| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the generation of seizure and an increase of friction between a carrier and a carrier holding member by centering the carrier of a planetary gear mechanism of a telescopic actuator even if the carrier is inclined.SOLUTION: A carrier holding member 74 which performs centering to a carrier 63 of a planetary gear mechanism 37 comprises: an annular main body part 74a which is fixed to fixed parts 42, 61; and an annular flange part 74c which extends to an axial line L from an internal periphery of the main body part 74a, and surrounds an external peripheral face 63b of the carrier 63 via a minute gap. Since grease is held in the gap, vibration and noise can be reduced by centering the carrier 63 by the carrier holding member 74. The oil pressure of the grease is raised by the rotation of the carrier 63, however, when the gap is narrowed by the radial displacement of the carrier 63, the oil pressure is raised and a tip side of the flange part 74c of the carrier holding member 74 is displaced to the radial outside, and a film thickness of the grease at the displaced portion is increased, thus preventing an increase of friction.</p> |
