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AssigneeVan Doorne's Transmissie B.V.
InventorsHendrikus Adrianus Arnoldus Wilhelmina Pelders, Pieter Abraham Veenhuizen
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A continuous variable transmission includes a pair of pulleys forming V-shaped grooves for receiving an endless transmission element for transmitting torque between the pulleys. Each pulley includes at least one axially movable sheave which may be urged axially in the direction of the transmission element by an urging element effecting a clamping force between the sheave and the 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 expressed as a factor corresponding to a percentage of the torque to be transmitted throughout a major part of the range of torques transmittable to the relevant transmission. The safety factor is set as a function of the torque to be transmitted and the actual transmission ratio, such that the actual safety factor at predefined transmission modes is reduced to a lower value at increased levels of actual torques to be transmitted and with increased actual transmission ratio values.
Continuous variable transmission comprising a pair of pulleys forming V-shaped grooves for receiving an 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 means, 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 the range of torques transmittable by the transmission, characterised in that the safety factor Sf is set as a function of the torque to be transmitted, and of the actual transmission ratio, such that the actual safety factor at predefined transmission modes is reduced from a nominal safety factor (Sfo) above value 1, to a value above 1 and lower than the nominal safety factor (Sfo), the predefined modes being related to related to relatively high torques within the range of transmittable torques, and to relatively high values of actual transmission ratios within the range of transmission ratios of the transmission.
Continuous variable transmission according to any of the preceding claims, characterised in that the pre-set transmission ratio threshold value conforms to medium transmission ratio value matching 1.
Continuous variable transmission according to any of the preceding claims, characterised in that the pre-set lowest safety factor value matches 1.1.
Continuous variable transmission according to any of the preceding claims, characterised in that the nominal safety factor value matches 1.3.
Control method for a continuous variable transmission applying the principles defined in any of the preceding claims.
Dependencies are inferred from the claim text.