Friction-type stepless speed change device

Abstract

A friction-type stepless speed change device includes a frictional transmission elements composed of a pair of driving discs connected to an input shaft, and an annular driven disc connected to an output shaft and embraced between and urged against opposite conical surfaces of the driving discs into wedge-engagement to generate frictional force and allow power transmission from the driving discs to the driven disc. The driving discs are at a variable eccentricity relative to the driven disc, with which an effective pitch diameter of the driving discs is varied to effect a stepless speed change. For reducing the size of the frictional transmission elements while preserving a required torque capacity, the device further comprises a driving rotary unit for transmitting power from the input shaft to the driving discs at an increased rotational speed, and a driven rotary unit for transmitting power from the driven disc to the output shaft at a reduced rotational speed.