Continuously variable gear transmission

Abstract

A continuously variable gear is described having an input shaft, a plurality of traction balls distributed radially around the axis, each traction ball is mounted on an axle passing there through, the axles are tiltable in the radial grooves in the housing and support plate. To control the position of the traction balls, the axles are guided in curved slots of a turnable iris plate. To control the axial placement of the traction balls, there is a rotatable input disc positioned adjacent to the traction balls, a rotatable output disc positioned adjacent to the traction balls opposite the input disc, and a pre-spanning ring around the traction balls such that each of the traction balls is making three-point contact with the input disc, the output disc and the pre-spanning ring, the contact surface of the pre-spanning ring having a specific curvature larger than the radius of the traction balls.

What is claimed is: 
     
         1 . An apparatus for facilitating control of the ratio of a continuously variable transmission (CVT), the apparatus comprising:
 a first member having a first plurality of radial grooves arranged angularly about an axis, the first plurality of radial grooves engaging a first end of ball axles of a plurality of traction balls of the CVT, wherein the first member is non-rotatable;   a second member having a second plurality of radial grooves arranged angularly about the axis, the second plurality of radial grooves engaging a second end of the ball axles; and   an actuator for rotating the first and second members relative to one another such that during operation of the CVT the first plurality of radial grooves can be angularly misaligned relative to the second plurality of grooves through a plane lying through the shaft, wherein an angular misalignment of the first and second plurality of radial grooves corresponds to a tilting of the ball axles in the first and second pluralities of radial grooves.