Continuously variable transmission mechanism

Claim 1

In a continuously variable transmission mechanism incorporating a variator having: a first sheave of adjustable effective diameter on a first axis, a second sheave of adjustable effective diameter on a second axis, a flexible drive band frictionally engaging and interconnecting the two sheaves, each sheave comprising an axially fixed pulley half and an axially moveable pulley half, inclined mutually facing surfaces of the pulley halves of each sheave defining a V-groove for the sheave, and the moveable pulley half of each sheave facing the fixed pulley half of the other sheave in order to maintain alignment of the band with the sheaves over a range of adjustment of the distance between the pulley halves of each sheave, the improvement comprising: a first sheave adjustment means including a fluid pressure operated piston and cylinder combination positioned to the side of the fixed pulley half of the first sheave for urging the moveable pulley half towards the fixed pulley half to adjust the width of the V-groove and thus the effective diameter of the first sheave for engagement with the band, the adjustment means for the first sheave being connected to the moveable pulley half thereof by slidable means extending through a hole in the center of the fixed pulley half, and the fixed pulley half being mounted to extend radially outward from the center of the hole; and a second sheave adjustment means including a fluid pressure operated piston and cylinder combination positioned to the side of the moveable pulley half of the second sheave for urging the moveable pulley half towards the fixed pulley half to adjust the width of the V-groove and thus the effective diameter of the second sheave for engagement with the band, whereby each of the piston and cylinder combinations lie on the same side of the band.