Patent ID: 8425360

Claim:
A planetary bearing structure, comprising: a planetary pin to be fixed to a carrier; and a planetary gear having two end surfaces perpendicular to an axial direction of the planetary gear and having a slide bearing to be mounted on an inner peripheral surface of a shaft hole, the planetary pin being configured to turnably support the planetary gear through the slide bearing, and rotate in such an manner that a first gap and a second gap are formed between the two end surfaces of the planetary gear and opposed wall surfaces of the carrier that face the two end surfaces of the planetary gear, wherein a pair of spiral grooves are formed on surfaces selected from the two end surfaces and the opposed wall surfaces defining the first and second gaps and are oppositely oriented to each other, and a lubricant oil passage is formed in which, when the gaps take an oil bath in lubricant oil by rotation of the carrier, lubricant oil sucked from the first gap passes between the planetary pin and the slide bearing and is discharged from the second gap.