Patent ID: 6612949
Filing Date: 2003-09-02
Classification: F16H,Y10T

Abstract:
Continuous variable transmission comprising:a pair of pulleys forming V-shaped grooves for receiving an endless transmission element, the endless transmission element for transmitting torque between the pulleys, each pulley comprising at least one axially movable sheave which may be urged axially in the direction of the transmission element by an urging means effecting a clamping force between said sheave and said transmission element, the effected clamping force corresponding to a force sufficient for transmitting a torque to be transmitted by at least virtually slipless friction between the pulley sheaves and the belt, increased by a safety margin expressable as a safety factor, Sf of the clamping force required for transmitting an actual torque to be transmitted, and applied throughout at least a major part of a range of torques transmittable by the transmission, wherein the safety factor Sf is set as a function of the torque to be transmitted, and of an actual transmission ratio, such that the actual safety factor at predefined transmission modes is reduced from a nominal safety factor (Sfo) of at least 1.3 to a value above 1 and lower than the nominal safety factor (Sfo), the predefined modes being related to relatively high torques within the range of transmittable torques, and to relatively high values of actual transmission ratios within a range of transmission ratios of the transmission.