Control valve system for a continuously variable belt driven transmission for motor vehicles

摘要

A control valve system for controlling the operation of a continuously variable belt-driven motor vehicle transmission includes a first hydraulic pump that supplies fluid to the displacement cylinders of the transmission through a main pressure regulating valve and a transmission ratio control valve as a function of the setting of the manual selector valve and as a function of the torque requirement and speed of the vehicle. The torque converter is supplied with hydraulic fluid by way of a relief valve which comes into operating in the event of failure of an electronic control unit and a decrease in the vehicle speed. A first emergency operation on/off valve transmits torque at converter discharge pressure, by way of a second emergency on/off valve, as emergency operation control pressure to a transmission ratio control valve.