Abstract: A rotary displacement piston pump is disclosed having rotatable single or dual valve/port plate(s). The valve plate, being rotatable forward and/or rearward with respect to the rotation of the piston carrier, alters the phasing of the land area of the pumping action thereby altering the phasing of piston speed inasmuch as the land area can be moved to a position to accelerate the piston(s) in a pre or decompression phase. In this way, pump noise, from colliding pressure fronts within the respective high and low pressure plenums, can be “tuned” out of the pump by adjusting the phasing and position of the valve plate(s) and raising or lowering the pre and decompression pressure(s) as necessary. Pump volume can also be controlled by advancing or retarding the valve plate(s), either in or out of synch, so as to shorten intake/exhaust piston stroke and overlap fluid flow between respective intake/exhaust plenums.

Abstract: A rotary displacement piston pump is disclosed having rotatable single or dual valve/port plate(s). The valve plate, being rotatable forward and/or rearward with respect to the rotation of the piston carrier, alters the phasing of the land area of the pumping action thereby altering the phasing of piston speed inasmuch as the land area can be moved to a position to accelerate the piston(s) in a pre or decompression phase. In this way, pump noise, from colliding pressure fronts within the respective high and low pressure plenums, can be “tuned” out of the pump by adjusting the phasing and position of the valve plate(s) and raising or lowering the pre and decompression pressure(s) as necessary. Pump volume can also be controlled by advancing or retarding the valve plate(s), either in or out of synch, so as to shorten intake/exhaust piston stroke and overlap fluid flow between respective intake/exhaust plenums.

Abstract: A pump system has a piston pump. The piston pump has a cylinder block with an inlet port, an outlet port, and a plurality of cylinders. Each cylinder in the plurality of cylinders is connected to the inlet port by an inlet passage and to the outlet port by an outlet passage. The piston pump has a plurality of pistons disposed in the plurality of cylinders. A drive shaft drives the pistons within the cylinders. A throttle member independently throttles flow in each inlet passage. The pump system has an electrohydraulic actuator governing movement of the throttle member.

Abstract: A hydraulic machine has at least one working chamber (11) of cyclically changing volume, and low-pressure and high pressure valves (15, 13) to control the connection of each of the at least one working chambers to low-pressure and high-pressure lines (16, 14) respectively. A method of operating the machine includes holding the low-pressure valve means (15) closed during at least an entire cycle of the chamber (11), starting at minimum chamber volume, such that gas dissolved in liquid in the chamber is released therefrom during an expansion of the chamber volume and re-dissolved during a reduction thereof.

Abstract: A hydraulic rotating axial piston engine having a housing enclosing a rotatable cylinder barrel. The engine has a number of axial cylinders with a number of reciprocating pistons. The pistons reciprocate between two defined end positions, and cooperate with a plate angled relative to a rotational axis of the barrel in order to obtain the reciprocating movement. The cylinders have ports alternatively acting as inlet and outlet ports. The housing has an inlet and an outlet channel, each having a kidney shaped port, facing towards the ports of the cylinders and communicating with a number of the cylinder ports. The housing has two parts, one of the housing parts defines the turning positions of the barrel in the end positions of the pistons. A second housing part defines the turning positions of the kidney shaped ports, relative to the end positions. The first and second parts of the housing are alternatively positionable in two different turning positions in the rotational direction of the cylinder barrel.

Abstract: A cam motor apparatus A is configured such that a cylinder block (2) rotating together with an output shaft (10) is internally provided with a plurality of cylinders (5, 5, . . . ) formed radially in a direction orthogonal to a rotational axis (X) of the cylinder block (2) and pistons (6) respectively housed in the cylinders are reciprocated by the action of working oil distributed thereto by a distribution valve (7) thereby rotating the output shaft. The cam motor apparatus A further includes a selector valve (9) for selectively communicating each of the cylinders with a supply passage (81) or a discharge passage (82) for working oil through the distribution valve. When the selector valve is in a low rotational speed position, working oil is supplied to and discharged from all the cylinders.

Abstract: A differential hydraulic motor comprises a swash plate joined to an output shaft, and a cylinder block joined to an input shaft. A change-over valve is provided which changes over according to the relative rotation of the output shaft and input shaft, and leads a different fluid pressure to pistons housed in the cylinder block according to whether these pistons are extending or contracting. A rotary distributor is provided which connects a high pressure port and low pressure port in a casing to the change-over valve even when the cylinder block is rotating. This rotary distributor comprises a port block which is free to slide in the casing. Pressure from the high pressure port acts on a piston formed on an end face of the port block so as to push the port block against a sliding surface of a cover block joined to the cylinder block.

Abstract: The present invention provides a swash plate type hydraulic actuator comprising cylinders provided with an inner oil passage, an outer oil passage, cylinder bores, radial valve holes extending between the inner oil passage and the outer oil passages, and ports opening into the cylinder bores and the valve holes, respectively. Distributing valves are slidably fitted in the valve holes for connecting the ports alternately to the inner oil passage and the outer oil passage. Swash plate holders, swash plates and eccentric rings supported on the swash plate holders so as to be engaged with the outer ends of the distributing valves respectively, are provided. Plungers are slidably fitted in the cylinder bores, respectively, in which the displacement can be changed whether or not the inclination of the swash plates is variable.

Abstract: A variable displacement axial piston hydraulic unit includes a flat port plate disposed between a stationery head and a rotatable cylinder barrel. An arcuate actuator piston extends from the port plate and is slidably disposed within an arcuate pocket in the head to define an actuator chamber. Similarly, an arcuate biasing piston extends from the port plate and is slidably disposed within an arcuate pocket defining a biasing chamber which continuously communicates with a discharge passage in the head. By selectably rotating the port plate relative to the head, the amount of fluid pressure carryover through TDC and BDC can be varied, thereby changing the swivel torque acting on the swashplate so that the swivel torque can be utilized to actually control the position of the swashplate. The rotational position of the port plate is controlled by controllably introducing pressurized fluid into the actuating chamber.

Abstract: A reversible flow pump (12) comprising: a first port (16) and a second port (20); a rotor (60) comprising a plurality of pump elements (74-80) movable through a fill mode and a discharge mode, a pump chamber (140) associated with each pump element (74) which are respectively filled and discharged; a ported shaft (30) rotatable between a first position and a second position, for carrying fluid to and from the various pump chambers (140), such that when in the first position fluid received at the first port (16) is communicated to fill each pump chamber (140) during the fill mode, at least a portion of such fluid is discharged therefrom and communicated to the second port (20), and wherein in the second position fluid flow is reversed. A brake system incorporating the pump is also disclosed.

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: In a hydrostatic continuously variable transmission, a pump cylinder of a swashplate type hydraulic pump is integrally and coaxially coupled with a motor cylinder of a swashplate type hydraulic motor. A number of distributor valves are radially arranged for reciprocal movement between radially inner and outer positions to put a large number of pump ports in the hydraulic pump into communication with the higher and lower pressure oil passages, and an eccentric ring circumscribed about the distributor valves is connected to an input member of the hydraulic pump for movement between a clutch OFF position and a clutch ON position. A clutch spring is connected to the eccentric ring for biasing the eccentric ring toward the clutch OFF position, and a weight is added to the eccentric ring and adapted to exhibit a centrifugal force for moving the eccentric ring toward the clutch ON position against a spring force of the clutch spring.

Abstract: A hydromechanical control system for a power drive unit having a hydraulic motor of the axial piston type, including a wobbler to vary the axial displacement of the pistons of the motor. A cylinder block is coupled to a shaft for rotation therewith. The cylinder block defines a plurality reciprocally movable therein. A port plate is provided at one end of the cylinder block, with kidney-shaped ports concentric with the axis of rotation of the cylinder block, in alignment with the cylinders and in communication with fluid supply and return conduits. A solenoid-operated piston-cylinder device rotatably adjusts the position of the port plate to adjust the positions of the ports relative to the incline plane of the wobbler.

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: A reversible power transmission unit comprising a housing and a cam block rotatably mounted in the housing and a pumping mechanism associated with opposed inclined surfaces of the cam block. A common shaft is rotatably mounted in the cam block and has its ends extending beyond the cam block. Each pumping mechanism includes a cylinder barrel mounted on the shaft for rotation with the shaft and having a plurality of cylinders with pistons slidable therein and operatively associated with a surface of the cam block. Each cylinder has a port opening to a valve plate provided with inlet and outlet ports in communication with inlet and outlet passages at each end of the housing. When one of the pumping mechanisms is operated as a motor, it drives the other pumping mechanism as a pump.

Abstract: An air motor having four circumferentially spaced, radially disposed cylinders the respective radially inner ends of which slidingly engage different faces of a cube-shaped cam that is eccentrically mounted with respect to a stationary motor housing. The cam serves as a drive shaft because its eccentric mounting causes it to rotate responsive to air pressure sequentially applied to the radially inner end of pistons that are fixedly mounted in circumferentially spaced relation to a circular piston chassis positioned radially outward of the cylinders. A cylindrical bore formed in the cam is partitioned into a pressure chamber and an exhaust chamber by a shoe seal member.

Abstract: A dental handpiece has a rotor with pistons in longitudinal bores, the pistons being displaced by air pressure and engaging against a swash plate to cause the rotor to rotate. The direction and speed of rotation is controlled by an air distributor member having a plate which controls the amount of and direction of the air flow.

Abstract: An electric-hydraulic pulse motor having an improved rotary guide valve means is provided. In the rotary guide valve, a valve member for controlling the supply of fluid to the hydraulic motor is adapted to be shifted for performing the controlling function by the effect of pressurized fluid. The valve member is supported on a valve shaft or a signal input shaft which is to be actuated by a conventional electric pulse motor or the like so that the valve member rotates with one of the two shafts but is allowed to be shifted transversely thereto to either of two eccentric positions by the effect of the pressurized fluid. Control for shifting the valve member is obtained by arranging the two shafts so that the relative movement between the two shafts controls the pressurized fluid so as to move the valve member to the desired one of the eccentric positions.

Abstract: Each of two drive wheels on a vehicle is independently driven by a wheel motor having four single acting hydraulic cylinders. Both wheel motors are supplied by a common engine driven pump. Two forward speeds are provided by a valve arrangement which can circulate the hydraulic fluid through all four, or only two, cylinders of each motor. Valves in a pair of valve units are shifted rapidly by camshafts and snap acting mechanisms to control the motor cylinders. Reverse drive is accomplished by a timing adjustment of the camshafts. The conventional gear differential, speed change gears and reversing gears are thereby eliminated.

Abstract: The invention relates to an axial piston pump comprising several piston-cylinder units actuated by means of an inclined disc. Said pump comprises a rotatably mounted inclined disc as well as a distributing slide in the form of an annular disc and eccentrically disposed relative to the pump axis, said slide connecting the outlet and inlet ports of the piston-cylinder units of the pump fixed in the rotating direction.