Toroidal continuously variable transmission

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 and to have a driven connection with a 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;
• primary oil pump means driven by the prime mover for producing a hydraulic pressure;
• secondary oil pump means driven in response to rotation of the road wheel for producing a hydraulic pressure;
• hydraulic servo means connected to the trunnion for moving 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 power roller 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 rotation axis of the input and output disks;
• feedback means for mechanically feeding a degree of progress for ratio changing back to the hydraulic servo means so that the power roller returns to the neutral position when a desired transmission ratio has been reached;
• the hydraulic servo means hydraulically operated by at least one of the hydraulic pressure from the primary oil pump means and the hydraulic pressure from the secondary oil pump means;
• and
• a hydraulic circuit that supplies the hydraulic pressure from the secondary oil pump means to the hydraulic servo means when the road wheel is rotated in a stopped state of the prime mover, so that an actual transmission ratio is brought closer to the desired transmission ratio.