US Patent 7354377 Continuously variable transmission

A belt continuously variable transmission includes a primary pulley (1), a secondary pulley (2), a belt (3), a hydraulic pump (21), a speed ratio control valve (13) that regulates hydraulic pressure from the hydraulic pump (21) and supplies the hydraulic pressure to the primary pulley (1) and the secondary pulley (2), a motor (14) that drives the speed ratio control valve (13), a controller (11) that controls the motor (14), and an oil temperature sensor (26) that detects the temperature of a working fluid. The controller (11) stops energization to the motor (14) when the temperature of the working fluid becomes greater than a first predetermined temperature while the vehicle is at rest in an idling state.