JP2019157935A - Rolling bearing - Google Patents

Abstract

To provide a rolling bearing which has a long life by suppressing generation of surface origin type peeling at least on one of a first raceway surface, a second raceway surface and a rolling surface.SOLUTION: A rolling bearing 1 includes an inner ring 3, an outer ring 6 and a plurality of rolling elements 10. The inner ring 3 has a first raceway surface 4. The outer ring 6 has a second raceway surface 7. Each of the plurality of rolling elements 10 has a rolling surface 11. A first residual compression stress at least in one axial direction of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is larger than a second residual compression stress at least in one circumferential direction of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rolling bearing.

  Japanese Patent Laying-Open No. 2011-7234 (Patent Document 1) is arranged between an inner ring having a first raceway surface, an outer ring having a second raceway surface, and an outer ring of an inner ring having a rolling surface. A rolling bearing provided with a rolling element is disclosed.

JP 2011-7234 A

  During the use of the rolling bearing, the contact stress between the inner ring and the rolling element continues to act on the inner ring and the rolling element, and the contact stress between the outer ring and the rolling element continues to act on the outer ring and the rolling element. These contact stresses generate fatigue cracks in at least one of the first raceway surface, the second raceway surface, and the rolling surface. When the rolling bearing is used for a long period of time, fatigue cracks develop and at least one part of the first raceway surface, the second raceway surface, and the rolling surface is peeled off. This peeling is called surface-origin type peeling. An object of the present invention is to provide a rolling bearing having a long life by suppressing occurrence of surface-origin separation on at least one of the first raceway surface, the second raceway surface, and the rolling surface. is there.

  The rolling bearing of the present invention includes an inner ring, an outer ring disposed on the outer peripheral side of the inner ring, and a plurality of rolling elements disposed between the inner ring and the outer ring. The inner ring has a first raceway surface. The outer ring has a second raceway surface facing the first raceway surface. Each of the plurality of rolling elements has a rolling surface in contact with the first raceway surface and the second raceway surface. The first residual compressive stress in the axial direction of at least one inner ring and outer ring of the first raceway surface, the second raceway surface, and the rolling surface is the first raceway surface, the second raceway surface, and the rolling surface. It is larger than the second residual compressive stress in the circumferential direction of at least one inner ring and outer ring.

  According to the rolling bearing of the present invention, it is possible to suppress occurrence of surface-origin separation on at least one of the first raceway surface, the second raceway surface, and the rolling surface, and a rolling bearing having a long life can be obtained. Can be provided.

It is a general | schematic fragmentary sectional perspective view of the rolling bearing which concerns on Embodiment 1 of this invention. It is a general | schematic partial expanded sectional view of the rolling bearing which concerns on Embodiment 1 of this invention. It is a figure which shows the graph showing distribution of the residual compressive stress provided to the rolling bearing of Example 1, Comparative example 2, and Comparative example 3 of this invention. In the thickness direction of at least one of the inner ring, the outer ring, and each rolling element of the equivalent stress acting on at least one of the inner ring, outer ring, and each rolling element of the rolling bearing of Example 1, Comparative Example 1 to Comparative Example 3 of the present invention. It is a figure which shows the graph showing distribution of. It is a figure which shows the graph showing distribution of the residual compressive stress provided to the rolling bearing of Example 2, Comparative example 4, and Comparative example 5 of this invention. At least one of the inner ring, the outer ring and each rolling element of equivalent stress acting on at least one of the inner ring, outer ring and each rolling element of the rolling bearings of Example 2, Comparative Example 1, Comparative Example 4 and Comparative Example 5 of the present invention. It is a figure which shows the graph showing distribution of one thickness direction. The anisotropy of the residual compressive stress applied to at least one of the first raceway surface, the second raceway surface, and the rolling surface of the rolling bearing according to the first embodiment of the present invention is the embodiment of the present invention. 2 is a graph showing an influence on a relationship between a ratio of equivalent stress acting on at least one of an inner ring, an outer ring and each rolling element of a rolling bearing according to No. 1 and a first residual compressive stress. Before using the rolling bearing according to the first embodiment of the present invention, each rolling element rolls with respect to the inner ring and the outer ring, thereby at least one of the first raceway surface, the second raceway surface, and the rolling surface. It is a figure which shows the graph showing the distribution of the at least 1 thickness direction of the inner ring | wheel, an outer ring | wheel, and each rolling element of the residual compressive stress provided to. It is a schematic plan view of the rolling bearing which concerns on Embodiment 2 of this invention. It is a general | schematic fragmentary expanded sectional view in sectional line XX shown by FIG. 9 of the rolling bearing which concerns on Embodiment 2 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
With reference to FIGS. 1-8, the rolling bearing 1 which concerns on Embodiment 1 is demonstrated. As shown in FIGS. 1 and 2, the rolling bearing 1 of the present embodiment includes an inner ring 3, an outer ring 6, and a plurality of rolling elements 10. The inner ring 3, the outer ring 6, and the plurality of rolling elements 10 are made of steel such as bearing steel, for example. The steel constituting the inner ring 3, the outer ring 6, and the plurality of rolling elements 10 may be high chromium bearing steel defined in JIS standards (JIS 4805: 2008). The steel constituting the inner ring 3, the outer ring 6 and the plurality of rolling elements 10 may be SUJ2 steel material defined in JIS standards.

  The inner ring 3 has a first raceway surface 4. The outer ring 6 has a second raceway surface 7 that faces the first raceway surface 4. The outer ring 6 is disposed on the outer peripheral side of the inner ring 3. The plurality of rolling elements 10 are disposed between the inner ring 3 and the outer ring 6. Each of the plurality of rolling elements 10 has a rolling surface 11 that contacts the first raceway surface 4 and the second raceway surface 7. The plurality of rolling elements 10 may be a plurality of rollers. The rolling bearing 1 may be a roller bearing. The rolling bearing 1 may further include a cage 15 that holds the plurality of rolling elements 10.

  The outer ring 6 can rotate around the shaft 2 with respect to the inner ring 3 via a plurality of rolling elements 10. Lubricating oil may be supplied to the rolling bearing 1 while the outer ring 6 rotates about the shaft 2 with respect to the inner ring 3. The rolling bearing 1 of the present embodiment is not particularly limited, but may be used under lean lubrication conditions (low Λ conditions). The lean lubrication condition (low Λ condition) is a condition in which the oil film parameter Λ defined by the equation (1) is 1 or less.

In equation (1), h _min represents the minimum oil film thickness, R _q1 represents the mean square roughness of the first raceway surface 4 or the second raceway surface 7, and R _q2 represents the mean square of the rolling surface 11. Represents roughness.

  The first radius of curvature in the axial direction (y direction) of at least one rolling bearing 1 of the inner ring 3, outer ring 6 and each rolling element 10 is that of at least one rolling bearing 1 of the inner ring 3, outer ring 6 and each rolling element 10. This is different from the second radius of curvature in the circumferential direction (x direction). In the present embodiment, the first radius of curvature of the inner ring 3 in the axial direction (y direction) is different from the second radius of curvature of the inner ring 3 in the circumferential direction (x direction). The first curvature radius in the axial direction (y direction) of the outer ring 6 is different from the second curvature radius in the circumferential direction (x direction) of the outer ring 6. The first curvature radius in the axial direction (y direction) of each rolling element 10 is different from the second curvature radius in the circumferential direction (x direction) of each rolling element 10. Specifically, the first radius of curvature of the inner ring 3 in the axial direction (y direction) may be larger than the second radius of curvature of the inner ring 3 in the circumferential direction (x direction). The first radius of curvature of the outer ring 6 in the axial direction (y direction) may be larger than the second radius of curvature of the outer ring 6 in the circumferential direction (x direction). The first curvature radius in the axial direction (y direction) of each rolling element 10 may be larger than the second curvature radius in the circumferential direction (x direction) of each rolling element 10.

The first residual compressive stress σ _y0 in the axial direction (y direction) of at least one inner ring 3 and outer ring 6 of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is the first raceway surface. 4. It is larger than the second residual compressive stress σ _x0 in the circumferential direction (x direction) of at least one inner ring 3 and outer ring 6 of the second raceway surface 7 and the rolling surface 11. Therefore, the first equivalent stress σ _e0 in at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 decreases. The first equivalent stress σ _e0 in at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is the first raceway surface 4, the second raceway surface 7 and the rolling surface 11. It becomes smaller than the yield stress of the material which comprises at least 1 of these. It is possible to suppress the occurrence of surface-origin separation on at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11. In this specification, equivalent stress means Mises stress.

On the other hand, the first equivalent stress σ _e0 in at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11 causes the first raceway surface 4, the second raceway surface 7, and When it is larger than the yield stress of the material constituting at least one of the rolling surfaces 11, plastic deformation occurs in at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11. A fatigue crack occurs in at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11, and surface-origin type separation occurs.

Hereinafter, with reference to Example 1, Example 2, and Comparative Example 1-5, the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 in at least one axial direction (y direction) The first residual compressive stress σ _y0 is set to be larger than the second residual compressive stress σ _x0 in at least one circumferential direction (x direction) of the first raceway surface 4, the second raceway surface 7 and the rolling contact surface 11. This indicates that the first equivalent stress σ _e0 in at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is reduced.

  The contact between the inner ring 3 and each rolling element 10 and the contact between the outer ring 6 and each rolling element 10 can be regarded as Hertzian contact. The contact surface between the inner ring 3 and each rolling element 10 and the contact surface between the outer ring 6 and each rolling element 10 can be regarded as an elliptical contact surface having a major radius a and a minor radius b. . The major radius a means the radius in the major axis direction of the contact ellipse, and the minor radius b means the radius in the minor axis direction of the contact ellipse. The major axis direction of the contact ellipse is the axial direction (y direction) of the rolling bearing 1, and the minor axis direction of the contact ellipse is the circumferential direction (x direction) of the rolling bearing 1.

In Example 1, Example 2, and Comparative Example 1-5, using Hertz's theory, an inner ring 3 and an outer ring having at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11 are used. 6 and equivalent stress generated in at least one of the rolling elements 10 were simulated. Specifically, the maximum contact surface pressure P _max acting between the rolling surface 11 and at least one of the first raceway surface 4 and the second raceway surface 7 is 3.0 GPa, and the short radius b is 1 mm. And at least one of the inner ring 3, the outer ring 6 and each rolling element 10 has the residual compressive stress distribution shown in Tables 1 and 2, the inner ring 3, the outer ring 6 and each rolling element 10 At least one equivalent stress was simulated.

As shown in Table 1, in Example 1, the residual compressive stress σ _x in at least one circumferential direction (x direction) of the inner ring 3, the outer ring 6 and each rolling element 10 is equal to the inner ring 3, the outer ring 6 and each rolling element. In at least one thickness direction of 10, the distribution A shown in FIG. In the first embodiment, the residual compressive stress σ _y in at least one axial direction (y direction) of the inner ring 3, the outer ring 6 and each rolling element 10 is the thickness direction of at least one of the inner ring 3, the outer ring 6 and each rolling element 10. 1 has a distribution B shown in FIG. The negative sign on the vertical axis in FIG. 3 means that the stress applied to at least one of the inner ring 3, the outer ring 6, and each rolling element 10 is a compressive stress.

In the first embodiment, anisotropic residual compressive stress is applied to at least one of the inner ring 3, the outer ring 6, and each rolling element 10. Specifically, the first residual compressive stress σ _y0 in at least one axial direction (y direction) of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11 is the first raceway surface 4. The second residual compressive stress σ _x0 in at least one circumferential direction (x direction) of the second raceway surface 7 and the rolling surface 11 is larger. In this specification, a large compressive stress means that the absolute value of the compressive stress is large.

Further, as shown in the distribution A and the distribution B in FIG. 3, the residual in the axial direction (y direction) in at least one surface layer region of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11. The compressive stress σ _y is larger than the residual compressive stress σ _x in the circumferential direction (x direction). The residual compressive stress σ _y in at least one axial direction (y direction) of the inner ring 3, the outer ring 6, and each rolling element 10 is equal to the inner ring 3, It may be maximum on at least one surface of the outer ring 6 and each rolling element 10 (that is, at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11).

On the other hand, as shown in Table 1, in Comparative Example 1, no residual compressive stress is applied to the inner ring 3, the outer ring 6, and each rolling element 10. In Comparative Example 2, the inner ring 3, at least one of residual compressive stress sigma _y of residual compressive stress sigma _x and axial (y-direction) of the circumferential direction (x direction) of the outer ring 6 and the rolling elements 10, the inner ring 3, an outer ring 6 and at least one thickness direction of each rolling element 10 has a distribution A shown in FIG. In Comparative Example 3, the inner ring 3, at least one of residual compressive stress sigma _y of residual compressive stress sigma _x and axial (y-direction) of the circumferential direction (x direction) of the outer ring 6 and the rolling elements 10, the inner ring 3, an outer ring 6 and at least one thickness direction of each rolling element 10 has a distribution B shown in FIG. In Comparative Example 2 and Comparative Example 3, isotropic residual compressive stresses σ _x and σ _y are applied to at least one of the inner ring 3, the outer ring 6, and each rolling element 10.

  As shown in FIG. 4, the equivalent stress of Example 1 in at least one surface layer region of the inner ring 3, the outer ring 6, and each rolling element 10 is lower than the equivalent stress of Comparative Example 2 and Comparative Example 3 in the surface layer region. Residual compressive stress applied to at least one of the inner ring 3, the outer ring 6, and each rolling element 10 is applied to at least one surface layer region of the inner ring 3, the outer ring 6, and each rolling element 10. The equivalent stress acting on at least one of 10 is reduced. In the present specification, the surface layer region is at least one surface of the inner ring 3, the outer ring 6 and each rolling element 10 (that is, at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11). To a depth where the equivalent stress is minimized. In FIG. 4, the horizontal axis indicates at least one position z / b in the thickness direction of the inner ring 3, the outer ring 6, and each rolling element 10, normalized by the short radius b of the contact ellipse. The surface layer region may be a region where z / b is 0.2 or less, for example. The surface layer region is, for example, 50 μm from at least one surface of the inner ring 3, the outer ring 6, and each rolling element 10 (that is, at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11). It may be a region up to the depth.

At least one surface layer region of the inner ring 3, the outer ring 6 and each rolling element 10 is at least one surface of the inner ring 3, the outer ring 6 and each rolling element 10, that is, the first raceway surface 4, the second raceway surface 7 and At least one of the rolling surfaces 11 is included. The first equivalent stress σ _e0 of Example 1 in at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is the first raceway surface 4, the second raceway surface 7 and It is lower than the first equivalent stress of Comparative Example 2 and Comparative Example 3 in at least one of the rolling surfaces 11. In FIG. 4, the position z / b = 0 is at least one of the inner ring 3, the outer ring 6 and each rolling element 10, that is, at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11. Represents one.

The reason why the equivalent stress and the first equivalent stress σ _e0 of Example 1 are lower than the equivalent stress and the first equivalent stress of Comparative Example 2 and Comparative Example 3 in the surface layer region, respectively, in the surface layer region is as follows. I think so. At least one first radius of curvature of the inner ring 3, the outer ring 6 and each rolling element 10 in the axial direction (y direction) is the first radius of curvature of the inner ring 3, the outer ring 6 and each rolling element 10 in the circumferential direction (x direction). 2 is different from the radius of curvature. Therefore, the contact stress between the inner ring 3 and each rolling element 10 in the axial direction (y direction) is different from the contact stress between the inner ring 3 and each rolling element 10 in the circumferential direction (x direction). The contact stress between the outer ring 6 and each rolling element 10 in the axial direction (y direction) is different from the contact stress between the outer ring 6 and each rolling element 10 in the circumferential direction (x direction). The anisotropic residual compressive stress of Example 1 is more anisotropic than the isotropic residual compressive stress of Comparative Example 2 and Comparative Example 3, and the anisotropic contact stress between the inner ring 3 and each rolling element 10 and the outer ring. 6 and the anisotropic contact stress between the rolling elements 10 can be dealt with more effectively.

  Thus, the anisotropic residual compressive stress applied to at least one of the inner ring 3, the outer ring 6, and each rolling element 10 is at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11. In at least one surface layer region of the inner ring 3, outer ring 6, and each rolling element 10 including one, the equivalent stress acting on at least one of the inner ring 3, outer ring 6 and each rolling element 10 is reduced. The equivalent stress in at least one surface layer region of the inner ring 3, the outer ring 6, and each rolling element 10 is the yield stress of the material constituting at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11. Smaller than. Therefore, it is possible to suppress the occurrence of surface-origin separation on at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11.

As shown in Table 2, in Example 2, the residual compression stress σ _x in at least one circumferential direction (x direction) of the inner ring 3, the outer ring 6, and each rolling element 10 is equal to the inner ring 3, the outer ring 6, and each rolling element. In at least one thickness direction of 10, it has a distribution C shown in FIG. In the second embodiment, the residual compressive stress σ _y in at least one axial direction (y direction) of the inner ring 3, the outer ring 6 and each rolling element 10 is the thickness direction of at least one of the inner ring 3, the outer ring 6 and each rolling element 10. 1 has a distribution D shown in FIG. The negative sign on the vertical axis in FIG. 5 means that the stress applied to at least one of the inner ring 3, the outer ring 6, and each rolling element 10 is a compressive stress.

In Example 2, anisotropic residual compressive stress is applied to at least one of the inner ring 3, the outer ring 6, and each rolling element 10. Specifically, the first residual compressive stress σ _y0 in at least one axial direction (y direction) of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11 is the first raceway surface 4. The second residual compressive stress σ _x0 in at least one circumferential direction (x direction) of the second raceway surface 7 and the rolling surface 11 is larger.

Further, as shown in the distribution C and the distribution D in FIG. 5, the residual in the axial direction (y direction) in at least one surface layer region of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11. The compressive stress σ _y is larger than the residual compressive stress σ _x in the circumferential direction (x direction). The residual compressive stress σ _y in at least one axial direction (y direction) of the inner ring 3, the outer ring 6, and each rolling element 10 is equal to the inner ring 3, It may be maximum in at least one of the outer ring 6 and each rolling element 10.

Specifically, the position z / b in the thickness direction at which the residual compressive stress σ _y in the at least one axial direction (y direction) of the inner ring 3, the outer ring 6 and each rolling element 10 is maximum is greater than 0, .03 or greater than 0.05. The position z / b in the thickness direction at which the residual compressive stress σ _y in the at least one axial direction (y direction) of the inner ring 3, the outer ring 6 and each rolling element 10 is maximum may be smaller than 1.00, 0 .90 or less than 0.80.

On the other hand, as shown in Table 2, in Comparative Example 1, no residual compressive stress is applied to the inner ring 3, the outer ring 6, and each rolling element 10. In Comparative Example 4, the inner ring 3, at least one of residual compressive stress sigma _y of residual compressive stress sigma _x and axial (y-direction) of the circumferential direction (x direction) of the outer ring 6 and the rolling elements 10, the inner ring 3, an outer ring 6 and at least one thickness direction of each rolling element 10 has a distribution C shown in FIG. In Comparative Example 5, the inner ring 3, at least one of residual compressive stress sigma _y of residual compressive stress sigma _x and axial (y-direction) of the circumferential direction (x direction) of the outer ring 6 and the rolling elements 10, the inner ring 3, an outer ring 6 and at least one thickness direction of each rolling element 10 has a distribution D shown in FIG. In Comparative Example 4 and Comparative Example 5, isotropic residual compressive stresses σ _x and σ _y are applied to at least one of the inner ring 3, the outer ring 6, and each rolling element 10.

  As shown in FIG. 6, the equivalent stress of Example 2 in at least one surface layer region of the inner ring 3, the outer ring 6, and each rolling element 10 is lower than the equivalent stress of Comparative Example 4 and Comparative Example 5 in the surface layer region. The residual compressive stress applied to at least one of the inner ring 3, the outer ring 6, and each rolling element 10 is applied to the inner ring 3, the outer ring 6, and each rolling element in at least one surface layer region of the inner ring 3, outer ring 6, and each rolling element 10. The equivalent stress acting on at least one of 10 is reduced.

At least one surface layer region of the inner ring 3, the outer ring 6 and each rolling element 10 is at least one surface of the inner ring 3, the outer ring 6 and each rolling element 10, that is, the first raceway surface 4, the second raceway surface 7 and At least one of the rolling surfaces 11 is included. The first equivalent stress σ _e0 of the second embodiment in at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is the first raceway surface 4, the second raceway surface 7 and It is lower than the first equivalent stress of Comparative Example 4 and Comparative Example 5 in at least one of the rolling surfaces 11. In FIG. 4, the position z / b = 0 is at least one of the inner ring 3, the outer ring 6 and each rolling element 10, that is, at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11. Represents one.

The reason why the equivalent stress and the first equivalent stress σ _{e0 of} Example 2 are lower than the equivalent stress and the first equivalent stress of Comparative Example 4 and Comparative Example 5, respectively, in the surface layer region is considered as follows. It is done. At least one first radius of curvature of the inner ring 3, the outer ring 6 and each rolling element 10 in the axial direction (y direction) is the first radius of curvature of the inner ring 3, the outer ring 6 and each rolling element 10 in the circumferential direction (x direction). 2 is different from the radius of curvature. Therefore, the contact stress between the inner ring 3 and each rolling element 10 in the axial direction (y direction) is different from the contact stress between the inner ring 3 and each rolling element 10 in the circumferential direction (x direction). The contact stress between the outer ring 6 and each rolling element 10 in the axial direction (y direction) is different from the contact stress between the outer ring 6 and each rolling element 10 in the circumferential direction (x direction). The anisotropic residual compressive stress of Example 2 is more anisotropic than the isotropic residual compressive stress of Comparative Example 4 and Comparative Example 5, and the anisotropic contact stress between the inner ring 3 and each rolling element 10 and the outer ring. 6 and the anisotropic contact stress between the rolling elements 10 can be dealt with more effectively.

  Thus, the anisotropic residual compressive stress applied to at least one of the inner ring 3, the outer ring 6, and each rolling element 10 is at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11. In at least one surface layer region of the inner ring 3, outer ring 6, and each rolling element 10 including one, the equivalent stress acting on at least one of the inner ring 3, outer ring 6 and each rolling element 10 is reduced. The equivalent stress in at least one surface layer region of the inner ring 3, the outer ring 6, and each rolling element 10 is the yield stress of the material constituting at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11. Smaller than. Therefore, it is possible to suppress the occurrence of surface-origin separation on at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11.

As in Example 1 and Example 2 shown in FIGS. 4 and 6, the first equivalent stress σ _e0 in at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11 is The inner race 3 having at least one of the first raceway surface 4, the second raceway surface 7 and the rolling contact surface 11, the outer race 6 and at least one second equivalent stress σ _{e2 of} each rolling element 10 is smaller. Also good. The second equivalent stress σ _e2 is the maximum value of the equivalent stress in at least one of the inner ring 3, the outer ring 6, and each rolling element 10. In other words, the equivalent stress ratio n shown in FIG. In this specification, the equivalent stress ratio n is given by the ratio n of the first equivalent stress σ _e0 to the second equivalent stress σ _e2 (n = σ _e0 / σ _e2 ).

The first residual compressive stress σ _y0 in the axial direction (y direction) of at least one inner ring 3 and outer ring 6 of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is the first raceway surface. 4. It is larger than the second residual compressive stress σ _x0 in the circumferential direction (x direction) of at least one inner ring 3 and outer ring 6 of the second raceway surface 7 and the rolling surface 11. Therefore, the first equivalent stress σ _e0 in at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11 can be reduced, and the equivalent stress ratio n can be less than 1. The first equivalent stress σ _e0 in at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is the first raceway surface 4, the second raceway surface 7 and the rolling surface 11. It becomes smaller than the yield stress of the material which comprises at least 1 of these. It is possible to suppress the occurrence of surface-origin separation on at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11.

The ratio of the first residual compressive stress σ _y0 to the maximum contact surface pressure P _max acting between each rolling element 10 and at least one of the inner ring 3 and the outer ring 6 may be −0.7 or more, − 0.6 or more may be sufficient and -0.5 or more may be sufficient. Therefore, the first equivalent stress σ _e0 in at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is the first raceway surface 4, the second raceway surface 7 and the rolling surface. It can be made smaller than at least one second equivalent stress σ _{e2 of the} inner ring 3, the outer ring 6, and each rolling element 10 having at least one of the surfaces 11. The ratio of the first residual compressive stress σ _y0 to the maximum contact surface pressure P _max between each rolling element 10 and at least one of the inner ring 3 and the outer ring 6 may be less than 0.0, and −0.1 Or may be -0.2 or less.

The anisotropy α of the residual compressive stress is greater than 1. The anisotropy α of the residual compressive stress is given by the ratio of the first residual compressive stress σ _{y0 to} the second residual compressive stress σ _x0 (α = σ _y0 / σ _x0 ). The anisotropy α of the residual compressive stress may be 1.3 or more, 1.5 or more, 1.75 or more, or 2.0 or more. The anisotropy α of the residual compressive stress is not particularly limited, but may be 20 or less, 10 or less, or 5.0 or less.

As shown in FIG. 7, the range of the first residual compressive stress σ _y0 in which the ratio n of the equivalent stress acting on the rolling bearing 1 becomes less than 1 as the anisotropy α of the residual compressive stress becomes larger than 1. Expanding. The negative sign on the horizontal axis in FIG. 7 means that the stress applied to at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is a compressive stress. For example, when the anisotropy α of the residual compressive stress is equal to 1.3, the first residual compressive stress σ _y0 of 1650 MPa or less causes the first equivalent stress σ _e0 to be lower than the second equivalent stress σ _e2 . I can. Therefore, by setting the anisotropy α of the residual compressive stress to be greater than 1, in the more types of rolling bearings 1 having various first residual compressive stress σ _y0 , the first raceway surface 4 and the second raceway surface 2 The first equivalent stress σ _e0 in at least one of the raceway surface 7 and the rolling surface 11 can be reduced. In more types of rolling bearings 1, it is possible to suppress occurrence of surface-origin separation on at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11.

In the surface layer region, the first residual compressive stress σ _y0 in at least one axial direction (y direction) of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is changed to the first raceway surface 4, Two methods that are larger than the second residual compressive stress σ _x0 in at least one circumferential direction (x direction) of the second raceway surface 7 and the rolling surface 11 will be exemplified below. The first method is to perform shot peening or burnishing on at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11.

In the second method, before the rolling bearing 1 is used, each rolling element 10 is moved to the inner ring 3 and the first maximum contact surface pressure higher than the second maximum contact surface pressure in the normal use state of the rolling bearing 1. The outer ring 6 is rolled for a short time. The ratio of the high first maximum contact surface pressure to the second maximum contact surface pressure may be greater than 1.0 and greater than 1.3. The ratio of the high first maximum contact surface pressure to the second maximum contact surface pressure is not particularly limited, but may be smaller than 3.0 or 2.5 or less. For example, the first maximum contact surface pressure may be 5.6 GPa and the second maximum contact surface pressure may be 3.0 GPa. For example, by rolling each rolling element 10 with respect to the inner ring 3 and the outer ring 6 with a first maximum contact surface pressure of 5.6 GPa before using the rolling bearing 1, as shown in FIG. The inner ring 3, the outer ring 6 and each rolling element including at least one surface of the outer ring 6 and each rolling element 10 (that is, at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11). In at least one surface layer region of 10, the first residual compressive stress σ _y0 can be made larger than the second residual compressive stress σ _x0 .

The effect of the rolling bearing 1 of this Embodiment is demonstrated.
The rolling bearing 1 according to the present embodiment includes an inner ring 3, an outer ring 6 disposed on the outer peripheral side of the inner ring 3, and a plurality of rolling elements 10 disposed between the inner ring 3 and the outer ring 6. The inner ring 3 has a first raceway surface 4. The outer ring 6 has a second raceway surface 7 that faces the first raceway surface 4. Each of the plurality of rolling elements 10 has a rolling surface 11 that contacts the first raceway surface 4 and the second raceway surface 7. The first residual compressive stress σ _y0 in the axial direction (y direction) of at least one inner ring 3 and outer ring 6 of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is the first raceway surface. 4. It is larger than the second residual compressive stress σ _x0 in the circumferential direction (x direction) of at least one inner ring 3 and outer ring 6 of the second raceway surface 7 and the rolling surface 11.

  At least one first radius of curvature of the inner ring 3, the outer ring 6, and each rolling element 10 in the axial direction (y direction) of the rolling bearing 1 is equal to the inner ring 3, the outer ring 6, and each of the rolling elements 1 in the circumferential direction (x direction). It differs from at least one second curvature radius of the rolling element 10. Therefore, the contact stress between the inner ring 3 and each rolling element 10 in the axial direction (y direction) of the rolling bearing 1 is between the inner ring 3 and each rolling element 10 in the circumferential direction (x direction) of the rolling bearing 1. Different from contact stress. The contact stress between the outer ring 6 and each rolling element 10 in the axial direction (y direction) of the rolling bearing 1 is the contact stress between the outer ring 6 and each rolling element 10 in the circumferential direction (x direction) of the rolling bearing 1. And different.

The first residual compressive stress σ _y0 in at least one axial direction (y direction) of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is used as the first raceway surface 4 and the second raceway. By making it larger than the second residual compressive stress σ _x0 in at least one circumferential direction (x direction) of the surface 7 and the rolling surface 11, anisotropic contact stress can be effectively dealt with. The first equivalent stress σ _e0 in at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 decreases. According to the rolling bearing 1 of the present embodiment, it is possible to suppress the occurrence of surface-origin separation on at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11, which is long. A rolling bearing 1 having a lifetime can be provided.

In the rolling bearing 1 of the present embodiment, the first equivalent stress σ _e0 in at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 is the first raceway surface 4, The inner ring 3 having at least one of the two raceway surfaces 7 and the rolling surface 11, the outer ring 6, and at least one second equivalent stress σ _{e2 of} each rolling element 10 may be smaller. The second equivalent stress σ _e2 is the maximum value of the equivalent stress in at least one of the inner ring 3, the outer ring 6, and each rolling element 10. According to the rolling bearing 1 of the present embodiment, it is possible to suppress the occurrence of surface-origin separation on at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11, which is long. A rolling bearing 1 having a lifetime can be provided.

The residual compressive stress σ _y in at least one axial direction (y direction) of the inner ring 3, the outer ring 6, and each rolling element 10 is the first in the thickness direction of at least one of the inner ring 3, the outer ring 6, and each rolling element 10. At least one of the raceway surface 4, the second raceway surface 7, and the rolling surface 11 may be the maximum. Therefore, the first equivalent stress σ _e0 acting on at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 decreases. According to the rolling bearing 1 of the present embodiment, it is possible to suppress the occurrence of surface-origin separation on at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11, which is long. A rolling bearing 1 having a lifetime can be provided.

The residual compressive stress σ _y in at least one axial direction (y direction) of the inner ring 3, the outer ring 6 and each rolling element 10 is equal to the inner ring 3, It may be maximum in at least one of the outer ring 6 and each rolling element 10. Therefore, the first equivalent stress σ _e0 acting on at least one of the inner ring 3, the outer ring 6 and each rolling element 10 is reduced. According to the rolling bearing 1 of the present embodiment, it is possible to suppress the occurrence of surface-origin separation on at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11, which is long. A rolling bearing 1 having a lifetime can be provided.

In the rolling bearing 1 of the present embodiment, the ratio of the first residual compressive stress σ _y0 to the maximum contact surface pressure acting between each of the plurality of rolling elements 10 and at least one of the inner ring 3 and the outer ring 6 is − It may be 0.7 or more and less than 0.0. Therefore, the first equivalent stress σ _e0 in at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11 is reduced, and the first equivalent stress σ _e0 is represented by the inner ring 3 and the outer ring. 6 and at least one second equivalent stress σ _{e2 of} each rolling element 10 can be made smaller. According to the rolling bearing 1 of the present embodiment, it is possible to suppress the occurrence of surface-origin separation on at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11, which is long. A rolling bearing 1 having a lifetime can be provided.

In the rolling bearing 1 of the present embodiment, the plurality of rolling elements 10 may be a plurality of rollers. The anisotropic residual compressive stress applied to at least one of the first raceway surface 4, the second raceway surface 7, and the rolling surface 11 is the first raceway surface 4, the second raceway surface 7, and the rolling surface. In at least one surface region R ₁ , R ₂ of the inner ring 3, the outer ring 6 and each roller including at least one of the moving surfaces 11, the equivalent stress acting on at least one of the inner ring 3, the outer ring 6 and each roller is reduced. . According to the rolling bearing 1 of the present embodiment, it is possible to suppress occurrence of surface-origin separation on at least one of the first raceway surface 4, the second raceway surface 7 and the rolling surface 11 of each roller. Thus, a rolling bearing 1 having a long life can be provided.

(Embodiment 2)
With reference to FIG.9 and FIG.10, the rolling bearing 1b which concerns on Embodiment 2 is demonstrated. Although the rolling bearing 1b of this Embodiment is equipped with the structure similar to the rolling bearing 1 of Embodiment 1, it differs mainly by the following points.

  In the rolling bearing 1b of the present embodiment, the plurality of rolling elements 10b are a plurality of balls. The rolling bearing 1b may be a deep groove ball bearing. The curvature radius of each rolling element 10b in the axial direction (y direction) is substantially equal to the curvature radius of each rolling element 10b in the circumferential direction (x direction). Each rolling element 10b has a substantially isotropic shape in the axial direction (y direction) and the circumferential direction (x direction).

  The at least one first radius of curvature of the inner ring 3 and the outer ring 6 in the axial direction (y direction) of the rolling bearing 1b is at least one second of the inner ring 3 and the outer ring 6 in the circumferential direction (x direction) of the rolling bearing 1b. It is different from the radius of curvature. In the present embodiment, the radius of curvature of the inner ring 3 in the axial direction (y direction) is different from the radius of curvature of the inner ring 3 in the circumferential direction (x direction). The radius of curvature of the outer ring 6 in the axial direction (y direction) is different from the radius of curvature of the outer ring 6 in the circumferential direction (x direction). Specifically, the curvature radius of the inner ring 3 in the axial direction (y direction) may be larger than the curvature radius of the inner ring 3 in the circumferential direction (x direction). The curvature radius of the outer ring 6 in the axial direction (y direction) may be larger than the curvature radius of the outer ring 6 in the circumferential direction (x direction).

In the present embodiment, the residual compressive stress σ _y in the axial direction (y direction) in at least one surface layer region of the inner ring 3 and the outer ring 6 including at least one of the first raceway surface 4 and the second raceway surface 7. Is larger than the residual compressive stress σ _x in the circumferential direction (x direction). In this embodiment, at least in one thickness direction, uneven distribution of the residual compressive stress sigma _x axial residual compressive stress sigma _y distribution and the circumferential direction of the (y-direction) (x-direction) of the inner ring 3 and the outer ring 6 And the distribution of the residual compressive stress σ _{y in} the axial direction (y direction) and the residual compression in the circumferential direction (x direction) in the thickness direction of at least one of the inner ring 3 and the outer ring 6 in the first embodiment, respectively. It may be the same as the distribution of the stress σ _x . In the present embodiment, anisotropic residual compressive stress is not applied to the rolling surface 11.

  The rolling bearing 1b according to the present embodiment has the same effects as the rolling bearing 1 according to the first embodiment as follows.

In the rolling bearing 1b of the present embodiment, a plurality of rolling elements 10b are a plurality of balls. In at least one of the first raceway surface 4 and the second raceway surface 7, the first residual compressive stress σ _y0 in the axial direction (y direction) is the second residual compressive stress σ in the circumferential direction (x direction). Greater than _x0 .

  In the rolling bearing 1b of the present embodiment, at least one first curvature radius of the inner ring 3 and the outer ring 6 in the axial direction (y direction) of the rolling bearing 1b is equal to the inner ring 3 in the circumferential direction (x direction) of the rolling bearing 1b. And at least one second radius of curvature of the outer ring 6. Therefore, the contact stress between the inner ring 3 and each ball in the axial direction (y direction) of the rolling bearing 1b is different from the contact stress between the inner ring 3 and each ball in the circumferential direction (x direction) of the rolling bearing 1b. . The contact stress between the outer ring 6 and each ball in the axial direction (y direction) of the rolling bearing 1b is different from the contact stress between the outer ring 6 and each ball in the circumferential direction (x direction) of the rolling bearing 1b.

The first residual compressive stress σ _y0 in at least one axial direction (y direction) of the first raceway surface 4 and the second raceway surface 7 is used as the first raceway surface 4, the second raceway surface 7 and the rolling. By making it larger than the second residual compressive stress σ _x0 in at least one circumferential direction (x direction) of the surface 11, an anisotropic contact stress can be effectively dealt with. The first first equivalent stress σ _e0 in at least one of the inner ring 3 and the outer ring 6 decreases. According to the rolling bearing 1b of the present embodiment, it is possible to suppress the occurrence of surface-origin separation on at least one of the first raceway surface 4 and the second raceway surface 7, and the rolling bearing has a long life. 1b may be provided.

  The first and second embodiments disclosed herein should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1, 1b Rolling bearing, 2 shafts, 3 inner rings, 4 first raceway surface, 6 outer race, 7 second raceway surface, 10, 10b rolling element, 11 rolling surface, 15 cage.

Claims (7)

An inner ring having a first raceway surface;
An outer ring disposed on the outer peripheral side of the inner ring, the outer ring has a second raceway surface facing the first raceway surface,
A plurality of rolling elements disposed between the inner ring and the outer ring, each of the plurality of rolling elements having a rolling surface in contact with the first raceway surface and the second raceway surface. And
The first residual compressive stress in the axial direction of the inner ring and the outer ring of at least one of the first raceway surface, the second raceway surface, and the rolling surface is the first raceway surface, the second raceway surface, and the second raceway surface. A rolling bearing that is greater than a second residual compressive stress in a circumferential direction of the at least one inner ring and the outer ring of the raceway surface and the rolling surface.   The first equivalent stress in the at least one of the first raceway surface, the second raceway surface, and the rolling surface is that of the first raceway surface, the second raceway surface, and the rolling surface. The second equivalent stress is smaller than at least one second equivalent stress of each of the inner ring, the outer ring and the plurality of rolling elements having the at least one, and the second equivalent stress is the inner ring, the outer ring, and the plurality of the plurality of rolling elements. The rolling bearing according to claim 1, wherein the rolling bearing is a maximum value of an equivalent stress in each of the at least one of the rolling elements.   The at least one axial compressive residual stress of each of the inner ring, the outer ring, and the plurality of rolling elements is the at least one thickness direction of the inner ring, the outer ring, and the plurality of rolling elements, respectively. 3. The rolling bearing according to claim 1, wherein the at least one of the first raceway surface, the second raceway surface, and the rolling surface is the largest.   The at least one axial compressive residual stress of each of the inner ring, the outer ring, and the plurality of rolling elements is the at least one thickness direction of the inner ring, the outer ring, and the plurality of rolling elements, respectively. 3. The rolling bearing according to claim 1, wherein the rolling bearing has a maximum inside the at least one of each of the inner ring, the outer ring, and the plurality of rolling elements.   The ratio of the first residual compressive stress to the maximum contact surface pressure acting between each of the plurality of rolling elements and at least one of the inner ring and the outer ring is −0.7 or more and less than 0.0. The rolling bearing according to any one of claims 1 to 4.   The rolling bearing according to any one of claims 1 to 5, wherein the plurality of rolling elements are a plurality of rollers. The plurality of rolling elements are a plurality of balls,
The at least one of the first raceway surface, the second raceway surface, and the rolling surface is at least one of the first raceway surface and the second raceway surface. Item 6. The rolling bearing according to any one of Items 5.

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