Raceway rings, rolling bearings, and methods for manufacturing raceway rings

Abstract

This invention provides a raceway that allows for the non-destructive and accurate measurement of compressive residual stress on the raceway surface. [Solution] The raceway ring (20) is made of hardened and tempered steel and has a raceway surface (20ca). The raceway surface is machined to impart compressive residual stress. The amount of retained austenite in the raceway surface is 3 volume percent or less. The residual magnetism in the raceway surface is 0.3 mT or less.

Description

Technical Field

[0001] The present invention relates to a raceway ring, a rolling bearing, and a method for manufacturing a raceway ring.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2020-197288 (Patent Document 1) describes a raceway ring. In the raceway ring described in Patent Document 1, machining is performed on the raceway surface of the raceway ring, whereby compressive residual stress is imparted to the raceway surface. In the raceway ring described in Patent Document 1, since compressive residual stress is imparted to the raceway surface, the rolling fatigue life is improved.

[0003] Japanese Patent No. 7031109 (Patent Document 2) describes a method for measuring residual stress. In the method for measuring residual stress described in Patent Document 2, the ratio of impedances before and after machining is measured based on the eddy current flowing through the specimen, and the residual stress is measured nondestructively based on the ratio of the impedances.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The impedance measured in the method for measuring residual stress described in Patent Document 2 is affected by the amount of retained austenite and residual magnetism at the measurement location. In particular, as the compressive residual stress at the machining location increases with machining, the amount of retained austenite decreases due to machining-induced transformation. Therefore, it is difficult to accurately measure the residual stress by the method for measuring residual stress described in Patent Document 2.

[0006] This invention has been made in view of the problems of the prior art described above. More specifically, this invention provides a raceway ring and a bearing using the same, which improve and enhance rolling fatigue life by applying compressive residual stress to the raceway surface, and which allows for accurate non-destructive measurement of the compressive residual stress on the raceway surface. [Means for solving the problem]

[0007] The raceway ring of the present invention is made of hardened and tempered steel and has a raceway surface. The raceway surface is machined to impart compressive residual stress. The amount of retained austenite in the raceway surface is 3 volume percent or less. The residual magnetism in the raceway surface is 0.3 mT or less. [Effects of the Invention]

[0008] According to the present invention, the raceway ring makes it possible to accurately measure compressive residual stress on the raceway surface in a non-destructive manner. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view of the rolling bearing 100. [Figure 2] This is a manufacturing process diagram showing the manufacturing method of the outer ring 20. [Figure 3] This is a cross-sectional view of the workpiece 50 prepared in preparation step S1. [Figure 4] This is a manufacturing process diagram showing a method for manufacturing the outer ring 20 according to a modified example. [Figure 5] This graph shows the measured impedance ratios for Sample 1 and Sample 2. [Figure 6] This graph shows the amount of retained austenite in the orbital surface and the compressive residual stress imparted to the orbital surface in Sample 3 and Sample 4. [Figure 7A] This graph shows the measurement results of the impedance ratio in Sample 3. [Figure 7B] This graph shows the measurement results of the impedance ratio in Sample 4. [Figure 8] A graph showing the amount of retained austenite on the raceway surface and the compressive residual stress applied to the raceway surface in Sample 5 and Sample 6. [Figure 9] A graph showing the measurement results of the impedance ratio in Sample 5 and Sample 6. [Figure 10] A graph showing the compressive residual stress on the raceway surface of the raceway wheels from Sample 7 to Sample 9. [Figure 11] A graph showing the results of the rolling fatigue life test for Samples 7 to Sample 9. [Figure 12] A graph showing the measurement results of the impedance ratio on the raceway surface of the raceway wheels of Sample 10 and Sample 11.

Embodiments for Carrying out the Invention

[0010] The details of the embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions will not be repeated. The rolling bearing according to the embodiment is designated as rolling bearing 100.

[0011] (Configuration of the rolling bearing 100) The configuration of the rolling bearing 100 will be described below.

[0012] FIG. 1 is a cross-sectional view of the rolling bearing 100. As shown in FIG. 1, the rolling bearing 100 is a tapered roller bearing. However, the tapered roller bearing is an example of the rolling bearing 100, and the rolling bearing 100 may be other than the tapered roller bearing. The rolling bearing 100 is, for example, for railway vehicles. However, the use of the rolling bearing 100 is not limited thereto.

[0013] The rolling bearing 100 has an inner ring 10, an outer ring 20, a plurality of rolling elements 30, and a cage 40. The central axis of the rolling bearing 100 is defined as the central axis A. The direction along the central axis A is defined as the axial direction. The direction along the circumference centered on the central axis A when viewed along the axial direction is defined as the circumferential direction. The direction perpendicular to the central axis A and passing through the central axis A is defined as the radial direction.

[0014] The inner ring 10 has a width surface 10a and a width surface 10b. The width surfaces 10a and 10b form both end faces in the axial direction. The width surface 10a faces one side in the axial direction (the left side in FIG. 1), and the width surface 10b faces the other side in the axial direction (the right side in FIG. 1). That is, the width surface 10b is the opposite surface of the width surface 10a in the axial direction.

[0015] The inner ring 10 has an inner circumferential surface 10c and an outer circumferential surface 10d. The inner circumferential surface 10c faces the inner side (the central axis A side) in the radial direction. The outer circumferential surface 10d faces the outer side (the side opposite to the central axis A) in the radial direction. That is, the outer circumferential surface 10d is the opposite surface of the inner circumferential surface 10c in the radial direction. The inner circumferential surface 10c is continuous with the width surface 10a and the width surface 10b at one end and the other end in the axial direction, respectively. The outer circumferential surface 10d is continuous with the width surface 10a and the width surface 10b at one end and the other end in the axial direction, respectively. The inner ring 10 is attached to a shaft (not shown) on the inner circumferential surface 10c.

[0016] The outer circumferential surface 10d has a flange portion 10da and a flange portion 10db. The flange portion 10da and the flange portion 10db are located at one end and the other end in the axial direction of the outer circumferential surface 10d, respectively. The outer circumferential surface 10d has a raceway groove 10dc. The outer circumferential surface 10d is recessed in the raceway groove 10dc. The raceway groove 10dc extends along the circumferential direction. The bottom surface of the raceway groove 10dc forms a raceway surface 10dd. The raceway surface 10dd is inclined such that the distance between the raceway surface 10dd and the inner circumferential surface 10c increases as it approaches the flange portion 10db side from the flange portion 10da side in a cross-sectional view passing through the central axis A and parallel to the axial direction.

[0017] The outer ring 20 has a width surface 20a and a width surface 20b. The width surfaces 20a and 20b form the end faces in the axial direction. Width surface 20a faces one side in the axial direction (the left side in Figure 1), and width surface 20b faces the other side in the axial direction (the right side in Figure 1). That is, width surface 20b is the opposite side of width surface 20a in the axial direction.

[0018] The outer ring 20 has an inner circumferential surface 20c and an outer circumferential surface 20d. The inner circumferential surface 20c faces inward (towards the central axis A) in the radial direction. The outer circumferential surface 20d faces outward (opposite to the central axis A) in the radial direction. That is, the outer circumferential surface 20d is the opposite surface of the inner circumferential surface 20c in the radial direction. The inner circumferential surface 20c is connected to the width surface 20a and width surface 20b at one end and the other end in the axial direction, respectively. The outer circumferential surface 20d is connected to the width surface 20a and width surface 20b at one end and the other end in the axial direction, respectively. The outer ring 20 is attached to the housing (not shown) at the outer circumferential surface 20d.

[0019] The inner circumferential surface 20c forms the raceway surface 20ca. The inner circumferential surface 20c (raceway surface 20ca) is inclined such that, in a cross-sectional view passing through the central axis A and parallel to the axial direction, the distance between the inner circumferential surface 20c (raceway surface 20ca) and the outer circumferential surface 20d decreases as it approaches the width surface 20b side from the width surface 20a side. The outer ring 20 is positioned radially outward of the inner ring 10 such that the inner circumferential surface 20c faces the outer circumferential surface 10d with a gap between them (the raceway surface 20ca faces the raceway surface 10dd with a gap between them).

[0020] The rolling elements 30 are tapered rollers. Each rolling element 30 has a rolling surface 30a. The rolling elements 30 are positioned between the inner ring 10 and the outer ring 20 such that their rolling surfaces 30a are in contact with the raceway surfaces 10dd and 20ca. Multiple rolling elements 30 are arranged along the circumferential direction. A cage 40 is positioned between the inner ring 10 and the outer ring 20 and holds multiple rolling elements 30 such that the distance between any two adjacent rolling elements 30 is within a certain range.

[0021] The outer ring 20 is made of hardened and tempered steel. The steel used for the outer ring 20 is, for example, SUJ2 as specified in the JIS standard. However, the steel used for the outer ring 20 is not limited to this.

[0022] The amount of retained austenite at the raceway surface 20ca is 3 volume percent or less. The condition "the amount of retained austenite at the raceway surface 20ca is 3 volume percent or less" is satisfied if the amount of retained austenite at any position within the region where the depth from the raceway surface 20ca is 200 μm or less is 3 volume percent or less. The steel at the raceway surface 20ca does not need to contain any retained austenite. From another perspective, the amount of retained austenite at the raceway surface 20ca may be 0 volume percent. The amount of retained austenite at the raceway surface 20ca is measured by X-ray diffraction. Condition A is defined as the amount of retained austenite at the raceway surface of the raceway ring being 3 volume percent or less.

[0023] The residual magnetism on the raceway surface 20ca is 0.3 mT or less. Preferably, the residual magnetism on the raceway surface 20ca is 0.1 mT or less. The residual magnetism on the raceway surface 20ca is measured using a teslameter (magnetic flux density meter). The residual magnetism on the raceway surface 20ca is measured non-destructively by the method described later. Condition B is defined as the residual magnetism on the raceway surface of the raceway ring being 0.3 mT or less.

[0024] The raceway surface 20ca is machined to impart compressive residual stress. The compressive residual stress applied to the raceway surface 20ca is the maximum value in the region where the depth from the raceway surface 20ca is 200 μm or less. Furthermore, the compressive residual stress is the compressive residual stress acting in the axial direction of the raceway surface. Note that "axial direction of the raceway surface" refers to the direction along the axial direction and parallel to the raceway surface (indicated by the arrow in Figure 1). The compressive residual stress applied to the raceway surface 20ca is, for example, 1400 MPa or more. However, the compressive residual stress applied to the raceway surface 20ca is not limited to this. Condition C is defined as the raceway surface of the raceway ring being machined to impart compressive residual stress.

[0025] In the above example, conditions A, B, and C are assumed to be satisfied on the raceway surface 20ca, but conditions A, B, and C may also be satisfied on the raceway surface 10dd. Alternatively, conditions A, B, and C may not be satisfied on the raceway surface 20ca, but conditions A, B, and C may be satisfied on the raceway surface 10dd. The inner ring 10 is made of hardened and tempered steel, and this steel is, for example, SNCM420H. The rolling elements 30 are made of hardened and tempered steel.

[0026] (Manufacturing method for the outer ring 20) The manufacturing method for the outer ring 20 is described below.

[0027] Figure 2 is a manufacturing process diagram showing the manufacturing method of the outer ring 20. As shown in Figure 2, the manufacturing method of the outer ring 20 includes a preparation step S1, a quenching step S2, a tempering step S3, a grinding step S4, a demagnetization step S5, a machining step S6, and a demagnetization step S7.

[0028] In preparation step S1, the workpiece 50 is prepared. Figure 3 is a cross-sectional view of the workpiece 50 prepared in preparation step S1. As shown in Figure 3, in preparation step S1, the workpiece 50 is formed into a shape similar to that of the outer ring 20 by processes such as forging and turning on the raw material. The workpiece 50 has a raceway surface 50a. The raceway surface 50a is the surface corresponding to the raceway surface 20ca.

[0029] In the quenching process S2, the workpiece 50 is quenched. The quenching involves heating and holding the workpiece 50 at a temperature above the A1 transformation point, and then M S This is carried out by cooling to a temperature below the A1 point. The tempering process S3 is performed by heating and holding the workpiece 50 at a temperature below the A1 transformation point. Tempering is performed so that the amount of retained austenite at the position that becomes the raceway surface 20ca is 3 volume percent or less.

[0030] In grinding step S4, the workpiece 50 is ground, thereby shaping it into the form of the outer ring 20. During grinding, the workpiece 50 (outer ring 20) is held, for example, by a magnetic chuck. Therefore, at the end of grinding step S4, the outer ring 20 is magnetized.

[0031] In the demagnetization process S5, the outer ring 20 is demagnetized. This demagnetization is performed, for example, by an AC-type demagnetizing device. This demagnetization is performed so that the residual magnetism on the raceway surface 20ca is 0.3 mT or less, preferably 0.1 mT or less.

[0032] In machining process S6, the raceway surface 20ca is machined, thereby imparting compressive residual stress to the raceway surface 20ca. This machining is, for example, burnishing. Since burnishing improves the surface roughness of the raceway surface 20ca, if the machining is burnishing, the finishing process on the raceway surface 20ca is omitted. After machining process S6 is completed, the outer ring 20 is further magnetized.

[0033] In the demagnetization process S7, the outer ring 20 is demagnetized. This demagnetization is performed, for example, by an AC-type demagnetizing device. This demagnetization is performed so that the residual magnetism on the raceway surface 20ca is 0.3 mT or less, preferably 0.1 mT or less. Normally, after the completion of the manufacturing process, the residual magnetism on the raceway surface of the raceway ring is about 0.5 mT to 1.0 mT. In other words, in the manufacturing method of the outer ring 20, the demagnetization process is performed before the machining process S6 and after the machining process S6.

[0034] The manufacturing method for the outer ring 20 further includes a residual stress measurement step S8. The residual stress measurement step S8 comprises a first step S81 and a second step S82. The first step S81 is performed after the demagnetization step S5 and before the machining step S6. The second step S82 is performed after the demagnetization step S7.

[0035] In the first step S81 and the second step S82, the impedance at the orbital surface 20ca is measured non-destructively using eddy currents, for example, by the method described in Patent Document 2. The impedance at the orbital surface 20ca is measured in a region where the depth from the orbital surface 20ca is 200 μm or less. The impedance at the orbital surface 20ca measured in the first step S81 is defined as the first impedance, and the impedance at the orbital surface 20ca measured in the second step S82 is defined as the second impedance. The value obtained by dividing the second impedance by the first impedance is defined as the impedance ratio. Since there is a predetermined relationship between the impedance ratio and the compressive residual stress, if this relationship is determined experimentally in advance, the residual compressive stress can be measured by measuring the impedance ratio.

[0036] Figure 4 is a manufacturing process diagram showing a modified method for manufacturing the outer ring 20. When machining is performed by a method other than burnishing (for example, shot peening, ultrasonic impact treatment, cavitation peening, laser peening, cold rolling, or rolling), the manufacturing method for the outer ring 20 further includes a finishing step S9, as shown in Figure 4. The finishing step S9 is performed after the machining step S6 and before the demagnetization step S7. In the finishing step S9, grinding or superfinishing is performed to improve the surface roughness of the raceway surface 20ca. While the finishing step S9 is being performed, the outer ring 20 is held in a magnetic chuck, for example. Therefore, after the finishing step S9 is completed, the outer ring 20 is further magnetized.

[0037] (Effect of outer ring 20) The effect of the outer ring 20 is explained below.

[0038] Sample 1 and Sample 2 were prepared as examples of raceway rings. Figure 5 is a graph showing the measured impedance ratios for Sample 1 and Sample 2. Sample 1 and Sample 2 are identical samples, but because magnetization and demagnetization operations have been performed, their residual magnetism levels are different. The impedance ratio was measured for both Sample 1 and Sample 2. In Sample 1, the residual magnetism on the raceway surface was 0.34 mT. On the other hand, in Sample 2, the residual magnetism on the raceway surface was 0.8 mT. The machining conditions for the raceway surfaces were the same for both Sample 1 and Sample 2. That is, the same compressive residual stress was applied to the raceway surfaces of both Sample 1 and Sample 2, but only the residual magnetism differed. As shown in Figure 5, the measured impedance ratios were different for Sample 1 and Sample 2. From this comparison, it can be seen that the residual magnetism on the raceway surface affects the measured impedance ratio.

[0039] Next, samples 3 through 6 were prepared as raceway samples. Figure 6 is a graph showing the amount of retained austenite and the compressive residual stress applied to the raceway surface in samples 3 and 4. Different machining conditions were applied to samples 3 and 4. That is, as shown in Figure 6, the compressive residual stress applied to the raceway surface differed between samples 3 and 4. As shown in Figure 6, the amount of retained austenite on the raceway surface in samples 3 and 4 was not less than 3 volume percent (condition A was not met). In addition, the residual magnetism on the raceway surface in samples 3 and 4 was 0.3 mT or less.

[0040] Figure 7A is a graph showing the measurement results of the impedance ratio in sample 3. Figure 7B is a graph showing the measurement results of the impedance ratio in sample 4. As shown in Figures 7A and 7B, the graphs showing the impedance ratios overlapped in sample 3 and sample 4, even though the compressive residual stress applied to the raceway surface was different. From this, it can be seen that if condition A is not met, it is not possible to accurately measure the difference in compressive residual stress applied to the raceway surface based on the impedance ratio.

[0041] Figure 8 is a graph showing the amount of retained austenite and the compressive residual stress applied to the raceway surface in samples 5 and 6. Different machining conditions were applied to samples 5 and 6. That is, as shown in Figure 8, the compressive residual stress applied to the raceway surface differed between samples 5 and 6. Also, as shown in Figure 8, the amount of retained austenite in the raceway surface was 3 volume percent or less in samples 5 and 6 (condition A was satisfied). The residual magnetism in the raceway surface was 0.3 mT or less in samples 5 and 6.

[0042] Figure 9 shows graphs illustrating the impedance ratio measurements for samples 5 and 6. As shown in Figure 9, the compressive residual stress applied to the raceway surface differed between samples 5 and 6, and the graphs showing the impedance ratios were separated. This indicates that, when conditions A and B are met, the compressive residual stress applied to the raceway surface can be accurately measured based on the impedance ratio.

[0043] Furthermore, samples 7 through 9 were prepared as rolling bearing samples. Samples 7 through 9 were angular contact ball bearings with designation number 7206. The raceways of samples 7 through 9 were formed from SUJ2 containing a large amount of non-metallic inclusions due to improvements in the steelmaking process.

[0044] Figure 10 is a graph showing the compressive residual stress on the raceway surface of the raceway rings for samples 7 through 9. The raceway surfaces of samples 7 and 8 were machined under different conditions. As a result, as shown in Figure 10, the compressive residual stress on the raceway surface of samples 7 and 8 was approximately 1200 MPa and over 1400 MPa, respectively. No machining was performed on the raceway surface of sample 9.

[0045] Rolling fatigue life tests were performed on samples 7 through 9. The rolling fatigue life tests were conducted with a maximum contact pressure of 3 GPa on the outer ring, a contact angle of 27°, a rotational speed of 3100 rpm, and VG56 lubricant. Figure 11 is a graph showing the rolling fatigue life test results for samples 7 through 9. As shown in Figure 11, in sample 7, L 10 The lifetime was 42.79 hours, and in sample 8, L 10 The lifetime was 588.31 hours, and in sample 9, L 10The lifespan was 31.66 hours. Sample 7, with a compressive residual stress of approximately 1200 MPa, had a rolling fatigue life similar to that of Sample 9, which was not machined. Sample 8, with a compressive residual stress of 1400 MPa or higher, showed an increased rolling fatigue life compared to Sample 9, which was not machined. From this comparison, it was found that increasing the residual compressive stress on the raceway surface to 1400 MPa or higher can improve the rolling fatigue life.

[0046] Next, samples 10 and 11 were prepared as raceway samples. The steel used for samples 10 and 11 was SNCM420H as specified in the JIS standard. After carburizing, samples 10 and 11 were machined under different conditions. In sample 10, the compressive residual stress on the raceway surface was approximately 1200 MPa, while in sample 11, the compressive residual stress on the raceway surface was 1400 MPa or higher. Figure 12 is a graph showing the measurement results of the impedance ratio on the raceway surface of the raceway rings of samples 10 and 11. As shown in Figure 12, in the raceway rings of samples 10 and 11, conditions A and B were met, so the graphs showing the impedance ratio were separated. Therefore, by measuring the impedance ratio, it is possible to distinguish between raceway rings like sample 10 and raceway rings like sample 11 that show an improvement in rolling fatigue life, and it is possible to prevent rolling bearings with raceway rings that do not show an improvement in rolling fatigue life from being shipped. Furthermore, by re-machining raceways like Sample 10 to increase compressive residual stress and creating raceways like Sample 11, the need for disposal is eliminated, and the product yield is improved.

[0047] (Note) The above embodiment includes the following configuration:

[0048] <Note 1> A steel raceway ring that has been hardened and tempered, Having an orbital surface, The aforementioned raceway surface is machined in such a way that compressive residual stress is applied to it. The amount of retained austenite in the aforementioned orbital plane is 3 volume percent or less. A raceway ring in which the residual magnetism on the aforementioned raceway surface is 0.3 mT or less.

[0049] <Note 2> The raceway ring described in Appendix 1, wherein the compressive residual stress applied to the raceway surface is 1400 MPa or less.

[0050] <Note 3> The remanent magnetism on the aforementioned raceway surface is 0.1 mT or less, as described in Appendix 1 or Appendix 2.

[0051] <Note 4> The aforementioned steel is SNCM420H as defined in the JIS standard, and the raceway ring is as described in any one of the items from Appendix 1 to Appendix 3.

[0052] <Note 5> It comprises an inner ring, an outer ring, and rolling elements, A rolling bearing in which at least one of the inner ring and the outer ring is a raceway ring as described in any one of the appendices 1 to 4.

[0053] <Note 6> A method for manufacturing a raceway ring having a raceway surface, The process of preparing the steel component to be processed, A step of performing heat treatment on the aforementioned workpiece, A step of tempering the aforementioned workpiece, A step of grinding the workpiece to be processed to obtain the raceway ring, A step of demagnetizing the aforementioned raceway surface, The process includes a step of machining the raceway surface, The tempering process for the workpiece is carried out so that the amount of retained austenite on the raceway surface is 3 volume percent or less. The process of demagnetizing the raceway surface is performed before the process of machining the raceway surface and after the process of machining the raceway surface, such that the residual magnetism on the raceway surface becomes 0.3 mT or less. A method for manufacturing a raceway, wherein compressive residual stress is applied to the raceway surface during the machining process of the raceway surface.

[0054] <Note 7> The process further comprises measuring the compressive residual stress applied to the raceway surface by machining performed on the raceway surface, The process of measuring the compressive residual stress applied to the raceway surface comprises a first step of measuring the impedance on the raceway surface after demagnetization of the raceway surface performed before machining of the raceway surface, and a second step of measuring the impedance on the raceway surface after demagnetization of the raceway surface performed after machining of the raceway surface. A method for manufacturing a raceway according to Appendix 6, wherein the compressive residual stress applied to the raceway surface is measured based on the ratio of the impedance measured in the first step to the impedance measured in the second step.

[0055] <Note 8> A method for manufacturing a raceway ring as described in Appendix 7, wherein if the compressive residual stress on the raceway surface measured in the step of measuring the compressive residual stress applied to the raceway surface is less than a threshold, the step of machining the raceway surface is performed again.

[0056] <Note 9> A method for manufacturing a raceway ring as described in any one of Appendix 6 to 8, wherein the process of machining the raceway surface is carried out by shot peening, ultrasonic impact treatment, cavitation peening, laser peening, burnishing, cold rolling, or rolling.

[0057] While embodiments of the present invention have been described above, various modifications of these embodiments are possible. Furthermore, the scope of the present invention is not limited to the embodiments described above. The scope of the present invention is indicated by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims. [Explanation of Symbols]

[0058] 100 Rolling bearing, 10 inner ring, 10a width surface, 10b width surface, 10c inner circumferential surface, 10d outer circumferential surface, 10da,10db flange, 10dc raceway groove, 10dd raceway surface, 20 outer ring, 20a,20b width surface, 20c inner circumferential surface, 20ca raceway surface, 20d outer circumferential surface, 30 Rolling element, 30a raceway surface, 40 cage, 50 workpiece, 50a raceway surface, A central axis, S1 preparation process, S2 quenching process, S3 tempering process, S4 grinding process, S5 demagnetizing process, S6 machining process, S7 demagnetizing process, S8 residual stress measurement process, S81 1st process, S82 2nd process, S9 finishing process.

Claims

1. A steel raceway ring that has been hardened and tempered, Having an orbital surface, The aforementioned raceway surface is machined in such a way that compressive residual stress is applied to it. The amount of retained austenite in the aforementioned orbital plane is 3 volume percent or less. A raceway ring in which the residual magnetism on the raceway surface is 0.3 mT or less.

2. The raceway according to claim 1, wherein the compressive residual stress applied to the raceway surface is 1400 MPa or less.

3. The raceway wheel according to claim 1, wherein the residual magnetism on the raceway surface is 0.1 mT or less.

4. The raceway according to claim 1, wherein the steel is SNCM420H as defined in the JIS standard.

5. It comprises an inner ring, an outer ring, and rolling elements, A rolling bearing wherein at least one of the inner ring and the outer ring is the raceway ring described in any one of claims 1 to 4.

6. A method for manufacturing a raceway ring having a raceway surface, The process of preparing the steel component to be processed, A step of performing heat treatment on the aforementioned workpiece, A step of tempering the aforementioned workpiece, A step of grinding the workpiece to be processed to obtain the raceway ring, A step of demagnetizing the aforementioned raceway surface, The process includes a step of machining the raceway surface, The tempering process for the workpiece is carried out so that the amount of retained austenite on the raceway surface is 3 volume percent or less. The process of demagnetizing the raceway surface is performed before the process of machining the raceway surface and after the process of machining the raceway surface, such that the residual magnetism on the raceway surface becomes 0.3 mT or less. A method for manufacturing a raceway, wherein compressive residual stress is applied to the raceway surface during the machining process of the raceway surface.

7. The process further comprises measuring the compressive residual stress applied to the raceway surface by machining performed on the raceway surface, The process of measuring the compressive residual stress applied to the raceway surface comprises a first step of measuring the impedance on the raceway surface after demagnetization of the raceway surface performed before machining of the raceway surface, and a second step of measuring the impedance on the raceway surface after demagnetization of the raceway surface performed after machining of the raceway surface. A method for manufacturing a raceway according to claim 6, wherein the compressive residual stress applied to the raceway surface is measured based on the ratio of the impedance measured in the first step to the impedance measured in the second step.

8. The method for manufacturing a raceway ring according to claim 7, wherein if the compressive residual stress on the raceway surface measured in the step of measuring the compressive residual stress applied to the raceway surface is less than a threshold, the step of machining the raceway surface is performed again.

9. The method for manufacturing a raceway according to any one of claims 6 to 8, wherein the step of machining the raceway surface is performed by shot peening, ultrasonic impact treatment, cavitation peening, laser peening, burnishing, cold rolling, or rolling.

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