Control system for a continuously variable transmission.

摘要

A control system for a continuously variable transmission for a motor vehicle has a transmission ratio control valve (TR) for controlling the transmission ratio. The system has a drive pulley (14) having a shiftable disc and a hydraulic cylinder for operating the disc, a driven pulley (15) having a shiftable disc and a hydraulic cylinder for operating the disc, a belt (16) engaged with both pulleys. When output torque of an automotive engine (1) increases, the transmission ratio control valve is operated to increase pressure of oil supplied to the cylinder (14a) of the drive pulley, thereby preventing the transmission from downshifting.