| 摘要 |
PROBLEM TO BE SOLVED: To attain reduction in a torque loss by providing a step difference with an outside diameter made different in the outer peripheral surface of two sintered oil-contained bearings, and forming an outer peripheral surface of large/small diametric parts, so as to place a rotary shaft and a bearing in a line contact condition. SOLUTION: Two sintered oil-contained bearings 3, 6 are provided with a step difference 7 by making an external diameter different in an external peripheral surface, and the external peripheral surface of large/small diametrical parts 8, 9 is formed by this step difference. A diameter D1 of the large diametrical part 8 is formed in dimensions which are slightly larger than the inside diameter of bearing hold parts 2, 5 of a bearing holder 1. The sintered oil-contained bearings 3, 6 can be fixedly press fitted to the bearing hold parts 2, 5 of the bearing holder 1, by press fitting this large diametric part 8 to the bearing hold parts 2, 5. When L2 is assumed as the length in the axial direction of the small diametrical part 9 of the sintered oil- contained bearings 3, 6 and L1 is assumed for the total length in the axial direction of the sintered oil-contained bearings 3, 6, the dimension is set so as to satisfy the relation 1/4 L1<=L2<=3/4 L1. In this way, a rotary shaft is placed in a condition coming substantially in line contact with the internal peripheral surface of the small diametrical part of the sintered oil-contained bearing.
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