Transmission ratio control system for a continuously variable transmission

摘要

A control system has a transmission ratio control valve having a spool for controlling oil supplied to a cylinder of a drive pulley to change the transmission ratio. The transmission ratio control valve has chambers at both ends of the spool. By controlling the amount of oil supplied to the chambers in accordance with the difference between desired transmission ratio and actual transmission ratio, the spool is shifted, so that the transmission ratio changing speed is controlled. The desired transmission ratio is determined by a desired speed of input of the transmission.