As you know, to transmit torque, friction CVTs need a clamping force.

In our CVT, the clamping force is realised by pushing all cones together in horizontal direction against hub and reaction ring.

The needed clamping force depends on input torque and transmission ratio and it is equal to the tangential force on the contact point divided by the friction coefficient.

Geometrically, the Hub orthogonal force depends on the cone position and in particular on the angle between the cone axle and the hub axle that is function of cone concavity radius:

Fhub = Fhoriz / sin 2 α

Where α is the angle between the cone axle and the hub axle.

Calculating the starting and the final Hub forces (orthogonal) needed to transmit all input torque we will choose the concavity radius for the cones in order to have the wanted value of sin 2 α and as a consequence the α angle .

In this way we will keep constant the horizontal clamping force: the hub orthogonal force will change during the balancing of the cone on the hub in accordance with the input torque.

On YOUTUBE and YAHOO Video you can watch the relative video