Patent ID: 7431674

Claim:
Continuously variable transmission ( 1 ) for motor vehicles, comprising: a primary pulley ( 2 ) and a secondary pulley ( 3 ), each of the primary pulley and the secondary pulley comprised of two conical pulley discs ( 21 , 22 ; 31 , 32 ), a drive belt ( 10 ) arranged around the primary pulley and the second pulley and clamped between the two conical pulley discs ( 21 , 22 ; 31 , 32 ) of each respective pulley ( 2 ; 3 ), the drive belt in contact with a first running surface ( 40 ) of at least one pulley disc ( 43 ) of the pulley discs of the primary pulley ( 2 ) and with a second running surface ( 40 ) of at least one pulley disc ( 43 ) of the pulley discs of the secondary pulley ( 3 ), the running surfaces each having, as seen in a cross section oriented perpendicular to a tangential direction, with a curvature, so that a pulley angle (α) between a tangent ( 41 ) on the running surface ( 40 ) and a radial direction ( 42 ) varies between a lowest value at the location of a radially innermost position on the running surface ( 40 ) and a highest value at the location of a radially outermost position on the running surface ( 40 ), the curvature of the first running surface ( 40 ) of the primary pulley ( 2 ) and the curvature of the second running surface ( 40 ) of the secondary pulley ( 3 ) differ from one another by the feature that the highest value for the pulley angle (α) of the secondary pulley ( 3 ) at a highest running radius (α(Rs)) is lower than the highest value for the pulley angle (α) of the primary pulley ( 2 ) at the same highest running radius (α(Rp)), wherein a range between the highest value and the lowest value for the pulley angle (α) of the secondary pulley ( 3 ), over a range of the running radius of the secondary pulley, is smaller than a corresponding range of the pulley angle (α) of the primary pulley ( 2 ) over a corresponding range of the running radius of the primary pulley.