Patent ID: 8517871

Claim:
A method of controlling a vehicular belt-driven continuously variable transmission for use in a vehicle traveling at speeds up to a maximum speed, the belt-driven continuously variable transmission including a continuously variable transmitting portion into which rotation from a power source is input without a reduction in speed while a vehicle is traveling forward, and a single hydraulic pressure chamber provided for a secondary pulley, the method comprising: shifting the continuously variable transmitting portion by controlling one of i) the supply and discharge of a hydraulic fluid and ii) the pressure of the hydraulic fluid with respect to a primary side cylinder provided for a primary pulley; and adjusting belt squeezing force of a belt, which is wound around the primary pulley and the secondary pulley, by adjusting the pressure supplied to a secondary side cylinder, which is formed of the single hydraulic pressure chamber, independently from performing one of i) control to supply and discharge of the hydraulic fluid and ii) control to adjust the pressure of the hydraulic fluid with respect to the primary side cylinder, wherein performing the control to adjust the pressure of the hydraulic fluid includes adjusting a first pressure regulating valve and wherein adjusting the pressure supplied to the secondary side cylinder includes adjusting a second pressure regulating valve; and wherein a cylinder pressure receiving area of the secondary side cylinder is set such that a safety factor, with respect to belt slip, of the belt squeezing force obtained when the pressure supplied to the second side cylinder is set to a predetermined lowest controllable pressure when the vehicle travels at maximum speed on a flat road, is a value less than or equal to 1.5.