JP2008279486A - Method for manufacturing outer ring for rolling bearing, and rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an outer ring for rolling bearing by which a rolling-formation is attained in a large diameter-enlarging ratio without causing crack in a ring-like base stock and a high precise outer ring for rolling bearing can stably be formed in a high yield, and to provide the rolling bearing. <P>SOLUTION: The outer ring 10 for bearing is manufactured through: a process for forming the ring-like base stock 11 with a forging; a first rolling-forming process for enlarging the diameter of the ring-like base stock 11 as rectangular cross section into a prescribed outer diameter D2; and a second rolling-forming process for forming an orbital groove 16 to an intermediate treated ring-like base stock 11A whose diameter is enlarged. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an outer ring for a rolling bearing and a rolling bearing, and more particularly to an improvement in a method for manufacturing an outer ring for a rolling bearing that expands the diameter by rolling and forms a raceway groove.

  The outer ring for a rolling bearing is formed into a ring-shaped material by hot forging, warm forging, or cold forging, and then the ring-shaped material is expanded in diameter by rolling, and the raceway is formed in the axially intermediate portion of the inner peripheral surface. A groove is formed, and further manufactured by cutting (see, for example, Patent Document 1). When the outer ring for rolling bearings is manufactured by such forging and rolling molding, the diameter of the cut-out portion at the time of forging can be made smaller than the inner diameter of the product, and the yield is improved. It is used.

  As shown in FIG. 5, the diameter expansion and the raceway grooves are formed at the same time by conventional rolling forming, and as shown in FIG. 5, forging is performed between a forming roll 1 and a mandrel 2 supported in parallel with each other and relatively rotatable. This is performed by pressing a part of the ring-shaped material 3 in the circumferential direction in the radial direction. In order to form the raceway groove 5 of the outer ring 4 for rolling bearings, the mandrel 2 has a ring-shaped convex part 6 having a generatrix shape approximate to the shape of the raceway groove 5 on a part of the outer peripheral surface.

Specifically, as shown in FIG. 5A, when the ring-shaped material 3 is loosely fitted to the mandrel 2 and rotated while pressing the mandrel 2 against the forming roll 1, the ring-shaped material 3 and The diameter of the forming groove 1 is increased while the forming roll 1 rotates and the raceway groove 5 is formed. At the initial stage of rolling molding, as shown in FIG. 5 (b), the ring-shaped material 3 is positioned at the axial center of the ring-shaped material 3 sandwiched between the ring-shaped convex portion 6 of the mandrel 2 and the molding roll 1. Only the diameter is expanded in a state where compressive stress is applied. When the shape of the ring-shaped convex portion 6 is almost transferred to the ring-shaped material 3, both end portions in the axial direction of the ring-shaped material 3 come into contact with both side portions of the ring-shaped convex portion 6 of the mandrel 2, and the outer ring for rolling bearings 4 is formed (see FIG. 5C).
JP 2006-181638 A

  According to the conventional rolling molding in which the above-described diameter expansion and raceway groove molding are performed simultaneously, as shown in FIG. 6, in the initial stage of rolling molding, the axial center portion (ring-shaped convex portion 6) of the ring-shaped material 3 is used. Compressive stress acts only on the portion sandwiched between the forming rolls 1 and the diameter of the ring-shaped convex portion 6 is expanded in a state where the compressive stress does not act on both axial portions. For this reason, cracks do not occur in the central region 3a in the axial direction of the ring-shaped material 3 that is expanded in diameter while compressive stress is applied, but both side regions 3b in the axial direction of the ring-shaped protrusion 6 are expanded. Since the diameter is expanded in a state where only the tensile stress associated with the diameter is applied, there is a problem that cracks are likely to occur. Therefore, molding cannot be performed under molding conditions having a large diameter expansion rate, and there is room for further improvement in order to improve the yield.

  Further, in the conventional rolling molding, since the binding force for determining the outer diameter dimension does not act on the outer peripheral surface of the ring-shaped material 3, the dimensional accuracy is low, and a large amount of cutting allowance is expected in the subsequent cutting process. There is a problem that the cutting cost becomes high as the yield decreases.

  The present invention has been made in view of the above-described problems, and its object is to enable rolling molding with a large diameter expansion rate without causing cracks in the ring-shaped material, and to provide a high-accuracy outer ring for a rolling bearing. It is an object of the present invention to provide a method of manufacturing an outer ring for a rolling bearing and a rolling bearing that can be stably molded with good yield.

The above object of the present invention is achieved by the following method.
(1) A method for manufacturing an outer ring for a rolling bearing having a cylindrical shape, having a raceway groove in an axially intermediate portion of an inner peripheral surface, and having a predetermined outer diameter,
Forming a ring-shaped material by forging;
A first rolling forming step of expanding the ring-shaped material to the predetermined outer diameter with a rectangular cross section;
A second rolling forming step of forming the raceway groove in the ring-shaped material;
The manufacturing method of the outer ring | wheel for rolling bearings characterized by providing.
(2) In the outer ring for a rolling bearing according to (1), in the second rolling forming step, the raceway groove is formed while constraining an outer peripheral portion of the ring-shaped material with a ring-shaped mold. Production method.
(3) A rolling bearing having an outer ring manufactured by the manufacturing method according to (1) or (2).

  The “outer ring for rolling bearing” referred to in the present invention includes those in which a post-process such as finishing is performed after the first and second rolling forming steps.

  According to the method for manufacturing an outer ring for a rolling bearing of the present invention, after the ring-shaped material is formed by forging, the ring-shaped material is expanded to a predetermined outer diameter with a rectangular cross section by the first rolling forming process. The diameter can be increased while compressive stress is applied to the entire region of the rectangular cross section. Thereby, generation | occurrence | production of a crack is suppressed and rolling shaping | molding with a big diameter expansion rate is attained.

  In addition, since the raceway groove is formed by the second rolling molding process on the ring-shaped material that has been expanded to the predetermined outer diameter by the first rolling molding process, the molding amount due to the pressing at the time of the raceway groove molding is reduced. Less and stable production is possible. In addition, since there is no diameter expansion in the second rolling molding process, the mandrel outer diameter can be increased to increase the rigidity, thereby improving the life of the mandrel and stabilizing the dimensional accuracy of the outer ring for the rolling bearing. To do.

  Also, in the second rolling molding process, if the raceway groove is molded while restraining the outer periphery of the ring-shaped material with a ring-shaped mold, it is possible to mold the outer ring for a rolling bearing with extremely high dimensional accuracy. This makes it possible to reduce the cutting process and reduce costs.

  Embodiments of a method for manufacturing an outer ring for a rolling bearing and a rolling bearing according to the present invention will be described below in detail with reference to the drawings.

  In the manufacturing method of the outer ring for a rolling bearing according to the present invention, after the ring-shaped material is only expanded in the first rolling forming step while maintaining the rectangular cross section, the second rolling forming step is performed without increasing the diameter of the raceway groove. A rolling bearing outer ring is manufactured only by molding.

  A ring-shaped material 11 for forming the outer ring 10 for a rolling bearing is prepared by forging a high carbon chrome bearing steel, a high speed steel, a stainless steel or the like by hot, warm, or cold forging. . The cross-sectional shape of the ring-shaped material 11 is rectangular, and its outer diameter D1 and inner diameter d1 are formed smaller than the outer diameter D2 and inner diameter d2 of the outer ring 10 for a rolling bearing that is a product.

  Such a ring-shaped material 11 is first subjected to only the diameter expansion with a rectangular cross section by the first rolling forming step. That is, as shown in FIG. 1, the ring-shaped material 11 is partially sandwiched between the first molding roll 12 and the first mandrel 13 that are supported in parallel and relatively rotatable. . Rectangular grooves 14 and 15 having substantially the same width as that of the outer ring 10 for rolling bearings are provided on the inner peripheral portion of the first forming roll 12 and the outer peripheral portion of the first mandrel 13, respectively.

  As shown in FIG. 2, when the first mandrel 13 is rotated against the first molding roll 12 while the ring-shaped material 11 is loosely fitted to the first mandrel 13, the ring-shaped material 11 and the first molding are formed. The roll 12 rotates with the rotation. As a result, the ring-shaped material 11 is expanded to an outer diameter approximate to the outer diameter D2 of the outer ring 10 for rolling bearings, and the intermediate-processed ring-shaped material 11A is formed.

  At this time, since the ring-shaped material 11 is expanded only in the rectangular cross section, the diameter can be expanded in a state where the compressive stress is applied to the entire area of the cross section, and therefore, the occurrence of cracks is greatly suppressed. Is done. For this reason, compared with the conventional rolling forming which shape | molds a diameter expansion and a raceway groove simultaneously, rolling shaping | molding with a large diameter expansion rate is attained, and production efficiency can be improved significantly.

  As described above, the intermediate-processed ring-shaped material 11A that has been expanded only to the predetermined outer diameter D2 with a rectangular cross section by the first rolling molding step is not subjected to the diameter expansion by the second rolling molding step. Only the molding of 16 is performed, and the outer ring 10 for a rolling bearing is manufactured.

  As shown in FIG. 3, the intermediate processing ring-shaped material 11 </ b> A whose diameter has been expanded with a rectangular cross section is fitted into a ring die 21 whose outer peripheral portion 17 is a ring-shaped mold, and the outer peripheral portion 17 is restrained. The second mandrel 23 is loosely fitted and set. The inner diameter of the ring die 21 has the same dimension as the outer diameter D2 of the outer ring 10 for a rolling bearing. On the outer peripheral portion of the second mandrel 23, a ring-shaped convex portion 24 having a generatrix shape that approximates the shape of the raceway groove 16 is formed in the central portion in the axial direction. In addition, since the second mandrel 23 performs only groove forming without increasing the diameter, the outer dimensions can be increased, and the outer diameter D4 of the second mandrel 23 is preferably the outer diameter D3 of the first mandrel 13. Is set larger than the inner diameter d1 of the ring-shaped material 11 formed by forging. As a result, the rigidity of the second mandrel 23 is increased, the life of the second mandrel 23 is improved, and the outer ring 10 for a rolling bearing can be manufactured with high accuracy. The outer peripheral portion 26 of the ring die 21 is backed up by contacting an auxiliary roll 22 that is supported in parallel and relatively rotatable with the second mandrel 23.

  As shown in FIG. 4, the intermediate processing ring-shaped material 11 </ b> A is fitted into the ring die 21, and the second mandrel 23 is pressed against the auxiliary roll 22 through the ring die 21 in a state of loosely fitting the second mandrel 23. When rotated while rotating, the intermediate processing ring-shaped material 11A, the ring die 21, and the auxiliary roll 22 rotate and the raceway groove 16 is formed on the inner peripheral portion of the intermediate processing ring-shaped material 11A.

  In the second rolling forming step, only the groove forming is performed without expanding the diameter, so that the tensile stress does not act on the intermediate-processed ring-shaped material 11A, and therefore no crack is generated. Further, the molding amount by pressing is small, and stable molding can be performed. Furthermore, since the intermediate-processed ring-shaped material 11A is groove-formed while the outer peripheral portion 17 is constrained by the ring die 21, it can be formed with high accuracy in both dimensional accuracy and roundness. Therefore, it is possible to reduce the conventional post-process cutting process and achieve a significant cost reduction.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. For example, the manufacturing method of the ring-shaped material is not particularly limited, and can be formed by any conventionally known method.

It is sectional drawing which shows the initial state of the 1st rolling shaping | molding process in which the ring-shaped raw material was clamped with the 1st shaping | molding roll and the 1st mandrel. It is sectional drawing which shows the completion state of the 1st rolling shaping | molding process by which the ring-shaped raw material was expanded in diameter with the rectangular cross section. It is sectional drawing which shows the initial state of the 2nd rolling shaping | molding process by which a raceway groove | channel is shape | molded by the intermediate process ring-shaped raw material expanded by the 1st rolling shaping | molding process. It is sectional drawing which shows the state by which the 2nd rolling shaping | molding process was complete | finished and the outer ring | wheel for rolling bearings was shape | molded. It is sectional drawing which shows the conventional rolling shaping | molding process in which diameter expansion and groove shaping are performed simultaneously along process order. It is VI section enlarged view in FIG.5 (b).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Outer ring | wheel 11 for rolling bearings Ring-shaped raw material 11A Intermediate processing ring-shaped raw material 16 Track groove 17 Outer peripheral part 21 of ring-shaped raw material Ring die (ring-shaped metal mold | die)
D2 Outer diameter of rolling bearing outer ring (predetermined outer diameter)

Claims (3)

A method for manufacturing an outer ring for a rolling bearing having a cylindrical shape, having a raceway groove in an axially intermediate portion of an inner peripheral surface, and having a predetermined outer diameter,
Forming a ring-shaped material by forging;
A first rolling forming step of expanding the ring-shaped material to the predetermined outer diameter with a rectangular cross section;
A second rolling forming step of forming the raceway groove in the ring-shaped material;
The manufacturing method of the outer ring | wheel for rolling bearings characterized by providing.   2. The method of manufacturing an outer ring for a rolling bearing according to claim 1, wherein in the second rolling forming step, the raceway groove is formed while restraining an outer peripheral portion of the ring-shaped material with a ring-shaped mold.   A rolling bearing comprising an outer ring manufactured by the manufacturing method according to claim 1.

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