Patent ID: 7063633

Claim:
A driving pulley for a continuously variable transmission, the driving pulley being coaxially mountable around a main shaft and rotatable at a variable rotation speed, the driving pulley comprising: a first flange having opposite first and second sides, the first side being provided with a conical wall; a second flange coaxial with the first flange and having a conical wall facing the conical wall of the first flange to form a drivebelt-receiving groove around which a drivebelt is wound, the second flange being axially movable with reference to the first flange; first means for connecting the first flange to the main shaft in a torque-transmitting engagement; second means for connecting the second flange to the main shaft in a torque-transmitting engagement; a positive assembly comprising: a positive carriage coaxial with the first flange and rigidly connected to the second flange; third means for connecting the positive carriage to the main shaft in a torque-transmitting engagement; at least two symmetrically-disposed pairs of radially-converging and mutually-opposite first ramps, each pair having one ramp connected to the positive carriage and another ramp connected to the second side of the first flange; and radially-movable flyweights, each set between a corresponding pair of first ramps; fourth means for generating a return force urging the second flange to move away from the first flange; a negative assembly comprising: a negative carriage coaxial and axially movable with reference to the first flange, the negative carriage being configured and disposed to be in engagement with the positive carriage; fifth means for connecting the negative carriage to the main shaft in a torque-transmitting engagement; at least two symmetrically-disposed pairs of radially-converging and mutually-opposite second ramps, each pair having one ramp connected to the negative carriage and another ramp connected to an end plate fixed with reference to the first flange; sixth means for connecting the end plate to the main shaft in a torque-transmitting engagement; and radially-movable flyweights, each set between a corresponding pair of second ramps; and seventh means for generating a return force urging the negative carriage away from the first flange.