Manufacturing method for bearing ring member and mold for reversal processing

Abstract

This method for manufacturing a ring member for a bearing comprises an inversion step, in which a ring-shaped workpiece member is clamped and deformed using a punch that is positioned on a first side in a prescribed direction and a die that is positioned on a second side. The punch has a first R surface that is formed in a circular arc shape. The die has a second R surface that is formed in a circular arc shape, and a taper surface that is slanted relative to the prescribed direction. The inversion step includes a first step, in which the punch and the die are used to deform the workpiece member while the first R surface and the second R surface are in contact with the workpiece member, and a second step, in which the punch and the die are used to deform the workpiece member while the first R surface and the taper surface are in contact with the workpiece member.

Description

[Technical Field]

[0001] One aspect of the present disclosure relates to a method for manufacturing a bearing ring member and a mold for reversal processing. [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, a ring member is formed through a process of sandwiching an annular workpiece between a punch and a die and performing a reversal process that changes the direction of the cross section by 90 degrees. The punch has a tapered shape, and the die has a compound R shape that combines multiple R surfaces with different radii. Patent Documents 2 to 5 also describe the formation of ring members for bearings by 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 is not easy to design the taper shape of the punch and the compound R shape of the die so that reversal processing can be performed well, and there is a problem that the design relies on experience and there is a large difference in design depending on the designer. If there is a large difference in design depending on the designer, the design work will be concentrated on a specific designer, and there is a risk of work efficiency decreasing.

[0005] Therefore, one aspect of the present disclosure aims to provide a method for manufacturing a bearing ring member that can facilitate the design and manufacture of a bearing ring member using reversal processing, and a mold for reversal processing. [Means for solving the problem]

[0006] A method for manufacturing a bearing ring member according to one aspect of the present disclosure is a method for manufacturing a cylindrical bearing ring member, and includes an inversion process in which a circular workpiece is sandwiched and deformed between a punch arranged on a first side in a predetermined direction and a die arranged on a second side opposite the first side, wherein the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, and the die has a second R surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second R surface and inclined so as to approach the radial center as it approaches the second side, and the inversion process includes a first process in which the workpiece is deformed by the punch and die with the first R surface and the second R surface in contact with the workpiece, and a second process in which, after the first process, the workpiece is deformed by the punch and die with the first R surface and the tapered surface in contact with the workpiece.

[0007] In this method for manufacturing a bearing ring member, the punch has a first rounded surface that is arc-shaped in a cross section parallel to the predetermined direction, and the die has a second rounded surface that is arc-shaped in a cross section parallel to the predetermined direction and a tapered surface formed on a second side of the second rounded surface that is inclined toward the radial center as it approaches the second side. In the reversing process, a first step is performed in which the workpiece is deformed by the punch and die while the first rounded surface and the tapered surface are in contact with the workpiece, and then a second step is performed in which the workpiece is deformed by the punch and die while the first rounded surface and the tapered surface are in contact with the workpiece. Because the punch and die have simple shapes or shapes consisting of a combination of simple shapes, it is possible to determine in advance based on geometric calculations whether reversing can be performed successfully. Therefore, this method for manufacturing a bearing ring member facilitates the design and manufacturing of bearing ring members.

[0008] In the first step, no slippage occurs between the workpiece and the second R-surface, and in the second step, slippage may occur between the workpiece and the tapered surface. In this case, the workpiece can be reversed well.

[0009] 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 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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[0010] The inclination angle of the tapered surface relative to the predetermined direction may be less than 30 degrees, and formula (2) may be satisfied when the inclination angle θ of the workpiece relative to the predetermined direction is 30 degrees. In this case, it is possible to prevent the punch from biting into the workpiece, and to perform reverse machining of the workpiece well. Details of the biting will be described later. Z d <W W ×A …(2) In equation (2), Z d is the distance between the radially inner edge of the second end of the workpiece and the contact point between the workpiece and the first R surface, and W W is the width of the workpiece, and A is a constant greater than or equal to 0.2 and less than or equal to 0.6.

[0011] The punch may have a cylindrical main body portion on which a first R surface is formed, the inclination angle of the tapered surface relative to the predetermined direction is less than 30 degrees, and formula (3) may be satisfied when the inclination angle θ of the workpiece relative to the predetermined direction is 30 degrees. In this case, it is possible to prevent the punch from biting into the workpiece, and to perform reverse machining of the workpiece well.

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[0012] The punch may have a cylindrical main body having a first rounded surface and a protrusion formed on a first side of the main body and protruding radially outward from the main body, and at the start of the second step, the radially inner edge of the end of the first side of the workpiece may be located radially inner than the outer edge of the protrusion. In this case, the workpiece can be reliably pressed in by the protrusion of the punch, and the workpiece can be successfully reversed.

[0013] The punch may have a cylindrical main body portion on which a first R surface is formed, and a protrusion portion formed on a first side of the main body portion and protruding radially outward from the main body portion, and formula (4) may be satisfied at the start of the second step. In this case, the workpiece can be reliably pressed into the punch by the protrusion portion, and the workpiece can be successfully reversed.

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[0014] The reversing step may be performed in a state in which the surface roughness of the first region of the first rounded surface that comes into contact with the workpiece in the second step is greater than the surface roughness of the second region of the first rounded surface other than the first region. In this case, it is possible to further suppress the punch from biting into the workpiece, and to perform the reversing process of the workpiece well.

[0015] The reversing step may be carried out in a state in which the surface roughness of the tapered surface is greater than the surface roughness of the second rounded surface, which further reduces the occurrence of the punch biting into the workpiece, allowing for good reversal processing of the workpiece.

[0016] The reversing step may be performed in a state in which the surface roughness of the first region of the first rounded surface that comes into contact with the workpiece in the second step is greater than the surface roughness of the second region of the first rounded surface other than the first region, and the surface roughness of the tapered surface is greater than the surface roughness of the second rounded surface. In this case, it is possible to further suppress the punch from biting into the workpiece, and to perform the reversing process of the workpiece well.

[0017] The reversing step may be performed in a state in which the surface roughness of the second region of the first rounded surface other than the first region that comes into contact with the workpiece in the second step is greater than the surface roughness of the first region of the first rounded surface. In this case, the protruding portion of the punch can more reliably press the workpiece into place, allowing for successful reversing of the workpiece.

[0018] The reversing step may be carried out with the surface roughness of the second rounded surface being greater than the surface roughness of the tapered surface, in which case the protruding portion of the punch can more reliably press the workpiece into place, thereby enabling the workpiece to be reversibly processed.

[0019] The reversing step may be performed in a state in which the surface roughness of the second region of the first rounded surface other than the first region that comes into contact with the workpiece in the second step is greater than the surface roughness of the first region of the first rounded surface, and the surface roughness of the second rounded surface is greater than the surface roughness of the tapered surface. In this case, the workpiece can be more reliably pressed in by the protruding portion of the punch, and the reversing process of the workpiece can be performed well.

[0020] The method for manufacturing a bearing ring member according to one aspect of the present disclosure may further include a step of polishing at least one of the punch and the die to achieve the above-described condition before the reversing step. In this case, it is possible to prevent a situation in which the above-described condition is no longer satisfied due to wear of at least one of the punch and the die, resulting in a malfunction.

[0021] The punch may further have an outer peripheral surface formed on the first side of the first R surface, and the die may further have an inner peripheral surface formed on the second side of the tapered surface, and the reversing step may further include, after the second step, a third step of ironing the workpiece by sandwiching the workpiece between the outer peripheral surface and the inner peripheral surface. In a typical reversing process, the thickness of the radially inner portion of the workpiece decreases and the thickness of the radially outer portion increases, but in this case, by performing ironing between the outer peripheral surface of the punch and the inner peripheral surface of the die, the roundness of the resulting bearing ring member can be improved.

[0022] The gap between the outer peripheral surface and the inner peripheral surface in the third step may be set to be equal to the thickness of the workpiece, in which case the thickness of the resulting bearing ring member can be adjusted to match the thickness of the workpiece.

[0023] The gap between the outer peripheral surface and the inner peripheral surface in the third step may be set smaller than the thickness of the workpiece, in which case the thickness of the resulting bearing ring member can be matched to the thickness of the radially inner portion of the workpiece whose thickness is reduced.

[0024] A reversal processing mold according to one aspect of the present disclosure is a reversal processing mold for manufacturing cylindrical bearing ring members, used for reversal processing in which a circular workpiece is clamped and deformed between a punch arranged on a first side in a predetermined direction and a die arranged on a second side opposite the first side, and is equipped with a punch having a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, and a die having a second R surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second R surface that is inclined so as to approach the radial center as it approaches the second side.

[0025] In this reversing die, the punch has a first rounded surface that is arc-shaped in a cross section parallel to the predetermined direction, and the die has a second rounded surface that is arc-shaped in a cross section parallel to the predetermined direction and a tapered surface formed on a second side of the second rounded surface that is inclined toward the radial center as it approaches the second side. This allows for a first step of deforming a workpiece with the punch and die while the first rounded surface and the second rounded surface are in contact with the workpiece during reversing, followed by a second step of deforming the workpiece with the punch and die while the first rounded surface and the tapered surface are in contact with the workpiece. Because the punch and die have simple shapes or shapes consisting of a combination of simple shapes, it is possible to determine in advance based on geometric calculations whether reversing can be performed successfully. This reversing die therefore facilitates the design and manufacture of bearing ring members. [Effects of the Invention]

[0026] According to one aspect of the present disclosure, it is possible to provide a method for manufacturing a bearing ring member and a mold for reversal processing that can facilitate the design and manufacturing of bearing ring members using reversal processing. [Brief explanation of the drawings]

[0027] [Figure 1] 1(a) is a cross-sectional view of a bearing ring member, and FIG. 1(b) is a cross-sectional view of a work member. [Figure 2] FIG. 2 is a cross-sectional view of a punch and a die. [Figure 3] 10A and 10B are diagrams showing an example of a state in which a punch bites into a workpiece member. [Figure 4] FIG. 2 is a cross-sectional view at the start of the first step. [Figure 5] 10 is a cross-sectional view showing a state in which the inclination angle of the workpiece is equal to the inclination angle of the tapered surface. [Figure 6] FIG. 10 is a cross-sectional view showing a state in which the tilt angle of the workpiece is 30 degrees. [Figure 7] 10(a) and 10(b) are diagrams for explaining the position of the contact point between the workpiece and the first rounded surface. [Figure 8] 10(a) and 10(b) are diagrams showing an example of a state in which the workpiece is not pressed in by the protruding portion of the punch. [Figure 9] 10 is a cross-sectional view showing a state in which the inclination angle of the workpiece is equal to the inclination angle of the tapered surface. [Figure 10] 10 is a diagram for explaining the position of the contact point between the workpiece and the second rounded surface. FIG. [Figure 11] 10 is a graph showing an example of a bending moment acting on a workpiece member in a reversing process. [Figure 12] 10A and 10B are diagrams showing a second modified example, in which (a) is a cross-sectional view of the punch and the workpiece at the start of the second step, and (b) is a cross-sectional view of the die and the workpiece at the start of the second step. [Figure 13]10A and 10B are diagrams showing a third modified example, in which (a) is a cross-sectional view of the punch and the workpiece at the start of the second step, and (b) is a cross-sectional view of the die and the workpiece at the start of the second step. [Figure 14] 1(a), (b) and (c) are cross-sectional views for explaining ironing. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be designated by the same reference numerals, and redundant description will be omitted.

[0029] In the method for manufacturing a bearing ring member according to the embodiment, the bearing ring member 1 shown in FIG. 1(a) is manufactured from the workpiece member 10 shown in FIG. 1(b). The bearing ring member 1 can be used, for example, as an inner or outer ring of a bearing. The manufactured bearing ring member 1 itself may be used as the inner or outer ring, or the inner or outer ring may be manufactured by further processing the bearing ring member 1. The bearing ring member 1 is formed in a cylindrical shape. The bearing to which the bearing ring member 1 is applied may be any bearing, such as a needle bearing, a cylindrical roller bearing, a tapered roller bearing, or a ball bearing. The workpiece member 10 is formed in an annular plate shape. FIGS. 1(a) and 1(b) show cross sections parallel to the axial direction of the bearing ring member 1 and the workpiece member 10.

[0030] FIG. 2 is a cross-sectional view of a punch 20 and a die 30 (a reversing die) used in a manufacturing method of a bearing ring member according to an embodiment. This manufacturing method includes an inversion step in which a workpiece 10 is sandwiched and deformed between the punch 20 and the die 30. The inversion step changes the direction of the cross section of the workpiece 10 by 90 degrees, forming a bearing ring member 1. Before the inversion step begins, the punch 20 is positioned on a first side S1 in a direction DR (a predetermined direction) relative to the die 30, and the die 30 is positioned on a second side S2 in the direction DR (the opposite side to the first side S1) relative to the punch 20. The punch 20 is then moved (lowered) along the direction DR to approach the die 30, whereby the workpiece 10 is sandwiched between the punch 20 and the die 30, and the workpiece 10 is subjected to inversion processing. The punch 20 and the die 30 share a common center line CL, and each of the punch 20 and the die 30 has a uniform cross-sectional shape in the radial direction. [Punch and die shapes]

[0031] As shown in FIG. 2, the punch 20 has a main body 21 and a protrusion 22. The main body 21 is formed in a substantially cylindrical shape with an axis parallel to the direction DR. A first R-face R1 is formed at the outer edge of the surface of the second side S2 of the main body 21. The first R-face R1 is a curved surface formed by rounding the corners of the second side S2 of the main body 21, and is formed in an arc shape in a cross section parallel to the direction DR ( FIG. 2 ). The first R-face R1 extends around the entire circumference of the outer edge. The central angle of the first R-face R1 in the cross section parallel to the direction DR is, for example, 90 degrees. The main body 21 has an outer peripheral surface 21a that is continuous with the first side S1 of the first R-face R1.

[0032] The protrusion 22 is formed on the first side S1 of the main body 21 and protrudes radially outward relative to the main body 21. The protrusion 22 is formed, for example, in a cylindrical shape with a diameter larger than that of the main body 21. The protrusion 22 has a stepped surface 22a facing the second side S2. The stepped surface 22a is continuous with the outer peripheral surface 21a of the main body 21.

[0033] The die 30 is formed, for example, in a substantially cylindrical shape with an axis parallel to the direction DR. The die 30 has a second R-surface R2, a tapered surface 31, and an inner peripheral surface 32. The second R-surface R2 is formed on the inner edge of the surface of the first side S1 of the die 30. The second R-surface R2 is a curved surface formed by rounding the corners of the first side S1 of the die 30, and is formed in an arc shape in a cross section parallel to the direction DR (FIG. 2). The second R-surface R2 extends around the entire circumference of the inner edge. The central angle of the second R-surface R2 in the cross section parallel to the direction DR is, for example, (90-α) degrees, where α is the inclination angle of the tapered surface 31 with respect to the direction DR. The second R-surface R2 defines an opening 30a of the die 30 that opens to the first side S1.

[0034] The tapered surface 31 is continuous with the second side S2 of the second rounded surface R2 and is inclined so as to approach the center in the radial direction as it approaches the second side S2. The inclination angle α of the tapered surface 31 with respect to the direction DR is, for example, smaller than 30 degrees. The inner circumferential surface 32 is continuous with the second side S2 of the tapered surface 31. [Reverse process]

[0035] As described above, in the reversing process, the workpiece 10 is sandwiched between the punch 20 and the die 30, and the workpiece 10 is subjected to reversing processing. More specifically, the reversing process includes a first process and a second process, in this order. In the first process, the workpiece 10 is deformed by the punch 20 and the die 30 with the first R surface R1 and the second R surface R2 in contact with the workpiece 10 (e.g., FIG. 6). In the second process, the workpiece 10 is deformed by the punch 20 and the die 30 with the first R surface R1 and the tapered surface 31 in contact with the workpiece 10 (e.g., FIG. 9).

[0036] In the first step, the workpiece 10 is deformed so as to rise up. In the second step, the workpiece 10 slides on the tapered surface 31, and is drawn into the die 30 together with the punch 20. After the start of the second step, the punch 20 further descends, causing the step surface 22a of the protruding portion 22 of the punch 20 to come into contact with the end 10a of the first side S1 of the workpiece 10, and the workpiece 10 is pushed in by the protruding portion 22. The workpiece 10 is then positioned between the outer peripheral surface 21a of the main body 21 of the punch 20 and the inner peripheral surface 32 of the die 30. Through the above steps, a cylindrical bearing ring member 1 is obtained. Conditions for performing the reversal process well are described below. [Condition 1]

[0037] The first condition is that the punch 20 does not bite into the workpiece 10 in the first step, and that the workpiece 10 does not get caught on the die 30 and slip off. In the first step, the punch 20 needs to continue to press the radially inner portion of the workpiece 10 while the radially outer portion of the workpiece 10 gets caught on the die 30. If this operation is not performed properly and biting occurs, there is a risk that the workpiece 10 will be drawn into the die 30 in a state where it is deformed into an unintended shape, as exemplified in FIGS. 3(a) and 3(b). Therefore, in the manufacturing method of a bearing ring member according to the embodiment, the first conditional expression described below is satisfied, and biting is suppressed.

[0038] Fig. 4 is a cross-sectional view taken along a plane parallel to the direction DR at the start of the first step. Fig. 5 is a cross-sectional view in a state where the inclination angle θ of the workpiece 10 relative to the direction DR is equal to the inclination angle α of the tapered surface 31. Fig. 6 is a cross-sectional view in a state where the inclination angle θ of the workpiece 10 between Fig. 4 and Fig. 5 is 30 degrees. Figs. 7(a) and 7(b) are diagrams for explaining the position of the contact point B between the workpiece 10 and the first R surface R1. Hatching indicating cross sections has been omitted from Figs. 4 to 6.

[0039] The inventors have found that if the following formula (5) (first conditional formula) is satisfied when the tilt angle θ of the workpiece 10 is 30 degrees, the occurrence of the punch 20 biting into the workpiece 10 can be suppressed. In this embodiment, the tilt angle θ of the workpiece 10 is 30 degrees in the first step. Z d <W W ×A …(5) In the above formula (5), Z d is the distance between the radially inner edge 10ba of the end 10b of the second side S2 of the workpiece member 10 and the contact point B between the workpiece member 10 and the first R surface R1, and W W is the width of the workpiece member 10, and A is a constant greater than or equal to 0.2 and less than or equal to 0.6.

[0040] The first conditional expression is that when the inclination angle θ shown in FIG. 6 is 30 degrees, the contact point B is located within the width W of the workpiece 10 from the edge 10ba of the workpiece 10. W This indicates that the workpiece 10 is located within a length range obtained by multiplying the workpiece 10 by a constant A. The constant A can be determined, for example, by experiment and / or simulation depending on the shapes, materials, etc. of the workpiece 10, punch 20, and die 30. In this example, the constant A is set to 2 / 5. The tilt angle θ of 30 degrees is, for example, the boundary value at which the workpiece 10 begins to slide on the die 30 (second R-surface R2). That is, in this example, no slippage occurs between the workpiece 10 and the second R-surface R2 until the tilt angle is reduced to 30 degrees, and slippage occurs between the workpiece 10 and the second R-surface R2 after the tilt angle becomes smaller than 30 degrees.

[0041] Equation (5) will be further explained. At the start of the first step shown in Figure 4, the contact points between the workpiece 10 and the first R-face R1 and the second R-face R2 are designated as Bs and Cs, respectively. At the start of the first step, the tilt angle θ of the workpiece 10 is 90 degrees, and the workpiece 10 is sandwiched between the punch 20 and the die 30 with its main surface perpendicular to the direction DR.

[0042] The outer diameter of the workpiece 10 is D bo and the inner diameter of the workpiece 10 is d biThe thickness of the workpiece 10 is t. The width W of the workpiece 10 is W is the outer diameter D bo and inner diameter d bi Using W W =(D bo -d bi ) / 2. The diameter of the main body 21 of the punch 20 is expressed as D p The radius of the first R surface R1 is r p The diameter of the protruding portion 22 of the punch 20 is D pL The inner diameter of the die 30 (the distance between the inner peripheral surfaces 32) is D d The radius of the second R surface R2 is r d and the diameter of the opening 30a is D h In this example, the diameter D of the protrusion 22 is pL and the inner diameter D of die 30 d The outer diameter D of the workpiece 10 is set to be approximately equal. bo is, for example, about 10 mm to 60 mm.

[0043] As shown in FIG. 4, the distance between the edge 10ba of the workpiece 10 and the point Bs is (D p / 2-r p )-d bi On the other hand, as shown in Figures 6 and 7, the distance between point Bs and contact point B is expressed as 2πr p × (90°-θ) / 360°, where (90°-θ) is the angle of inclination of the workpiece 10 from the start of the first step until the inclination angle θ reaches 30 degrees, and 2πr p ×(90°-θ) / 360° is the radius r corresponding to that angle p Therefore, the distance Z between the edge 10ba and the contact point B is d is Z d ={(D p / 2-r p )-d bi / 2}+2πr p × (90°-θ) / 360°. As described above, the width W of the workpiece 10 W is W W =(D bo -d bi) / 2, the first conditional expression can also be expressed as the following expression (6). That is, when the following expression (6) is satisfied at the point in time when the tilt angle θ of the workpiece 10 is 30 degrees, a state is achieved in which the punch 20 is caught by the die 30 and the biting of the workpiece 10 is suppressed. As described above, in this example, the constant A is set to 2 / 5.

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[0044] A second condition is that the end face of the workpiece 10 must be able to be pressed into by the protruding portion 22 of the punch 20 in the second step. If the end face of the workpiece 10 cannot be pressed into by the protruding portion 22 in the second step, there is a risk that the workpiece 10 will be crushed by the protruding portion 22, as illustrated in Figures 8(a) and 8(b). Therefore, in the manufacturing method for a bearing ring member according to the embodiment, the second conditional expression, which will be explained below as Expression (7), is satisfied, and the protruding portion 22 is able to reliably press into the workpiece 10.

[0045] Fig. 9 is a cross-sectional view in a state where the inclination angle θ of the workpiece 10 is equal to the inclination angle α of the tapered surface 31. Fig. 10 is a diagram for explaining the position of the contact point C between the workpiece 10 and the second R-surface R2. Hatching indicating the cross section is omitted in Fig. 9.

[0046] The inventors have discovered that if the following formula (7) (second conditional formula) is satisfied at the start of the second step (the state shown in Figure 9), the workpiece member 10 can be reliably pushed in by the protrusion 22.

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[0047] Further explanation of equation (7) is as follows. As shown in FIG. 9, the first term on the right side (D h / 2-r d cosα) is the distance from the center line CL to the contact point C in the radial direction. The second term on the right side, {t / cosα-(Z D + t × tan α) sin α} is the distance in the radial direction between the edge 10aa of the workpiece member 10 and the contact point C. Therefore, the entire right side of equation (7) represents the distance from the center line CL to the edge 10aa of the workpiece member 10 in the radial direction.

[0048] As shown in FIGS. 9 and 10, the distance Z between the edge 10ab of the workpiece 10 and the contact point C D is Z D =(D bo -D h ) / 2+2πr d ×(90°-α) / 360°. The first term on the right side (D bo -D h ) / 2 is the distance in the radial direction between the edge 10ab and the contact point Cs between the workpiece 10 and the second R surface R2 at the start of the first step (see FIG. 4). d × (90°-α) / 360° is the distance between point Cs and contact point C. (90°-α) is the angle of inclination of the workpiece 10 from the start of the first step until the inclination angle θ becomes angle α, and 2πr d ×(90°-α) / 360° is the radius r corresponding to the angle d As shown in Figure 5, the diameter D h Regarding, for example, D h / 2=D d / 2+3 / 4×W W sinα+r dIn this case, the diameter D h is D h =D d +3 / 2×W W sinα+2r d It is expressed as cosα. [Action and effect]

[0049] In the manufacturing method of the bearing ring member 1 according to the embodiment, the punch 20 has a first R-surface R1 that is formed in an arc shape in a cross section parallel to the direction DR, and the die 30 has a second R-surface R2 that is formed in an arc shape in a cross section parallel to the direction DR, and a tapered surface 31 that is formed on a second side S2 of the second R-surface R2 and that is inclined so as to approach the center in the radial direction as it approaches the second side S2. In the reversing process, a first step is performed in which the workpiece 10 is deformed by the punch 20 and the die 30 with the first R-surface R1 and the second R-surface R2 in contact with the workpiece 10, and then a second step is performed in which the workpiece 10 is deformed by the punch 20 and the die 30 with the first R-surface R1 and the tapered surface 31 in contact with the workpiece 10. Because the punch 20 and the die 30 have a simple shape or a shape consisting of a combination thereof, it is possible to determine in advance based on geometric calculations whether reversing can be performed well. Therefore, according to this manufacturing method for the bearing ring member 1, it is possible to simplify the design and manufacturing of the bearing ring member 1. Furthermore, it is possible to simplify the design of the punch 20 and the die 30, thereby reducing differences depending on the designer. Furthermore, it is possible to increase the number of designers, thereby distributing the load. Furthermore, it is possible to improve work efficiency and reduce prototyping costs.

[0050] When the inclination angle θ of the workpiece 10 relative to the direction DR is 30 degrees, the above formulas (5) and (6) are satisfied. This makes it possible to prevent the punch 20 from biting into the workpiece 10 while it is caught on the die 30, and allows the workpiece 10 to be reversed well.

[0051] At the start of the second step, the radially inner edge 10aa of the end 10a on the first side S1 of the workpiece member 10 is located radially inward of the outer edge of the protruding portion 22 of the punch 20. This allows the protruding portion 22 to reliably press the workpiece member 10 into place, thereby enabling good inversion processing of the workpiece member 10.

[0052] At the start of the second step, the above formula (7) is satisfied, which allows the workpiece 10 to be reliably pressed in by the protruding portion 22 of the punch 20, and the workpiece 10 can be reversed well. [Variations]

[0053] As a first modification, in the above embodiment, slippage occurs between the workpiece 10 and the second R-surface R2 in the range where the tilt angle of the workpiece 10 in the first step is reduced to less than 30 degrees, but slippage does not have to occur between the workpiece 10 and the second R-surface R2 throughout the entire first step. Similar to the above embodiment, the first modification also makes it possible to simplify the manufacture of the bearing ring member 1. Whether or not slippage occurs can be determined using the predicted value M of the limit bending moment of the workpiece 10, which will be explained below.

[0054] If the bending moment (maximum bending moment) acting on the workpiece 10 is smaller than the predicted value M of the limit bending moment of the workpiece 10 calculated by the following equation (8), no slippage occurs between the workpiece 10 and the die 30, and the workpiece 10 stands up without slipping on the die 30 in the first step.

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[0055] FIG. 11 is a graph showing an example of the bending moment acting on the workpiece 10 in the reversing step. The horizontal axis of FIG. With respect to the horizontal direction (direction perpendicular to the axial direction) of the workpiece 10 The vertical axis represents the tilt angle θ (°), and the vertical axis represents the bending moment (N·m) acting on the workpiece 10. As shown in Fig. 11, in this example, the bending moment is smaller than the predicted value M of the limit bending moment when the tilt 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 die 30 within this range.

[0056] In order to perform the reversal processing of the workpiece 10 successfully, the workpiece 10 needs to start sliding relative to the die 30 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 the first modified example described above, 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. In other words, the shapes of the punch 20 and the die 30 are determined so that the bending moment acting on the workpiece 10 in the first step is smaller than the predicted value M. As a result, no slippage occurs between the workpiece 10 and the second R surface R2 of the die 30 in the first step, allowing the workpiece to be raised up successfully, and in the second step, the workpiece 10 slides on the tapered surface 31 of the die 30, allowing the workpiece 10 to be reliably drawn into the die 30.

[0057] FIG. 12 shows a second modified example. FIG. 12(a) is a cross-sectional view of the punch 20 and workpiece 10 at the start of the second step, and FIG. 12(b) is a cross-sectional view of the die 30 and workpiece 10 at the start of the second step. In the punch 20 of the second modified example, the first region 41 of the first rounded surface R1 that contacts the workpiece 10 during the second step is roughened. In FIG. 12(a), the roughened area of the first region 41 is indicated by an arrow AR. As a result, the surface roughness of the first region 41 is greater than the surface roughness of the second region 42 of the first rounded surface R1 other than the first region 41. The surface roughness is the arithmetic mean roughness Ra (JIS B 0601 4.2.1). The second region 42 and the outer peripheral surface 21a may be ground or lapped to improve sliding.

[0058] Furthermore, in the die 30 of the second modified example, the tapered surface 31 is roughened. In Fig. 12(b), the range of the roughened tapered surface 31 is indicated by an arrow AR. As a result, the surface roughness of the tapered surface 31 is greater than the surface roughness of the second rounded surface R2. The second rounded surface R2 and the inner peripheral surface 32 may be ground surfaces or lapped surfaces to improve sliding.

[0059] In the second modified example, the reversing process is performed in a state in which the surface roughness of the first region 41 is greater than the surface roughness of the second region 42, and the surface roughness of the tapered surface 31 is greater than the surface roughness of the second R-surface R2. As with the above embodiment, the second modified example also makes it possible to facilitate the manufacture of the bearing ring member 1. Furthermore, depending on the size of the workpiece 10, the punch 20 may be prone to biting into the workpiece 10. However, by performing the reversing process in the above state, biting can be reliably suppressed, and the reversing process can be performed satisfactorily.

[0060] The manufacturing method of the bearing ring member 1 according to the second modification may include a step of polishing at least one of the punch 20 and the die 30 to achieve the above-described condition before the reversing step. For example, when the punch 20 wears due to repeated reversing processes and biting is likely to occur, the second region 42 of the punch 20 may be polished. Alternatively, when the die 30 wears and biting is likely to occur, the second R-surface R2 of the die 30 may be polished. This prevents a situation in which the above-described condition is no longer met due to wear of at least one of the punch 20 and the die 30, resulting in a biting defect. Note that in the second modification, both the first condition that the surface roughness of the first region 41 is greater than that of the second region 42 and the second condition that the surface roughness of the tapered surface 31 is greater than that of the second R-surface R2 are satisfied. However, the reversing may be performed when only one of the first and second conditions is satisfied.

[0061] FIG. 13 shows a third modified example, where FIG. 13(a) is a cross-sectional view of the punch 20 and workpiece 10 at the start of the second step, and FIG. 13(b) is a cross-sectional view of the die 30 and workpiece 10 at the start of the second step. In the punch 20 of the third modified example, the second region 42 of the first R surface R1 and a portion of the outer peripheral surface 21a that is continuous with the second region 42 are roughened. In FIG. 13(a), the roughened area is indicated by an arrow AR. As a result, the surface roughness of the second region 42 is greater than the surface roughness of the first region 41. In the third modified example, the first region 41 and the outer peripheral surface 21a other than the above-mentioned portion may be ground or lapped to improve sliding.

[0062] In addition, in the die 30 of the third modified example, the region including the second rounded surface R2 is roughened. In Fig. 13(b), the roughened range is indicated by an arrow AR. As a result, the surface roughness of the second rounded surface R2 is greater than the surface roughness of the tapered surface 31. In the third modified example, the tapered surface 31 and the inner peripheral surface 32 may be ground surfaces that have been subjected to a grinding process or lapped surfaces that have been subjected to a lapping process to improve sliding.

[0063] In the third modified example, the reversing process is performed in a state in which the surface roughness of the second region 42 is greater than that of the first region 41, and the surface roughness of the second R-surface R2 is greater than that of the tapered surface 31. As with the above embodiment, the third modified example also makes it possible to facilitate the manufacture of the bearing ring member 1. Furthermore, depending on the size of the workpiece 10, it may be difficult to press the workpiece 10 with the protruding portion 22 of the punch 20, but by performing the reversing process in the above state, it is possible to reliably prevent the occurrence of pressing failures and perform the reversing process well.

[0064] The manufacturing method of the bearing ring member 1 according to the third modification may include a step of polishing at least one of the punch 20 and the die 30 to achieve the above-described condition before the reversing step. For example, when the punch 20 wears due to repeated reversing processes and a pressing failure is likely to occur, the first region 41 of the punch 20 may be polished. Alternatively, when the die 30 wears and a pressing failure is likely to occur, the tapered surface 31 of the die 30 may be polished. This prevents a malfunction caused by wear of at least one of the punch 20 and the die 30, which causes the above-described condition to be no longer met. Note that in the third modification, both the first condition that the surface roughness of the second region 42 is greater than that of the first region 41 and the second condition that the surface roughness of the second R surface R2 is greater than that of the tapered surface 31 are satisfied. However, the reversing may be performed when only one of the first and second conditions is satisfied.

[0065] As a fourth modified example, the reversing step may further include a third step after the second step in which the workpiece 10 is sandwiched between the outer peripheral surface 21a of the punch 20 and the inner peripheral surface 32 of the die 30, thereby ironing the workpiece 10. Fig. 14 is a cross-sectional view for explaining the ironing step. In Fig. 14, the first R-surface R1, the second R-surface R2, etc. are omitted.

[0066] As an example, the gap (radial gap) between the outer peripheral surface 21a and the inner peripheral surface 32 in the third step may be set equal to the thickness of the workpiece 10. In normal reversal processing, the thickness of the radially inner portion of the workpiece 10 decreases and the thickness of the radially outer portion increases. By making the gap between the outer peripheral surface 21a and the inner peripheral surface 32 equal to the thickness of the workpiece 10 as in this example, the workpiece 10 can be squeezed (thinned) on the radially outer side where the thickness increases, and the thickness of the bearing ring member 1 obtained after processing can be matched to the thickness of the workpiece 10.

[0067] As another example, the gap between the outer peripheral surface 21a and the inner peripheral surface 32 in the third step may be set to be smaller than the thickness of the workpiece 10. For example, the gap may be set to be equal to the thickness of the radially inner portion of the workpiece 10 after normal reversal processing. In this case, the thickness of the bearing ring member 1 obtained after processing can be matched to the thickness of the radially inner portion of the workpiece 10, the thickness of which is reduced.

[0068] As with the above embodiment, the fourth modified example also makes it possible to facilitate the manufacture of the bearing ring member 1. Furthermore, by performing ironing between the outer peripheral surface 21 a of the punch 20 and the inner peripheral surface 32 of the die 30, the roundness of the resulting bearing ring member 1 can be improved.

[0069] The present disclosure is not limited to the above-described embodiment and modified examples. In the above-described embodiment, both the first conditional expression regarding the bite and the second conditional expression regarding the pushing-in failure are satisfied, but only one of the first conditional expression and the second conditional expression may be satisfied. In the reversing step of the above-described embodiment, the punch 20 descends and approaches the die 30, thereby sandwiching the workpiece 10 between the punch 20 and the die 30. However, the punch 20 and the die 30 may move relative to each other. For example, the workpiece 10 may be sandwiched between the punch 20 and the die 30 by moving the two components closer to each other.

[0070] In the above embodiment, the punch 20 (main body 21) is formed in a substantially cylindrical shape, and the die 30 is formed in a substantially cylindrical shape. However, conversely, the punch 20 (main body 21) may be formed in a substantially cylindrical shape, and the die 30 may be formed in a substantially cylindrical shape. In this case, the first R-face R1 is formed on the inner edge of the surface of the second side S2 of the main body 21 of the punch 20. In the die 30, the second R-face R2 is formed on the outer edge of the surface of the first side S1 of the die 30. The tapered surface 31 is inclined so as to approach the radial center toward the first side S1 (so as to move away from the radial center toward the second side S2). In other words, it is sufficient that the tapered surface 31 is inclined with respect to the direction DR (predetermined direction). [Explanation of symbols]

[0071] 1...bearing ring member, 10...work member, 10a, 10b...end portion, 10aa, 10ab, 10ba...edge, 20...punch (die for reversing processing), 21...main body portion, 21a...outer peripheral surface, 22...protrusion portion, 30...die (die for reversing processing), 30a...opening, 31...tapered surface, 32...inner peripheral surface, 41...first region, 42...second region, DR...direction (predetermined direction), R1...first R surface, R2...second R surface, S1...first side, S2...second side.

Claims

1. A method for manufacturing a cylindrical bearing ring member, comprising: a reversing step of sandwiching and deforming an annular workpiece between a punch disposed on a first side in a predetermined direction and a die disposed on a second side opposite to the first side, the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, the die has a second rounded surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second rounded surface and inclined with respect to the predetermined direction, The inverting step includes: a first step of deforming the workpiece with the punch and the die while the first rounded surface and the second rounded surface are in contact with the workpiece; a second step of deforming the workpiece by the punch and the die in a state where the first R surface and the tapered surface are in contact with the workpiece after the first step, In the first step, no slippage occurs between the workpiece member and the second rounded surface, In the second step, slippage occurs between the workpiece and the tapered surface, The 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 member calculated by equation (1). [Equation 1] In equation (1), W W is the width of the workpiece, t is the thickness of the workpiece, and Y is the yield stress of the workpiece.

2. A method for manufacturing a cylindrical bearing ring member, comprising: a reversing step of sandwiching and deforming an annular workpiece between a punch disposed on a first side in a predetermined direction and a die disposed on a second side opposite to the first side, the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, the die has a second rounded surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second rounded surface and inclined with respect to the predetermined direction, The inverting step includes: a first step of deforming the workpiece with the punch and the die while the first rounded surface and the second rounded surface are in contact with the workpiece; a second step of deforming the workpiece by the punch and the die in a state where the first R surface and the tapered surface are in contact with the workpiece after the first step, the inclination angle of the tapered surface with respect to the predetermined direction is less than 30 degrees, A method for manufacturing a bearing ring member, wherein formula (2) is satisfied when the inclination angle θ of the work member with respect to the predetermined direction is 30 degrees. Z ｄ <W Ｗ ×A …(2) In the formula (2), Z ｄ is the distance between the radially inner edge of the second end of the workpiece and the contact point between the workpiece and the first R-surface, and W Ｗ is the width of the workpiece, and A is a constant greater than or equal to 0.2 and less than or equal to 0.

6.

3. A method for manufacturing a cylindrical bearing ring member, comprising: a reversing step of sandwiching and deforming an annular workpiece between a punch disposed on a first side in a predetermined direction and a die disposed on a second side opposite to the first side, the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, the die has a second rounded surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second rounded surface and inclined with respect to the predetermined direction, The inverting step includes: a first step of deforming the workpiece with the punch and the die while the first rounded surface and the second rounded surface are in contact with the workpiece; a second step of deforming the workpiece by the punch and the die in a state where the first R surface and the tapered surface are in contact with the workpiece after the first step, the punch has a cylindrical body portion on which the first R surface is formed, the inclination angle of the tapered surface with respect to the predetermined direction is less than 30 degrees, A method for manufacturing a bearing ring member, wherein formula (3) is satisfied when the inclination angle θ of the work member with respect to the predetermined direction is 30 degrees. [Equation 2] In the formula (3), D ｐ is the diameter of the body, and r ｐ is the radius of the first R surface, and d ｂｉ is the inner diameter of the workpiece, and D ｂｏ is the outside diameter of the workpiece and A is 2 / 5.

4. A method for manufacturing a cylindrical bearing ring member, comprising: a reversing step of sandwiching and deforming an annular workpiece between a punch disposed on a first side in a predetermined direction and a die disposed on a second side opposite to the first side, the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, the die has a second rounded surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second rounded surface and inclined with respect to the predetermined direction, The inverting step includes: a first step of deforming the workpiece with the punch and the die while the first rounded surface and the second rounded surface are in contact with the workpiece; a second step of deforming the workpiece by the punch and the die in a state where the first R surface and the tapered surface are in contact with the workpiece after the first step, the punch has a cylindrical main body portion on which the first R surface is formed, and a protrusion portion formed on the first side of the main body portion and protruding radially outward from the main body portion, A method for manufacturing a bearing ring member, wherein, at the start of the second step, the radially inner edge of the first side end of the work member is located radially inward of the outer edge of the protrusion.

5. A method for manufacturing a cylindrical bearing ring member, comprising: a reversing step of sandwiching and deforming an annular workpiece between a punch disposed on a first side in a predetermined direction and a die disposed on a second side opposite to the first side, the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, the die has a second rounded surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second rounded surface and inclined with respect to the predetermined direction, The inverting step includes: a first step of deforming the workpiece with the punch and the die while the first rounded surface and the second rounded surface are in contact with the workpiece; a second step of deforming the workpiece by the punch and the die in a state where the first R surface and the tapered surface are in contact with the workpiece after the first step, the punch has a cylindrical main body portion on which the first R surface is formed, and a protrusion portion formed on the first side of the main body portion and protruding radially outward from the main body portion, A method for manufacturing a bearing ring member, wherein formula (4) is satisfied at the start of the second step. [Equation 3] In the formula (4), D ｐＬ is the diameter of the protrusion, and D ｈ is the diameter of the opening in the die defined by the second rounded surface, and r ｄ is the radius of the second R surface, α is the inclination angle of the tapered surface with respect to the predetermined direction, t is the thickness of the workpiece, and Z Ｄ is the distance between the radially outer edge of the first end of the work member and the contact point between the work member and the second R-surface.

6. A method for manufacturing a cylindrical bearing ring member, comprising: a reversing step of sandwiching and deforming an annular workpiece between a punch disposed on a first side in a predetermined direction and a die disposed on a second side opposite to the first side, the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, the die has a second rounded surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second rounded surface and inclined with respect to the predetermined direction, The inverting step includes: a first step of deforming the workpiece with the punch and the die while the first rounded surface and the second rounded surface are in contact with the workpiece; a second step of deforming the workpiece by the punch and the die in a state where the first R surface and the tapered surface are in contact with the workpiece after the first step, A method for manufacturing a bearing ring member, in which the inversion process is carried out in a state in which the surface roughness of a first region of the first R surface that comes into contact with the workpiece in the second process is greater than the surface roughness of a second region of the first R surface other than the first region.

7. A method for manufacturing a cylindrical bearing ring member, comprising: a reversing step of sandwiching and deforming an annular workpiece between a punch disposed on a first side in a predetermined direction and a die disposed on a second side opposite to the first side, the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, the die has a second rounded surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second rounded surface and inclined with respect to the predetermined direction, The inverting step includes: a first step of deforming the workpiece with the punch and the die while the first rounded surface and the second rounded surface are in contact with the workpiece; a second step of deforming the workpiece by the punch and the die in a state where the first R surface and the tapered surface are in contact with the workpiece after the first step, The method for manufacturing a bearing ring member includes carrying out the inversion step in a state in which the surface roughness of the tapered surface is greater than the surface roughness of the second R surface.

8. A method for manufacturing a cylindrical bearing ring member, comprising: a reversing step of sandwiching and deforming an annular workpiece between a punch disposed on a first side in a predetermined direction and a die disposed on a second side opposite to the first side, the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, the die has a second rounded surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second rounded surface and inclined with respect to the predetermined direction, The inverting step includes: a first step of deforming the workpiece with the punch and the die while the first rounded surface and the second rounded surface are in contact with the workpiece; a second step of deforming the workpiece by the punch and the die in a state where the first R surface and the tapered surface are in contact with the workpiece after the first step, A method for manufacturing a bearing ring member, in which the inversion step is carried out in a state in which the surface roughness of a first region of the first R surface that comes into contact with the workpiece in the second step is greater than the surface roughness of a second region of the first R surface other than the first region, and the surface roughness of the tapered surface is greater than the surface roughness of the second R surface.

9. A method for manufacturing a cylindrical bearing ring member, comprising: a reversing step of sandwiching and deforming an annular workpiece between a punch disposed on a first side in a predetermined direction and a die disposed on a second side opposite to the first side, the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, the die has a second rounded surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second rounded surface and inclined with respect to the predetermined direction, The inverting step includes: a first step of deforming the workpiece with the punch and the die while the first rounded surface and the second rounded surface are in contact with the workpiece; a second step of deforming the workpiece by the punch and the die in a state where the first R surface and the tapered surface are in contact with the workpiece after the first step, A method for manufacturing a bearing ring member, in which the inversion process is carried out in a state in which the surface roughness of a second region other than the first region on the first R surface that contacts the work member in the second process is greater than the surface roughness of the first region on the first R surface.

10. A method for manufacturing a cylindrical bearing ring member, comprising: a reversing step of sandwiching and deforming an annular workpiece between a punch disposed on a first side in a predetermined direction and a die disposed on a second side opposite to the first side, the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, the die has a second rounded surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second rounded surface and inclined with respect to the predetermined direction, The inverting step includes: a first step of deforming the workpiece with the punch and the die while the first rounded surface and the second rounded surface are in contact with the workpiece; a second step of deforming the workpiece by the punch and the die in a state where the first R surface and the tapered surface are in contact with the workpiece after the first step, a second rounded surface having a surface roughness greater than that of the tapered surface;

11. A method for manufacturing a cylindrical bearing ring member, comprising: a reversing step of sandwiching and deforming an annular workpiece between a punch disposed on a first side in a predetermined direction and a die disposed on a second side opposite to the first side, the punch has a first R surface formed in an arc shape in a cross section parallel to the predetermined direction, the die has a second rounded surface formed in an arc shape in a cross section parallel to the predetermined direction, and a tapered surface formed on the second side of the second rounded surface and inclined with respect to the predetermined direction, The inverting step includes: a first step of deforming the workpiece with the punch and the die while the first rounded surface and the second rounded surface are in contact with the workpiece; a second step of deforming the workpiece by the punch and the die in a state where the first R surface and the tapered surface are in contact with the workpiece after the first step, A method for manufacturing a bearing ring member, in which the inversion step is carried out in a state in which the surface roughness of a second region other than the first region of the first R surface that contacts the workpiece in the second step is greater than the surface roughness of the first region of the first R surface, and the surface roughness of the second R surface is greater than the surface roughness of the tapered surface.

12. 12. The method for manufacturing a bearing ring member according to claim 6, further comprising, before the inverting step, a step of polishing at least one of the punch and the die to achieve the above-mentioned state.

13. The punch further has an outer circumferential surface formed on the first side of the first R surface, the die further has an inner circumferential surface formed on the second side of the tapered surface, 12. The method for manufacturing a bearing ring member according to claim 1, wherein the inverting step further includes a third step, after the second step, of ironing the work member by sandwiching the work member between the outer peripheral surface and the inner peripheral surface.

14. 14. The method for manufacturing a bearing ring member according to claim 13, wherein the gap between the outer peripheral surface and the inner peripheral surface in the third step is set to be equal to the thickness of the workpiece member.

15. The method for manufacturing a bearing ring member according to claim 13, wherein the gap between the outer peripheral surface and the inner peripheral surface in the third step is set to be smaller than a thickness of the workpiece member.

16. The method for manufacturing a bearing ring member according to any one of claims 1 to 11, wherein the tapered surface is inclined so as to approach a radial center side as it approaches the second side.

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