Method for repairing and manufacturing races of radial rolling bearings, and method for repairing and manufacturing races of thrust rolling bearings

Abstract

A method is realized that can prevent the occurrence of internal defects in a build-up layer having a raceway surface on its surface. [Solution] The method includes a build-up process in which a raceway surface 4a provided on the inner or outer peripheral surface of a used raceway ring 3a is irradiated with a laser 10 emitted from a laser light source, and while supplying a welding material 11 to the portion of the raceway surface 4a irradiated with the laser 10, the laser light source is rotated relative to the raceway ring 3a and displaced relative to the raceway ring 3a in the axial direction, thereby forming a build-up portion 15 on the raceway surface 4a. In the build-up process, the direction of irradiation of the laser 10 onto the raceway surface 4a is inclined forward with respect to the direction of relative displacement of the laser light source in the axial direction with respect to the raceway ring 3a with respect to the normal direction of the raceway surface 4.

Description

[Technical field]

[0001] The present disclosure relates to a method for repairing and manufacturing races of radial rolling bearings, and a method for repairing and manufacturing races of thrust rolling bearings. [Background technology]

[0002] The rotating shaft of a rotating machine such as a machine tool or industrial machine is supported by a rolling bearing against a part that does not rotate during use, such as a housing. A rolling bearing includes a pair of raceways that have raceway surfaces on opposing faces over the entire circumference and are arranged coaxially with each other, and a plurality of rolling elements that are freely rollable and arranged between the raceway surfaces of the pair of raceways. Specific examples of such rolling bearings include radial rolling bearings that mainly support radial loads, and thrust rolling bearings that mainly support axial loads.

[0003] A radial rolling bearing comprises an inner ring having an inner ring raceway on its outer peripheral surface, an outer ring having an outer ring raceway on its inner peripheral surface and arranged coaxially with the inner ring radially inside the inner ring, and a plurality of rolling elements arranged freely to roll between the inner ring raceway and the outer ring raceway.

[0004] A thrust rolling bearing has raceway surfaces on axially opposing sides around the entire circumference, and comprises a pair of raceways arranged coaxially with each other, and a number of rolling elements arranged freely rollable between the raceway surfaces of the pair of raceways.

[0005] Regardless of whether a rolling bearing is a radial rolling bearing or a thrust rolling bearing, when it is used for a long time under a load, the raceway surface may wear or metal fatigue may occur, causing the raceway surface to peel off. When damage such as wear or peeling occurs on the raceway surface, it is possible to replace the raceway ring or the entire rolling bearing including the raceway ring.

[0006] However, in terms of reducing the operating costs of rotating machinery, it is desirable to continue using the raceways after repairing the raceways that have been damaged by wear, spalling, or the like, rather than replacing the raceways or rolling bearings. This is particularly true for large bearings such as roll neck bearings for steel rolling mills. For example, large tapered roller bearings and cylindrical roller bearings are used as roll neck bearings.

[0007] JP 2021-25598 A describes a method for repairing a raceway, in which a build-up portion is formed on the inner raceway around the entire circumference by laser cladding, and a new inner raceway is formed by polishing the surface of the build-up portion. According to the method described in JP 2021-25598 A, a raceway surface that has been damaged by wear, peeling, or the like can be repaired without providing a machining allowance in advance on the surface layer of the inner raceway. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent Publication No. 2021-25598 Summary of the Invention [Problem to be solved by the invention]

[0009] When repairing a wide axial range using the conventional method described in JP 2021-25598 A, it is possible to form a build-up portion by arranging a plurality of annular beads on the inner ring raceway without gaps in the axial direction by rotating the laser light source relative to the inner ring and displacing it relative to the axial direction, or by forming a build-up portion composed of beads wound spirally without gaps. However, when such a build-up portion is formed using the conventional method described in JP 2021-25598 A, there is a risk of internal defects.

[0010] Internal defects occur when gas present in the powder metal or gas mixed in from the outside creates bubbles in the molten metal material (molten pool) during laser cladding processing, and the metal material solidifies before the bubbles can be expelled to the outside.

[0011] Consider the case of forming an overlay portion on the inner ring raceway by arranging a plurality of annular beads in the axial direction without gaps, using the conventional method described in JP 2021-25598 A. For example, first, a laser is irradiated onto the inner ring raceway, and the inner ring is rotated once while supplying a welding material to the portion irradiated with the laser to form an annular bead. Next, the inner ring is displaced in the axial direction relative to the laser light source. At this time, the amount of relative displacement of the inner ring in the axial direction relative to the laser light source is adjusted so that there is no gap between two beads adjacent to each other in the axial direction. Then, the inner ring raceway is again irradiated with a laser, and the inner ring is rotated once while supplying a welding material to the portion irradiated with the laser to form an annular bead. As described above, the overlay portion is formed by repeating the process of forming an annular bead and the process of displacing the inner ring in the axial direction relative to the laser light source.

[0012] As shown in Fig. 8, when forming a buildup portion 103 configured by arranging a plurality of annular beads 102 side by side with no gaps in the axial direction on an inner ring raceway 101 of an inner ring 100, of two axially adjacent beads 102, the one axial side portion of the bead 102 on the other axial side (right side in Fig. 8) is arranged so as to overlap in the radial direction with the other axial side portion (right side in Fig. 8) of the bead 102 on one axial side (left side in Fig. 8). The bead 102 has a substantially partial elliptical cross-sectional shape, as shown in an exaggerated manner in Fig. 9.

[0013] Here, in the conventional method described in JP 2021-25598 A, the laser 104 is irradiated radially onto the inner ring raceway 101. For this reason, when the laser 104 is irradiated radially to form the bead 102 on the other axial side of the bead 102 on one axial side (the portion with diagonal grid in FIG. 9 ), it may not be possible to sufficiently heat the portion of the inner ring raceway 101 located radially inside the end portion on the other axial side of the bead 102 on one axial side.

[0014] Even when the build-up portion is formed by a bead wound spirally without any gaps, when a laser is irradiated radially to a portion of the bead axially adjacent to a previously formed portion to form a bead, it may not be possible to sufficiently heat the portion located radially inside the axial end of the previously formed portion.

[0015] In any case, if there are areas where laser heating cannot be performed sufficiently, the molten metal material in those areas is likely to solidify early before the air bubbles are expelled, making it more likely that internal defects caused by air bubbles will occur inside the buildup portion.

[0016] The above problems occur not only when a build-up portion is formed by laser cladding to repair a raceway surface, but also when a build-up portion is formed by laser cladding in the area where the raceway surface is to be formed when manufacturing a raceway from scratch.

[0017] An object of the present disclosure is to provide a method for repairing and manufacturing a raceway that can prevent the occurrence of internal defects in an overlay layer having a raceway surface on its surface. [Means for solving the problem]

[0018] A method for repairing a raceway of a radial rolling bearing according to one aspect of the present disclosure includes the steps of: The method includes a build-up process in which a laser emitted from a laser light source is irradiated onto an orbital surface provided on the inner or outer peripheral surface of a used raceway ring, and while supplying a melting material to the portion of the orbital surface irradiated with the laser, the laser light source is rotated relative to the raceway ring and displaced relative to the raceway ring in the axial direction, thereby forming a build-up portion on the orbital surface that is constituted by arranging a plurality of annular beads in the axial direction with no gaps therebetween, or by a build-up bead wound spirally with no gaps therebetween.

[0019] In particular, in one embodiment of the method for repairing a raceway of a radial rolling bearing disclosed herein, in the build-up process, the direction of irradiation of the laser with respect to the raceway surface is inclined forward with respect to the axial relative displacement direction of the laser light source with respect to the raceway surface with respect to the normal direction of the raceway surface (the normal direction of the portion of the raceway surface irradiated with the laser).

[0020] In one embodiment of the method for repairing a raceway of a radial rolling bearing disclosed herein, the inclination angle of the laser irradiation direction relative to the normal direction of the raceway surface can be greater than or equal to 5 degrees and less than 90 degrees, preferably greater than or equal to 10 degrees and less than or equal to 20 degrees, and more preferably greater than or equal to 15 degrees and less than or equal to 20 degrees.

[0021] A method for manufacturing a raceway of a radial rolling bearing according to one embodiment of the present disclosure includes: A method for manufacturing a raceway of a radial rolling bearing comprising a cylindrical substrate, a buildup layer covering an inner circumferential surface or an outer circumferential surface of the substrate over the entire circumference, and a raceway surface provided over the entire circumference on a surface of the buildup layer, comprising: a build-up process in which a laser emitted from a laser light source is irradiated onto an inner peripheral surface or an outer peripheral surface of the base material, and a welding material is supplied to the portion of the inner peripheral surface or the outer peripheral surface of the base material irradiated with the laser, while the laser light source is rotated relative to the base material and displaced relative to the base material in the axial direction, thereby forming a build-up portion on the inner peripheral surface or the outer peripheral surface of the base material, which is constituted by arranging a plurality of annular beads in a line with no gaps in the axial direction, or which is constituted by beads wound in a spiral shape with no gaps; a machining step of machining a surface of the build-up portion to form the build-up layer having the raceway surface on a surface thereof; Equipped with.

[0022] In particular, in one embodiment of the method for manufacturing a raceway of a radial rolling bearing according to the present disclosure, in the build-up process, the direction of irradiation of the laser with respect to the inner or outer surface of the substrate is set to a direction inclined forward with respect to the axial relative displacement direction of the laser light source with respect to the substrate, with respect to the normal direction of the inner or outer surface of the substrate (the normal direction of the portion of the inner or outer surface of the substrate that is irradiated with the laser).

[0023] In one embodiment of the method for manufacturing a raceway of a radial rolling bearing according to the present disclosure, the inclination angle of the laser irradiation direction relative to the normal direction of the inner or outer circumferential surface of the base material can be set to be greater than or equal to 5 degrees and less than 90 degrees, preferably greater than or equal to 10 degrees and less than or equal to 20 degrees, and more preferably greater than or equal to 15 degrees and less than or equal to 20 degrees.

[0024] The method for repairing a raceway of a thrust rolling bearing according to the present disclosure includes: The method includes a build-up process in which a laser emitted from a laser light source is irradiated onto a raceway surface provided on the axial side of a used raceway ring, and while supplying a welding material to the portion of the raceway surface irradiated with the laser, the laser light source is rotated relative to the raceway ring and displaced radially relative to the raceway ring, thereby forming a build-up portion constituted by arranging a plurality of annular weld beads radially on the raceway surface, or constituted by beads wound in a spiral shape without any gaps.

[0025] In particular, in one embodiment of the method for repairing a raceway of a thrust rolling bearing disclosed herein, in the build-up process, the direction of irradiation of the laser with respect to the raceway surface is inclined forward with respect to the radial relative displacement direction of the laser light source with respect to the raceway surface with respect to the normal direction of the raceway surface.

[0026] In one embodiment of the method for repairing a raceway of a thrust rolling bearing disclosed herein, the inclination angle of the laser irradiation direction relative to the normal direction of the raceway surface can be greater than or equal to 5 degrees and less than 90 degrees, preferably greater than or equal to 10 degrees and less than 20 degrees, and more preferably greater than or equal to 15 degrees and less than 20 degrees.

[0027] A method for manufacturing a raceway of a thrust rolling bearing according to one aspect of the present disclosure includes: A method for manufacturing a raceway of a thrust rolling bearing comprising a hollow circular base material, a buildup layer covering an axial side surface of the base material over an entire circumference, and a raceway surface provided over the entire circumference on a surface of the buildup layer, comprising: A build-up process is provided in which a laser emitted from a laser light source is irradiated onto the axial side surface of the base material, and a welding material is supplied to the portion of the axial side surface of the base material irradiated with the laser, while the laser light source is rotated relative to the axial side surface of the base material and displaced relative to the axial direction in a radial direction, thereby forming a build-up portion on the axial side surface of the base material by arranging a plurality of annular weld beads in a radially spaced relationship on the axial side surface of the base material, or by forming a build-up portion composed of beads wound in a spiral shape without gaps, a machining step of machining a surface of the build-up portion to form the build-up layer having the raceway surface on a surface thereof; Equipped with.

[0028] In particular, in one embodiment of the method for manufacturing a raceway of a thrust rolling bearing according to the present disclosure, in the build-up process, the direction of irradiation of the laser with respect to the axial side surface of the substrate is inclined forward with respect to the radial relative displacement direction of the laser light source with respect to the raceway, with respect to the normal direction of the axial side surface of the substrate.

[0029] In one embodiment of the method for manufacturing a raceway of a thrust rolling bearing according to the present disclosure, the inclination angle of the laser irradiation direction relative to the normal direction of the axial side surface of the substrate can be greater than or equal to 5 degrees and less than 90 degrees, preferably greater than or equal to 10 degrees and less than 20 degrees, and more preferably greater than or equal to 15 degrees and less than 20 degrees. Effect of the Invention

[0030] According to the method for repairing and manufacturing a raceway of a radial rolling bearing, and the method for repairing and manufacturing a raceway of a thrust rolling bearing disclosed herein as described above, it is possible to prevent the occurrence of internal defects in an overlay layer having a raceway surface on its surface. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a partially cutaway perspective view showing a radial cylindrical roller bearing including a raceway to which a method for repairing a raceway of a radial rolling bearing according to a first embodiment of the present disclosure can be applied. FIG. [Diagram 2] FIG. 2 is an enlarged schematic view of a portion corresponding to part X in FIG. [Diagram 3] Figure 3(A) is a partially enlarged cross-sectional view showing the original inner ring raceway before repair, Figure 3(B) is a partially enlarged cross-sectional view showing the state where a buildup portion has been formed on the original inner ring raceway, and Figure 3(C) is a partially enlarged cross-sectional view showing the state where the buildup portion has been machined to form a new inner ring raceway. [Figure 4] Figure 4(A) is a partially enlarged schematic diagram showing how a bead is formed on the inner ring raceway, as viewed in cross section along an imaginary plane perpendicular to the central axis of the inner ring, and Figure 4(B) is a partially enlarged schematic diagram showing how a bead is formed on the inner ring raceway, as viewed in cross section along an imaginary plane including the central axis of the inner ring. [Diagram 5] FIG. 5 is a cross-sectional view that illustrates a state in which the inner peripheral surface of the inner ring is restrained by a deformation prevention jig when laser cladding is performed. [Figure 6] FIG. 6 is a cross-sectional view showing a thrust cylindrical roller bearing including a raceway to which the method for repairing a raceway of a thrust rolling bearing according to a second embodiment of the present disclosure can be applied. [Figure 7] FIG. 7 is a partially enlarged schematic diagram showing the formation of a bead on the raceway surface, in a cross section taken along an imaginary plane including the center axis of the thrust race. [Figure 8] FIG. 8 is a cross-sectional view showing an example of a build-up portion formed by arranging a plurality of annular beads side by side with no gaps in the axial direction. [Figure 9]FIG. 9 is an enlarged cross-sectional view showing an annular bead. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to Figures 1 to 5. In this example, a case will be described in which a method for repairing a raceway of a radial rolling bearing according to one aspect of the present disclosure is applied to an inner ring 3 of a radial cylindrical roller bearing 2 that uses cylindrical rollers (including needles) as rolling elements 1, as shown in Figure 1.

[0033] However, the method for repairing the raceways of a radial rolling bearing according to one embodiment of the present disclosure can also be applied to the outer ring of a radial cylindrical roller bearing, the inner ring and / or outer ring of a radial tapered roller bearing that uses tapered rollers as rolling elements, the inner ring and / or outer ring of a radial ball bearing that uses balls, or the inner ring and / or outer ring of a radial self-aligning roller bearing that uses spherical rollers.

[0034] Furthermore, the method for manufacturing the raceway of a radial rolling bearing according to one embodiment of the present disclosure can be applied to the inner ring and / or outer ring of a radial cylindrical roller bearing, the inner ring and / or outer ring of a radial tapered roller bearing that uses tapered rollers as rolling elements, the inner ring and / or outer ring of a radial ball bearing that uses balls, or the inner ring and / or outer ring of a radial self-aligning roller bearing that uses spherical rollers.

[0035] Furthermore, the method for repairing and manufacturing the raceway of a thrust rolling bearing according to one embodiment of the present disclosure can be applied to the raceway of a thrust cylindrical roller bearing that uses cylindrical rollers (including needles) as the rolling elements as shown in the second example, the raceway of a thrust tapered roller bearing that uses tapered rollers, the raceway of a thrust ball bearing that uses balls, or the raceway of a thrust self-aligning roller bearing that uses spherical rollers.

[0036] The method for repairing a raceway of a radial rolling bearing according to one embodiment of the present disclosure and the method for repairing a raceway of a thrust rolling bearing according to one embodiment of the present disclosure can be preferably applied to large rolling bearings that support a large load, such as a rolling bearing that supports the roll neck of a steel rolling mill. That is, the method for repairing a raceway of a radial rolling bearing according to one embodiment of the present disclosure and the method for repairing a raceway of a thrust rolling bearing according to one embodiment of the present disclosure can achieve particularly significant cost reduction effects and carbon dioxide emission reduction effects when applied to the raceway of a large rolling bearing.

[0037] According to the method for manufacturing the race of the radial rolling bearing and the method for manufacturing the race of the thrust rolling bearing of the present disclosure, the build-up layer provided with the raceway surface can be made of a metal material different from the metal material constituting the base material, which makes it easy to adjust the raceway surface to the desired properties.

[0038] <Structure of radial cylindrical roller bearings> The radial cylindrical roller bearing 2 comprises an inner ring 3 having an inner ring raceway 4 around its entire circumference on its outer peripheral surface, an outer ring 6 having an outer ring raceway 5 around its entire circumference on its inner peripheral surface and arranged coaxially with the inner ring 3 on the radial outside of the inner ring 3, and a plurality of rolling elements 1 each of which is cylindrically configured and arranged freely rollable between the inner ring raceway 4 and the outer ring raceway 5.

[0039] In the description of this example, unless otherwise specified, the axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction of the inner ring 3. The axial direction, radial direction, and circumferential direction of the inner ring 3 coincide with the axial direction, radial direction, and circumferential direction of the outer ring 6. Moreover, one axial side refers to the left side in Figures 1 to 3(C) and Figure 4(B), and the other axial side refers to the right side in Figures 1 to 3(C) and Figure 4(B).

[0040] In this example, the inner ring 3 is repaired by the method for repairing raceways of radial rolling bearings according to the present disclosure. The inner ring 3 is basically constructed using the original (used) inner ring 3a (see FIG. 3(A)) before repair as the base material 7.

[0041] It should be noted that when a raceway is manufactured by the method for manufacturing a raceway of a radial rolling bearing according to one embodiment of the present disclosure or the method for manufacturing a raceway of a thrust rolling bearing according to one embodiment of the present disclosure, i.e., when an unused raceway is manufactured from scratch, the raceway is constructed using a cylindrical or hollow circular metal member as a base material with no raceway surface on its surface.

[0042] As shown in Figure 2, the inner ring 3 in this example has, from the surface side, a buildup layer 8 made of a metal material different from the base material 7 on the surface portion including at least the inner ring raceway 4, and a mixed layer 9 of the metal material constituting the base material 7 and the metal material constituting the buildup layer 8, which is present in the portion located directly below the buildup layer 8.

[0043] The substrate 7 has a cylindrical shape and is made of a metal material made of hard metal such as high carbon chromium steel such as SUJ2-4, high carbon chromium steel that has been subjected to carburizing or carbonitriding treatment, carbon steel such as S53C, carburizing steel such as SCr420 or SCM420, etc. Before being repaired, the substrate 7 alone constitutes the inner ring 3a, and the original inner ring 3a has the original inner ring raceway 4a on its outer circumferential surface.

[0044] The buildup layer 8 covers the entire outer peripheral surface of the base material 7, including the original inner ring raceway 4a. The repaired inner ring raceway 4 is formed on the outer peripheral surface of the buildup layer 8. The buildup layer 8 is made of a metal material that can ensure sufficient bonding strength with the base material 7 and can also ensure sufficient performance of the inner ring raceway 4, such as an Fe-based alloy, a Cu-based alloy, a Ni-based alloy, a Co-based alloy, or a carbon alloy.

[0045] The mixed layer 9 is a layer in which the metal material constituting the base material 7 and the metal material constituting the build-up layer 8 are mixed. More specifically, the mixed layer 9 is formed by melting, mixing, and solidifying the metal material constituting the original inner ring 3a (base material 7) and the powdered welding material 11, which is the metal material constituting the build-up portion 15, during repair. That is, as shown in FIG. 4(A) and FIG. 4(B), when forming each bead 16 constituting the build-up portion 15 by laser cladding, the original inner ring raceway 4a is irradiated with a laser 10 emitted from a laser source, and the powdered welding material 11 is supplied to the part of the original inner ring raceway 4a irradiated with the laser 10. As a result, the powdered welding material 11 is heated and melted, and solidified to form the bead 16. At this time, the metal material present in the surface layer portion of the original inner ring raceway 4a irradiated with the laser 10 is heated and melted until it reaches or exceeds the melting point by the irradiation of the laser 10, and is mixed with the molten powdered welding material 11. Therefore, a mixed layer 9 is formed at the boundary between the substrate 7 and the buildup portion 15 by solidifying the metallic material constituting the substrate 7 and the metallic material constituting the buildup portion 15 in a melted and mixed state. The mixed layer 9 exists in the portion located directly below the buildup layer 8 even after the buildup portion 15 is subjected to appropriate machining such as cutting, grinding, and polishing to form the buildup layer 8 having the inner ring raceway 4 on its surface.

[0046] The inner ring 3 has a rehardened layer 12 in a portion located immediately below the mixed layer 9, and has a retempered layer 13 in a portion located immediately below the rehardened layer 12. That is, the inner ring 3 has, in the portion where the inner ring raceway 4 is formed, a build up layer 8, mixed layer 9, rehardened layer 12, and retempered layer 13, in that order from the radially outer side.

[0047] The re-hardened layer 12 is a portion of the substrate 7 that has been re-hardened by being heated to a temperature above the hardening temperature and below the melting point when the original inner ring raceway 4a is irradiated with a laser 10 during the formation of the build-up layer 8 by laser cladding.

[0048] The re-tempered layer 13 is a portion of the substrate 7 that has been tempered by being heated to a temperature above the tempering temperature but below the hardening temperature when the original inner ring raceway 4a is irradiated with a laser 10 to form the build-up layer 8 by laser cladding.

[0049] <How to repair the inner ring> First, as shown in Fig. 3(A), a radial cylindrical roller bearing 2 in which damage such as wear and flaking has occurred in the original inner ring raceway 4a due to long-term use is removed from the installation location and disassembled, and the original inner ring 3a is taken out. If necessary, first, the surface of the original inner ring raceway 4a provided on the outer circumferential surface of the original inner ring 3a is degreased and cleaned. This removes oil present on the surface layer of the original inner ring raceway 4a, and also removes foreign matter such as wear powder, flaking debris, and moisture adhering to the surface of the original inner ring raceway 4a.

[0050] The method for degreasing and cleaning the surface of the original inner ring raceway 4a is not particularly limited. For example, solvent degreasing, alkaline degreasing by immersing in an alkaline solution, electrolytic degreasing by passing an electric current between a material immersed in an alkaline solution and an electrode, etc. can be used. Additionally or alternatively, laser cleaning can be performed, or the material can be washed with an organic solvent, etc., and then dried by hot air drying, heat drying, etc. If necessary, the original inner ring raceway 4a can be subjected to appropriate mechanical processing such as cutting, grinding, and polishing to smooth the surface before degreasing and cleaning the surface of the original inner ring raceway 4a.

[0051] Next, as shown in FIG. 3(B), a build-up process is performed in which a build-up portion 15 is formed by laser cladding so as to cover the entire outer peripheral surface of the portion of the original inner ring 3a (base material 7) where the original inner ring raceway 4a was formed.

[0052] In the build-up process, the original inner raceway 4a is irradiated with a laser 10 emitted from a laser light source (not shown), and a powder welding material 11 is supplied from a nozzle 14 to the part of the original inner raceway 4a irradiated with the laser 10 by spraying it together with a shielding gas, while the laser light source and the original inner raceway 3a are rotated relative to each other and displaced relative to each other in the axial direction. As a result, a build-up portion 15 is formed on the outer circumferential surface of the part of the original inner raceway 3a (base material 7) that includes the original inner raceway 4a, the build-up portion 15 being formed by arranging a plurality of annular beads 16 side by side without gaps in the axial direction or by beads wound spirally without gaps. In the build-up process, the irradiation direction of the laser 10 on the original inner raceway 4a is inclined forward with respect to the axial relative displacement direction of the laser light source with respect to the original inner raceway 3a with respect to the normal direction of the inner raceway 4 after repair (the normal direction of the part irradiated with the laser 10).

[0053] Specifically, in this example, the laser light source is displaced relative to the original inner ring 3a toward the other axial direction. The inner ring raceway 4 after repair is formed of a cylindrical surface whose outer diameter does not change in the axial direction. For this reason, the laser 10 emitted from the laser light source is irradiated to the original inner ring raceway 4a in a direction inclined toward the other axial direction (right side in FIG. 4(B)) with respect to the radial direction of the original inner ring 3a (up and down direction in FIG. 4(B)), that is, in the direction of a virtual straight line α that approaches the other axial direction toward the other side as it approaches the radial outside. Then, the original inner ring 3a is rotated once relative to the laser light source while supplying the powder welding material 11 from the nozzle 14 by spraying it together with the shielding gas to the part irradiated with the laser 10, thereby forming one annular bead 16. The bead 16 has a cross-sectional shape that is approximately partially elliptical or approximately rectangular.

[0054] The inclination angle θ of the irradiation direction of the laser 10 with respect to the normal direction of the inner ring raceway 4 (irradiation angle of the laser 10) is not limited to this, but can be 5 degrees or more and less than 90 degrees, preferably 10 degrees or more and 20 degrees or less, and more preferably 15 degrees or more and 20 degrees or less. If the irradiation angle θ of the laser 10 is less than 5 degrees, when the laser 10 is irradiated to a portion adjacent to the other axial side of the previously formed bead 16 to form the next bead 16, the portion located radially inside the end portion on the other axial side of the previously formed bead 16 cannot be sufficiently heated, and it may not be possible to sufficiently prevent the occurrence of internal defects.

[0055] In this example, a processing device is used in which a nozzle 14 for ejecting the powder welding material 11 and the shielding gas is supported and fixed around a laser light source for emitting the laser 10. Therefore, when the irradiation angle θ of the laser 10 is changed, the spraying angle of the powder welding material 11 and the shielding gas from the nozzle 14 also changes. However, when implementing the present disclosure, a processing device having a structure that allows the spraying angle of the powder welding material 11 and the shielding gas from the nozzle 14 to be adjusted independently of the irradiation angle of the laser 10 can also be used. In any case, when performing laser cladding, the powder welding material 11 and the shielding gas are sprayed onto the part of the original inner ring raceway 4a that was irradiated with the laser 10.

[0056] The output of laser 10 is appropriately set according to the radial height H of bead 16 (the radial height of the portion of bead 16 that has the greatest radial height), the axial width W of bead 16 (the axial width of the portion of bead 16 that has the greatest axial width), and the like. For example, in the case of an inner ring 3a of a single row cylindrical roller bearing having a designation number NUP206, where the radial height H of bead 16 is about 1.0 mm to 1.5 mm and the axial width W is about 4.0 mm to 6.0 mm, the output of laser 10 can be, but is not limited to, about 2.5 kW to 3.5 kW.

[0057] The powder welding material 11 is composed of a metal powder such as an Fe-based alloy, a Cu-based alloy, a Ni-based alloy, a Co-based alloy, or a carbon alloy. An appropriate amount of the powder welding material 11 is supplied depending on the outer diameter dimension of the original inner ring 3a, the radial height H and the axial width W of the bead 16, etc. When implementing the present disclosure, a wire welding material can be used instead of the powder welding material 11.

[0058] Next, the laser light source is displaced relative to the original inner ring 3a in the other axial direction. Specifically, the laser light source is displaced to the other axial direction, or the original inner ring 3a is displaced to one axial direction. At this time, the amount of axial displacement of the original inner ring 3a relative to the laser light source is adjusted so that no gap exists between two axially adjacent beads 16, i.e., between the bead 16 previously formed on one axial side and the bead 16 to be formed next on the other axial side.

[0059] Specifically, of two axially adjacent beads 16, the one axial side portion of the bead 16 on the other axial side is disposed so as to overlap in the radial direction with the other axial side portion of the bead 16 on the one axial side previously formed. In other words, the bead 16 on the other axial side is formed so as to cover the other axial side portion of the bead 16 on the one axial side with its one axial side portion.

[0060] The axial dimension L of the portion where two axially adjacent beads 16 overlap in the radial direction is appropriately determined according to the axial width W, radial height H, etc. of the beads 16. For example, in the case of an inner ring 3a of a single row cylindrical roller bearing with a bearing number of NUP206, where the axial width W of the beads 16 is about 4.0 mm to 6.0 mm and the radial height H is about 1.0 mm to 1.5 mm, the axial dimension L of the portion where two axially adjacent beads 16 overlap in the radial direction can be, but is not limited to, 1.0 mm to 3.5 mm, preferably 2.0 mm to 3.0 mm. If the axial dimension L is smaller than 1.0 mm, a gap may be generated between the beads 16, exposing the original inner ring raceway 4a. If the axial dimension L is larger than 3.5 mm, the material cost and processing time may increase.

[0061] After the laser light source is displaced relative to the original inner ring 3a toward the other axial direction, a laser 10 is again irradiated onto the original inner ring raceway 4a from a direction inclined relative to the normal direction of the inner ring raceway 4 (in this example, the radial direction of the original inner ring 3a), and powder welding material 11 is supplied to the portion irradiated with the laser 10 by spraying it from a nozzle 14 together with shielding gas, while the original inner ring 3a is rotated once relative to the laser light source, to form a single annular bead 16.

[0062] As described above, in the build-up process of this example, the work of forming one annular bead 16 and the work of relatively displacing the laser light source and the original inner ring 3a in the axial direction are repeated to form a build-up portion 15 consisting of multiple annular beads 16 arranged side by side with no gaps in the axial direction.

[0063] When carrying out the method for repairing a raceway of a radial rolling bearing according to one aspect of the present disclosure, it is also possible to form a build-up portion consisting of beads wound in a spiral shape without gaps on the outer circumferential surface of the original inner ring by rotating the original inner ring relative to the laser light source while displacing it in the axial direction. In this case, the amount of axial relative displacement of the original inner ring relative to the laser light source per rotation is adjusted so that no gaps exist between axially adjacent portions of the beads.

[0064] When the original inner raceway 4a is irradiated with a laser 10 to perform laser cladding, the metal material present in the surface layer of the original inner raceway 4a irradiated with the laser 10 of the original inner raceway 3a (base material 7) is melted together with the powdered welding material 11, which is the metal material constituting the weld bead 8b, and a molten pool 17 is formed in which these are mixed. Then, when the irradiation position of the laser 10 shifts from the molten pool 17 due to the relative rotation between the laser light source and the original inner raceway 3a, the metal material constituting the molten pool 17 is cooled and solidified. As a result, a build-up portion 15 (bead 16) is formed on the original inner raceway 4a, and at the same time, a mixed layer 9 of the metal material constituting the base material 7 and the metal material constituting the build-up portion 15 (bead 16) is formed at the boundary between the base material 7 and the bead 16.

[0065] Furthermore, when the original inner raceway 4a is irradiated with a laser 10 to perform laser cladding, the metal material of the original inner raceway 3a (base material 7) in a portion that is below the surface layer portion of the original inner raceway 4a is also heated. The portion directly below the mixed layer 9 is re-quenched by being heated to a temperature equal to or higher than the quenching temperature and lower than the melting point. As a result, a re-quenched layer 12 is formed in the portion directly below the mixed layer 9.

[0066] Furthermore, the portion located directly below the re-hardened layer 12 is tempered by heating to a temperature equal to or higher than the tempering temperature and lower than the quenching temperature. As a result, a re-tempered layer 13 is formed in the portion located directly below the re-hardened layer 12. Note that even if the portion located below the re-tempered layer 13 is heated, the temperature is lower than the tempering temperature, so there is almost no structural change. Note that the re-hardened layer 12 and the re-tempered layer 13 are omitted in Figs. 3(A) to 3(C) and 4.

[0067] When forming the cladding portion 15 on the original inner raceway 4a by laser cladding, at least a part of the surface of the original inner ring 3a (base material 7) can be restrained except for the part where the original inner raceway 4a exists. This makes it possible to prevent the base material 7 from being deformed due to the influence of heat generated by the irradiation of the laser 10. For example, as shown in FIG. 5, a cylindrical deformation prevention jig 18 can be fitted inside the original inner ring 3a (base material 7) to restrain the inner peripheral surface of the original inner ring 3a. In addition to or instead of the inner peripheral surface of the original inner ring 3a (base material 7), the axial side surface (side surface on one axial side and / or the other axial side) of the original inner ring 3a can also be restrained. Also, if the heat generated by the irradiation of the laser 10 does not deform the original inner ring 3a or is not a problem, the attachment of the deformation prevention jig 18 can be omitted.

[0068] Also, the original inner ring 3a (base material 7) can be preheated before laser cladding. By preheating the original inner ring 3a, it is possible to prevent the temperature of the part of the original inner ring 3a irradiated with the laser 10 from changing rapidly when the original inner ring raceway 4a is irradiated with the laser 10, causing damage such as cracks in the part. However, it is preferable that the preheating temperature is equal to or lower than the tempering temperature, specifically, equal to or lower than 200 degrees. In other words, if the preheating temperature exceeds the tempering temperature, tempering is applied to the surface of the original inner ring 3a (base material 7), and the hardness of the surface of the original inner ring 3a may decrease.

[0069] After forming the build-up portion 15 on the outer peripheral surface of the portion of the original inner ring 3a (base material 7) including the original inner ring raceway 4a by laser cladding, the build-up portion 15 is subjected to appropriate machining such as cutting, grinding, and polishing to form a new inner ring raceway 4 (see FIG. 3(C)). In this way, a new (repaired) inner ring 3 is obtained. The process for forming the new inner ring raceway 4 is basically the same as the process for forming the original inner ring raceway 4a on the outer peripheral surface of the original inner ring 3a. In this example, a grindstone is pressed against the outer peripheral surface of the build-up portion 15, and the original inner ring 3a including the build-up portion 15 is rotated around its central axis while the grindstone is oscillated around the center of curvature of the generatrix shape (cross-sectional shape) of the new inner ring raceway 4. In this way, the outer peripheral surface of the build-up portion 15 is polished to form a new inner ring raceway 4, and a new inner ring 3 is obtained by further performing cleaning or the like as necessary. The outer peripheral surface of the part including the inner ring raceway 4a of the new inner ring 3 is constituted by a build-up layer 8 formed after grinding.

[0070] The repaired inner ring 3 obtained as described above is combined with the outer ring 6 and the rolling elements 1 to assemble the repaired radial cylindrical roller bearing 2, which is then reassembled in its installation location.

[0071] It should be noted that when carrying out the method for manufacturing a raceway of a radial rolling bearing according to one embodiment of the present disclosure, the method can be carried out essentially in the same manner as the repair method of this example, except that a cylindrical substrate having no raceway surface on its surface is used.

[0072] According to this example, the radial cylindrical roller bearing 2 can be repaired and reused, which reduces costs and reduces carbon dioxide emissions compared to manufacturing a new radial cylindrical roller bearing 2 and replacing it.

[0073] In addition, in this example, the direction of irradiation of the laser 10 to the original inner ring raceway 4a is inclined forward with respect to the relative displacement direction of the laser light source in the axial direction with respect to the original inner ring 3a with respect to the normal direction of the inner ring raceway 4 (in this example, the radial direction of the original inner ring 3a). Therefore, when forming the bead 16 on the other axial side in the portion adjacent to the other axial side of the bead 16 on the one axial side previously formed, the portion of the original inner ring raceway 4a located radially inside the end of the other axial side of the bead 16 on the one axial side can be sufficiently heated. Therefore, in the portion of the original inner ring raceway 4a located radially inside the end of the other axial side of the bead 16 on the one axial side previously formed, it is possible to prevent the molten metal material from solidifying early before the bubbles generated inside are discharged. Therefore, it is possible to prevent the occurrence of internal defects caused by bubbles inside the build-up portion 15 formed by the multiple annular beads 16.

[0074] [Example 2] A second example of an embodiment of the present disclosure will be described with reference to Figures 6 and 7. This example is an example in which one race 21 of a pair of races (thrust races) 21, 22 constituting a thrust cylindrical roller bearing 20 that uses cylindrical rollers (including needles) as rolling elements 19 is repaired by a method for repairing races of a thrust rolling bearing according to one aspect of the present disclosure.

[0075] <Structure of thrust cylindrical roller bearing> The thrust cylindrical roller bearing 20 includes a pair of races 21, 22, a plurality of rolling elements 19, and a cage .

[0076] In the description of this example, unless otherwise specified, the axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction of one raceway 21. The axial direction, radial direction, and circumferential direction of one raceway 21 coincide with the axial direction, radial direction, and circumferential direction of the other raceway 22. Moreover, one axial side refers to the lower side in Figures 6 and 7, and the other axial side refers to the upper side in Figures 6 and 7.

[0077] Each of the pair of raceways 21, 22 is configured as a hollow circular plate, and has raceway surfaces 24, 25 on opposing axial side surfaces. That is, of the pair of raceways 21, 22, one raceway 21 arranged on one axial side has raceway surface 24 on a side surface on the other axial side, and the other raceway 22 arranged on the other axial side has raceway surface 25 on a side surface on one axial side. Raceway surfaces 24, 25 are configured by flat surfaces perpendicular to central axis O of thrust cylindrical roller bearing 20.

[0078] The rolling elements 19 are cylindrical in shape. Each rolling element 19 has a central axis oriented in a radial direction and is held by a cage 23 and is disposed between the raceway surfaces 24, 25 of a pair of raceways 21, 22 so as to be able to roll freely.

[0079] In this example, one of the races 21 is repaired by the method for repairing races of a thrust rolling bearing according to the present disclosure. The race 21 is basically constructed using the original race 21a before repair as the base material 7a.

[0080] The raceway ring 21 has basically the same layer structure as the inner ring 3 of the first example. That is, the raceway ring 21 has, on the surface portion of at least the portion including the raceway surface 24, a build-up layer made of a metal material different from the base material 7a, and a mixed layer of the metal material constituting the base material 7a and the metal material constituting the build-up layer, which is present in a portion located directly below the build-up layer, from the surface side.

[0081] The base material 7a is made of hard metal and has a hollow circular plate shape. Before being restored, the base material 7a alone constitutes the raceway ring 21a, and the original raceway ring 21a has an original raceway surface 24a on the other axial side.

[0082] The build-up layer is made of a metal material that can ensure sufficient bonding strength with the base material 7a and sufficient performance of the raceway surface 24, and covers the entire circumference of the other axial side surface of the base material 7a including the original raceway surface 24a. The new raceway surface 24 is provided on the other axial side surface of the build-up layer.

[0083] The mixed layer is formed during repair by melting, mixing, and solidifying the metal material constituting the original raceway 21a (base material 7a) and the powder welding material 11a, which is the metal material constituting the buildup portion 15a.

[0084] Furthermore, the bearing ring 21 has a re-hardened layer in a portion located directly below the mixed layer, which is hardened again by heating to a temperature equal to or higher than the hardening temperature and lower than the melting point during repair, and has a re-tempered layer in a portion located directly below the re-hardened layer, which is tempered by heating to a temperature equal to or higher than the tempering temperature and lower than the hardening temperature during repair.

[0085] <How to repair raceways> First, the original raceway ring 21a to be repaired is taken out by disassembling the thrust cylindrical roller bearing 20. Furthermore, if necessary, the original raceway surface 24a is degreased and cleaned to remove oil and / or foreign matter.

[0086] Next, a build-up process is performed in which a build-up portion 15a is formed by laser cladding so as to cover the entire circumference of the side surface on the other axial side of the portion of the original raceway surface 24a (base material 7a) where the original raceway surface 24a was formed.

[0087] In the build-up process, the original raceway surface 24a is irradiated with a laser 10a emitted from a laser light source (not shown), and the powder welding material 11a is supplied from a nozzle 14 to the part of the original raceway surface 24a irradiated with the laser 10a by spraying it together with a shielding gas, while the laser light source and the original raceway surface 24a are rotated relative to each other and displaced relative to each other in the radial direction. As a result, a build-up portion 15 is formed on the other axial side of the part of the original raceway ring 21 (base material 7a) that includes the original raceway surface 24a, the build-up portion 15 being formed by arranging a plurality of annular beads 16a side by side with no gaps in the radial direction or by beads wound in a spiral shape with no gaps. In the build-up process, the irradiation direction of the laser 10a on the original raceway surface 24a is inclined forward with respect to the radial relative displacement direction of the laser light source with respect to the original raceway ring 21a with respect to the normal direction of the raceway surface 24 after repair (the normal direction of the part irradiated with the laser 10a).

[0088] In this example, the laser light source is displaced radially outward relative to the original raceway ring 21a. The raceway surface 24 after repair is formed of a flat surface perpendicular to the central axis O of the thrust cylindrical roller bearing 20. For this reason, the original raceway surface 24a is irradiated with a laser 10a emitted from the laser light source radially outward with respect to the axial direction of the original raceway ring 21a, that is, from the direction of a virtual straight line β that moves radially outward toward the other axial side, and the original raceway ring 21a is rotated once relative to the laser light source while supplying powder welding material 11a from a nozzle 14a by spraying it together with a shielding gas onto the part irradiated with the laser 10a, thereby forming a single annular bead 16a.

[0089] The inclination angle θ of the irradiation direction of laser 10 with respect to the normal direction of orbital plane 24 (irradiation angle of laser 10) is not limited to this, but can be greater than or equal to 5 degrees and less than 90 degrees, preferably greater than or equal to 10 degrees and less than or equal to 20 degrees, and more preferably greater than or equal to 15 degrees and less than or equal to 20 degrees.

[0090] Next, the laser light source is displaced radially outward relative to the original raceway 21a. Specifically, the laser light source is displaced radially outward, or the original raceway 21a is displaced radially inward. At this time, the amount of radial displacement of the original raceway 21a relative to the laser light source is adjusted so that no gap exists between two radially adjacent beads 16, i.e., between the bead 16 on the radially inner side previously formed and the bead 16 on the radially outer side to be formed next.

[0091] Specifically, of two radially adjacent beads 16, the radially inner portion of the radially outer bead 16 is arranged to overlap in the axial direction with the radially outer portion of the previously formed radially inner bead 16. In other words, the radially outer bead 16 is formed so that its radially inner portion covers the radially outer portion of the radially inner bead 16.

[0092] After the laser light source is displaced radially outward relative to the original raceway 21a, the laser 10 is again irradiated onto the original raceway surface 24a from a direction inclined with respect to the axial direction of the original raceway 21a, and the powder welding material 11 is supplied to the portion irradiated with the laser 10 by spraying it from the nozzle 14 together with a shielding gas, while the original raceway 21a is rotated once relative to the laser light source, thereby forming a single annular bead 16a.

[0093] As described above, in this example, by repeating the steps of forming one annular bead 16a and displacing the laser light source and the original raceway 21a relative to one another in the radial direction, a buildup portion 15a is formed in which a plurality of annular beads 16a are arranged side by side with no gaps in the axial direction.

[0094] In this example, the laser light source is displaced radially outward relative to the original raceway 21a, but when carrying out the method for repairing a raceway of a thrust rolling bearing according to one aspect of the present disclosure, the laser light source can also be displaced radially inward relative to the original raceway. In this case, the laser emitted from the laser light source is irradiated onto the original raceway surface from the radially outward side with respect to the axial direction of the original raceway.

[0095] In addition, when carrying out the method for repairing a raceway of a thrust rolling bearing according to one aspect of the present disclosure, the original raceway can be rotated relative to the laser light source while being displaced relative to the laser light source in the radial direction to form a buildup portion composed of beads wound in a spiral shape without gaps on the outer circumferential surface of the original raceway. In this case, the amount of radial displacement of the original raceway relative to the laser light source per rotation is adjusted so that no gaps exist between radially adjacent portions of the beads.

[0096] It should be noted that when carrying out the method for manufacturing a raceway of a thrust rolling bearing according to one embodiment of the present disclosure, the method can be carried out essentially in the same manner as the repair method of this example, except that a hollow circular base material having no raceway surface on its surface is used.

[0097] According to this embodiment, when the radially outer bead 16a is formed in a portion adjacent to the radially outer side of the previously formed radially inner bead 16a, the portion of the original raceway surface 24a located on one axial side of the radially outer end of the radially inner bead 16a can be sufficiently heated. Therefore, the molten metal material in the portion of the original raceway surface 24a located on one axial side of the radially outer end of the previously formed radially inner bead 16a can be prevented from solidifying early before the bubbles generated inside are discharged. Therefore, the occurrence of internal defects due to bubbles can be prevented inside the buildup portion 15a formed by the multiple annular beads 16a.

[0098] The configuration and the effects of other parts of the second example are similar to those of the first example. EXAMPLES

[0099] An experiment conducted to confirm the effects of the present disclosure will be described.

[0100] This experiment was carried out using as a specimen a radial cylindrical roller bearing 2 as shown in Fig. 1. Two types of specimens were prepared: one repaired by the method for repairing raceways of a radial rolling bearing according to one embodiment of the present disclosure (exemplary specimen), and one repaired by a conventional method (comparison specimen).

[0101] In the embodiment, when forming the build-up portion 15 on the original inner ring raceway 4a by laser cladding, the inclination angle θ of the irradiation direction of the laser 10 with respect to the radial direction of the original inner ring 3a was set to 15 degrees, and the build-up portion 15 was formed by arranging multiple annular beads 16 side by side without any gaps on the original inner ring raceway 4a. After that, the build-up portion 15 was polished to form a new inner ring raceway 4.

[0102] On the other hand, in the comparative example, when forming the build-up portion, the laser was irradiated from the radial direction of the inner ring.

[0103] The conditions for the laser cladding, other than the direction of laser irradiation, were the same for the example and the comparison product.

[0104] The specifications of the cylindrical roller bearing used as the test specimen and the conditions for laser cladding are as follows: <Radial cylindrical roller bearing specifications> Part number: NUP206 Inner diameter: 30(mm) Outer diameter: 62(mm) Width: 16(mm) Material of inner ring 3 and outer ring 6: SUJ2 Rolling element 1 material: SUJ2 Number of rolling elements 1: 13 Diameter of rolling element 1: 9 (mm)

[0105] <Laser cladding conditions for the product> Laser output: 3.0 (kW) Powder welding material: Powder high speed steel Powder supply rate: 30(g / min) Scanning speed (relative rotation speed of the laser light source to the inner ring): 900 (mm / min) Number of beads that make up the overlay: 3

[0106] <Laser cladding conditions for comparison products> Laser output: 3.0 (kW) Powder welding material: Powder high speed steel Powder supply rate: 30(g / min) Scanning speed: 1000 (mm / min) Number of beads that make up the overlay: 2

[0107] The rolling fatigue life was measured for the above-mentioned example and comparison products. Specifically, the example and comparison products were operated under the conditions shown below, and the test was stopped when the vibration of the radial cylindrical roller bearing began to increase, and the rolling fatigue life was determined to be the time when flaking was visible on the inner ring raceway. <Operating conditions and life test conditions for radial cylindrical roller bearings> Lubrication conditions: ISO-VG68 equivalent mineral oil (oil bath method) Test load: 5(kN) Dynamic equivalent load / Basic dynamic load rating (P / C) = 0.13 Rotation speed: 500(min -1 )

[0108] The radial cylindrical roller bearing incorporating the comparison product experienced large vibrations (vibration acceleration of 4.5 mm / s 2 The reason for this is believed to be that in the comparative product, internal defects that existed inside the build-up were exposed on the surface of the inner raceway by grinding away the build-up. After operating the radial cylindrical roller bearing incorporating the comparative product for 100 hours, the radial cylindrical roller bearing was disassembled and the inner raceway of the comparative product was visually inspected, confirming that peeling had occurred in multiple places on the inner raceway. The comparative product was then cut and the cross section was observed. In contrast, the radial rolling bearing incorporating the implementation product did not generate any significant vibrations even after 300 hours of operation (vibration acceleration was 2.5 mm / s 2After 300 hours had passed, the radial cylindrical roller bearing incorporating the test sample was disassembled and the inner raceway of the test sample was inspected, but no peeling was found. The test sample was then cut and the cross section was inspected, but no noticeable damage was found. [Explanation of symbols]

[0109] 1 Rolling element 2 Radial cylindrical roller bearings 3, 3a Inner ring 4, 4a Inner raceway 5 Outer raceway 6 Outer ring 7 Base material 8 Overlay layer 9 Mixed layer 10 Laser 11 Powder welding material 12 Re-hardened layer 13 Re-tempered layer 14 Nozzles 15 Overlay part 16 Beads 17 Molten Pool 18 Deformation prevention jig 19 Rolling elements 20 Thrust cylindrical roller bearing 21 Raceway ring 22 Raceway ring 23 Cage 24 Raceway surface 25 Raceway surface 100 Inner Circle 101 Inner raceway 102 Bead 103 Overlay part 104 Laser

Claims

1. a build-up process for forming a build-up portion on the raceway surface, which is provided on the inner or outer peripheral surface of a used raceway ring, by irradiating a laser emitted from a laser light source onto the raceway surface, and supplying a welding material to the portion of the raceway surface irradiated with the laser while rotating the laser light source relative to the raceway ring and displacing the laser light source relative to the raceway ring in the axial direction, whereby a plurality of annular beads are arranged on the raceway surface with no gaps in the axial direction, or a build-up portion formed of beads wound spirally with no gaps in between, In the overlay process, the irradiation direction of the laser with respect to the raceway surface is inclined forward with respect to a relative displacement direction of the laser light source with respect to the raceway ring in the axial direction with respect to a normal direction of the raceway surface. How to repair radial rolling bearing races.

2. 2. The method for repairing a raceway of a radial rolling bearing according to claim 1, wherein an inclination angle of the laser irradiation direction with respect to a normal direction of the raceway surface is equal to or greater than 15 degrees and less than 90 degrees.

3. A method for manufacturing a raceway of a radial rolling bearing comprising: a cylindrical substrate; an overlay layer covering an inner peripheral surface or an outer peripheral surface of the substrate over an entire circumference; and a raceway surface provided over the entire circumference on a surface of the overlay layer, the method comprising the steps of: a build-up process in which a laser emitted from a laser light source is irradiated onto an inner peripheral surface or an outer peripheral surface of the base material, and a welding material is supplied to the portion of the inner peripheral surface or the outer peripheral surface of the base material irradiated with the laser, while the laser light source is rotated relative to the base material and displaced relative to the base material in the axial direction, thereby forming a build-up portion on the inner peripheral surface or the outer peripheral surface of the base material, which is constituted by arranging a plurality of annular beads in a line with no gaps in the axial direction, or which is constituted by beads wound in a spiral shape with no gaps; a machining step of machining a surface of the build-up portion to form the build-up layer having the raceway surface on a surface thereof; Equipped with In the cladding process, the irradiation direction of the laser with respect to the inner peripheral surface or the outer peripheral surface of the base material is set to a direction inclined forward with respect to a relative displacement direction of the axial direction of the laser light source with respect to the base material with respect to a normal direction of the inner peripheral surface or the outer peripheral surface of the base material. A manufacturing method for raceways of radial rolling bearings.

4. 4. The method for manufacturing a raceway of a radial rolling bearing according to claim 3, wherein an inclination angle of the laser irradiation direction with respect to a normal direction of the inner peripheral surface or the outer peripheral surface of the base material is 15 degrees or more and less than 90 degrees.

5. a build-up process for forming a build-up portion on the raceway surface provided on the axial side surface of a used raceway ring by irradiating a laser emitted from a laser light source onto the raceway surface, and supplying a welding material to the portion of the raceway surface irradiated with the laser while rotating the laser light source relative to the raceway ring and displacing the laser light source relative to the raceway ring in the radial direction, thereby forming a build-up portion on the raceway surface by arranging a plurality of annular weld beads in a radially adjacent manner with no gaps therebetween, or by forming a build-up portion composed of beads wound in a spiral shape with no gaps therebetween; In the overlay process, the direction of irradiation of the laser with respect to the raceway surface is inclined forward with respect to a radial relative displacement direction of the laser light source with respect to the raceway ring with respect to a normal direction of the raceway surface. How to repair thrust rolling bearing races.

6. 6. The method for repairing a raceway of a thrust rolling bearing according to claim 5, wherein an inclination angle of the laser irradiation direction with respect to a normal direction of the raceway surface is equal to or greater than 15 degrees and less than 90 degrees.

7. A method for manufacturing a raceway of a thrust rolling bearing including a hollow circular base material, a buildup layer covering an axial side surface of the base material over an entire circumference, and a raceway surface provided over the entire circumference on a surface of the buildup layer, comprising: A build-up process is provided in which a laser emitted from a laser light source is irradiated onto the axial side surface of the base material, and a welding material is supplied to the portion of the axial side surface of the base material irradiated with the laser, while the laser light source is rotated relative to the axial side surface of the base material and displaced relative to the axial direction in a radial direction, thereby forming a build-up portion on the axial side surface of the base material by arranging a plurality of annular weld beads in a radially spaced relationship on the axial side surface of the base material, or by forming a build-up portion composed of beads wound in a spiral shape without gaps, a machining step of machining a surface of the build-up portion to form the build-up layer having the raceway surface on a surface thereof; In the cladding process, the irradiation direction of the laser with respect to the axial side surface of the base material is inclined forward with respect to the radial relative displacement direction of the laser light source with respect to the base material with respect to the normal direction of the axial side surface of the base material. A method for manufacturing a raceway of a thrust rolling bearing.

8. 8. The method for manufacturing a race for a thrust rolling bearing according to claim 7, wherein an inclination angle of the laser irradiation direction with respect to a normal direction to the axial side surface of the base material is 15 degrees or more and less than 90 degrees.

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