Method of manufacturing ring member for bearing

Abstract

To provide a method of manufacturing a ring member for a bearing capable of suppressing the occurrence of warpage in a reversing process.SOLUTION: The method for manufacturing a ring member for a includes an inversion step of performing inversion processing in which a workpiece member 10 having an annular workpiece main body portion 11 is sandwiched between a punch 30 and a die 40, and the workpiece member 10 is deformed such that the workpiece main body portion 11 has a cylindrical shape, and in the inversion step, the inversion processing is performed in a state where at least one of a central axial A30 of the punch 30 and a central axial A40 of the die 40 deviates from the central axial A10 of the workpiece member 10.SELECTED DRAWING: Figure 2

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 the inner or outer ring of a bearing. In this manufacturing method, the ring member is formed by clamping an annular workpiece member between a punch and a die and undergoing an inversion process in which the direction of the cross section is changed by 90 degrees. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-97809 Summary of the Invention [Problem to be solved by the invention]

[0004] In the manufacturing method described above, in order to ensure the quality of the manufactured ring member, it is required to prevent unnecessary deformation (for example, warpage) from occurring in the ring member during the inversion step.

[0005] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for manufacturing a bearing ring member that can suppress the occurrence of warping during the reversing step. [Means for solving the problem]

[0006] The manufacturing method of a ring member for a bearing of the present invention is [1] "a manufacturing method of a ring member for a bearing, comprising an inversion step of clamping a workpiece having a circular workpiece main body portion between a punch and a die, and performing an inversion process to deform the workpiece so that the workpiece main body portion becomes cylindrical, and in the inversion step, the inversion process is performed in a state where the central axis of at least one of the punch and the die is shifted from the central axis of the workpiece."

[0007] In this method for manufacturing a bearing ring member, in the inversion step, the inversion process is performed with the central axis of at least one of the punch and the die offset from the central axis of the workpiece. This makes it possible to prevent warping of the workpiece during the inversion process. The finding that warping can be prevented by performing the inversion process with the central axis of the punch or the die offset from the central axis of the workpiece is a finding discovered by the present inventors.

[0008] The manufacturing method of a bearing ring member of the present invention may be [2] "the manufacturing method of a bearing ring member according to [1], wherein in the reversing step, the reversing is performed in a state in which the central axis of at least one of the punch and the die is shifted from the central axis of the workpiece in a direction parallel to or perpendicular to the warpage direction in which warpage occurs in the workpiece during the reversing process." In this case, the occurrence of warpage in the reversing step can be effectively suppressed.

[0009] The manufacturing method of the bearing ring member of the present invention may be [3] "the manufacturing method of the bearing ring member according to [1] or [2], further comprising a confirmation step of performing the reversing process using a test die different from the die instead of the die before the reversing step, and confirming the warpage direction in which warpage occurs in the work member during the reversing process." In this case, the warpage direction in which warpage occurs in the work member during the reversing process can be known in advance.

[0010] The manufacturing method of the bearing ring member of the present invention may be [4] "the manufacturing method of the bearing ring member according to [3], wherein the test die has an inclined surface inclined at an angle of 30° or more with respect to the axial direction, and the inclined surface comes into contact with the workpiece during the reversing process in the checking step." In this case, warping can be reliably induced in the workpiece during the checking step.

[0011] The manufacturing method of a bearing ring member of the present invention may be [5] "the manufacturing method of a bearing ring member according to any one of [2] to [4], wherein in the reversing step, the reversing process is performed in a state in which the central axis of at least one of the punch and the die is shifted from the central axis of the workpiece in a direction parallel to or perpendicular to the warpage direction set based on the anisotropy of the workpiece." In this case, the warpage direction is set based on the anisotropy of the workpiece, and thus the occurrence of warpage in the reversing step can be effectively suppressed. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a method for manufacturing a bearing ring member that can suppress the occurrence of warping in the reversing step. [Brief explanation of the drawings]

[0013] [Figure 1] 1(a) is a cross-sectional view of a workpiece member, and FIG. 1(b) is a cross-sectional view of a bearing ring member. [Figure 2] FIG. 10 is a cross-sectional view illustrating an example of a reversing step. [Figure 3] FIG. 10 is a cross-sectional view illustrating another example of the reversing step. [Figure 4] 10(a), (b) and (c) are cross-sectional views for explaining the inversion step. [Figure 5] FIG. 1 is a diagram illustrating the causes of warpage. [Figure 6] This is an orthogonal table in which the extracted factors are assigned. [Figure 7] 1 is a graph showing the contribution rate of each factor to warpage. [Figure 8] This is a diagram showing the cause and effect of "mold misalignment / tilt." [Figure 9] FIG. 10 is a cross-sectional view for explaining a confirmation step. [Figure 10] FIG. 10 is a diagram for explaining a confirmation process. [Figure 11] 10(a) and 10(b) are diagrams for explaining the confirmation step. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted. [Method of manufacturing bearing ring components]

[0015] In the manufacturing method of a bearing ring member according to the embodiment, as shown in FIGS. 1 to 4, a bearing ring member 20 is manufactured from a workpiece member 10. FIGS. 1 to 4 show cross sections (cross sections passing through the central axis A10) parallel to the axial direction (direction parallel to the central axis A10) 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. While some of the components are omitted in FIGS. 1 to 4, each component has a uniform shape in the radial direction. This also applies to the other figures. Hereinafter, the direction parallel to the central axes of the workpiece member 10, the ring member 20, and the punch 30, die 40, and test die 50 (described later) will be referred to as the axial direction, the direction perpendicular to the central axis will be referred to as the radial direction, and the direction along the circumference of a circle centered on the central axis A10 when viewed from a direction parallel to the central axis A10 will be referred to as the circumferential direction.

[0016] 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.

[0017] 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 edge of the main body portion 21 on a first side S1 (the upper side in FIG. 1 ), and the other flange portion 23 extends radially outward from an edge of the main body portion 21 on a second side S2 (the side opposite to the first side S1) in the axial direction. Each of the flange portions 22, 23 is formed, for example, in the shape of an annular plate.

[0018] 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 inner edge of the workpiece main body 11 in the radial direction to one axial side (the upper side in FIG. 1 ) (first side S1), and the outer flange 13 extends from the outer edge of the workpiece main body 11 in the radial direction 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 cylindrical shape.

[0019] The manufacturing method of the bearing ring member of the embodiment includes an inversion process in which the workpiece member 10 is clamped between a punch 30 and a die 40 along the axial direction and inverted to deform the workpiece member 10 so that the workpiece main body 11 becomes cylindrical (FIG. 4). In the inversion process, the direction of the cross section of the workpiece member 10 changes by approximately 90 degrees. Each of the punch 30 and the die 40 has a uniform cross-sectional shape in the radial direction.

[0020] The punch 30 has a punch body 31 and a punch protrusion 32. The punch body 31 is formed in a substantially cylindrical shape with an axis parallel to the axial direction. An R-surface 33 is formed on the inner edge of the second side S2 of the punch body 31. The R-surface 33 is a curved surface formed by rounding the corners of the second side S2 of the punch body 31, and is formed in an arc shape in a cross section parallel to the axial direction ( FIG. 2 ). The punch protrusion 32 is formed on the end of the first side S1 of the punch body 31, and protrudes radially inward from the punch body 31. The punch protrusion 32 is formed, for example, in a cylindrical shape. The punch body 31 has a cylindrical inner surface 34 between the R-surface 33 and the punch protrusion 32.

[0021] The die 40 has a die body 41 and a die protrusion 42. The die body 41 is formed in a substantially cylindrical shape with an axis parallel to the axial direction. An R-surface 43 is formed on the outer edge of the first side S1 of the die body 41. The R-surface 43 is a curved surface formed by rounding the corners of the first side S1 of the die body 41, and is formed in an arc shape in a cross section parallel to the axial direction (FIG. 2). The die protrusion 42 is formed on the end of the second side S2 of the die body 41 and protrudes radially outward from the die body 41. The die protrusion 42 is formed, for example, in a cylindrical shape. The die body 41 has a cylindrical outer surface 44 between the R-surface 43 and the die protrusion 42.

[0022] The punch 30 has a central axis A30, and the die 40 has a central axis A40. In this embodiment, the central axis A30 of the punch 30 is offset from the central axis A10 of the workpiece member 10 and the central axis A40 of the die 40. That is, the workpiece member 10, punch 30, and die 40 are arranged so that the central axis A30 of the punch 30 is offset from the central axis A10 of the workpiece member 10 and the central axis A40 of the die 40. The distances from the central axis A30 to the central axes A10 and A40 are, for example, 0.05 mm or more and 0.5 mm or less. That is, when viewed from the axial direction, the central axis A30 of the punch 30 is spaced from the central axis A10 of the workpiece member 10 and the central axis A40 of the die 40. The central axis A30 of the punch 30 is parallel to the central axis A10 of the workpiece member 10 and the central axis A40 of the die 40. The central axis A40 of the die 40 is positioned on the same straight line as the central axis A10 of the workpiece 10. The direction in which the central axis A30 of the punch 30 is shifted is parallel to or perpendicular to the warpage direction in which warpage occurs in the workpiece 10 during reversal processing. This warpage direction is confirmed, for example, by a confirmation process described below. The direction in which the central axis A30 of the punch 30 is shifted may be any direction other than perpendicular or parallel to the warpage direction.

[0023] 3, the central axis A40 of the die 40 may be offset from the central axis A10 of the workpiece member 10 and the central axis A30 of the punch 30. In this example, the central axis A10 of the workpiece member 10 and the central axis A30 of the punch 30 are positioned on the same straight line. When viewed from the axial direction, the central axis A40 of the die 40 is spaced apart from the central axis A10 of the workpiece member 10 and the central axis A30 of the punch 30. In this way, one of the central axis A30 of the punch 30 and the central axis A40 of the die 40 may be offset from the central axis A10 of the workpiece member 10.

[0024] Alternatively, both the central axis A40 of the die 40 and the central axis A30 of the punch 30 may be offset from the central axis A10 of the workpiece member 10. In this case, the central axes A30, A10, and A40 may be aligned linearly in the radial direction. The central axes A30, A10, and A40 may be aligned in a direction parallel to the warp direction or in a direction perpendicular to the warp direction.

[0025] The direction in which the central axis A30 of the punch 30 is offset from the central axis A10 of the workpiece member 10 may intersect the direction in which the central axis A40 of the die 40 is offset from the central axis A10 of the workpiece member 10. For example, the direction in which the central axis A30 is offset from the central axis A10 may be parallel to the direction of warping, and the direction in which the central axis A40 is offset from the central axis A10 may be perpendicular to the direction of warping. Alternatively, the direction in which the central axis A40 is offset from the central axis A10 may be parallel to the direction of warping, and the direction in which the central axis A30 is offset from the central axis A10 may be perpendicular to the direction of warping.

[0026] As shown in FIG. 4, in the reversing process, the reversing process is performed in a state in which the central axis A30 of the punch 30 is misaligned with the central axis A10 of the workpiece 10 and the central axis A40 of the die 40. At the start of the reversing process, the punch 30 is positioned on a first side S1 relative to the die 40, and the die 40 is positioned on a second side S2 relative to the punch 30 (FIG. 4(a)). At the start of the reversing process, the workpiece 10 is placed on the die 40 with the workpiece main body 11 of the workpiece 10 in contact with the upper surface of the die 40. Then, for example, by moving (lowering) the punch 30 along the axial direction to approach the die 40, the workpiece 10 is sandwiched between the punch 30 and the die 40, and the workpiece 10 is deformed so as to rise outward in the radial direction (FIG. 4(b)). That is, in the inversion step, the workpiece member 10 is deformed so that the surface 11a of the workpiece member 10 facing the punch 30 (first side S1) before the inversion step faces radially outward after the inversion step.

[0027] Through the above steps, the workpiece main body 11, inner flange 12, and outer flange 13 of the workpiece member 10 become the main body 21, flange 22, and flange 23 of the ring member 20, respectively, and the ring member 20 (inner ring member) is obtained. As described above, in the inversion step of this embodiment, the inversion process is performed with the central axis A30 of the punch 30 offset from the central axis A10 of the workpiece member 10 and the central axis A40 of the die 40. This makes it possible to suppress warping of the workpiece member 10 during the inversion step. Note that the inversion process may also be performed with the central axis A40 of the die 40 offset from the central axis A10 of the workpiece member 10 and the central axis A30 of the punch 30, as in the modified example described above. In this case, it is also possible to suppress warping of the workpiece member 10 during the inversion step. [Analysis results]

[0028] The finding that warpage of the workpiece 10 can be suppressed by performing reversal processing while the central axis A30 of the punch 30 or the central axis A40 of the die 40 is shifted from the central axis A10 of the workpiece 10 is a finding discovered by the present inventor based on the following analysis. As will be explained below, in this analysis, data sets were set using an experimental design method, and 3D-CAE analysis was performed on each data set.

[0029] As shown in Figure 5, we first extracted possible causes of warpage of the workpiece during the inversion process. In Figure 5, "misalignment" of the "punch" refers to the central axis of the punch being misaligned with the central axis of the workpiece. "misalignment" of the "die" refers to the central axis of the die being misaligned with the central axis of the workpiece. "misalignment" of the "work" refers to the central axis of the workpiece being misaligned with the central axes of the punch and the die.

[0030] "Anisotropy" of "Work" refers to the anisotropy of the workpiece material. Details of anisotropy will be given later. "Dimensions" of "Work" refer to the height of the inner flange portion and outer flange portion. "Material hardness" of "Work" refers to the hardness of the workpiece material. "Inclination" of "Punch / Work" refers to the inclination of the central axis of the workpiece material relative to the central axis of the punch. "Friction" of "Punch / Work" refers to the magnitude of the static friction coefficient between the punch and the workpiece material. "Inclination" of "Die / Work" refers to the inclination of the central axis of the workpiece material relative to the central axis of the die. "Friction" of "Die / Work" refers to the magnitude of the static friction coefficient between the die and the workpiece material.

[0031] The anisotropy of a workpiece material refers to the degree to which the strain (ε1) in a first direction perpendicular to the first direction when the workpiece material is stretched (compressed) in that direction is not equal to the strain (ε2) in the second direction perpendicular to the first direction (see Fundamentals of Plastic Processing, Takao Kawanami et al., Morikita Publishing, 1st edition, 3rd printing, October 15, 1996). Anisotropy can be expressed, for example, as the r-value = ε1 / ε2.

[0032] Next, the extracted factors were assigned to an orthogonal array as shown in Figure 6, and eight data sets, No. 1 to No. 8, were set (design of experiments). The "die misalignment / tilt" shown in Figure 6 is a factor that combines the four factors shown in Figure 5: "punch" misalignment, "workpiece" misalignment, "die" misalignment, and "tilt" of the punch relative to the die. Four levels were set for the "die misalignment / tilt" factor. "1" to "4" in the "die misalignment / tilt" column in Figure 6 indicate the level at which "die misalignment / tilt" was set for each data set.

[0033] For the first level of "Die Misalignment / Tilt," the "punch" misalignment was set to 0.1 mm, the "work" misalignment was set to none, the "die" misalignment was set to none, and the "tilt" of the punch relative to the die was set to none. For the second level of "Die Misalignment / Tilt," the "punch" misalignment was set to none, the "work" misalignment was set to 0.1 mm, the "die" misalignment was set to none, and the "tilt" of the punch relative to the die was set to none. For the third level of "Die Misalignment / Tilt," the "punch" misalignment was set to none, the "work" misalignment was set to none, the "die" misalignment was set to 0.1 mm, and the "tilt" of the punch relative to the die was set to none. For the fourth level of "mold misalignment / tilt," the "punch" misalignment was set to none, the "workpiece" misalignment was set to none, the "die" misalignment was set to none, and the "tilt" of the punch relative to the die was set to 0.1 degrees.

[0034] The "workpiece anisotropy" shown in Figure 6 corresponds to the "anisotropy" of the "workpiece" shown in Figure 5. Two levels were set for "workpiece anisotropy." At the first level of "workpiece anisotropy," the workpiece was set to have no anisotropy. At the second level of "workpiece anisotropy," the workpiece was set to have anisotropy.

[0035] The "Work dimensions" shown in Figure 6 correspond to the "dimensions" of the "Work" shown in Figure 5. Two levels were set for the "Work dimensions." In the first level of "Work dimensions," the heights of the inner flange and outer flange were set to the design values. In the second level of "Work dimensions," the heights of the inner flange and outer flange were set to the actual measured values.

[0036] The "friction" shown in Figure 6 corresponds to the "friction between punch and workpiece" and the "friction between die and workpiece" shown in Figure 5. Two levels of "friction" were set. In the first level of "friction," the static friction coefficient between the punch and workpiece and the static friction coefficient between the die and workpiece were set to 0.1. In the second level of "friction," the static friction coefficients were set to 0.04.

[0037] The "workpiece hardness" shown in Figure 6 corresponds to the "material hardness" of the "workpiece" shown in Figure 5. Two levels of "workpiece hardness" were set. In the first level of "workpiece hardness," the hardness of the workpiece material was set to the hardness of SK85 (carbon tool steel). In the second level of "workpiece hardness," the hardness of the workpiece material was set to 1.1 times the hardness of SK85.

[0038] Next, 3D-CAE analysis was performed on each of the eight data sets to calculate the amount of warpage during reversal processing. Then, based on the warpage results, the contribution rate of each factor shown in Figure 6 was calculated. Figure 7 shows the results showing the contribution rate of each factor. As shown in Figure 7, the factor that contributed most to the amount of warpage was "mold misalignment / tilt." The factor that contributed next to the amount of warpage was "workpiece anisotropy." The factor that contributed next to the amount of warpage was "friction." The factor that contributed next to the amount of warpage was "workpiece dimensions." The factor that contributed least to the amount of warpage was "workpiece hardness."

[0039] Next, we created a factor-effect diagram (Figure 8) for each factor constituting "mold misalignment / tilt," which had the greatest contribution to warpage. The "punch misalignment" value in Figure 8 represents the warpage amount when "mold misalignment / tilt" is at the first level, i.e., the average of the warpage amounts in data set No. 1 and data set No. 2. The "workpiece misalignment" value in Figure 8 represents the warpage amount when "mold misalignment / tilt" is at the second level, i.e., the average of the warpage amounts in data set No. 3 and data set No. 4. The "die misalignment" value in Figure 8 represents the warpage amount when "mold misalignment / tilt" is at the third level, i.e., the average of the warpage amounts in data set No. 5 and data set No. 6. The "punch tilt" value in Figure 8 represents the warpage amount when "mold misalignment / tilt" is at the fourth level, i.e., the average of the warpage amounts in data set No. 7 and data set No. 8.

[0040] 7, it can be seen that warpage is effectively suppressed when the central axis of the punch is misaligned with the central axis of the workpiece member, and when the central axis of the die is misaligned with the central axis of the workpiece member. From the above, the present inventors have discovered the finding that warpage of the workpiece member 10 can be suppressed by performing reversal processing in a state in which the central axis A30 of the punch 30 or the central axis A40 of the die 40 is misaligned with the central axis A10 of the workpiece member 10. [Action and effect]

[0041] As described above, in the manufacturing method of the bearing ring member of the embodiment, in the reversing step, the reversing process is performed in a state where at least one of the central axis A30 of the punch 30 and the central axis A40 of the die 40 is misaligned with the central axis A10 of the workpiece member 10. This makes it possible to suppress warping of the workpiece member during the reversing step.

[0042] In the reversing process, the reversing process is performed in a state in which at least one of the central axis A30 of the punch 30 and the central axis A40 of the die 40 is shifted from the central axis A10 of the workpiece 10 in a direction parallel to or perpendicular to the warpage direction in which warpage occurs in the workpiece 10 during the reversing process. This makes it possible to effectively suppress the occurrence of warpage in the reversing process. [Confirmation process]

[0043] The method for manufacturing a bearing ring member may include a confirmation step, prior to the reversing step, of confirming the warpage direction in which warpage occurs in the work member during reversing. In the confirmation step, for example, as shown in Figures 9 to 11, the reversing process is performed using a test die 50 instead of the die 40, thereby confirming the warpage direction.

[0044] First, the timing for checking the warpage direction of the workpiece member 10 will be explained. For example, in the production process of the ring member 20, a coil material around which a thin plate is wound is unwound, and the unwound thin plate is placed in a press. After the entire unwound thin plate is placed in the press, more coil material around which a thin plate is wound is added (the coil material is replaced). The timing for checking the warpage direction of the workpiece member 10 is before the coil material is replaced. For example, the warpage direction of the workpiece member 10 can be checked by cutting off a portion of the coil material and performing a checking process on the cut-off portion.

[0045] The test die 50 is a die having a different shape from the die 40. The shape of the test die 50 is set so that warping of the workpiece 10 is more likely to occur when the test die 50 is used than when the die 40 is used. The test die 50 has a central axis A50. The test die 50 has a test die main body 51 and a test die protrusion 52. The test die main body 51 is formed in a substantially cylindrical shape with an axis parallel to the axial direction. The test die main body 51 has an inclined surface 53 (tapered surface) inclined with respect to the axial direction formed on the radially outer side. The inclined surface 53 is inclined with respect to the axial direction so as to move away from the central axis A50 as it moves toward the second side S2. In this example, the inclination angle θ of the inclined surface 53 with respect to the axial direction is 30 degrees. The inclination angle θ may be greater than 30 degrees. The test die protrusion 52 is formed at the end of the second side S2 of the test die body 51 and protrudes radially outward from the test die body 51. The test die protrusion 52 is formed, for example, in a cylindrical shape. The test die body 51 has a cylindrical outer surface 54 between the inclined surface 53 and the test die protrusion 52.

[0046] When the reversing process is performed in the confirmation process, the central axis A30 of the punch 30, the central axis A50 of the test die 50, and the central axis A10 of the workpiece 10 are aligned on the same line and are not misaligned. When the reversing process is performed in the confirmation process, the workpiece 10 is sandwiched between the punch 30 and the test die 50 and deformed so that it rises outward in the radial direction. When the reversing process in the confirmation process begins, the punch 30 is positioned on the first side S1 of the test die 50, and the test die 50 is positioned on the second side S2 of the punch 30. When the reversing process in the confirmation process begins, the workpiece 10 is placed on the test die 50 with the workpiece main body 11 of the workpiece 10 in contact with the top surface of the test die 50. Then, for example, by moving (lowering) the punch 30 along the axial direction to approach the test die 50, the workpiece 10 is sandwiched between the punch 30 and the test die 50 and the workpiece 10 is deformed so that it rises outward in the radial direction. At this time, the inclined surface 53 of the test die 50 comes into contact with the workpiece 10 .

[0047] In the reversal process performed by the punch 30 and the test die 50, the workpiece 10 is prone to warping due to the presence of the inclined surface 53, and warping can occur in the workpiece 10, for example, as shown in Figures 10, 11(a) and 11(b). Here, the direction in which the diameter of the workpiece 10 is the minimum distance D is defined as the warping direction of the workpiece 10. The warping direction of the workpiece 10 can be confirmed by the above confirmation process.

[0048] In the reversing process after the confirmation process, the reversing process is performed in a state where at least one of the central axis A30 of the punch 30 and the central axis A40 of the die 40 is shifted from the central axis A10 of the workpiece 10, for example, in a direction parallel to or perpendicular to the warpage direction confirmed in the confirmation process. This makes it possible to effectively suppress the occurrence of warpage in the reversing process. Note that the finding that warpage can be suppressed by performing the reversing process in a state where the central axis A30 of the punch 30 and the central axis A40 of the die 40 are shifted from the central axis A10 of the workpiece 10 is a newly discovered finding.

[0049] 10, 11(a), and 11(b), direction D1 is a direction parallel to the warpage direction of the workpiece member 10. Direction D2 is a direction perpendicular to direction D1, i.e., a direction perpendicular to the warpage direction of the workpiece member 10. In the reversing process after the confirmation process, reversing processing is performed in a state in which at least one of the central axis A30 of the punch 30 and the central axis A40 of the die 40 is shifted from the central axis A10 of the workpiece member 10 in direction D1 or direction D2.

[0050] This method for manufacturing a bearing ring member includes a confirmation step in which, prior to the reversing step, reversing is performed using a test die 50 different from the die 40 instead of the die 40, and the warpage direction in which warpage will occur in the workpiece 10 during reversing is confirmed. This makes it possible to know in advance the warpage direction in which warpage will occur in the workpiece 10 during reversing.

[0051] The test die 50 has an inclined surface 53 inclined at an angle of 30° or more relative to the axial direction, and during the reversal process in the confirmation step, the inclined surface 53 comes into contact with the workpiece 10. This ensures that the workpiece 10 is warped during the confirmation step. [Variations]

[0052] A manufacturing method of a bearing ring member according to a modified example will be described. In the manufacturing method of a bearing ring member according to the modified example, in the confirmation step, reversal processing is performed using a test die 50, and instead of confirming the warpage direction in which warpage occurs in the workpiece member 10 during reversal processing, the warpage direction is confirmed based on the anisotropy of the workpiece member 10.

[0053] In the confirmation process of the manufacturing method of the bearing ring member according to the modified example, the warpage direction is confirmed based on the anisotropy of the workpiece member 10. Specifically, if the anisotropy of the coil material, which is the material of the workpiece member 10, i.e., the r-value of the coil material, is known, the warpage direction can be determined by performing 3D-CAE analysis using the test die 50 as a model. The r-value of the coil material may be determined by cutting off a portion of the coil material and performing a tensile test on the cut portion. In this case, it is desirable to cut off the end of the coil material before unwinding it and determine the r-value of the cut coil material. Thus, in the modified example, the warpage direction of the workpiece member 10 is set based on the anisotropy of the workpiece member 10.

[0054] In the reversing step of the manufacturing method of a bearing ring member according to the modified example, the reversing process is performed in a state in which at least one of the central axis A30 of the punch 30 and the central axis A40 of the die 40 is shifted from the central axis A10 of the workpiece 10 in a direction parallel to or perpendicular to the direction of warpage confirmed in the confirmation step. This allows the warpage direction to be set based on the anisotropy of the workpiece 10, making it possible to effectively suppress the occurrence of warpage in the reversing step.

[0055] The present invention is not limited to the above-described embodiment and modifications. For example, the materials and shapes of the components are not limited to those described above, and various materials and shapes can be adopted.

[0056] This manufacturing method for a bearing ring member may also be used to produce an outer ring. When producing an outer ring, a cylindrical punch and a cylindrical die that surrounds the punch when viewed from the axial direction are used in the reversing step. When producing an outer ring, the reversing step involves sandwiching the workpiece 10 between the punch and the die with the central axis of the punch offset from the central axis of the workpiece 10 and the central axis of the die, and performing a reversing process to deform the workpiece 10 so that it rises radially inward.

[0057] In the above-described method for manufacturing a bearing ring member, a method for manufacturing the ring member 20 from a U-shaped workpiece member 10 has been described, but the workpiece member may also be flat. That is, the workpiece member may not have a flange portion. In this case, the ring member formed does not have a flange portion.

[0058] In the above-described method for manufacturing a bearing ring member, the warpage direction of the workpiece 10 is checked by performing a confirmation step. However, a method other than performing a confirmation step may be used to check the warpage direction of the workpiece 10. For example, the warpage direction of the workpiece 10 may be checked by performing a reversing process on the workpiece 10 using the punch 30 and die 40 that are actually used in the reversing step.

[0059] The inclination angle of the inclined surface 53 of the test die 50 relative to the axial direction is 30 degrees or more, but the inclination angle may be smaller than 30 degrees. [Explanation of symbols]

[0060] 10...workpiece member, 11...workpiece main body, 30...punch, 40...die, 50...test die, 53...inclined surface, A10, A30, A40...central axis, D1...direction (parallel direction), D2...direction (perpendicular direction).

Claims

1. a reversing step of clamping a workpiece member having an annular workpiece main body portion between a punch and a die, and performing reversing processing to deform the workpiece member so that the workpiece main body portion becomes cylindrical; In the inverting step, the inverting process is performed in a state where the central axis of at least one of the punch and the die is shifted from the central axis of the workpiece.

2. 2. The method for manufacturing a bearing ring member according to claim 1, wherein in the inversion process, the inversion processing is performed in a state in which the central axis of at least one of the punch and the die is shifted from the central axis of the workpiece in a direction parallel to or perpendicular to a warping direction in which warping occurs in the workpiece during the inversion processing.

3. 3. The method for manufacturing a bearing ring member according to claim 1, further comprising a confirmation step of, before the reversing step, performing the reversing process using a test die different from the die instead of the die, and confirming the warpage direction in which warpage occurs in the workpiece member during the reversing process.

4. The test die has an inclined surface inclined at an angle of 30° or more with respect to an axial direction, The method for manufacturing a bearing ring member according to claim 3 , wherein the inclined surface comes into contact with the workpiece during the reversing process in the checking step.

5. 3. The method for manufacturing a bearing ring member according to claim 2, wherein in the inversion step, the inversion processing is performed in a state in which the central axis of at least one of the punch and the die is shifted from the central axis of the workpiece in a direction parallel to or perpendicular to a warpage direction set based on the anisotropy of the workpiece.

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