| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a wheel supporting rolling bearing device whose bearing ring has a longer life. <P>SOLUTION: The rolling bearing device comprises: a rotary side bearing ring 1 to be rotated integrally with a wheel; a stationary side bearing ring 2 having an outer ring raceway groove in the inner peripheral face, opposed to an inner ring raceway groove formed in the outer peripheral face of the rotary side bearing ring 1; and a number of rolling elements 3 provided between the raceway grooves of the bearing rings 1, 2. The carbon content of a bearing ring material is 0.45-0.75 mass%, the area ratio of spherically shaped carbides each of which has the aspect ratio of the major axis diameter to the minor axis diameter being 2 or smaller and the minor axis diameter being 0.7μm or larger, out of all carbides existing in the metal structure of the bearing ring material before plastic forming, is 70% or more, an average space between the spherically shaped carbides is 15μn or smaller, the gain size number of each of past austenite crystal grains in the raceway groove after subjected to induction hardening is 6 or greater, and the surface hardness is HV650 or more. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
