Abstract: In order to eliminate leakage and provide a more efficient system, a variable displacement hydraulic apparatus (10) includes a cylinder block (12) having a plurality of hydraulic cylinders (14) therein. Each of the cylinders (14) has a hydraulic piston (16) disposed therein for reciprocating movement relative thereto. The cylinders (14) and pistons (16) are disposed about an axis (18) of the hydraulic apparatus (10). The hydraulic apparatus (10) also includes a shaft (20) operatively associated with the pistons (16) for relative driven movement therebetween and a valve block (22) having a hydraulic fluid inlet port (24) for supplying hydraulic fluid to the cylinders (14) together with a hydraulic fluid outlet port (26) for returning hydraulic fluid from the cylinders (14). The inlet and outlet ports (24 and 26) communicate with the cylinders (14) through a port plate (28) having at least one port slot (30) therethrough.

Abstract: A constant velocity joint (10) rotationally connecting rotationally mounted first and second members (12 and 14) together each having an axis of rotation (16 and 18) in accordance with the invention and includes at least one axial bore (42) within the first shaft offset from and parallel to the axis of rotation of the first member, a plurality of axial channels (46) extending along each axial bore which are located in a peripheral wall (44) of each axial bore; at least one axial bore (42) within the second member offset from and parallel to the axis of rotation of the second member, a plurality of channels (46) extending along each axial bore which are located in a peripheral wall (44) of each axial bore of the second member; at least one pair of rods connected together by a joint (28) having at least one degree of rotational freedom, one of the rods of each pair of connected rods being disposed in an axial bore within the first member and another of the rods of each pair of connected rods being disposed in a

Abstract: A bent-axis hydraulic apparatus having a case in which a rotatable cylinder block is positioned and which is associated with a rotatable shaft at a drive angle therebetween. A split angle spline drive interconnects the cylinder block of the hydraulic axial piston unit with a rotatable shaft for transmission of torque therebetween without any side loading on the pistons of the axial piston unit. The split angle spline drive has two series of external teeth associated one with the cylinder block and the other with the rotatable shaft which individually mesh at two locations opposite the axis of rotation thereof with two spaced-apart sets of internal teeth on a ring gear that is rotatably-mounted in fixed location within the case of the hydraulic apparatus. The tooth mesh center lines are equally spaced from the pivot point for the cylinder block and the rotatable shaft to achieve synchronization.

Abstract: The problem of controlling overspeed and/or oscillation of a variable displacement hydromechanical actuation system is solved by a multi-stage flow regulating valve (18) which includes a valve body (20, 22) having a fluid inlet (24) and a fluid outlet (26) defining a flow path (A,B) through the valve body. A first stage valve piston (30) is reciprocally mounted within a cylinder (28) in the valve body (20) in the flow path between the inlet and the outlet for restricting fluid flow in response to a first range of incoming fluid pressure. The first stage piston (30) has an inlet orifice (34) exposed to the incoming fluid and an outlet port (36) in registry with the outlet (26) of the valve body (20). A second stage valve piston (44) is reciprocally mounted within the first stage piston (30) and has an orifice plate (46) for covering the inlet orifice (34) of the first stage valve piston (30). The orifice plate has smaller orifices (48) for further restricting fluid flow through the valve body.

Abstract: An improved hydraulic apparatus is disclosed which may function as either a hydraulic pump or hydraulic motor. A port plate (18) is provided with a high pressure arcuate prot (82) which permits the full range of rotation of the port plate to be used in linearly adjusting the rate of fluid flow into the cylinders (22) of the cylinder block (20). The invention provides a maximum range of adjustability of the volume of fluid flow passing through the cylinders.

Abstract: An intermittently assisted hydrostatic bearing (10) for a hydraulic apparatus having a rotatable surface which is periodically assisted from a pressure balance of less than 100% to a pressure balance greater than 100% pressure balance includes a pressurized fluid supply source (28) for supplying a pressurized fluid, a supply channel (30, 31, 32 and 34) for supplying pressurized fluid from the pressurized fluid supply source to a point (36) between cooperating opposed bearing surfaces (24) and a pressure producing device (48) which communicates with the fluid supply channel and in response to a command signal causes the hydrostatic bearing to attain a greater than 100% pressure balance. The invention further includes a check valve (60) positioned in the supply channel (32) to prevent the reverse flow of fluid into the pressurized fluid supply source (28).