Patent ID: 7367909

Claim:
Drive belt ( 3 ) for a transmission realising a continuously variable transmission ratio comprising at least one continuous band ( 11 ), having a radially inwardly oriented surface ( 12 ) and a radially outwardly oriented surface ( 13 ), and an array of plate-like transverse elements ( 20 ) engaging said continuous band ( 11 ) such that the elements ( 20 ) may slide along a longitudinal direction thereof, which continuous band ( 11 ) is curved in a transverse direction at a non-infinite crowning radius of curvature Rcrown and is provided with an internal residual stress distribution defining a curling radius of curvature Rcurl at which a continuous band ( 11 ) would be curved in its longitudinal direction when cut, whereby during operation the continuous band ( 11 ) can be bent in its longitudinal direction at a minimum radius of curvature Rmin and whereby a ratio between the curling radius and the minimum radius Rcurl/Rmin defines a pre-bending factor f PB , characterised in that, the pre-bending factor f PB satisfies the equation: f PB =(δ i=δo )/δ o wherein: δi is the largest perpendicular distance in the radial direction between a neutral line NL in the cross section of the continuous band ( 11 ) where the stress due to pure longitudinal bending would be zero and the radially inner most surface ( 12 ) of the band ( 11 ) and δo is the largest perpendicular distance in the radial direction between the said neutral line NL and the radially outer most surface ( 13 ) of the band ( 11 ).