PLANETARY GEAR DEVICE

PROBLEM TO BE SOLVED: To provide a planetary gear device preventing the wear or seizure of a pinion gear and a carrier, consisting of a reduced number of parts, and assembled by reduced time and labor. SOLUTION: The pinion gear 14 is rotatably supported in the outer peripheral surface of a pinion shaft 13 secured between a pair of carriers 11, 11 sandwiching a needle roller 15 between them. A hard coating containing a DLC is formed in the surface opposite to both end surfaces of the pinion gear 14 and the needle roller 15 of the carriers 11, 11. In the motion of the planetary gear device, even when the end surfaces of the pinion gear 14 and the needle roller 15 slidably contact the surfaces of the carriers 11, 11. the wear or seizure can be prevented owing to the hard coating. A washer between the pinion gear 14 and the needle roller 15, and the carriers 11, 11 can be reduced, so that the number of the parts can be reduced and the effort of assembling can be reduced. COPYRIGHT: (C)2009,JPO&INPIT