Patent ID: 6916265

Claim:
A power transfer apparatus provided between an input shaft and an output shaft for selectively changing the speed of the output shaft relative to the speed of the input shaft, the power transfer apparatus comprising: a clutch having a clutch inner hub fixed to the input shaft, a clutch guide, a plurality of clutch discs attached to the clutch inner hub, a plurality of clutch plates attached to the clutch guide so as to be disposed alternately with the clutch discs, a clutch piston and biasing unit for biasing the clutch piston in a direction in which the clutch discs engage with the clutch plates; a transmission brake serially disposed in an axial direction of the clutch and having a brake inner hub coupled with the clutch piston at one end thereof, a plurality of brake discs coupled with the brake inner hub and a plurality of brake plates coupled with a casing in such a manner as to be disposed alternately with the brake discs; an actuator serially disposed in an axial direction of the transmission brake for disengaging the clutch against force of the biasing unit at the same time of activating the transmission brake; and a planetary carrier sub-assembly serially disposed in the axial direction of the clutch and having a planetary carrier rotatably disposed around the input shaft and the output shaft and coupled with the clutch guide, a first pinion gear rotatably carried on the planetary carrier, a second pinion gear having the number of teeth which is different from that of the first pinion gear, a first sun gear fixed to the input shaft and meshing with the first pinion gear and a second sun gear fixed to the output shaft and meshing with the second pinion gear, wherein the clutch, transmission brake, planetary carrier sub-assembly and actuator are serially disposed along the axial direction, and radial positions of the clutch, transmission brake, planetary carrier sub-assembly and actuator overlap each other.