Patent ID: 7118501

Claim:
A V-belt continuously variable transmission comprising: an input shaft; an output shaft; a primary pulley that is connected to the input shaft and whose groove width is configured to change in accordance with a supplied fluid pressure; a secondary pulley that is connected to the output shaft and whose groove width is configured to change in accordance with a supplied fluid pressure; a V-belt that is wrapped around the primary pulley and the secondary pulley; and a controller that is configured to: compute a pulley ratio maintenance thrust force, which is a thrust force necessary for maintaining a speed ratio, for each of the pulleys; compute a thrust force correction amount for achieving a target speed change speed; and when the speed ratio is to be increased: set the fluid pressure supplied to the primary pulley to a fluid pressure necessary for ensuring a torque capacity of the V-belt and necessary for maintaining the speed ratio; set the fluid pressure supplied to the secondary pulley to a fluid pressure that is higher than the fluid pressure necessary for ensuring the torque capacity of the V-belt and necessary for maintaining the speed ratio, thereby attaining the target speed change speed; supply a fluid pressure to the primary pulley corresponding to the pulley ratio maintenance thrust force; and supply a fluid pressure to the secondary pulley corresponding to the sum of the pulley ratio maintenance thrust force and the thrust force correction amount.