Patent ID: 8096918

Claim:
A variator comprising a pair of races mounted for rotation about a common axis and having respective shaped faces which together define an annular cavity containing at least one roller which runs upon the shaped faces of the races to transfer drive from one race to the other, the roller having a roller axis and being mounted upon a carrier through bearings which permit the roller to spin about its axis and also to precess relative to the carrier to change the inclination of the roller axis to the common axis and so to enable changes in variator ratio, the variator further comprising a sun and a ring which are concentric with and mounted for rotation about the common axis, the carrier engaging with the sun and the ring so that relative rotation of the sun and ring causes a tilting motion of the carrier and a consequent change in the inclination of the roller axis, the variator further comprising a mechanism for controlling rotation of the sun and ring, the mechanism comprising a planet which is mounted in the annular cavity and which operatively engages with the sun and the ring, an actuator which is operatively coupled to the planet, and an arrangement for controlling rotation of the planet independently of its engagement with the sun and the ring.