| 摘要 |
PROBLEM TO BE SOLVED: To prevent damage even under a condition in which a lubricating oil quantity is very low by smoothly connecting an axial directional end face and a chamfered part of a roller together via a curved face with a specific radius of curvature and specifying a composite roughness of center line mean roughness of the axial directional end face and that of the flange part with which the end face is brought into side contact. SOLUTION: An axial directional end face 9 and a chamfered part 10 of a roller 6 are smoothly connected together via a curved face 17 with a radius of curvature of 0.08mm or more. In this way, damage such as a bite and a seizure, which is caused because of edge stress, between the roller end face and a flange part inside face can be prevented even when a skew of the roller 6 is caused under a defective lubricating condition. In addition, a composite roughness (σ1 <2> +σ2 <2> )<1/2> of a center line mean roughnessσ1 of the axial directional end face 9 functioning as a sliding contact face and a center line mean roughnessσ2 of the flange part inside face with which the sliding contact face is brought into slide contact is set to be 0.09μm Ra or less. In this way, damage such as a bite and a seizure can be prevented even if a lubrication oil quantity taken into the contact part is low. Therefore, reliability and durability a rotational supporting part can be improved.
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