Continuously variable transmission

摘要

A belt type continuously variable transmission (CVT) and a planetary gear unit are composed in a continuously variable transmission system for an automobile to deliver an output from the output shaft in the normal and reverse directions with a neutral position therebetween. A control mechanism with a hydraulic circuit controls hydraulic pressure of primary and secondary hydraulic servos for controlling axial forces applying to respective primary and secondary pulleys of the belt type continuously variable transmission. When an axial force difference is produced between the primary pulley and the secondary pulley, the belt type continuously variable transmission changes its speed corresponding to a torque transmission direction and normal and reverse rotation directions. When axial forces of the primary and secondary pulleys come to be equal, then the belt type continuously variable transmission self-converges so that the output shaft becomes the non-drive state and is stably held at the neutral position without a driving starter device and a normal and reverse rotation switching device.