material is replaced with the second intermediate material. It is located on the end surface in the axial direction of the large-diameter side cylindrical portion to be configured.

Moreover, when implementing the manufacturing method of the bearing ring for rolling bearings described in Claim 1 mentioned above, Preferably, as described in Claim 2, in the said upsetting process, a disk-shaped main-body part and this main body A first intermediate material is formed which includes a protrusion having a diameter smaller than that of the main body provided in a state of protruding in the axial direction at a central portion in the radial direction of the portion. And the said formation process is performed, making the axial direction end surface of the protrusion of this 1st intermediate material contact | abut to the bottom face of the said hole for shaping | molding.

Moreover, when implementing the manufacturing method of the bearing ring for rolling bearings described in any one of Claims 1 to 3 described above, for example, as described in Claim 4, the cutting step is performed using a metal. This is done by applying shearing to the wire or rod.

According to the method for manufacturing a bearing ring for a rolling bearing according to the present invention configured as described above, it is easy to remove a defect caused by a burr generated on the outer peripheral edge of an axial end of a cylindrical material. Even if it remains, it can be present only on the end face in the axial direction of the inner ring or outer ring, which hardly deteriorates the performance of the rolling bearing.
That is, in the manufacturing method of the bearing ring for rolling bearings according to claim 1, it corresponds to the outer peripheral edge of the axial end portion of the cylindrical material, which is positioned on the axial end surface of the first intermediate material by the upsetting process. The forming step is performed while bringing the portion to be formed, that is, the defect portion based on the burr generated on the outer peripheral edge of the axial end portion of the cylindrical material into contact with the bottom surface of the forming hole. For this reason, the second intermediate material can be made from the first intermediate material while the defective portion is kept in contact with the bottom surface. Therefore, in the second intermediate material, the defective portion can be positioned on the axial end surface of the small-diameter side cylinder portion, which is a portion corresponding to the bottom surface of the molding hole. As a result, the defect portion can be finally positioned on the axial end surface of the inner ring through a separation / punching process and the like performed thereafter.

Moreover, in the manufacturing method of the bearing ring for rolling bearings according to claim 3, it corresponds to the outer peripheral edge of the axial end portion of the cylindrical material, which is positioned on the axial end surface of the first intermediate material by the upsetting process. The molding step is performed while a defect portion based on the burr generated on the outer peripheral edge of the axial end portion of the columnar material is brought into contact with the inner stepped portion provided on the inner peripheral surface of the molding hole. For this reason, the second intermediate material can be made from the first intermediate material in a state where the defective portion is kept in contact with the inner step surface. Therefore, in the second intermediate material, the defective portion can be positioned on the axial end surface of the large-diameter side cylindrical portion, which is a portion corresponding to the inner stepped portion of the molding hole. As a result, the defect portion can be finally positioned on the axial end surface of the outer ring through a separation / punching process and the like performed thereafter.

Note that the outer peripheral edge of the columnar material in the axial direction is present on the end surface opposite to the axial end surface of the first intermediate material to be brought into contact with the bottom surface (or the inner stepped portion) of the molding hole. The portion corresponding to (defect portion) can be located on the end surface in the axial direction of the inner ring, as in the case of the above-described prior art.
As described above, in any of the inventions according to claim 1 and claim 3, the hot friction forging utilizes the fact that the friction coefficient of the contact portion between the receiving die and the first intermediate material is increased. The position of the defective portion due to the burrs can be restricted to the end face in the axial direction of the finally obtained inner ring or outer ring. For this reason, since the operation of removing the defective portion can be easily performed using a flat blade tool or the like, it is possible to prevent a problem that the cutting edge of the complete tool is lost. As a result, it is possible to improve the machining efficiency of the rolling bearing race and reduce the machining cost.

According to the method for manufacturing a bearing ring for a rolling bearing according to claim 2, the axial end face (tip face) of the protrusion is formed into the forming hole at the initial stage of the forming process (immediately after the pressing by the pressing die). Can be brought into contact with the bottom surface. For this reason, the defect part based on a burr | flash which existed in the axial direction end surface of this protrusion part can be reliably located in the axial direction end surface of the inner ring finally obtained.
In addition, according to the method for manufacturing a bearing ring for rolling bearings according to claim 4, since the burr generated on the outer peripheral edge of the axial end portion of the columnar material becomes large, the effect when the present invention is implemented becomes more remarkable. can get.

[First example of embodiment]
1 and 2 show a first example of an embodiment of the present invention corresponding to claims 1, 2, and 4, respectively. The feature of this example is that the shape of the first intermediate material 9a obtained by the upsetting process is devised, and the subsequent molding process is performed by forming the end face in the axial direction of the first intermediate material 9a on the die 10. The point is that the contact is made in contact with the bottom surface 23 of the service hole 15. Other processes are the same as those in the prior art shown in FIGS. The structure of the pair of dies 10 and punches 11 used in the molding process is the same as in the case of the prior art described above. Accordingly, the following description will focus on the process that is the feature of this example and the shape of the first intermediate material 9a. The black circles in FIGS. 1 and 2 indicate the positions of burrs or defective parts based on the burrs, as in the case shown in FIGS.

In the case of this example, a cylindrical material 8 as shown in FIG. 1A obtained by subjecting a wire or rod made of high carbon chromium bearing steel (SUJ2) to hot shearing is used. Then, the first intermediate material 9a as shown in (B) is obtained by performing an upsetting process that compresses in the axial direction with heat. In the case of this example, the first intermediate material 9a is made to be more discreet than the main body 27 provided in a state of protruding in the axial direction at the disk-shaped main body 27 and the radial center of the main body 27. A small-diameter projection 28 is formed. In the case of this example, the outer diameter D ₂₇ of the main body 27 is larger than the inner diameter r ₁₃ of the inner peripheral surface side small diameter portion 13 of the die 10 used in the molding process, and the inner peripheral surface side large diameter portion 12. It regulates so as to be smaller than the inner diameter _{r 12} of the _{(r 13 <D 27 <r} 12). Further, the outer diameter D ₂₈ of the protrusion 28 is restricted so as to be smaller than the inner diameter r ₁₃ of the inner peripheral surface side small diameter portion 13 (D ₂₈ <r ₁₃ ). In the case of this example, the axial dimension L ₂₈ of the protrusion 28 is smaller than the axial depth L _{13 of the} inner peripheral surface side small diameter part 13 (L ₂₈ <L ₁₃ ).

In the case of this example, in order to form the first intermediate material 9a having the shape as described above, the upsetting process is performed around the cylindrical material 8 and the shape of the inner peripheral surface is a stepped shape. This is done with the mold placed. In other words, the outer circumferential surface on one end side in the axial direction of the cylindrical material 8 is loosely inserted into the center of the portion of the inner circumferential surface of the mold where the inner diameter is reduced, and the other axial end of the cylindrical material 8 is Upsetting is performed in a state where a portion having a large inner diameter is arranged around the side outer peripheral surface. And in the radial direction intermediate part of the axial direction end surface of the said protrusion 28, the part equivalent to the axial direction edge part outer periphery of the said columnar raw material 8, ie, the axial direction edge part outer peripheral part of this cylindrical material 8, A defect portion based on the generated burr is located. In this way, the defective portion appearing on the axial end surface of the protrusion 28 is annular, and its diameter d _9a is the same as or slightly the same as the outer diameter D ₈ of the cylindrical material ₈ {see FIG. 5A). (D _9a ≧ D ₈ ).

  In the case of this example, in order to obtain the second intermediate material 19 from the first intermediate material 9a having the above-described configuration, as shown in FIGS. The material 9a is inserted into the molding hole 15 of the die 10 from the protrusion 28 side. Then, the side surface (one axial end surface) of the main body portion 27 constituting the first intermediate material 9 a is brought into contact with the inner stepped portion 14 provided on the inner peripheral surface of the molding hole 15. And the punch 11 is pushed in from the axial direction other end side of the said 1st intermediate material 9a similarly to the case of the prior art mentioned above. As a result, the axial end surface (tip surface) of the projection 28 is brought into contact with the bottom surface 23 of the molding hole 15 in the initial stage of the molding process.

  As described above, in the case of this example, at the initial stage of the molding process, a portion corresponding to the outer peripheral edge of the columnar material 8 in the axial direction, which is present on the axial end surface of the protrusion 28, that is, The defect portion based on the burr generated at the outer peripheral edge of the axial end portion of the columnar material 8 can be brought into contact with the bottom surface 23 of the molding hole 15. As described above, at the time of hot forging, the friction coefficient of the contact portion between the die 10 and the first intermediate material 9a becomes considerably high. The amount of the relative displacement of the defective portion present in the direction end surface with respect to the bottom surface 23 of the molding hole 15 is small. Therefore, in the case of this example, the first intermediate material 9a to the second intermediate material with the defective portion existing on the axial end surface of the protrusion 28 kept in contact with the bottom surface 23. 19 can be made. Therefore, in the second intermediate material 19, the defective portion can be positioned on one end surface in the axial direction of the small diameter side cylindrical portion 21, which is a portion corresponding to the bottom surface 23 of the molding hole 15. Accordingly, one end surface in the axial direction of the inner ring intermediate material 25 after the separation / punching process shown in FIG. 1D, and further, the inner ring 3 after the diameter expansion / track surface forming process shown in FIG. Defects caused by burrs can be located on one end surface in the axial direction.

  In addition, about the defect part which appeared in the axial direction other end surface of the said 1st intermediate material 9a, as shown to (A)-> (C) of FIG. The outer peripheral surface side small diameter portion 16 of the punch 11 is pushed into the inner diameter side, and the step surface provided between the outer peripheral surface side small diameter portion 16 and the intermediate diameter portion 18 of the punch 11 is brought into contact with the progress of the molding process. Touch. For this reason, also in the case of this example, the defective part which appeared on the other end surface in the axial direction of the first intermediate material 9a is positioned on the other end surface in the axial direction of the small diameter side cylindrical portion 21 in the second intermediate material 19. I can do things. For this reason, a defect portion can be positioned on the other axial end surface of the inner ring 3 as shown in FIG. 1 (E) through the subsequent separation / punching step and diameter expansion / track surface forming step.

  As described above, in the case of this example, the defect portion based on the burr generated on the outer peripheral edge of the columnar material 8 in the axial direction can be positioned on both axial end surfaces of the inner ring 3. For this reason, after performing the cold rolling process, it is possible to easily remove the defective portions existing on both end faces in the axial direction of the inner ring 3 by a turning process using a single-edged cutting tool or the like. As in the case of the prior art described above, since there is no occurrence of a defective portion in the inner ring raceway 6 or the boundary portion 26, it is not necessary to scrape the defective portion with a total shape tool. For this reason, it is possible to effectively prevent the problem that the cutting edge of the total shape tool is lost. Furthermore, even if a defective portion remains on the axial end surface of the inner ring 3, it is difficult to cause a problem in the performance (rolling accuracy and durability) of the rolling bearing including the inner ring 3.

In particular, in the case of this example, since the columnar material 8 is obtained by hot shearing, large burrs are likely to occur on the outer peripheral edge of the columnar material 8 in the axial direction. However, in the case of this example, as described above, since the defective portion due to the burrs can be positioned only on the end surface in the axial direction of the inner ring 3, along with the removal operation of this defective portion, The blade tip is not lost early.
Therefore, according to this example, it is possible to improve the machining efficiency of the rolling bearing race and reduce the machining cost.

[Second Example of Embodiment]
FIG. 3 shows a second example of an embodiment of the present invention corresponding to claims 3 and 4. The feature of this example is that the molding process is performed while bringing the defective portion appearing on the axial end surface of the first intermediate material 9b into contact with the inner stepped portion 14 provided on the inner peripheral surface of the molding hole 15. . Other steps and structures are substantially the same as those in the first example of the embodiment described above and the prior art described above. Therefore, overlapping description and illustration are omitted, and hereinafter, the characteristic part of this example will be mainly described. Explained.

In the case of this example, as shown in FIG. 3A, as the first intermediate material 9b, the diameter d _9b of the defect portion that appeared on the axial end surface is the same as that in the case of the first example of the above-described embodiment. The diameter d _{9a of the} defective portion appearing in the first intermediate material 9a (see (B) in FIG. 1, (A) in FIG. 2) is made larger (d _9b > d _9a ). Specifically, the diameter d _9b is made larger than the inner diameter r ₁₃ (see FIG. 2B) of the inner peripheral surface side small-diameter portion 13 of the die 10 used in the molding step described later, and the inner periphery is smaller than the inner diameter _{r 12} of the side large-diameter portion 12 {shown in FIG. 2 (B) _{see} (r 13 <d 9b <} r 12).

As described above, the method for regulating the diameter d _{9b of the} defect portion appearing on the axial end surface of the first intermediate material 9b is not particularly limited. For example, the metal used in the case of the first example of the embodiment described above. This can be realized by using a material having a diameter larger than that of a wire rod or bar made of metal. Alternatively, in the upsetting process, the lubricant supplied between the pressing die used for compressing the columnar material 8 in the axial direction and the axial end surface of the columnar material 8 is more than in the case of the first example. It can also be realized by increasing the number, or changing to one having better lubricity. That is, by reducing the coefficient of friction between the pressing die and the axial end surface of the cylindrical material 8, the diameter of the axial end surface itself of the cylindrical material 8 is increased.

In the case of this example using the first intermediate material 9b having the above-described configuration, the defect portion that appears on one end surface in the axial direction of the first intermediate material 9b is used for forming the die 10 in the subsequent forming process. It is made to contact | abut to the inner side level | step-difference part 14 provided in the internal peripheral surface of the hole 15. FIG. Then, as in the case of the above-described prior art, the punch 11 is pushed in from the other axial end side of the first intermediate material 9b. In this case, at the time of hot forging, the friction coefficient of the contact portion between the die 10 and the first intermediate material 9b becomes considerably high. Therefore, the shaft of the first intermediate material 9b is not processed until the molding process is completed. Of the one end surface in the direction, the amount of relative displacement of the defective portion in contact with the inner stepped portion 14 relative to the inner stepped portion 14 is small. For this reason, the second intermediate material 19 is made from the first intermediate material 9b in a state where the defective portion existing on one end surface in the axial direction of the first intermediate material 9b is kept in contact with the inner stepped portion 14. I can do things. Therefore, in the second intermediate material 19, the defective portion may be located on one end surface in the axial direction of the large-diameter side cylindrical portion 20, which is a portion corresponding to the inner stepped portion 14 of the molding hole 15. it can. Therefore, as in the case of the first example described above, by performing the separation / punching step and the diameter expansion / track surface forming step, a defective portion caused by burring in one end surface in the axial direction of the outer ring 2 is formed. Can be positioned.

  In the case of this example as well, as in the case of the first example of the above-described embodiment and the above-described prior art, the defective portion that appears on the other end surface in the axial direction of the first intermediate material 9b is finally removed. The inner ring 3 can be positioned on the other axial end surface. Therefore, in this example, the defect part based on the burr | flash which generate | occur | produced in the axial direction edge part outer periphery of the said column-shaped raw material 8 is located in the axial direction one end surface of the outer ring | wheel 2, and the axial direction other end surface of the inner ring | wheel 3. You can make it. For this reason, after performing the cold rolling process, the defective portion located on the axial end surfaces of the outer ring 2 and the inner ring 3 can be easily removed by a turning process using a single-blade tool or the like. Therefore, even in this example, since there is no occurrence of a defective portion in the inner ring raceway 6 and the boundary portion 26, it is not necessary to remove burrs using the total shape bit, and the cutting edge of the total shape bit is lost. Then, it is possible to effectively prevent the problem described above from occurring. In the case of this example, it is also possible to remove the defective portion at the same time in a state where the inner ring 3 is arranged on the inner diameter side of the outer ring 2.

In the case of this example, as described above, in order to obtain the first intermediate material 9b, it is necessary to use a wire or rod having a large diameter or to devise a lubricant to be used. Even when the method is adopted, the cost increases compared to the case of the first example of the embodiment described above. That is, the time required for the cutting process becomes longer, and the cost required for the lubricant increases. However, in the case of this example as well, it is possible to prevent the cutting edge of the overall cutting tool from being lost, so that the machining cost can be reduced compared to the case of the above-described conventional technique.
Other processes and obtained actions and effects are the same as those of the first example of the embodiment described above and the above-described conventional technique.

  In each of the above-described prior art and each of the above-described embodiments, only a single row deep groove type radial ball bearing has been described as an example of a rolling bearing. However, the present invention is not limited to such a ball. It is not limited to bearings. For example, the present invention can also be implemented when manufacturing an outer ring and an inner ring that constitute a cylindrical roller bearing, a tapered roller bearing, or the like.

Sectional drawing which shows the manufacturing process of the 1st example of embodiment of this invention. Sectional drawing which shows typically the implementation condition of a formation process similarly. The figure similar to FIG. 2 which shows the 2nd example of embodiment of this invention. The partial cut perspective view which shows an example of the radial ball bearing which incorporated the inner ring | wheel and outer ring | wheel used as the object of the manufacturing method by this invention. The figure similar to FIG. 1 which shows the conventional process process. The same figure as FIG.

DESCRIPTION OF SYMBOLS 1 Radial ball bearing 2 Outer ring 3 Inner ring 4 Ball 5 Outer ring raceway 6 Inner ring raceway 7 Cage 8 Cylindrical material 9, 9a, 9b First intermediate material 10 Die 11 Punch 12 Inner surface side large diameter part 13 Inner surface side small diameter Part 14 Inner step part 15 Molding hole 16 Outer peripheral surface side small diameter part 17 Outer peripheral surface side large diameter part 18 Medium diameter part 19 Second intermediate material 20 Large diameter side cylindrical part 21 Small diameter side cylindrical part 22 Bottom part 23 Bottom face 24 Middle for outer ring Material 25 Intermediate material for inner ring 26 Boundary part 27 Body part 28 Projection part

Claims (4)

An outer ring having an outer ring raceway formed in the axially intermediate portion of the inner peripheral surface over the entire circumference, an inner ring having an inner ring raceway formed in the axially intermediate portion of the outer peripheral surface over the entire circumference, the inner ring raceway and the above-described A method for manufacturing a bearing ring for a rolling bearing, comprising a rolling bearing having a plurality of rolling elements provided between the outer ring raceway and a plurality of rolling elements, wherein the outer ring and the inner ring are made of a single material. Because
A cutting step of cutting a metal wire or bar into a predetermined length by cutting it into a predetermined length;
This columnar material is axially compressed into a disk-shaped first intermediate material,
This first intermediate material is formed in a receiving mold, and a molding hole in which an inner peripheral surface side large diameter portion positioned on the opening side and an inner peripheral surface side small diameter portion positioned on the bottom side are continuously connected by an inner stepped portion. Inside, the outer peripheral surface side small diameter portion on the distal end side and the outer peripheral surface side large diameter portion on the proximal end side are axially directed by a die having an intermediate diameter portion between the outer peripheral surface side small diameter portion and the outer peripheral surface side large diameter portion. Stepped bottom cylindrical shape with stepped portions at the axially intermediate portions of the inner and outer peripheral surfaces, with one axial side as the large-diameter side cylindrical portion and the other side as the small-diameter side cylindrical portion. A molding process that is a hot forging process with two intermediate materials;
The second intermediate material is separated into the large diameter side cylindrical portion and the small diameter side cylindrical portion at the boundary position between the large diameter side cylindrical portion and the small diameter side cylindrical portion, and the bottom portion of the second intermediate material is punched out. A part obtained from the large-diameter side cylinder part is an intermediate material for the outer ring, and a part obtained from the small-diameter side cylinder part is an intermediate material for the inner ring, and has a separation / punching step,
Of the axial end surface of the first intermediate material, the diameter of the portion corresponding to the outer peripheral edge of the cylindrical material in the axial direction is defined as the inner diameter of the inner peripheral surface side small-diameter portion of the receiving hole of the receiving mold. and smaller than, equivalent to molding process for making the second intermediate material from the first intermediate material, in the axial end outer peripheral edge of the cylindrical material within the axial end surface of the first intermediate material The small-diameter side cylinder that constitutes the second intermediate material is a defect portion based on burrs generated on the outer peripheral edge of the columnar material in the axial direction. Of rolling bearing raceway ring , which is positioned on the axial end face of the part . The upsetting process forms a first intermediate material consisting of a disc-shaped main body and a protrusion having a smaller diameter than the main body provided in the axially protruding central portion of the main body. The method for manufacturing a bearing ring for a rolling bearing according to claim 1, wherein the forming step is performed while the axial end surface of the protrusion of the first intermediate material is brought into contact with the bottom surface of the forming hole. An outer ring having an outer ring raceway formed in the axially intermediate portion of the inner peripheral surface over the entire circumference, an inner ring having an inner ring raceway formed in the axially intermediate portion of the outer peripheral surface over the entire circumference, the inner ring raceway and the above-described A method for manufacturing a bearing ring for a rolling bearing, comprising a rolling bearing having a plurality of rolling elements provided between the outer ring raceway and a plurality of rolling elements, wherein the outer ring and the inner ring are made of a single material. Because
A cutting step of cutting a metal wire or bar into a predetermined length by cutting it into a predetermined length;
This columnar material is axially compressed into a disk-shaped first intermediate material,
This first intermediate material is formed in a receiving mold, and a molding hole in which an inner peripheral surface side large diameter portion positioned on the opening side and an inner peripheral surface side small diameter portion positioned on the bottom side are continuously connected by an inner stepped portion. Inside, the outer peripheral surface side small diameter portion on the distal end side and the outer peripheral surface side large diameter portion on the proximal end side are axially directed by a die having an intermediate diameter portion between the outer peripheral surface side small diameter portion and the outer peripheral surface side large diameter portion. Stepped bottom cylindrical shape with stepped portions at the axially intermediate portions of the inner and outer peripheral surfaces, with one axial side as the large-diameter side cylindrical portion and the other side as the small-diameter side cylindrical portion. A molding process that is a hot forging process with two intermediate materials;
The second intermediate material is separated into the large diameter side cylindrical portion and the small diameter side cylindrical portion at the boundary position between the large diameter side cylindrical portion and the small diameter side cylindrical portion, and the bottom portion of the second intermediate material is punched out. A part obtained from the large-diameter side cylinder part is an intermediate material for the outer ring, and a part obtained from the small-diameter side cylinder part is an intermediate material for the inner ring, and has a separation / punching step,
Of the axial end surface of the first intermediate material, the diameter of the portion corresponding to the outer peripheral edge of the cylindrical material in the axial direction is defined as the inner diameter of the inner peripheral surface side small-diameter portion of the receiving hole of the receiving mold. more, and, to be smaller than the inner diameter of the inner peripheral surface side large diameter portion, the molding process for making the second intermediate material from the first intermediate material, the axial end face of the first intermediate material The portion corresponding to the outer peripheral edge of the columnar material in the axial direction is brought into contact with the inner stepped portion provided on the inner peripheral surface of the molding hole, and the axial direction of the columnar material is A manufacturing method of a bearing ring for a rolling bearing , wherein a defect portion based on a burr generated on an outer peripheral edge of an end portion is positioned on an axial end surface of the large-diameter side cylindrical portion constituting the second intermediate material . The manufacturing method of the bearing ring for rolling bearings described in any one of Claims 1-3 which performs a cutting process by giving a shearing process to metal wires or rods.

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