Category:Van Doorne transmissions

English: A Van Doorne transmission is a continuously variable transmission. It uses two pulleys and a belt between them. The effective diameter of these pulleys may be varied, so as to vary the ratio between driving and driven shafts. In the Van Doorne transmission, this expansion is arranged by using vee pulleys formed of two movable conical half-pulleys. The belt is stiff transversely, so that it always runs at the same width between the walls of the vee. Moving each pulley half axially relative to the other changes the effect diameter of the pulley (for a belt of fixed width). One pulley is controlled, the other is spring-loaded to maintain belt tension. The first belts were rubber and fabric, later belts use a chain of steel links.
They were most notably used in the DAF Variomatic transmission. Pulleys there are controlled by engine manifold vacuum. Two separate transmissions were provided, one for each side and arranged between the differential and the final drive.