Importance

Loading Importance Indicators...

Abstract

A variable speed drive system comprises a driving pulley, a driven pulley and a drive belt passing around the two pulleys. Each pulley comprises a hub and two annular flanges on the hub between which the drive belt passes. One flange is movable axially relative to the hub so that the belt is able to assume different radial positions relative to the hub. An annular diaphragm spring acts on the movable flange in the axial direction. A central part of this diaphragm spring is in axial rocking bearing engagement against an annular abutment member fastened to the hub. Flyweights constrained to rotate with the diaphragm are arranged to deform it, by virtue of the centrifugal force developed as a result of such rotation, in the direction which tends to move the movable flange towards the other flange. The diaphragm has a force/axial deformation characteristic which features a neutral point at which the force changes direction. As a result, the diaphragm opposes the action of the flyweights after the movable flange has moved a particular distance towards the other flange. Optionally, a spring cooperates with the movable flange of the driven pulley to urge it axially towards the other flange. This can be a coil spring around the hub and bearing on the movable flange of the driven p ulley and on the annular abutment member.

Loading the Abstract Image...

First Claim