Transmission ratio control system for a continuously variable transmission.

摘要

A control system is described for a continuously variable transmission having a spool type transmission ratio control valve for controlling oil supply to a cylinder of a drive pulley of the transmission in order to change the transmission ratio. The transmission ratio control valve is itself controlled by a hydraulic circuit (Figure 2b of the system). By controlling flow of oil supplied to the spool valve in accordance with a desired transmission ratio, the spool is shifted, so that the transmission ratio changing speed is controlled. In the invention the transmission ratio changing speed is corrected in response to the speed of changing of the desired transmisson ratio.