| 摘要 |
PROBLEM TO BE SOLVED: To provide a rolling bearing which can have a long life even when it is used under a water mixed lubricating condition. SOLUTION: The rolling bearing for supporting a wheel is composed of two inner races 1, 1 having a raceway surface 1a on their outer circumferential surfaces, an outer race 2 having a double row raceway surfaces 2a, 2a opposed to the raceway surfaces 1a, 1a on its inner circumferential surface, and a plurality of balls 3 arranged between both of the opposed raceway surfaces 1a, 2a so as to roll. The inner races 1 and the outer race 2 are formed such that the maximum lengths L of surface holes and oxide based non-metallic inclusions existing in a contact region in the raceway surfaces 1a, 2a with the balls 3 are 80μm or less respectively in the case that a contact angle is within an initial contact angle of -5°to +5°. In addition, the inner races 1 and the outer race 2 are formed by forging a round bar shape material made of steel. The contact regions in the raceway surfaces 1a, 2a are formed from the portion to be included within the cylindrical range from 40 to 85% of the round bar shape material when the center of the round bar shape material in the radial direction is shown as 0%, and the outside surface in the radial direction is shown as 100%. COPYRIGHT: (C)2008,JPO&INPIT
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