バリオマチック

thumb|right|Belt and pulleys of a Van Doorne transmission|alt=A pair of conical pulleys, with a flat belt running between them. The lower pulley is formed from two separate movable cones. In the current configuration, the cones have been moved apart so the belt "falls" into space between them. By moving the cones closer, the belt is forced to ride higher on the sides of the cones, changing the pulley ratio. thumb|right|Variomatic transmission and rear axle. The larger green drums on the left contain the vacuum mechanism that controls the variable pulleys. The rear wheels are driven by separate