Patent ID: 7044873

Claim:
A continuously variable transmission system for use in a vehicle, the system comprising: a continuously variable transmission comprising: a drive pulley, which has a fixed disk and a movable disk disposed opposing the fixed disk to form a V-shaped pulley grove; a drive pulley, which has a fixed disk and a movable disk disposed opposing the fixed disk to form a V-shaped pulley groove, a V-belt that is fitted into each pulley groove and wound around the drive pulley and driven pulley; a first spring for applying an urging force to the movable disk of the drive pulley to urge the movable disk to the corresponding fixed disk side; and a second spring for applying an urging force to the movable disk of the driven pulley to urge the movable disk to the corresponding fixed disk side; an oil pressure supply device for supplying oil pressure to each movable disk; and a clutch for controlling the transmission of torque from an engine of the vehicle to the drive pulley, wherein a width of each pulley groove is variable in accordance with oil pressure applied to the movable disks, wherein a gear ratio is set in accordance with the widths of the pulley grooves in the drive pulley and driven pulley, wherein the first spring sets the pulley width of the drive pulley and the second spring sets the pulley width of the driven pulley when the oil pressure supply device is inoperative, and wherein a ratio of spring constants of the first spring and the second spring is set such that when the oil pressure supply device is inoperative, an offset between a median plane of the pulley groove in the drive pulley and a median plane of the pulley groove in the driven pulley is reduced.