Transmission device

Abstract

Provided is a transmission device including a transmission unit, in which a differential device is arranged on one side in an axial direction and a gear reducer is arranged on the other side in the axial direction. The transmission unit is housed inside a transmission case with an oil storing part at a bottom part of the transmission case. A differential case () includes a body part (); an oil introducing port () open to the one side in the axial direction thereof; and an oil discharging port () open to the other side in the axial direction. A large-diameter gear part (P), which revolves in the same direction as a carrier (C) rotates, is arranged such that a bottom part thereof in a revolution trajectory is dipped below an oil storing surface (f) of an oil storing part (O) at the bottom part of the transmission case (). In the transmission case (), a first oil guide (G) is provided so as to extend toward the one side in the axial direction from a position radially outward of the revolution trajectory for capturing an oil lifted up from the oil storing part (O) by the large-diameter gear part (P) revolving and for guiding the same to the oil introducing port (). Consequently, even when an oil surface of the oil storing part is set to a low level, the oil lifted up by the large-diameter gear part of the planetary gear can be efficiently supplied into the differential case, which suppresses a churning resistance of the oil and improves transmission efficiency.