| 摘要 |
PROBLEM TO BE SOLVED: To provide a bearing of excellent high rotating speed performance and stably holding lubricating oil by specifying the ratio the width of a dynamic pressure generating groove to the pitch, and the angle of the groove against the rotating direction. SOLUTION: A rotary shaft 1 is inserted into a sleeve 2, two set of dynamic pressure generating grooves 4, 5 are provided at groove angles B1, B2 on the bearing parts 6 of the sleeve 2, and a clearance is kept between the bearing part 6 and the rotary shaft 1 so as to be filled with lubricating oil. By the ratio the width (d) of the dynamic pressure generating grooves 4, 5 to the pitch (e) between grooves, k=d/e, the relation against the groove angles is set as follows: k×sin(B1), k×sin(B2)≈0.1. When squeeze action is generated on the rotary shaft 1 due to unbalance or the like, force applied to the face of the bearing part 6 becomes large at non-groove parts, and lubricating oil is forced to escape toward the grooves 4, 5. By setting the angles B1, B2 and the ratio (k) in a fixed relation, oil holding property against lubricating oil and discharge of air are improved, and stability at high rotating speed and improvement of the bearing life can be attained.
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