Patent ID: 6652412
Filing Date: 2003-11-25
Classification: F16H

Abstract:
A speed change control system which controls a speed ratio of a toroidal transmission including a power roller gripped between an input disk and an output disk, a trunnion which supports the power roller rotatably and displaces in the axial direction, and a fluid pressure cylinder which drives the trunnion in the axial direction, the control system comprising:a speed change control valve which controls the fluid pressure supplied to the fluid pressure cylinder; a speed change link; an actuator which drives the speed change control valve via the speed change link; a first feedback mechanism which generates a first feedback amount according to the gyration angle of the power roller; a second feedback mechanism which generates a second feedback amount according to the axial displacement of the power roller and varies a feedback gain for the second feedback amount according to the gyration angle of the power roller; and a feedback link connected to the first and second feedback mechanisms, which combines the first and second feedback amounts and transmits the combined amount to the speed change control valve via the speed change link, wherein the second feedback mechanism varies the feedback gain so that the feedback gain becomes smaller as the speed ratio of the transmission increases.