Abstract: An axial piston fluid engine having single-acting cylinders incorporating swivel-joint attachment of the cylinders to rotary control valves wherein straight-line piston movement is established for the elimination of side forces on the pistons. The pistons and the control valves are operatively connected to a common wobble drive member and arranged in geometry of lever positions to coactively time the drive fluid into and out of the cylinders intermittently.

Abstract: In order to entirely eliminate pressure drop sensors in a variable displacement hydraulic motor (10), and to change the wobbler angle mechanically rather than hydraulically, the hydraulic motor (10) includes a motor housing (26) having a plurality of hydraulic cylinders (32) and a plurality of hydraulic pistons (34) radially disposed about an axis (36) thereof. A servovalve (40) is provided for controlling the rate and direction of flow of hydraulic fluid to and from the hydraulic cylinders (32), and the wobbler (22) is operatively associated with the hydraulic pistons (34) in a variably angularly positionable manner for varying displacement of the hydraulic motor (10). With this arrangement, the hydraulic motor (10) includes a cam system (22a, 30) for automatically varying the angular positioning of the wobbler (22) relative to the axis (36) of the hydraulic motor (10) responsive to a load-related torque at an output shaft (12) thereof.

Abstract: A variable displacement piston machine includes a valve plate (3) provided with high-pressure and low-pressure ports (5, 6) to supply and discharge fluid into and from piston chambers (80) in a cylinder block (2) and first and second control ports (P1, P2) disposed in opposite directions between the ports; a pivotable inclined swash plate (4) to adjust the stroke of pistons 1 in the piston chambers (80); and a feedback valve (100) having a second spool actuated by pressure of fluid introduced into an introduction passage (41) with a throttle valve (42), and a first spool (S1) slidably fitted in the second spool (S2).

Abstract: An apparatus for moving a fluid medium comprising a positive displacement member movable to move the fluid medium and a drive mechanism adapted to be driven by a motor for driving the positive displacement member to move the fluid medium. The drive mechanism includes a driving member, a driven member, a resilient coupling and a wobble plate for driving the positive displacement member. The angle of the wobble plate is adjustable by varying the relative angular position of a driving member and a driven member.