Patent ID: 6776062
Filing Date: 2004-08-17
Classification: F16H,Y10T

Abstract:
A power transmission system for transmitting a driving force of a prime mover to driving wheels via a stepped transmission,said stepped transmission including: an input shaft connected to the prime mover, an output shaft connected to the driving wheels, a plurality of gear pairs for at least three speed positions of said stepped transmission, each formed by an input gear arranged on said input shaft, and an output gear arranged on said output shaft and in mesh with said input gear, with one gear of said input gear and said output gear being rotatably supported on said input shaft or said output shaft, connecting/disconnecting clutch means, for selectively connecting and disconnecting said one gear of said input gear and said output gear of each of said plurality of gear pairs to and from said input shaft or said output shaft rotatably supporting said one gear, to thereby establish a speed position of said stepped transmission by a connected one of said gear pairs including said connected one gear, and a driving force assist mechanism for supplying the driving force of the prime mover to said output shaft when a shift in speed position is carried out by said connecting/disconnecting clutch means, wherein said driving force assist mechanism comprises: an auxiliary shaft arranged in parallel with said input shaft and said output shaft; an intermediate gear integrally formed with said auxiliary shaft and connected to said input shaft; an auxiliary gear rotatably supported on said auxiliary shaft and connected to said output shaft; and an assist clutch for fastening said auxiliary gear to said auxiliary shaft to thereby transmit the driving force of the prime mover from said input shaft through said auxiliary shaft and said auxiliary gear to said output shaft, wherein said auxiliary gear comprises a plurality of auxiliary gears having respective different numbers of gear teeth, and selectively fastened to said auxiliary shaft by said assist clutch.