| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing an inner ring for a radial rolling bearing, for increasing static strength and creep strength while reducing a material cost and a heat treatment cost.SOLUTION: A method for manufacturing an inner ring 2 includes: subjecting a processed intermediate material made of steel having a carbon content of 0.45 wt.% or more to a heat treatment including an induction hardening processing on only an outer circumferential surface and an inner circumferential surface of the material; to form an outside hardened layer 7 in a surface layer part of the outer circumferential surface including a groove inner surface of a raceway groove 3, in which the hardened layer has a Vickers hardness of 700 or more and a compressive residual stress of 150 MPa or more; to form an inside hardened layer 8 having a Vickers hardness of 700 or more in a surface layer part of the inner circumferential surface; and to form a non-hardened layer 9 having a Vickers hardness of 500 or less between the outside hardened layer 7 and the inside hardened layer 8. The inner ring thickness t mm in the deepest part of the raceway groove 3, the thickness d1 mm of the outside hardened layer 7, the thickness d2 mm of the inside hardened layer 8 and the thickness d3 mm of the non-hardened layer 9 satisfy d1/t≥0.15, d2/t≥0.10 and d3/t≥0.3. |
