Patent ID: 7192380
Filing Date: 2007-03-20
Classification: F16H

Abstract:
1. A toroidal continuously variable transmission comprising: an input disk to which rotation of a prime mover is transmitted; an output disk coaxially arranged with and opposed to the input disk, the output disk adapted to have a driving connection with road wheel; a power roller interposed between the input and output disks under axial preload for power transmission; a trunnion rotatably supporting the power roller to permit a tilting motion of the power roller about a trunnion axis perpendicular to a rotation axis of the power roller for ratio changing; a hydraulic servo mechanism connected to the trunnion to move the trunnion in a direction of the trunnion axis so as to cause the tilting motion of the power roller by creating an offset of the trunnion from a neutral position in the direction of the trunnion axis, the neutral position being a non-ratio-changing position at which the rotation axis of the power roller intersects a common rotation axis of the input and output disks; a primary oil pump driven by the prime mover to produce a hydraulic pressure; a secondary oil pump driven in response to rotation of the road wheel to produce a hydraulic pressure; the hydraulic servo mechanism hydraulically operated by either of the hydraulic pressure from the primary oil pump and the hydraulic pressure from the secondary oil pump; and wherein the secondary oil pump comprises a pumping element and a pump driving element; and wherein the secondary oil pump is held at the inoperative state by maintaining the pumping element in a spaced, contact-free relationship with the pump driving element by a modulated hydraulic pressure constantly produced during operation of the prime mover.