Manufacturing method of bearing ring member

Abstract

To provide a method of manufacturing a bearing ring member capable of finely performing inversion machining of a work member.SOLUTION: A method of manufacturing a bearing ring member includes an inverting step for pinching a work member 10 having an annular work body portion 11 with a punch disposed on a first side S1 in an axial direction and a die disposed on a second side S2 on the opposite side to the first side S1, and deforming the work member 10 so that the work body portion 11 becomes a cylindrical shape. The inverting step includes: a first step for deforming the work member by the punch and the die while sliding is not generated between the work member 10 and the die, and a second step for deforming the work member by the punch and the die while sliding is generated between the work member 10 and the die, in this order.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a bearing ring member. [Background technology]

[0002] Patent Document 1 describes a method for manufacturing a ring member used in manufacturing inner or outer rings of bearings. In this manufacturing method, the ring member is formed through a process of clamping an annular workpiece member between a punch and a die and performing a reversal process to change the direction of the cross section by 90 degrees. Patent Documents 2 to 5 also describe the formation of ring members for bearings using a similar reversal process. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-341255 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-090407 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-097809 [Patent Document 4] Japanese Patent Application Laid-Open No. 2006-123003 [Patent Document 5] Japanese Patent Publication No. 2020-022987 Summary of the Invention [Problem to be solved by the invention]

[0004] In the manufacturing method described above, it may be difficult to perform the inversion process properly depending on the shape of the workpiece, such as when the workpiece is thin, has a large diameter or width, or has a flange.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for manufacturing a bearing ring member that allows for good reversal processing of a workpiece member. [Means for solving the problem]

[0006] The method for manufacturing a bearing ring member of the present invention includes an inversion process in which a workpiece having a circular workpiece main body portion is clamped between a punch arranged on a first side in the axial direction and a die arranged on a second side opposite the first side, and the workpiece main body portion is deformed so that it becomes cylindrical.The inversion process includes, in this order, a first process in which the workpiece is deformed by the punch and die while no slippage occurs between the workpiece and the die, and a second process in which the workpiece is deformed by the punch and die while slippage occurs between the workpiece and the die.

[0007] In this method for manufacturing a bearing ring member, the reversing process includes a first process in which the workpiece is deformed by a punch and a die while no slippage occurs between the workpiece and the die, and a second process in which the workpiece is deformed by the punch and a die while slippage occurs between the workpiece and the die. As a result, in the first process, no slippage occurs between the workpiece and the die, allowing the workpiece to be properly raised. Furthermore, in the second process, the workpiece slides on the die, preventing unintended deformation, such as bending of the workpiece. Therefore, this method for manufacturing a bearing ring member allows the workpiece to be properly reversed.

[0008] The bending moment acting on the workpiece in the first step may be smaller than the predicted value M of the limit bending moment of the workpiece body calculated by formula (1). In this case, no slippage occurs between the workpiece and the die in the first step, and the workpiece can be satisfactorily raised.

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[0009] In the second step, a second die different from the first die used in the first step may be used. In this case, by using different dies in the first and second steps, it is possible to achieve the above-mentioned good reversal processing.

[0010] The first die has a first die R surface formed in an arc shape, and the second die has a second die R surface also formed in an arc shape and an inclined surface formed on a second side of the second die R surface and inclined with respect to the axial direction, and in the first step, the first die R surface may come into contact with the workpiece, and in the second step, after the second die R surface has come into contact with the workpiece, the inclined surface may come into contact with the workpiece. In this case, in the second step, the workpiece can be slid on the inclined surface, thereby achieving the above-mentioned good reversal processing.

[0011] The first die has a cylindrical first die body, and the second die has a cylindrical second die body, and in the first step, the workpiece is sandwiched between the punch and the first die body, and in the second step, the workpiece is sandwiched between the punch and the second die body, and the diameter of the second die body may be smaller than the diameter of the first die body. In this case, the workpiece can slide easily on the second die in the second step, thereby achieving the above-mentioned good reversal processing.

[0012] In the first step, the workpiece may be sandwiched between the punch and the first die with the surface of the workpiece facing one of the first side and the second side, and in the second step, the workpiece may be sandwiched between the punch and the second die with the surface of the workpiece facing the other of the first side and the second side. In this case as well, the above-mentioned good reversal processing can be achieved.

[0013] The surface roughness of the second contact surface of the second die that comes into contact with the workpiece in the second step may be smaller than the surface roughness of the first contact surface of the first die that comes into contact with the workpiece in the first step. In this case, the workpiece can slide more easily on the second die in the second step, achieving the above-mentioned good reversal processing.

[0014] The Rockwell C scale hardness of the second contact surface of the second die, which comes into contact with the workpiece in the second step, may be greater than the Rockwell C scale hardness of the first contact surface of the first die, which comes into contact with the workpiece in the first step. In this case, the workpiece can more easily slide on the second die in the second step, thereby achieving the above-mentioned good reversal processing.

[0015] In the second step, the workpiece may be clamped between the punch and the die while being pushed radially toward the punch by the pushing member. In this case, the workpiece can slide easily on the die in the second step, achieving the above-described excellent reversal processing.

[0016] In the second step, a hook punch having a hook portion may be used, and the hook portion may be hooked onto the workpiece, so that the workpiece is sandwiched between the hook punch and the die. In this case, the workpiece can easily slide on the die in the second step, and the above-mentioned good reversal processing can be achieved.

[0017] The workpiece may further have an inner flange portion extending from a radial inner edge of the workpiece body portion to one side in the axial direction, and an outer flange portion extending from a radial outer edge of the workpiece body portion to one side in the axial direction. When the workpiece has such a shape, it may be difficult to perform the reversal processing well, but according to this manufacturing method of a bearing ring member, the reversal processing of the workpiece can be performed well even in such a case. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a method for manufacturing a bearing ring member that allows for good reversal processing of a workpiece member. [Brief explanation of the drawings]

[0019] [Figure 1] 10(a) and 10(b) are cross-sectional views illustrating a first step of the inversion step. [Figure 2] 10(a) and 10(b) are cross-sectional views illustrating a second step of the inversion step. [Figure 3] 10 is a graph showing an example of a bending moment acting on a workpiece member in a reversing process. [Figure 4] 10(a) to 10(d) are cross-sectional views illustrating the first and second steps of the first modified example. [Figure 5] 10(a) to 10(d) are cross-sectional views illustrating the first and second steps of the second modified example. [Figure 6] 10(a) to 10(d) are cross-sectional views illustrating the first and second steps of the third and fourth modified examples. [Figure 7] 13(a) and 13(b) are cross-sectional views illustrating a second step of the fifth modified example. [Figure 8] 13(a) and 13(b) are cross-sectional views illustrating a second step of the sixth modified example. [Figure 9] 13(a) and 13(b) are cross-sectional views illustrating a second step of the seventh modified example. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted.

[0021] In the method for manufacturing a bearing ring member according to the embodiment, a bearing ring member 20 is manufactured from a workpiece member 10, as shown in Figures 1 and 2. Figures 1 and 2 show cross sections parallel to the axial direction (direction parallel to the central axis CL) of the workpiece member 10 and the ring member 20. In this example, the workpiece member 10 and the ring member 20 have a substantially U-shaped cross section.

[0022] The ring member 20 is an inner ring ring member that can be used, for example, as the inner ring of a bearing. The manufactured ring member 20 itself may be used as the inner ring, or an inner ring may be manufactured by further processing the ring member 20. The bearing to which the ring member 20 is applied may be any bearing, such as a needle bearing, a cylindrical roller bearing, a tapered roller bearing, or a ball bearing.

[0023] The ring member 20 has a main body portion 21 and a pair of flange portions 22, 23. The main body portion 21 is formed in a cylindrical shape and has a cylindrical raceway surface 21a facing radially outward. One flange portion 22 extends radially outward from an end portion of the main body portion 21 on a first axial side S1 (upper side in FIG. 2 ), and the other flange portion 23 extends radially outward from an end portion of the main body portion 21 on a second axial side S2 (opposite side to the first axial side S1). Each of the flange portions 22, 23 is formed, for example, in a substantially annular plate shape.

[0024] The workpiece member 10 has a workpiece main body 11, an inner flange 12, and an outer flange 13. The workpiece main body 11 is formed in the shape of an annular plate and has a surface 11a that becomes the raceway surface 21a of the ring member 20. In this example, the surface 11a is an annular flat surface. The inner flange 12 extends from the radial inner edge of the workpiece main body 11 to one axial side (upper side in FIG. 1 ), and the outer flange 13 extends from the radial outer edge of the workpiece main body 11 to the same axial side. In other words, the inner flange 12 and the outer flange 13 protrude from the workpiece main body 11 to the same side. Each of the inner flange 12 and the outer flange 13 is formed, for example, in a substantially cylindrical shape.

[0025] The manufacturing method of the bearing ring member of the embodiment includes an inversion step in which the workpiece member 10 is clamped between a punch and a die and deformed so that the workpiece main body 11 becomes cylindrical. The inversion step changes the direction of the cross section of the workpiece member 10 by 90 degrees, causing the annular plate-shaped workpiece main body 11 to become cylindrical, thereby forming the ring member 20. The inversion step includes a first step (FIG. 1) in which the workpiece member 10 is deformed from an initial shape to a predetermined intermediate shape, and a second step (FIG. 2) in which the workpiece member 10 is deformed from the intermediate shape to a final shape.

[0026] 1, a first punch 30A and a first die 40A are used in the first step. The first punch 30A and the first die 40A share a common central axis CL, and each of the first punch 30A and the first die 40A has a uniform cross-sectional shape in the radial direction.

[0027] The first punch 30A has a first punch body 31A and a first punch protrusion 32A. The first punch body 31A is formed in a substantially cylindrical shape with an axis parallel to the axial direction. A first punch R surface 35A is formed on the inner edge of the second side S2 of the first punch body 31A. The first punch R surface 35A is a curved surface formed by rounding the corners of the second side S2 of the first punch body 31A, and is formed in an arc shape in a cross section parallel to the axial direction ( FIG. 1 ). The first punch protrusion 32A is formed on the first side S1 of the first punch body 31A and protrudes radially inward from the first punch body 31A. The first punch protrusion 32A is formed, for example, in a cylindrical shape.

[0028] The first die 40A has a first die body 41A and a first die protrusion 42A. The first die body 41A is formed in a substantially cylindrical shape with an axis parallel to the axial direction. A first die R surface 45A is formed on the outer edge of the first side S1 of the first die body 41A. The first die R surface 45A is a curved surface formed by rounding the corners of the first side S1 of the first die body 41A, and is formed in an arc shape in a cross section parallel to the axial direction (FIG. 1). The first die protrusion 42A is formed on the second side S2 of the first die body 41A and protrudes radially outward from the first die body 41A. The first die protrusion 42A is formed, for example, in a cylindrical shape. In this specification, the expression "the first punch body 31A is cylindrical and the first die body 41A is columnar" means that the first die body 41A is formed in a substantially columnar shape so as to sandwich the workpiece 10 between itself and the first punch body 31A from the radially inner side, and includes the case where the first die body 41A has a hollow portion on the central axis CL as shown in Fig. 1. This also applies to the second die body 41B.

[0029] As shown in FIG. 2, a second punch 30B and a second die 40B are used in the second step. The second punch 30B and the second die 40B share a common central axis CL, and each of the second punch 30B and the second die 40B has a uniform cross-sectional shape in the radial direction. In this example, the second punch 30B is identical to the first punch 30A, and the second die 40B is different from the first die 40A. The second punch 30B has a second punch body portion 31B identical to the first punch body portion 31A and a second punch protruding portion 32B identical to the first punch protruding portion 32A. The second punch body portion 31B has a second punch rounded surface 35B corresponding to the first punch rounded surface 35A.

[0030] The second die 40B has a second die body 41B and a second die protrusion 42B. The second die body 41B is formed in a substantially cylindrical shape with an axis parallel to the axial direction. The second die body 41B is configured similarly to the first die body 41A except that it has an inclined surface 46. That is, the second die body 41B has a second die R surface 45B and the inclined surface 46. The second die R surface 45B is formed on the outer edge of the first side S1 of the second die body 41B. The second die R surface 45B is a curved surface formed by rounding the corners of the first side S1 of the second die body 41B, and is formed in an arc shape in a cross section parallel to the axial direction ( FIG. 2 ).

[0031] The inclined surface (tapered surface) 46 is formed on the second side S2 of the second die R surface 45B. The inclined surface 46 is inclined with respect to the axial direction so as to move away from the central axis CL as it approaches the second side S2. The second die protrusion 42B is formed on the second side S2 of the second die body 41B and protrudes radially outward from the second die body 41B. The second die protrusion 42B is formed, for example, in the same cylindrical shape as the first die protrusion 42A.

[0032] In the inversion process, first, as shown in FIG. 1, the workpiece 10 is sandwiched between the first punch 30A and the first die 40A, and the workpiece 10 is deformed so as to rise outward in the radial direction (first process). At the start of the first process, the first punch 30A is positioned on the first side S1 relative to the first die 40A, and the first die 40A is positioned on the second side S2 relative to the first punch 30A (FIG. 1(a)). Then, by moving (lowering) the first punch 30A along the axial direction and approaching the first die 40A, the workpiece 10 is sandwiched between the first punch 30A and the first die 40A, and the workpiece 10 is deformed so as to rise outward in the radial direction (FIG. 1(b)). In the first process, the first punch R surface 35A and the first die R surface 45A come into contact with the workpiece 10. In the first step, the workpiece 10 is sandwiched between the first punch body 31A and the first die body 41A with the surface 11a of the workpiece 10 facing the first side S1.

[0033] In the first step, the workpiece 10 is deformed by the first punch 30A and the first die 40A (first die R surface 45A) without any slippage occurring between the workpiece 10 and the first die 40A. This allows the workpiece 10 to be properly erected. Whether or not slippage will occur can be determined using the predicted value M of the limit bending moment of the workpiece 10, which will be described below.

[0034] If the bending moment (maximum bending moment) acting on the workpiece 10 in the first step is smaller than the predicted value M of the limit bending moment of the workpiece 10 calculated by the following formula (2), no slippage occurs between the workpiece 10 and the first die 40A, and the workpiece 10 stands up on the first die 40A in the first step without slipping.

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[0035] FIG. 3 is a graph showing an example of the bending moment acting on the workpiece 10 during the reversing process. The horizontal axis of FIG. 3 represents the inclination angle θ (°) of the workpiece 10 (workpiece main body 11) with respect to the horizontal direction (direction perpendicular to the axial direction) (see FIG. 1(b)), and the vertical axis represents the bending moment (N·m) acting on the workpiece 10. As shown in FIG. 3, in this example, the bending moment is smaller than the predicted value M of the limit bending moment when the inclination angle θ is in the range of 0 degrees or more and approximately 40 degrees or less. In this case, no slippage occurs between the workpiece 10 and the first die 40A within this range.

[0036] In order to perform the reverse machining of the workpiece 10 successfully, the workpiece 10 must begin to slide relative to the die within a range in which the bending moment acting on the workpiece 10 is smaller than the predicted value M of the limit bending moment. In this example, the bending moment (maximum bending moment) acting on the workpiece 10 in the first process is smaller than the predicted value M of the limit bending moment of the workpiece 10. In other words, the shapes of the first punch 30A and the first die 40A, the descending stroke of the first punch 30A, etc. are determined so that the bending moment acting on the workpiece 10 in the first process is smaller than the predicted value M. As a result, no slippage occurs between the workpiece 10 and the first die 40A in the first process, allowing the workpiece 10 to be raised up successfully. Furthermore, as will be described below, in the second process, the workpiece 10 can slide on the second die 40B, allowing the workpiece 10 to be deformed successfully.

[0037] In the second step, as shown in FIG. 2, the workpiece 10 processed in the first step is sandwiched between the second punch 30B and the second die 40B, and the workpiece 10 is deformed so that the workpiece main body 11 becomes cylindrical. In this example, the workpiece 10 is deformed so that the surface 11a of the workpiece main body 11 faces radially outward. In the second step, the workpiece 10 is first sandwiched between the second punch R surface 35B and the second die R surface 45B (FIG. 2(a)). Then, the workpiece 10 is sandwiched between the second punch R surface 35B and the inclined surface 46. Thus, in the second step, after the second die R surface 45B comes into contact with the workpiece 10, the inclined surface 46 comes into contact with the workpiece 10.

[0038] Thereafter, as the second punch 30B further descends, the second punch protrusion 32B comes into contact with the inner flange portion 12 of the workpiece member 10, and the workpiece member 10 is pushed toward the second side S2 by the second punch protrusion 32B. The workpiece member 10 is then positioned between the second punch body portion 31B and the second die body portion 41B (FIG. 2(b)). Through the above steps, the workpiece body portion 11, inner flange portion 12, and outer flange portion 13 of the workpiece member 10 become the body portion 21, flange portion 22, and flange portion 23 of the ring member 20, respectively, and the ring member 20 is obtained.

[0039] In the second step, the workpiece 10 is deformed by the second punch 30B and the second die 40B while slippage occurs between the workpiece 10 and the second die 40B (the second die R surface 45B and the inclined surface 46). This prevents unintended deformation, such as bending of the workpiece 10. In other words, if no slippage occurs between the workpiece 10 and the second die 40B in the second step, the workpiece 10 may bend into an unintended shape. However, the occurrence of slippage between the workpiece 10 and the second die 40B in the second step prevents such deformation. Note that no slippage occurs between the workpiece 10 and the first punch 30A or the second punch 30B in either the first step or the second step. [Action and effect]

[0040] In the manufacturing method of the bearing ring member of the embodiment, the reversing process includes a first process in which the workpiece member 10 is deformed by the first punch 30A and the first die 40A while no slippage occurs between the workpiece member 10 and the first die 40A, and a second process in which the workpiece member 10 is deformed by the second punch 30B and the second die 40B while slippage occurs between the workpiece member 10 and the second die 40B. As a result, in the first process, no slippage occurs between the workpiece member 10 and the first die 40A, allowing the workpiece member 10 to be properly raised. Furthermore, in the second process, the workpiece member 10 slides on the second die 40B, preventing unintended deformation, such as bending of the workpiece member 10. Therefore, the manufacturing method of the bearing ring member of the embodiment allows the workpiece member 10 to be properly reversed.

[0041] The bending moment acting on the workpiece member 10 in the first step is smaller than the predicted value M of the limit bending moment of the workpiece main body 11 calculated by the above formula (2). As a result, no slippage occurs between the workpiece member 10 and the first die 40A in the first step, and the workpiece member 10 can be satisfactorily raised.

[0042] In the second step, a second die 40B is used that is different from the first die 40A used in the first step. By using different dies in the first and second steps, it is possible to achieve the excellent reversal processing described above.

[0043] In the first step, the first die R surface 45A comes into contact with the workpiece 10, and in the second step, the second die R surface 45B comes into contact with the workpiece 10, and then the inclined surface 46 comes into contact with the workpiece 10. This allows the workpiece 10 to slide on the inclined surface 46 in the second step, thereby achieving the excellent reversal processing described above.

[0044] The workpiece 10 has an inner flange 12 extending from the radial inner edge of the workpiece main body 11 to one side in the axial direction, and an outer flange 13 extending from the radial outer edge of the workpiece main body 11 to the same side in the axial direction. When the workpiece 10 has such a shape, it may be difficult to perform reversal processing well, but according to the manufacturing method of a bearing ring member of the embodiment, reversal processing of the workpiece 10 can be performed well even in such a case. [Variations]

[0045] 4 is a cross-sectional view illustrating the first and second steps of the first modified example. The first step of the first modified example is the same as the first step of the above embodiment. In the first modified example, the second die body 41B of the second die 40B does not have an inclined surface 46. The diameter D2 of the second die body 41B is smaller than the diameter D1 of the first die body 41A.

[0046] As with the above embodiment, the first modified example also allows for good reversal processing of the workpiece 10. Furthermore, since the diameter D2 of the second die body 41B is smaller than the diameter D1 of the first die body 41A, the workpiece 10 slides easily on the second die 40B in the second step, thereby achieving good reversal processing.

[0047] 5 is a cross-sectional view illustrating the first and second steps of the second modified example. In the second modified example, the first punch body 31A of the first punch 30A is formed in a generally cylindrical shape, and the first die body 41A of the first die 40A is formed in a generally cylindrical shape, unlike the above embodiment. As in the above embodiment, the second punch body 31B of the second punch 30B is formed in a generally cylindrical shape, and the second die body 41B of the second die 40B is formed in a generally cylindrical shape. As in the first modified example, the second die body 41B does not have an inclined surface 46.

[0048] In the first step of the second modified example, the workpiece 10 is sandwiched between the first punch body 31A and the first die body 41A with the surface 11a of the workpiece 10 facing the second side S2. In the second step, the workpiece 10 is sandwiched between the second punch body 31B and the second die body 41B with the surface 11a of the workpiece 10 facing the first side S1. That is, in the second modified example, a step of reversing the orientation of the workpiece 10 in the axial direction is included between the first and second steps, and the orientation of the workpiece 10 in the axial direction is opposite between the first and second steps.

[0049] The second modified example also enables the workpiece 10 to be reversed satisfactorily, as in the above embodiment. In the second modified example, the first punch body 31A and the second die body 41B may be formed in a generally cylindrical shape, and the first die body 41A and the second punch body 31B may be formed in a generally columnar shape. Alternatively, the first punch body 31A and the second punch body 31B may be formed in a generally cylindrical shape, and the first die body 41A and the second die body 41B may be formed in a generally columnar shape. Alternatively, the first punch body 31A and the second punch body 31B may be formed in a generally columnar shape, and the first die body 41A and the second die body 41B may be formed in a generally columnar shape. Furthermore, the orientation of the workpiece 10 in the axial direction may be reversed between the first and second steps, and in the first step, the workpiece 10 may be sandwiched between the first punch body portion 31A and the first die body portion 41A with the surface 11a of the workpiece 10 facing the first side S1, and in the second step, the workpiece 10 may be sandwiched between the second punch body portion 31B and the second die body portion 41B with the surface 11a of the workpiece 10 facing the second side S2.

[0050] FIG. 6 is a cross-sectional view illustrating the first and second steps of the third and fourth modified examples. In the third modified example, the surface roughness of the second contact surface 47B of the second die 40B, which contacts the workpiece 10 in the second step, is smaller than the surface roughness of the first contact surface 47A of the first die 40A, which contacts the workpiece 10 in the first step. The surface roughness is the arithmetic mean roughness Ra (JIS B 0601 4.2.1). As in the first modified example, the second die body 41B of the third modified example does not have an inclined surface 46. In this example, the first contact surface 47A is the first die R surface 45A, and the second contact surface 47B is the second die R surface 45B. The surface roughness of the first contact surface 47A can be adjusted, for example, by forming a black coating, lathing, or grinding (forming lathing or grinding marks). The surface roughness of the second contact surface 47B can be adjusted by, for example, grinding or lapping, or by forming a coating layer. By selectively performing these processes, the surface roughness of the first contact surface 47A and the second contact surface 47B can be adjusted so that the surface roughness of the second contact surface 47B is smaller than the surface roughness of the first contact surface 47A.

[0051] As with the above embodiment, the third modified example also allows for good reversal processing of the workpiece 10. Furthermore, since the surface roughness of the second contact surface 47B is smaller than the surface roughness of the first contact surface 47A, the workpiece 10 can slide more easily on the second die 40B in the second step, thereby achieving good reversal processing.

[0052] Continuing with reference to FIG. 6 , a fourth modified example will be described. In the fourth modified example, instead of adjusting the surface roughness of the first contact surface 47A and the second contact surface 47B, the Rockwell C scale hardness is adjusted. Specifically, the Rockwell C scale hardness of the second contact surface 47B is greater than that of the first contact surface 47A. The fourth modified example is similar to the third modified example except for this point. In this example, the first die R surface 45A is formed of a material that is easily worn, while the second die R surface 45B is formed of a material that is resistant to wear. As a result, the Rockwell C scale hardness of the second contact surface 47B is greater than that of the first contact surface 47A. The material of the first contact surface 47A may be, for example, steel, die steel (e.g., SKD11), etc. The material of the second contact surface 47B may be, for example, cemented carbide, high-speed steel (e.g., SKH51), etc. The Rockwell C scale hardness of the second contact surface 47 B may be adjusted by forming a coating layer on the second contact surface 47 B. The Rockwell C scale hardness is a hardness defined by JIS Z 2245.

[0053] As with the above embodiment, the fourth modified example also allows for good reversal machining of the workpiece 10. Furthermore, since the Rockwell C scale hardness of the second contact surface 47B is greater than the Rockwell C scale hardness of the first contact surface 47A, the workpiece 10 slides more easily on the second die 40B in the second step, thereby achieving good reversal machining.

[0054] FIG. 7 is a cross-sectional view illustrating the second step of the fifth modified example. The first step of the fifth modified example is, for example, the same as the first step of the above-described embodiment. In the second step of the fifth modified example, the workpiece member 10 is clamped between the second punch 30B and the second die 40B while being pushed from the inside to the outside in the radial direction by the push member 51 (while being pushed toward the second punch 30B along the radial direction). The push member 51 includes, for example, a plurality of (e.g., eight) block members 51a arranged along the circumferential direction. Each block member 51a is disposed on the second die 40B and is movable in the radial direction along the second die 40B. As the block members 51a move radially outward, the push member 51 pushes the workpiece member 10 radially outward. This pushing force may be a force from any mechanism or power source, such as a spring, hydraulic pressure, air, a motor, or a cam. Similar to the first modified example, the second die body 41B of the fifth modified example does not have the inclined surface .

[0055] The fifth modified example also allows for satisfactory reversal processing of the workpiece 10, as in the above embodiment. Furthermore, since the workpiece 10 is sandwiched between the second punch 30B and the second die 40B while the pressing member 51 presses the workpiece 10 radially toward the second punch 30B, the workpiece 10 slides easily over the second die 40B in the second step, achieving satisfactory reversal processing. In the fifth modified example, the first punch body 31A and the second punch body 31B may be formed in a substantially cylindrical shape, and the first die body 41A and the second die body 41B may be formed in a substantially cylindrical shape. In this case, in the second step, the workpiece 10 may be sandwiched between the second punch 30B and the second die 40B while the pressing member 51 presses the workpiece 10 from the outside to the inside in the radial direction (while pressing the workpiece 10 radially toward the second punch 30B).

[0056] FIG. 8 is a cross-sectional view illustrating the second step of the sixth modified example. The first step of the sixth modified example is the same as, for example, the first step of the above embodiment. In the second step of the sixth modified example, a second punch 30B (hook punch) having a hook portion 52 is used, and the hook portion 52 is hooked onto the workpiece member 10, and the workpiece member 10 is sandwiched between the second punch 30B and the second die 40B. The second punch 30B is configured to include multiple (e.g., eight) divided portions 53 arranged along the circumferential direction. Each divided portion 53 is movable in the radial direction.

[0057] In this example, the hook portion 52 is provided in each divided portion 53. That is, each divided portion 53 has a main body portion 53a and a protruding portion 53b that protrudes radially inward from an end portion of the main body portion 53a on the first side S1, and the protruding portion 53b functions as the hook portion 52. In other words, the hook portion 52 includes a plurality of portions (protruding portions 53b) arranged along the circumferential direction.

[0058] In the second step, the hook portion 52 moves downward (to the second side S2) while moving radially inward. Specifically, a cam 54 is disposed below the second punch 30B. The cam 54 has an inclined guide surface 54a facing the second punch 30B. The second punch 30B (each divided portion 53) has an inclined surface 30Ba corresponding to the guide surface 54a. The inclined surface 30Ba and the guide surface 54a are inclined so as to approach the central axis CL as they extend downward. During reversal processing, the pushing jig J pushes the second punch 30B downward, causing the inclined surface 30Ba to come into contact with the guide surface 54a, and the inclined surface 30Ba is guided by the guide surface 54a. As a result, the second punch 30B moves obliquely radially inward and downward.

[0059] In the second step, due to this movement of the second punch 30B, the hook portion 52 hooks onto the outer flange portion 13, and the outer flange portion 13 is pulled inward in the radial direction, as shown in Figure 8(a). During this hooking operation, the hook portion 52 comes into contact with the inner surface of the outer flange portion 13. In parallel with this hooking operation, the inner flange portion 12 is pushed outward on the inner diameter side by the push member 51, as in the fifth modified example. Thereafter, the second punch 30B moves straight downward, as shown in Figure 8(b), thereby completing the reversal process.

[0060] As with the above embodiment, the sixth modified example also allows for good reversal processing of the workpiece 10. Furthermore, since the hook portion 52 is hooked onto the workpiece 10 and the workpiece 10 is sandwiched between the second punch 30B and the second die 40B, the workpiece 10 can easily slide on the second die 40B in the second step, thereby achieving good reversal processing.

[0061] 9 is a cross-sectional view illustrating the second step of the seventh modified example. The seventh modified example is similar to the sixth modified example, except for the points described below. In the seventh modified example, the contact surface 51b of the pressing member 51 that comes into contact with the workpiece 10 is inclined with respect to the axial direction so as to move away from the central axis CL as it moves downward (to the second side S2). In addition, in the seventh modified example, the second punch 30B has a circular member 55, a hook portion 52 that is movable relative to the circular member 55, and a guide member 56 that guides the movement of the hook portion 52. The circular member 55 is composed of a single member that is formed into a circular ring shape in a plan view, for example.

[0062] The hook portion 52 has an inclined surface 52a, and the guide member 56 has an inclined guide surface 56a. The inclined surface 52a and the guide surface 56a are inclined so as to approach the central axis CL as they extend downward. During the reversing process, as shown in FIG. 9(a), the push jig J pushes the hook portion 52 downward, and the inclined surface 52a is guided by the guide surface 56a, causing the hook portion 52 to move diagonally inward and downward in the radial direction. This causes the hook portion 52 to protrude from the annular member 55. Concurrently with this protruding movement, the inner flange portion 12 is pushed outward by the push member 51 on the inner diameter side. Then, as shown in FIG. 9(b), the tip end 52b of the hook portion 52 hooks onto the outer flange portion 13 and presses the inner surface of the outer flange portion 13 downward. This completes the reversing process.

[0063] As with the above embodiment, the seventh modified example also allows for good reversal processing of the workpiece 10. Furthermore, since the hook portion 52 is hooked onto the workpiece 10 and the workpiece 10 is sandwiched between the second punch 30B and the second die 40B, the workpiece 10 can easily slide over the second die 40B in the second step, thereby achieving good reversal processing. Note that in the sixth and seventh modified examples, the pressing member 51 may be omitted.

[0064] The present invention is not limited to the above-described embodiment and modifications. For example, the materials and shapes of each component are not limited to those described above, and various materials and shapes can be used. The workpiece member 10 may have any shape, for example, it may have only the workpiece main body 11 without the inner flange portion 12 and the outer flange portion 13.

[0065] The ring member 20 may be an outer ring ring member that can be used as the outer ring of a bearing. In this case, the manufactured ring member 20 itself may be used as the outer ring, or the ring member 20 may be further processed to manufacture the outer ring. When the ring member 20 is an outer ring ring member, the main body portion 21 has a raceway surface 21a facing radially inward, and the pair of flange portions 22, 23 extend radially inward from the main body portion 21. In the first step, the workpiece member 10 is deformed so that it rises radially inward, and in the second step, the workpiece member 10 is deformed so that the surface 11a of the workpiece main body portion 11 faces radially inward. In this case, too, the workpiece member 10 is deformed in the reversing step so that the workpiece main body portion 11 becomes cylindrical. In this case, the first punch main body portion 31A and the second punch main body portion 31B may be formed in a substantially cylindrical shape, and the first die main body portion 41A and the second die main body portion 41B may be formed in a substantially cylindrical shape.

[0066] In the above embodiment, the workpiece 10 is sandwiched between the punch and the die as the punch approaches the die, but the punch and the die can simply move relative to each other, and for example, the workpiece 10 can be sandwiched between the punch and the die as they move closer to each other. [Explanation of symbols]

[0067] 10...workpiece member, 11...workpiece main body portion, 11a...surface, 12...inner flange portion, 13...outer flange portion, 20...ring member (bearing ring member), 30A...first punch, 30B...second punch, 40A...first die, 41A...first die main body portion, 40B...second die, 41B...second die main body portion, 45A...first die R surface, 45B...second die R surface, 46...inclined surface, 47A...first contact surface, 47B...second contact surface, 51...pressing member, 52...hook portion, S1...first side, S2...second side.

Claims

1. a turning step of clamping a workpiece member having an annular workpiece main body portion between a punch arranged on a first side in the axial direction and a die arranged on a second side opposite to the first side, and deforming the workpiece member so that the workpiece main body portion becomes cylindrical; The inverting step includes: a first step of deforming the workpiece with a punch and a die in a state where no slippage occurs between the workpiece and the die; a second step of deforming the workpiece with a punch and a die while slippage occurs between the workpiece and the die, A method for manufacturing a bearing ring member, wherein the bending moment acting on the workpiece member in the first step is smaller than a predicted value M of the limit bending moment of the workpiece main body portion calculated by equation (1). [Equation 1] In the formula (1), W W is the width of the workpiece body, t is the thickness of the workpiece body, and Y is the yield stress of the workpiece body.

2. a turning step of clamping a workpiece member having an annular workpiece main body portion between a punch arranged on a first side in the axial direction and a die arranged on a second side opposite to the first side, and deforming the workpiece member so that the workpiece main body portion becomes cylindrical; The inverting step includes: a first step of deforming the workpiece with a punch and a die in a state where no slippage occurs between the workpiece and the die; a second step of deforming the workpiece with a punch and a die while slippage occurs between the workpiece and the die, In the second step, a second die different from the first die used in the first step is used, The first die has a first die R surface formed in an arc shape, the second die has a second die R surface formed in an arc shape, and an inclined surface formed on the second side of the second die R surface and inclined with respect to the axial direction, In the first step, the first die R surface contacts the workpiece, In the second step, the inclined surface contacts the workpiece after the second die R surface contacts the workpiece.

3. a turning step of clamping a workpiece member having an annular workpiece main body portion between a punch arranged on a first side in the axial direction and a die arranged on a second side opposite to the first side, and deforming the workpiece member so that the workpiece main body portion becomes cylindrical; The inverting step includes: a first step of deforming the workpiece with a punch and a die in a state where no slippage occurs between the workpiece and the die; a second step of deforming the workpiece with a punch and a die while slippage occurs between the workpiece and the die, In the second step, a second die different from the first die used in the first step is used, The first die has a first die body formed in a cylindrical shape, The second die has a second die body formed in a cylindrical shape, In the first step, the workpiece is sandwiched between a punch and the first die body, In the second step, the workpiece is sandwiched between the punch and the second die body, A method for manufacturing a bearing ring member, wherein the diameter of the second die body portion is smaller than the diameter of the first die body portion.

4. In the first step, the workpiece is sandwiched between the punch and the first die with the surface of the workpiece facing one of the first side and the second side, 4. The method for manufacturing a bearing ring member according to claim 2 or 3, wherein in the second step, the work member is clamped between the punch and the second die with the surface of the work member facing the other of the first side and the second side.

5. a turning step of clamping a workpiece member having an annular workpiece main body portion between a punch arranged on a first side in the axial direction and a die arranged on a second side opposite to the first side, and deforming the workpiece member so that the workpiece main body portion becomes cylindrical; The inverting step includes: a first step of deforming the workpiece with a punch and a die in a state where no slippage occurs between the workpiece and the die; a second step of deforming the workpiece with a punch and a die while slippage occurs between the workpiece and the die, In the second step, a second die different from the first die used in the first step is used, A method for manufacturing a ring member for a bearing, wherein the surface roughness of the second contact surface that contacts the work member in the second step in the second die is smaller than the surface roughness of the first contact surface that contacts the work member in the first step in the first die.

6. a turning step of clamping a workpiece member having an annular workpiece main body portion between a punch arranged on a first side in the axial direction and a die arranged on a second side opposite to the first side, and deforming the workpiece member so that the workpiece main body portion becomes cylindrical; The inverting step includes: a first step of deforming the workpiece with a punch and a die in a state where no slippage occurs between the workpiece and the die; a second step of deforming the workpiece with a punch and a die while slippage occurs between the workpiece and the die, In the second step, a second die different from the first die used in the first step is used, A method for manufacturing a bearing ring member, wherein the Rockwell C scale hardness of a second contact surface that contacts the workpiece in the second step in the second die is greater than the Rockwell C scale hardness of a first contact surface that contacts the workpiece in the first step in the first die.

7. a turning step of clamping a workpiece member having an annular workpiece main body portion between a punch arranged on a first side in the axial direction and a die arranged on a second side opposite to the first side, and deforming the workpiece member so that the workpiece main body portion becomes cylindrical; The inverting step includes: a first step of deforming the workpiece with a punch and a die in a state where no slippage occurs between the workpiece and the die; a second step of deforming the workpiece with a punch and a die while slippage occurs between the workpiece and the die, In the second step, the workpiece is clamped between the punch and the die while being pressed radially toward the punch by a pressing member.

8. a turning step of clamping a workpiece member having an annular workpiece main body portion between a punch arranged on a first side in the axial direction and a die arranged on a second side opposite to the first side, and deforming the workpiece member so that the workpiece main body portion becomes cylindrical; The inverting step includes: a first step of deforming the workpiece with a punch and a die in a state where no slippage occurs between the workpiece and the die; a second step of deforming the workpiece with a punch and a die while slippage occurs between the workpiece and the die, In the second step, a hook punch having a hook portion is used, the hook portion is hooked onto the workpiece, and the workpiece is sandwiched between the hook punch and the die.

9. 9. The method for manufacturing a bearing ring member according to claim 1, wherein the second step uses a second die that is different from the first die used in the first step.

10. A method for manufacturing a bearing ring member according to any one of claims 1 to 9, wherein the workpiece further has an inner flange portion extending from a radial inner edge of the workpiece main body portion to one side in the axial direction, and an outer flange portion extending from a radial outer edge of the workpiece main body portion to the one side in the axial direction.

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