Abstract: In accordance with at least one aspect of this disclosure, a variable displacement pump system can include, a variable displacement pump disposed in a main line and configured to supply pressure to receive a low pressure fluid and to output a high pressure fluid. The main line can connect a hydraulic fluid source to a plurality of system actuators, where the variable displacement pump is disposed in the main line between the hydraulic fluid source and the plurality of system actuators to pressurize the hydraulic fluid.

Abstract: A pump operation piston biased by a neutral spring mechanism and a larger volume operation spring biased by a larger volume operation spring in a larger volume direction operatively move pump and motor volume adjusting members, respectively, is provided. A first pressure control valve commonly controls supply-discharge of pressure oil that presses the pump operation piston in a first slide direction and the motor operation piston in a smaller volume direction. A second pressure control valve controls supply-discharge of pressure oil that presses the pump operation piston in a second slide direction. Biasing forces of the neutral spring mechanism and the larger volume operation spring are so set that, after the pump operation piston is moved in the first slide direction by a predetermined distance, the motor operation piston starts moving.

Abstract: Hydraulic axial piston unit having a rotational group for driving or being driven by a driving shaft, and a tiltable displacement element for adjusting the displacement volume of the rotational group. The rotational group includes a rotatable cylinder block in which working pistons are mounted reciprocally moveable in cylinder bores for conveying hydraulic fluid from an inlet port to an outlet port on a valve segment. At least two control ports are located on the valve segment each between the inlet port and the outlet port. The control ports can be brought sequentially in fluid connection with the cylinder bores when the cylinder block is rotating. At least one hydraulic fluid injector is connected fluidly to one control port, for sequentially injecting pressurized hydraulic fluid via the control port into the passing cylinder bores. Via the other control port hydraulic fluid can be drained from passing cylinder bores.

Abstract: Manual displacement control device (MDC) for hydraulic units has an input shaft mounted rotatably about an input shaft axis in an input shaft block. The input shaft protrudes from the input shaft block with a first end, onto which a rotating torque can be applied. The MDC further includes a control spool housed in a control housing, which is moveable by means of rotating the input shaft for controlling a servo pressure. The control device has positioning means for adjusting and fixing the lateral position of the input shaft with respect to the control housing in a direction perpendicular to the input shaft axis and perpendicular to the direction of a restoring force exerted on the input shaft. The hydraulic unit is adjustable to its neutral position by means of a servo spring bracket providing an end stop surface for a servo spring seat towards the displacement element.

Abstract: A hydraulic device (1) comprises a housing (2) and a shaft (3) which is rotatable about a first axis of rotation (4). The shaft (3) has a flange (8), a partly spherical portion (16) and a plurality of pistons (9), which are fixed to the flange (8). The device (1) also has a plurality of cylindrical sleeves (11), wherein each sleeve (11) has a sleeve bottom (13) comprising a sleeve opening (14) including a centreline (23). The sleeves (11) cooperate with the pistons (9) to form respective compression chambers (12) of variable volume. A barrel plate (15) is mounted on the partly spherical portion (16) and has barrel plate ports (21) including respective centrelines (22). The sleeves (11) are rotatable about a second axis of rotation (19) which intersects the first axis of rotation (4) by an acute swash angle.

Abstract: A system, including: a fluidic actuator which can be acted upon by a pressurized fluid and has an actuator member, a pressurized fluid provision device which is adapted to carry out a position control of the actuator member and, within the position control, to act upon the fluidic actuator with the pressurized fluid in order to move the actuator member into a prescribed position, and a hose arrangement, including at least one hose via which the fluidic actuator is fluidically connected to the pressurized fluid provision device, wherein the pressurized fluid provision device is adapted to carry out the position control taking into account a system model describing the hose arrangement, the actuator and/or the pressurized fluid provision device.

Abstract: A pump system includes a pressure compensator and a speed compensator for controlling the displacement of a variable displacement pump having an inlet and an outlet. The variable displacement pump is driven by a drive shaft powered by an electric motor. The pressure compensator adjusts the displacement of the variable displacement pump based on a pump pressure at the pump outlet. The speed compensator adjusts a maximum magnitude of the displacement of the variable displacement pump based on a speed of the electric motor.

Abstract: An example pump includes: (i) a swash block having (a) a first trunnion arm, (b) a second trunnion arm, and (c) a first curved support surface and a second curved support surface disposed on an exterior surface of the swash block; and (ii) a housing comprising (a) a first bore, (b) a second bore, and (c) an internal chamber having a first curved bushing and a second curved bushing, where the swash block is supported within the internal chamber of the housing by the first trunnion arm being positioned in the first bore of the housing, the second trunnion arm being positioned in the second bore of the housing, the first curved support surface being positioned against the first curved bushing of the housing, and the second curved support surface being positioned against the second curved bushing of the housing.

Abstract: A variable displacement pump comprising a pumping piston (10), cylinder head (2); a rotating shaft (3); regulating means (4) of the displacement of the pump, said means in turn comprising: a structure (41) having a variable inclination; a fluid-dynamic actuator (42) for regulating an inclination of said structure (41); command means (43) for the actuator (42), which assume a non-equilibrium and an equilibrium position, said command means (43) in turn comprising: a sliding body (431) being able to take at least a first position in which it places a chamber (420) acting on said actuator (42) in communication with a first zone (51) at least initially having a pressure that is different from a pressure present in said chamber (420); a sliding element (432) with respect to the sliding body (431) for resetting said equilibrium configuration, said sliding element (432) being distinct from said actuator (42) and being mechanically actuated in consequence of a variation of an inclination of said structure (41).

Abstract: A hydrostatic axial piston machine has a housing. In the housing of the hydrostatic axial piston machine, an actuating pressure cylinder is formed at an angle to the drive shaft. A control valve is inserted into the actuating pressure cylinder in a cartridge type of design. In order to enable maximum movement of an actuating piston in the direction toward the control valve, the cartridge is of shortened design. To this end, an actuating pressure port, which is arranged between a high-pressure port and a low-pressure port, and an actuating pressure passage are arranged completely inside the cartridge.

Abstract: A variable displacement swash plate type piston pump includes first and second housing members fastened to each other by fastening members, a rotary shaft, a swash plate. A section of the inner circumferential surface of the first housing member has a recess. A bulging portion is arranged in a section of the outer circumferential wall of the first housing member. A section of the outer circumferential wall of the second housing member has a closing portion that closes the opening of the recess. The fastening members include first and second fastening members arranged at positions that are on the opposite sides of the recess, inside the width of the swash plate in a direction along the inclination axis of the swash plate, and closer to the rotary shaft than the distal ends of the bulging portion and the closing portion in the bulging direction.

Abstract: Provided is a variable displacement pump which includes a cylinder block including a plurality of cylinder bores formed in a rotation shaft in a circumferential direction and rotating together with the rotation shaft, a piston provided inside each of the plurality of cylinder bores to be slidable, and a swash plate supported to be tiltable with respect to the rotation shaft while a distal end portion of the piston is slidable thereon and which sucks and discharges a working fluid by moving the piston in a reciprocating manner with a stroke in accordance with an inclination angle of the swash plate, the variable displacement pump including: a control piston which includes a piston portion pressing the swash plate and controls the inclination angle of the swash plate; a piston accommodation portion which is formed in the housing and accommodates the piston portion; and a hollow cylindrical guide portion which is disposed between the piston accommodation portion and the piston portion and includes an inner perip

Abstract: A variable displacement axial piston pump including a cylinder block defining a plurality of cylinder bores, each receiving a piston. A swash plate having a piston-supporting surface is pivotally supported relative to the cylinder block. A port block defines first and second pumping ports arranged in fluid communication with the plurality of cylinder bores such that, during operation of the pump, one of the first and second pumping ports is configured to supply fluid to the cylinder bores for pumping, and the other of the first and second pumping ports is configured to receive fluid pumped from the plurality of cylinder bores. The swash plate partially defines at least one variable volume control chamber, and the swash plate is operable to tilt with respect to the port block in response to a fluid pressure change in the at least one control chamber.

Abstract: A hydrostatic axial piston machine includes a pot-like housing, a connection plate that closes the pot-like housing, a rotatably mounted cylinder drum, and pistons arranged in cylinder chambers of the cylinder drum. The cylinder chambers are each alternately connected via a cylinder chamber opening to a low-pressure control opening and a high-pressure control opening of a resting control part. The control part has two switching regions located between the low-pressure and high pressure control openings. A piston reverses its movement direction in a dead center within the two switching regions. In the switching region, the cylinder chambers are connected via a connecting line to a fluid volume arranged in the housing. The fluid volume extends between the connection plate and the housing such that it is sealed to an interior by the connection plate and the housing.

Abstract: A hydrostatic axial piston machine includes a double-acting actuating cylinder configured to adjust the piston displacement. The actuating cylinder has two actuating chambers that are connected to two spatially separated cartridge valves. The two cartridge valves are inserted obliquely into a wall section of the axial piston machine. The wall section on the one hand forms a wall of the housing of the axial piston machine and on the other hand forms a wall of the actuating cylinder.

Abstract: A hydraulic axial piston machine includes a drive shaft, a swashplate pivotable about a pivot axis to change inclination relative to a drive shaft axis, and an actuating piston approximately parallel to the drive shaft axis. The actuating piston has a first end which engages and adjusts the swashplate and a second end which bounds an actuating chamber. Fluid flows to the actuating chamber to pivot the swashplate one direction and is forced out of the actuating chamber when the swashplate pivots the other direction. A return element on the actuating piston incorporates a position of the actuating piston and thus the inclination of the swashplate into a control valve. The return element is positioned such that its longitudinal axis and an actuating piston longitudinal axis span a plane that differs from a plane perpendicular to the pivot axis.

Abstract: An axial piston pump has a swash-plate construction, in particular for hydraulic systems. A cylinder drum (3) can be rotationally driven about a rotational axis (7) in a pump housing (1). Pistons (9) are axially displaceable and support at their actuation ends a swash plate (15). The swash plate can be pivoted by an adjusting device (21) to the desired angles of inclination relative to the rotational axis (7) for adjusting the stroke of the pistons (9) and the fluid pressure generated. The adjusting device has an adjusting piston (35) in a hydraulically actuated adjusting cylinder (31). Their movement can be transmitted to the swash plate (15) by a driven connection having a pivot joint (37, 39; 29, 43). The pivot joint is formed by a ball joint (37, 39) arranged between the piston (35) and the piston rod (41) of the adjusting cylinder (31).

Abstract: A variable displacement swash-plate compressor includes an actuator that is configured to change the inclination angle of a swash plate. The actuator includes a movable body that moves along a drive shaft axis. The movable body includes an acting portion that is configured to push the swash plate with the pressure in a control pressure chamber. The swash plate includes a receiving portion that contacts and is pushed by the acting portion. The acting portion and the receiving portion contact each other at an acting position. A drive-shaft-parallel line segment is defined that contains the acting position and connects a proximal end of the acting portion and a proximal end of the receiving portion to each other, while extending in parallel with the drive shaft axis. The drive-shaft-parallel line segment is shorter when the inclination angle of the swash plate is maximized than when the inclination angle is minimized.

Abstract: An adjusting device of an axial piston machine having a displacement volume that is adjusted by a pivoting yoke. The adjusting device has a cylinder, which is radially spaced from and tangential to the yoke pivot axis. A piston communicates with the yoke and is adjusted by hydraulic pressure change. A control arrangement has a position regulating valve with a control piston which can set the hydraulic pressure acting on the piston. A mechanical return can transfer the yoke pivoting position to the control piston. The valve is axially parallel to the cylinder and radially spaced from the yoke pivot axis. The return comprises an axially movable sensing piston and coaxial return spring which are axially adjacent to the valve. The sensing piston abuts a yoke surface that is eccentric with respect to the pivot axis and connected to the control piston by the return spring.

Abstract: Fail-safe methods for utilizing an over-center pump/motor in a hydraulic hybrid vehicle are disclosed. A high-pressure fluid shutoff valve and an optional electrically or manually operated valve are additionally provided as means to ensure disconnection of the high pressure source in the event of a failure. Displacement stroke position and pressure differentials across the pump/motor are continually monitored. On detection of various modes of failure or irregularity in control of displacement, actions are taken including any of: the high pressure and low pressure accumulators are shut off automatically or manually, a check valve between the high and low pressure ports of the pump/motor is activated, and a small amount of pressurized fluid is released from the high pressure circuit to depressurize the captive fluid. Safe startup and shutdown procedures are also specified.

Abstract: A hydrostatic machine having an actuating device for adjusting a displacement volume of the hydrostatic machine is provided. The actuating device has a return element for actuating a control valve as a function of a position of the actuating device. A valve unit is further provided for adjusting an actuating pressure of the actuating device, which is activated mechanically by means of the return element.

Abstract: The invention relates to a cylinder drum (1?) for a hydrostatic piston engine, having at least one kidney-shaped control port/cylinder bore transition (5?, 5?, 5??) which leads into a cylinder bore (2, 2?a) for receiving a piston that can be axially displaced therein, wherein the kidney-shaped control port/cylinder bore transition (5?, 5?, 5??) is configured perpendicular to the flow direction in a stepless and edge-free manner.

Abstract: A pressure regulating restriction for allowing a cylinder bore and a valve plate discharge port to communicate with each other before the cylinder bore communicates with the valve plate discharge port, and an oil passage for allowing the valve plate discharge port and the cylinder bore to temporarily communicate with each other in a time period after the cylinder bore is freed from the communication with the valve plate suction port until the cylinder bore communicates with the pressure regulating restriction. The oil passage has length capable of transmitting high pressure in the oil passage on a side of the cylinder bore at the time of the communication and of restoring the pressure in the oil passage on the side of the cylinder bore to the pressure on a side of the valve plate discharge port before the communication with a next cylinder bore at the time of non-communication.

Abstract: An adjustment device for a pivoting cradle of a hydraulic machine, in particular of an axial piston machine, is disclosed. Said adjustment device has an actuating piston to which pressure medium for pivoting the pivoting cradle about a pivoting axis is applied via an actuating pressure space. In order to control the feeding in of pressure medium and the relieving of the actuating pressure space, a control valve is provided. Said control valve has a control piston configured to be adjusted by an electric actuator, wherein the electric actuator is controlled by a control device. In this context, the control device controls the electric actuator as a function of a control difference formed from a setpoint pivoting angle and an actual pivoting angle of the pivoting cradle. The actual pivoting angle of the pivoting cradle is fed back electrically to the control device here.

Abstract: Provides is a variable displacement swash plate type compressor comprising a drive shaft, a lug plate fixedly installed at one side of the drive shaft, a swash plate dispose at another side of the drive shaft and rotated by the lug plate to vary a tilt angle thereof, a sleeve reciprocally moving along the drive shaft to let the swash plate rotate, and a spring supported between the sleeve and the lug plate, characterized in that the variable displacement swash plate type compressor comprises a restriction ring installed around the drive shaft between the lug plate and the sleeve to contact with the swash plate at a maximum tilt angle of the swash plate, wherein an end of the restriction ring is contacted with the lug plate and another end of the restriction ring is supported by the spring. Thus, since the direct contact between the swash plate and the lug plate is prevented, when the swash plate reaches at the maximum tilt angle, it is possible to reduce the noise and the wear remarkably.

Abstract: A hydraulic actuator unit includes a first electric motor assembly formed by mounting one of a pair of electric motors to one of a pair of electric motor covers, wherein the first electric motor assembly is detachably mounted to a pump case so as to rotate a first control shaft around its axis line, and a second electric motor assembly formed by mounting the other one of the pair of electric motors to the other one of the pair of electric motor covers, wherein the second electric motor assembly is detachably mounted to the pump case so as to rotate a second control shaft around its axis line.

Abstract: In various embodiments, cylinder assemblies are coupled in series pneumatically, thereby reducing a range of force produced by or acting on the cylinder assemblies during expansion or compression of a gas.

Abstract: A hydraulic system includes an engine driven variable displacement hydraulic pump which supplies fluid to a hydraulic consumer and an electronic control unit. A flow rate adjusting unit includes a stop that can be brought into engagement with an adjusting piston. In order conform the power output of the pump to the operating conditions of the vehicle, the stop of the flow rate adjusting unit includes adjusting devices that can be controlled by the control unit, so that the maximum flow rate of the pump can be varied by the electronic control unit. The electronic control unit generates a control signal for the adjusting device as a function of a sensed engine speed.

Abstract: In a bent axis hydraulic machine, a back plate and cylinder barrel vary in distance from a drive plate as a stroke angle of the cylinder barrel changes, thereby minimizing unswept fluid volume in the cylinders of the barrel at any stroke angle. Distance is controlled by one or more rollers, engaging respective tracks that define a profile of contact that determines the distance as a function of the stroke angle. Telescoping fluid supply channels are employed to maintain a fluid supply to the cylinder barrel as the distance changes.

Abstract: A hydraulic stepless transmission having increased layout freedom and a compact structure with the functions of conventional hydraulic stepless transmission retained and having increased easiness of production. In the hydraulic stepless transmission, the movable swash plate (input side swash plate) of a variable displacement plunger hydraulic pump or motor is tilted by a hydraulic servo mechanism. The hydraulic servo mechanism has a power piston connected to one end of the input side swash plate for tilting the swash plate, a servo spool (13) placed normal to the direction of sliding of the power piston and substantially parallel to the input side swash plate, and a feedback link for connecting the servo spool and the input side swash plate.

Abstract: An axial piston machine is provided, which has a swivel cradle, the inclination of which can be modified in relation to a rotational axis of a cylinder drum. A regulation system acts on the swivel cradle, which has a first regulator for adjusting the inclination of the swivel cradle in a first displacement direction and a second regulator for adjusting the inclination in an opposite second displacement direction. The first and second regulators are located on opposite sides of the swivel cradle in relation to the rotational axis. The axial piston machine also has a device for limiting the displacement of the swivel cradle, which has a first adjustable limiting device and a second adjustable limiting device, which each act on the swivel cradle and are located on opposite sides of the swivel cradle in relation to the rotational axis.

Abstract: The present disclosure relates to an apparatus for controlling the angle of a swash plate of a hydraulic pump, and more particularly, to an apparatus for controlling the angle of a swash plate of a hydraulic pump in order to fix the swash plate at a desired angle by using an electric motor and an electromagnet. The apparatus for controlling the angle of a swash plate of a hydraulic pump includes a swash plate and a swash plate shaft coupled to the swash plate to be rotatable, and the apparatus further includes: an electric motor which directly connects the swash plate shaft or transmits a rotating force through a link connected to the swash plate shaft to pivot the swash plate; and an electromagnet which generates a magnetic force so that the swash plate moving according to the operation of the electric motor is fixed at a target angle.

Abstract: A first swash plate (30) and a second swash plate (40) are disposed on either side of a cylinder block (4), and a plurality of cylinders (6) are disposed in the cylinder block (4). A first piston (8) and a second piston (9) are inserted opposite to each other in each cylinder (6) such that the first piston (8) slides on the first swash plate (30) and the second piston (9) slides on the second swash plate (40). By providing a servo mechanism (33) that tilts the first swash plate (30) and a tilt linking mechanism (40, 70) that tilts the second swash plate (40) in conjunction with the tilting of the first swash plate (30), tilt angles of the two swash plates (30, 40) can be controlled by the single servo mechanism (33).

Abstract: A variable displacement bent axis unit comprising a housing and a yoke pivotally disposed therein wherein the yoke has a cam member attached thereto. A control mechanism that changes the displacement of the unit has a control valve disposed therein that engages the cam member. The cam member itself has a non-linear feedback profile such that the feedback profile provides a linearized speed ratio.

Abstract: The invention concerns a variable pump or hydraulic motor with a drive shaft with a first axis of rotation and first plungers connected to the drive shaft and rotatable around the first axis of rotation. A port plate mounted in the housing can rotate around an axis intersecting the first axis, for adjusting the stroke volume. The port plate positioning drive comprises two counter-acting hydraulic actuators acting on the port plate in the direction of the first plungers.

Abstract: Disclosed is a wobble plate type variable displacement compressor that uses a constant velocity universal joint mechanism, which comprises an inner ring and an outer ring, balls that are held between guide grooves of the inner ring and the outer ring to transmit power, wherein a wobble plate is connected and fixed to the outer ring. In the compressor, the connecting structure for the outer ring and the wobble plate is formed by providing a plurality of concave portions arranged in a circumferential direction on one member, by plastically deforming the other member partially at locations corresponding to the concave portions such that it fits into the concave portions, and by fixing both members to each other in the axial direction and in the rotational direction by means of the plastic deformation.

Abstract: The variable displacement swash plate compressor includes a housing, a drive shaft, a swash plate, a piston, a bleed passage, a supply passage and a low-melting member. The housing has a cylinder bore, a suction chamber, a discharge chamber and a crank chamber. The swash plate is supported in the crank chamber by the drive shaft and inclination angle of the swash plate is adjustable. The piston is reciprocally movably received in the cylinder bore. The bleed passage is formed in the housing in communication with the crank chamber and the suction chamber. The supply passage is formed in the housing in communication with the discharge chamber and the crank chamber. The low-melting member is disposed in the bleed passage so as to restrict fluid flow therethrough and has a lower melting point than the housing. When the low-melting member is melted, an opening of the bleed passage is increased.

Abstract: Provides is a variable displacement swash plate type compressor comprising a drive shaft, a lug plate fixedly installed at one side of the drive shaft, a swash plate dispose at another side of the drive shaft and rotated by the lug plate to vary a tilt angle thereof, a sleeve reciprocally moving along the drive shaft to let the swash plate rotate, and a spring supported between the sleeve and the lug plate, characterized in that the variable displacement swash plate type compressor comprises a restriction ring installed around the drive shaft between the lug plate and the sleeve to contact with the swash plate at a maximum tilt angle of the swash plate, wherein an end of the restriction ring is contacted with the lug plate and another end of the restriction ring is supported by the spring. Thus, since the direct contact between the swash plate and the lug plate is prevented, when the swash plate reaches at the maximum tilt angle, it is possible to reduce the noise and the wear remarkably.

Abstract: The invention concerns a hydraulic axial piston machine with a housing, in which a cylinder drum having at least one cylinder is arranged to be rotatable around an axis, in which cylinder is located a piston that is supported on a swashplate, whose inclination angle is adjustable in an adjustment plane. It is endeavoured to keep the cost of manufacturing individual parts of the axial piston machine small. For this purpose it is provided that on the side facing away from the cylinder drum (4) the swashplate (12) has a spherical bearing surface (15), which rests on a spherical supporting surface (16) in a bottom part (3) of the housing (2) and comprises an inclination protection (31-34), which counteracts an inclination of the swashplate (12) perpendicularly to the adjustment plane.

Abstract: A pump/compressor that utilizes a wedge at a fixed angle to operate the pump's pistons at a fixed stroke. Alternatively the wedge can be moved axially to increase or decrease the clearance volume. Variable fluid flow at any clearance volume is achieved by rotating the wedge with respect to the port plate thereby changing the timing of the pistons with respect to the fixed port plate which changes the timing of the intake and output cycles. This results in a portion of the intake charge being breathed back into the intake port and a portion of the output charge being breathed back from the outlet port. This causes the pistons to not take in a full charge from the inlet port and to not pump out a full charge into the outlet port. Thus, fluid flow is varied. The design results in a smaller pump as the wedge is supported by the pump housing rather than a mechanical linkage required of prior adjustable angle swashplate designs.

Abstract: A hydraulic motor includes a rotor supporting a plurality of piston elements projecting away from opposing faces of the rotor. The rotor is adapted to rotate about a first axis. The hydraulic motor further includes a pair of drum plates each supporting a plurality of cup elements. The plurality of cup elements are adapted to engage the piston elements. Each drum plate is arranged on an opposing side of the rotor and is adapted to rotate about a second axis in angled relation to the first axis. Each of a pair of swashplates is in operative engagement with a respective one of the drum plates and each is adapted to pivot relative to the rotor to move with the respective drum plate between a maximum displacement position and a minimum displacement position to thereby change the angled relation between the first axis and the second axis. The pair of swashplates are further independently pivotable between three different settings.

Abstract: A hydraulic actuator for a hydraulic servomotor 4 is disclosed. The hydraulic servomotor 4 has a first chamber 5 and a second chamber 6 associated therewith. The hydraulic actuator is connected to a fluid source 2 and a fluid drain 3, and it comprises a valve assembly arranged between the fluid source 2 and the fluid drain 3 to control fluid pressures in the chambers 5, 6. At least one auxiliary valve 11 is fluidly connected between the valve assembly and the fluid drain 3, said auxiliary valve(s) 11 being of a kind which is normally closed in a de-energized state. In the case of a power cut off the auxiliary valve(s) 11 will close, thereby preventing fluid flow from the valve assembly towards the fluid drain 3. This causes a servomotor piston member 12 to be hydraulically locked in its instantaneous position, thereby locking the hydraulic servomotor 4. The valve assembly may be designed without taking the locking function into consideration.

Abstract: Two motors are arranged on opposing sides of a common shaft, drive plates of the pump/motors being rigidly coupled to each other, for example by being in hard contact with opposing sides of the shaft. By providing hard contact between the pump/motor drive plates and a common shaft, the drive plates and shaft act as a substantially solid element under compression, thereby substantially canceling axial loads generated by the pump/motors directly through the shaft. Residual axial loads are handled via bearings positioned on the shaft adjacent the drive plates in such a manner that the drive plates are in light contact only with the bearings. As a result, friction experienced by the bearings is substantially reduced as compared to conventional systems, thereby improving the efficiency of the system.

Abstract: A floating cup pump assembly incorporating a tilted swashplate structure with cup elements projecting away from either side of the swashplate structure. The swashplate structure is positioned between a first group of matedly engaged piston elements and a second group of matedly engaged piston elements. The piston elements rotate around a first axis and the cup elements rotate around a different axis causing the cups to reciprocate relative to the piston elements.

Abstract: The variable capacity compressor has a rotor 21, as a rotating member, fixed to a drive shaft 10 and rotating integrally with the drive shaft 10, a swash plate 24, as a tilting member, tiltably and slidably attached to the drive shaft 10, a linkage mechanism 40 linking the rotor 21 and the swash plate 24 at a position corresponding to an upper dead center of the swash plate 24, transferring rotation of the rotor 21 to the swash plate 24, and guiding the tilting movement of the swash plate 24, and a tilting movement guide 60 provided between the rotor 21 and the swash plate 24 and anterior to the linkage mechanism 40 in the rotating direction and guiding changes of the inclination angle of the swash plate 24 with respect to the drive shaft 10.

Abstract: Improvements in trunnion shaft-controlled swashplate axial hydraulic piston pumps as well as hydraulic systems used in hydrostatic transmissions utilized. e.g., in zero-turn-radius (ZTR) wheeled vehicles, such as grass mowers, with one embodiment thereof pertaining to, in combination, the noted pump, devoid of any internal servo control, and a reversible power actuator, for controlling the angle of the swashplate, externally affixed to the housing containing the pump and operatively interconnected with an end of the trunnion shaft extending from the pump housing, with the power actuator being one of a rotary actuator, a fluid power axial cylinder and a rotary electronic actuator.

Abstract: The universal hybrid (26) comprises a two-cycle engine (28), boosted by the engine power reciprocating compressor (32) and a hydraulic pump (34). The pump plunger (148) fastened to engine piston (72) provide direct energy transmission to the compressor and pump. The plunger and compressor piston (94) moving in opposite direction coupled each to one of two diametrically opposite rotor's (36) axial rods, which double-sided interact with the pivotable swash plate (42). The swash plate turn provides simultaneously the engine, compressor and pump variable displacement volume with engine invariable compression ratio while the swash plate turn axis fixed. This increases the engine power range using the minimum specific fuel consumption. The swash plate turn axis shifting provides the engine compression ratio change for the either kind of fuel use.

Abstract: The invention relates to a reversible axial piston machine (1) consisting of a cylinder drum (5) which rotates about a rotational axis (7) and in which pistons can be displaced in cylinders (6), said pistons being supported against an inclined surface (8). The angle of adjustment (?1, ?2) of the inclined surface (8) can be adjusted in both pivoting directions by means of a control piston (24) pertaining to the adjusting device (12), said control piston extending essentially parallel to the direction of the rotational axis (7) of the cylinder drum (5). The zero position of the adjustment of the inclined surface (8) can be adjusted without play by means of a zero position adjusting device (32).

Abstract: An axial piston machine having a swashplate or an oblique axis which can be adjusted by means of servopistons and has a valve segment and an adjustment unit for the electrically proportional adjustment of the volumetric displacement. The adjustment unit comprises proportional magnets which can be activated electrically, and a control piston for controlling the oil pressure which moves the servopistons. The proportional magnets act on the control piston along a common tappet axis, a feedback device for feeding back the current swashplate or oblique-axis valve-segment position to the control piston being provided. The feedback device comprises spring levers 6, 6? which can pivot about an axis, the spring levers 6, 6? each being mounted on the pivot axis 5 with a bearing shell 15, which are each composed of two component shells which support the spring lever 6, 6? at separate locations on the pivot axis 5, and which each essentially enclose a half-space about the pivot axis 5.

Abstract: An assembly includes a piston and a transition arm coupled to the piston. The position of the transition arm is adjustable to vary a stroke of the piston. A balance member is adjustable relative to the transition arm to counterbalance the transition arm in varying positions. A control rod is coupled to the transition arm and the balance member. Linear movement of the control rod moves the transition arm in a first direction to change the stroke of the piston and moves the balance member in a second direction substantially opposite the first direction to counterbalance the transition arm. A method of counterbalancing a variable stroke assembly includes moving a transition arm coupled to a piston to vary a stroke of the piston, and moving a balance member in a direction substantially opposite to the direction of movement of the transition arm to counterbalance the transition arm.