Abstract: A roller-control unit for a continuously-variable-ratio transmission of the toroidal-race rolling-traction type, in which the roller carriage (10, 14) is connected by a pivotal joint (30) to the piston (15) of a hydraulic piston-and-cylinder unit (15, 16). The piston (15) is double-acting, and the piston/cylinder contact is the only locus through which the roller carriage (10, 14) makes contact with the fixed structure of the transmission. The piston (15) may have an inner part (32) to which the roller carriage (10, 14) is jointed, and a sleeve-like outer part (33, 34) which makes the necessary sliding and sealing contacts with the cylinder (16), but allows the roller carriage (10, 14) the necessary freedom of pivoting movement during use.

Abstract: A hydraulic ram unit for a transmission of the toroidal-race, rolling-traction type. The ram is connected to the rollers of the transmission so that the position of the ram within its stroke is related to the angular setting of the rollers and so to the transmitted ratio. The ram pistons move within cylinders the inlet and outlet ports of which are located in the cylinder end walls, with the outlet ports axially protruding of the inlet ports. If a piston overshoots its normal stroke it tends first to restrict flow through the outlet port and then to contact and obstruct it, so creating firstly hydraulic and then contact forces to resist further overshoot, without substantially restricting the inlet port. Novel construction for the ram itself, and for the ram cylinders and casing are also described.