Patent attributes
A planetary gear device includes: a housing cover disposed at one end portion of a housing in an axis direction, the housing being configured to house a sun gear and a planetary gear inside the housing; and a carrier cover disposed next to the housing cover in the axial direction in the inside, and configured to support a shaft of the planetary gear from one end portion side in the axial direction. One opposing part of a pair of opposing parts opposite to each other in the housing cover and the carrier cover includes a cone-shaped part whose diameter varies in the axial direction, and the other opposing part of the pair of opposing parts includes a sliding part configured to slide on a peripheral surface of the cone-shaped part with a same axis as an axis of the cone-shaped part.