Planetary gear device

Abstract

A planetary gear device includes a sun gear; a plurality of planetary gears; a planetary carrier at which the plurality of planetary gears are rotatably provided; and a ring gear, wherein the planetary carrier includes an oil feeding passage which feeds lubricating oil to at least one of the plurality of planetary gears, wherein the ring gear is a double helical gear in which a pair of rows of internal teeth are arranged in a direction of an axis line of the ring gear and the internal teeth of one of the rows and the internal teeth of the other of the rows are inclined in different directions, the ring gear including at least one discharge passage, wherein the at least one discharge passage includes an inlet-side portion and an outlet-side portion, the inlet-side portion being closer to an inlet configured to open in a region between the pair of rows of internal teeth at an inner peripheral surface of the ring gear, and the outlet-side portion being closer to an outlet configured to open in a region of an outer peripheral surface of the ring gear, and wherein the inlet-side portion is formed at the ring gear so that the inlet-side portion is inclined in a rotation direction of the planetary carrier, with respect to a reference line extending in a radial direction of the ring gear.