| 摘要 |
PROBLEM TO BE SOLVED: To rationally lighten a bearing retainer by forming thickness reduced part around the retainer periphery of a bearing press fitting part except for a predetermined range receiving the reaction of a helical gear. SOLUTION: A bearing retainer 10 is equipped with a bearing press fitting part 11 and a mounting flange 12, and so on. A plurality of thickness reduced parts 13 is circumferentially formed around the retainer periphery of the bearing press fitting part 11 at equal intervals in the remaining range except for twoβangle ranges centering around F1 receiving reaction F1 when a helical gear is rotated in a normal direction and twoβangle ranges centering around F2 receiving reaction F2 when the helical gear is rotated in a reverse direction. Respective predetermined angle ranges 2βare set from Hertzian elastic contact theory. By the foregoing structure, each of the reaction of the helical gear is supported in the predetermined ranges at the time of rotation in normal and reverse directions, and the bearing press fitting part 11 outside the predetermined ranges does not receive reaction regardless of rotational directions, therefore the thickness reduced parts 13 can be increased while retaining necessary strength ridigity and the bearing retainer 10 can be lightened to the maximum extent.
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