Variable hydraulic machine

Abstract

A hydraulic machine is disclosed in several embodiments as a pump, as a motor, and as a combination pump/motor. The machine's fixed cylinders are positioned circumferentially to a drive shaft, the pistons being driven by, or acting against, a split swash-plate which is supported primarily by the same main bearing in which the drive shaft rotates. The inclination of the split swash-plate is adjusted by an axially-movable servo mechanism which is also arranged circumferentially to the drive shaft. Preferred embodiments include, among other features, (i) various gimballed-yoke supports for the non-rotating portion of the swash-plate, (ii) various designs for a rotating valve-plate, and (iii) a radial valve system. The unique arrangement of elements provides a machine that is remarkably compact and lightweight, being (a) significantly smaller than commercially-available machines having similar horsepower ratings and (b) operable hydrodynamically (i.e., at constant horsepower) at reduced speeds. In one preferred embodiment, pump and motor units are mounted side-by-side within a combined housing having integrated fluid passageways for transferring operating fluid between the units, and the combined housing itself is mounted within a surrounding reservoir.