Constant speed hydraulically controlled toric transmission with concentric, two piston valve, governor and constant ratio means

Abstract

Abstract A variable-ratio frictional drive gear comprises two axially spaced torus discs between which there is a set of circumferentially spaced drive rollers in frictional rolling contact with toroidal surfaces on the discs. Each roller is rotatably mounted in a roller carriage which can tilt about an axis at right angles to the axis of rotation of the roller so as to vary the distances from the gear axis at which the roller engages respectively the two discs, thus varying the drive ratio of the gear. The variable-ratio frictional drive gear further includes a first piston which is slidable in a second hollow piston under the influence of hydraulic fluid wherein axial movement of the first piston is arranged to effect tilting movement of at least one of the roller carriages. First means are provided to reduce the pressure, which, in use, is applied to the first piston by the hydraulic fluid, such reduction occurring when the first piston reaches a predetermined axial position relative to the second piston. The latter is slidable in a cylinder under the influence of control fluid supplied by a governor and second means are provided which tend to maintain the ratio of the pressures of the hydraulic fluid supplied to the governor and the control fluid supplied by the governor at a constant or substantially constant value.

Inventors

• 👤 R Sharpe
• 👤 J Triffit

Bibliographic Details