Abstract: A hybrid drive system in a vehicle includes a prime mover, a starting device connected to the prime mover, and a transmission having a transmission input shaft connected to the starting device. A pump/motor is functionally interconnected between the starting device and the transmission. A first accumulator is in fluid communication with the motor/pump for storing a hydraulic fluid under pressure and a second accumulator is in fluid communication with the pump/motor for storing hydraulic fluid discharged from the first accumulator. Discharge of the first accumulator drives the pump/motor to provide a drive torque to the transmission input shaft and to provide a drive torque to the prime mover for starting the prime mover.

Abstract: A start/stop arrangement in a fluid system comprising a controllable pump unit for supplying fluid pressure to at least one implement; a prime mover connected to a transmission device arranged to drive the pump unit; wherein the pump unit is installed on an outgoing power take off and is arranged to supply fluid pressure to the implement fluid system, that the pump unit is arranged accumulate fluid pressure in the accumulator. The fluid system further comprises a controllable motor unit connected to a fluid accumulator; that fluid pressure from the accumulator is arranged to drive the motor unit; and that the motor unit is connected to the prime mover by an overrun clutch, wherein the motor unit is arranged to supply torque to and start the prime mover when at least one predetermined condition is fulfilled. The invention further relates to a method for controlling the start/stop arrangement.

Abstract: A hydraulic system including a hydraulic power source (102) having an output and a directional control valve (106) coupled to the output of the hydraulic power source. The system also includes a hydraulic cylinder (108) coupled to the directional control valve that receives hydraulic fluid at a first port and expels it at a second port as it moves a load (114) at a movement rate, a fixed displacement motor (150) coupled the directional control valve and receiving hydraulic fluid expelled by the hydraulic cylinder and a variable displacement pump (154) attached to a drive arm (152) of the motor.

Abstract: The present invention relates to a piece of working equipment, in particular to an excavator or to a machine for the transfer of material, having an element movable via at least one working hydraulic cylinder, wherein at least one energy recovery hydraulic cylinder is provided for the recovery of energy from the movement of the movable element. In accordance with the invention, the energy recovery hydraulic cylinder is filled with gas at the bottom side and has a hollow piston rod.

Abstract: A method is provided for controlling a hydraulic cylinder in a work machine, which hydraulic cylinder is arranged to move an implement in relation to a part of a vehicle, with the hydraulic cylinder being controlled by a hydraulic machine. The method includes the steps of detecting initiation of a movement of the implement that is such that the piston of the hydraulic cylinder is moved in a first direction, of driving the hydraulic machine in a first rotational direction, prior to the movement of the implement taking place, so that a line from the hydraulic machine is pressurized, which line is arranged to connect the hydraulic machine to the side of the cylinder toward which the piston will be moved during the movement of the implement.

Abstract: The invention relates to a drive (1) having an energy storage device and a method for storing brake energy. A drive (1) has an energy storage device having a hydrostatic piston engine (9) and a storage element (11) which is connected thereto. In a high-pressure storage line (10), an adjustable throttle location (15) is arranged between the piston engine (9) and the storage element (11). During the braking operation, the adjustable throttle location (15) is adjusted in accordance with a detected requested brake torque. The pressure medium is conveyed from the hydrostatic piston engine (9) via the adjustable throttle location (15) into the storage element (11).

Abstract: A hydraulic system including an accumulator and a hydraulic transformer is disclosed. The hydraulic transformer includes first and second variable displacement pump/motor units mounted on a rotatable shaft. The rotatable shaft has an end adapted for connection to an external load. The first variable displacement pump/motor unit includes a first side that fluidly connects to a pump and a second side that fluidly connects to a tank. The second variable displacement pump/motor unit includes a first side that fluidly connects to the accumulator and a second side that fluidly connects with the tank.

Abstract: A hydraulic system adapted to recover inertial energy is disclosed. The hydraulic system includes a pump, a variable displacement pump/motor having an input/output shaft, an accumulator, and a valve arrangement. The valve arrangement is operable in: a) a first mode where the variable displacement pump/motor is driven by the pump to rotate the input/output shaft and the load; b) a second mode where the variable displacement pump/motor uses inertial energy from a deceleration of the load to charge the accumulator; and c) a third mode where the variable displacement pump/motor is driven by the accumulator to rotate the input/output shaft and the load. The hydraulic system also includes a controller for controlling operation of the pump, the variable displacement pump/motor and the valve arrangement.

Abstract: Equipment having an energy management system includes an articulated arm, a work implement, an energy management system, and a hydraulic circuit. The articulated arm includes hydraulic actuators designed to maneuver the articulated arm, and the work implement is fastened to the articulated arm. The energy management system is adjustable between a first configuration and a second configuration, and includes a hydraulic rotating machine and an electric rotating machine coupled to the hydraulic rotating machine. When the energy management system is in the first configuration, the hydraulic rotating machine and the electric rotating machine function as an electric motor powering a hydraulic pump. When the energy management system is in the second configuration, the hydraulic rotating machine and the electric rotating machine function as a hydraulic motor powering an electric generator.

Abstract: A power transfer system for a vehicle that comprises a an internal combustion engine, one or more drive wheels, and power transfer apparatus transfers power from the prime mover to the wheels for propelling the vehicle. The system further comprises an auxiliary hydraulic pump that has a drive shaft that coupled to a power take-off unit driven by engine, and to an auxiliary hydraulic motor powered by hydraulic fluid supplied from a hydraulic energy storage device such as an accumulator. As a result, the auxiliary hydraulic pump can be powered by hydraulic fluid from the accumulator when the prime mover is not operating, or by the prime mover when operating. A tandem arrangement of one way clutches can be employed to avoid the need to disconnect the auxiliary hydraulic pump from the prime mover during operation of the auxiliary hydraulic motor, and vice versa.

Abstract: The invention relates to a mobile machine having a traction drive and working hydraulics. The drive unit has a radial piston pump which is driven by a drive set and supplies working hydraulics. The radial piston pump is arranged on the axis of the output drive shaft of the drive set, between the drive set and a gearbox which is connected thereto via the output drive shaft. The drive set, the radial piston pump and the gearbox in this case form a compact drive unit.

Abstract: The present invention relates to a hydraulic drive system having a pressure-regulated hydraulic pump for the provision of a system pressure and having a secondarily regulated hydraulic motor. In accordance with the invention, a control is provided which sets the desired system pressure during operation in dependence on an operating parameter of the hydraulic motor.

Abstract: A support for supporting a structure on a surface, comprising at least one support element, each support element comprising a piston, a cylinder in which the piston is moveable, and a brake for maintaining the piston in a position that is stable relative to the cylinder, wherein the piston and the cylinder are arranged so that a loading associated with the structure effects an adjustment of the support element, and wherein an increase in hydraulic pressure within the cylinder, effected by the loading associated with the structure, activates the brake.

Abstract: An hydraulic transmission device (10,110) comprising an hydraulic motor (16, 18), an hydraulic pump (20), a fluid accumulator (22). The device has an accumulator-driven mode, an energy-recovery mode, a pump-driven mode. In the pump-driven mode, the pump supplies the motor with fluid drawn from an unpressurized reservoir; and in the energy-recovery mode, the motor is supplied by the pump drawing fluid from said reservoir. An assembly (1) comprising a device (10,110) as defined above, a shaft (11, 13), and a mass (12, 14) mounted eccentrically on the shaft.

Abstract: An energy storage system includes a reservoir defining an interior chamber, a collapsible bladder positioned within the interior chamber and having working fluid therein, a one-way valve in fluid communication with the interior chamber and operable to permit entry of replacement air into the interior chamber as working fluid exits the bladder, a reversible pump/motor in fluid communication with the bladder, and an accumulator containing working fluid and gas. The accumulator is in selective fluid communication with the reversible pump/motor to deliver pressurized working fluid to the reversible pump/motor when operating as a motor, and to receive pressurized working fluid discharged by the reversible pump/motor when operating as a pump.

Abstract: A circuit having at least one hydraulic motor, two main ducts for feeding or discharging the at least one motor, a low-pressure fluid source, and a high-pressure accumulator forming a high-pressure fluid source. The circuit is suitable for operating in an energy recovery mode in which the feed main duct is connected to the low-pressure fluid source and the discharge main duct is connected to the high-pressure accumulator, and in an energy delivery mode in which the connections are inverted. The low-pressure fluid source has a high-flow-rate booster pump suitable for delivering a flow-rate of fluid that is sufficient to feed fluid to the at least one hydraulic motor while the motor is at maximum speed in energy recovery mode, and an adjustable pressure limiter suitable for being controlled so as to cause the pressure of the fluid at the outlet of the low-pressure fluid source to vary.

Abstract: Hydraulically driven arrangement for the linear movement of a mass body consisting of two double acting cylinders coupled in parallel, whereby one operating cylinder is a control cylinder for controlling the movement of the mass body, which is split into an acceleration phase, a movement phase and a brake phase. The other operating cylinder is connected as a drive cylinder to the hydraulic power pack as an energy storage, in a manner that the power pack during the acceleration phase of the mass body generates the drive energy for the drive cylinder, and the drive cylinder in the brake phase of the mass body, which serves as a pump for charging the hydraulic power pack. The control cylinder and drive cylinder each have a piston with a one-sided piston rod coupled to the mass body. The control cylinder and the drive cylinder are controlled by hydraulically separated, independent control circuits.

Abstract: A hydraulic system is adapted to recover potential and kinetic energy of a work attachment of a work machine. A valve arrangement may configure the hydraulic system in various modes. The hydraulic system may provide suspension and/or actuation for the work attachment. The energy of the work attachment may move a rod of a first cylinder. The rod may pressurize fluid within the first cylinder. The pressurized fluid may flow from the first cylinder through a valve and into an accumulator. The first cylinder may amplify pressure of the fluid. The pressurized fluid in the accumulator may actuate the first cylinder. The movement of the rod of the first cylinder may cause simultaneous actuation of a second cylinder. A controller may monitor pressures and positions of components of the hydraulic system and control the valve arrangement.

Abstract: The invention relates to a drive (1) having an energy recovery function. The drive having an energy recovery function comprises a hydrostatic piston machine (9) and at least one storage element (13) which is connected to said hydrostatic piston machine. Said hydrostatic piston machine (9) and the at least one storage element (13) are connected together by means of a storage line. Said storage line is divided into a first storage line section (11) and into a second storage line section (12) by a throttle value unit (15). Said throttle valve unit (15) comprises a control pressure valve unit (16) and a built-in valve (17). The control pressure valve unit (16) produces a control pressure which acts upon the built-in valve (17).

Abstract: A hydrostatic drive in an open circuit is provided. The hydrostatic drive has a hydraulic pump and a hydraulic motor. The hydraulic pump and the hydraulic motor are connected to one another via a feed line. In addition, the hydrostatic drive has a storage element for storing pressure energy. A first valve device, which is arranged downstream of the hydraulic motor, alternately connects the downstream connection of the hydraulic motor to a tank volume or to the storage element.

Abstract: A fluid system includes a controllable first pump unit for supplying fluid pressure to at least one implement; a prime mover arranged to supply a driving torque to the first pump The first pump unit is arranged to supply fluid pressure to the implement. The fluid system further includes a controllable second pump unit connected to a fluid accumulator. The prime mover is arranged to supply a driving torque to the second pump unit in order to accumulate fluid pressure in the accumulator during periods of low demand. Fluid pressure from the accumulator is arranged to drive the second pump unit to assist the prime mover during periods of high demand in order to supply an additional driving torque in excess of the available driving torque from the prime mover.

Abstract: A power generation control method of a hybrid construction machine capable of maintaining voltage of a capacitor in an appropriate range while minimizing capacitance of the capacitor and of surely preventing a system from being rendered inoperative, and the hybrid construction machine are provided. For this purpose, swing power corresponding to electric power consumed by a swing motor for swinging a part of a body relative to other parts is sequentially calculated, a value of the calculated swing power is converted to a smaller value, a power generation command of a generator motor is sequentially generated using the converted value, and the generated power generation command is output to an inverter for driving the generator motor.

Abstract: A hydraulic drive system for an actuator uses a pair of pressure compensated hydraulic machines to control flow to and from the drive chambers of the actuator by varying the controlled pressure of one of the machines. The machines are mechanically coupled to permit energy recovery and charge an accumulator to store supplies energy. The drive system may be combined with other services including a transmission for incorporation in a vehicle. The transmission uses a pressure compensated supply and torque control of the wheels.

Abstract: A method of varying a charge in an accumulator includes providing an accumulator containing working fluid and gas, providing a reservoir containing gas, transferring gas from the reservoir to the accumulator to increase the gas pressure in the accumulator, and transferring gas from the accumulator to the reservoir to decrease the gas pressure in the accumulator.

Abstract: A hydraulic circuit is provided having a hydraulic actuator and a flow control valve. The flow control valve has a pressure adjusting element fluidly coupled to the hydraulic actuator and situated to affect a pressure of fluid being directed to the hydraulic actuator. The flow control valve also has an energy directing element operatively coupled to the pressure adjusting element and situated to be driven by the pressure adjusting element when the pressure adjusting element is selectively throttling fluid being directed to the hydraulic actuator.

Abstract: An accumulator system includes an accumulator containing working fluid and gas, an isolation valve through which working fluid selectively flows to and from the accumulator, an actuator operably coupled to the isolation valve, and a passageway fluidly communicating the actuator with gas in the accumulator. The actuator maintains the isolation valve in an open configuration at a first gas pressure to allow working fluid to flow to and from the accumulator. The actuator also allows the isolation valve to close at a second gas pressure less than the first gas pressure.

Abstract: The present invention relates to a hydraulic drive system for driving an apparatus, with a drive unit, a first and a second hydraulic displacement machine, with which the drive unit is connectable or connected for transmitting mechanical energy, and a third and a fourth hydraulic displacement machine, which are connectable or connected with the apparatus for transmitting mechanical energy, wherein the first hydraulic displacement machine is hydraulically connected or connectable with the third hydraulic displacement machine, and wherein a high-pressure accumulator is provided, which is hydraulically connected or connectable with the second and the fourth hydraulic displacement machine.

Abstract: A speed of a hydraulic actuator is matched with that of an electric actuator when the hydraulic actuator and the electric actuator are concurrently actuated. When determination units (71, 72) determine that a boom hydraulic cylinder (31) and a rotation generator motor (11) are concurrently actuated based on a controlled variable of a boom control lever (41) and a controlled variable of a rotation control lever (42), a torque of the rotation generator motor (11) is restricted based on a pump discharge pressure (Pp). Therefore, for example, a torque limit command is generated and output such that a torque limit value (TL2) of the rotation generator motor (11) is decreased with a decrease in discharge pressure (Pp) of a hydraulic pump (3).

Abstract: A hydraulic cylinder assembly for a fluid pump including a cylinder, a bearing attached to an approximate first end of the cylinder, a rod slideably mounted within the bearing, and a piston located about an end of the rod in the cylinder opposite the bearing. A central axis of the rod is offset from, and parallel to, a centerline of the cylinder to impede a rotation of the piston about the rod. The hydraulic cylinder assembly further including a hydraulic pump fluidly connected to the cylinder, the pump configured to provide a hydraulic pressure to the cylinder during an up-stroke of the piston and rod and the pump further configured to generate electricity on the down-stroke of the piston and rod.

Abstract: A hybrid construction machine includes a control valve provided in a flow passage that connects an actuator to a regenerative hydraulic motor, an opening of which is controlled by a pilot pressure led to a pilot chamber thereof; and a solenoid pilot control valve that leads a pressure on an upstream side of the control valve to the pilot chamber. In the control valve, a pressure receiving area of a main spool for receiving the pilot pressure is equal to an area obtained by subtracting a pressure receiving area of the main spool for receiving a pressure of an outflow port in a direction for moving the main spool against a biasing force of a biasing member from a pressure receiving area of the main spool for receiving a pressure of the outflow port in a direction for moving the main spool against the pilot pressure.

Abstract: The invention relates to a drive with an energy recovery and retarder function. The drive (1) comprises a hydrostatic piston engine (12) which is connected to an accumulator (16) for storing pressure energy and to a pressure limiting valve (19) for generating a braking action. Arranged downstream of the pressure limiting valve (19) is a cooler (45). The drive (1) also comprises a hydraulic motor (35) for driving a cooler fan (33), wherein the hydraulic motor (35) is acted on with a pressure medium which is delivered by the hydrostatic piston engine (12).

Abstract: An integral accumulator/reservoir system including a low pressure vessel having a low-pressure vessel wall defining a low-pressure vessel cavity; a high-pressure accumulator having a high-pressure accumulator wall defining a high-pressure accumulator cavity, the high-pressure accumulator being disposed in the low-pressure vessel cavity, the high-pressure accumulator wall including an aluminum layer; a flexible bladder, the flexible bladder being disposed in the high-pressure accumulator cavity; and a sensor module operably connected to the aluminum layer.

Abstract: An apparatus for energy recovery is provided. The apparatus comprises a hydrostatic machine and at least one hydraulic storage component. The hydraulic storage component is connected to the hydrostatic machine via a working line. A valve device is provided for influencing the volumetric flow in the working line between the hydraulic storage component and the hydrostatic machine. The valve device comprises a brake pressure regulating valve unit with a valve and a pilot valve unit which acts on the valve with a control pressure. The invention also relates to a method for controlling the apparatus for energy recovery. In order to store released energy, a required braking torque is determined by a control electronics system. The volume from the hydrostatic piston machine into the working line is increased and the pilot valve is actuated by the control electronics system such that the valve is moved towards its open position.

Abstract: A hybrid system for a machine is disclosed. The system has a pump configured to generate fluid flow within a hydraulic system and a first actuator actuated by fluid pressurized by the pump. The system also has a first motor configured to be selectively actuated by pressurized fluid directed from the first actuator by an external load and directed to the first motor by a first control valve. The system further has a first generator configured to be actuated by the first motor and a power source configured to actuate the pump. The system also has a powertrain including a first driveshaft and at least one traction device, the powertrain configured to transfer kinetic energy from the traction device to the first driveshaft during deceleration of the machine. The system further has a second generator configured to be selectively actuated by the kinetic energy transferred by the powertrain.

Abstract: The invention relates to a hydrostatic drive. The hydrostatic drive (1) includes a hydraulic pump (3) and a hydraulic motor (7). The hydraulic pump (3) may be connected by way of a first working line (5) to a first working line connection (8) of the hydraulic motor (7) and by way of a second working line (6) to a second working line connection (9) of the hydraulic motor (7). Furthermore, the hydrostatic drive (1) includes a first storage means (40) for storing pressure energy and a second storage means (41). For recovery of the pressure energy stored in the first storage means, the latter may be connected, at least for one direction of conveying, to a first or second working line (5, 6) which is on the suction side in relation to the hydraulic pump (3) in this direction of conveying.

Abstract: This disclosure relates to a hydraulic system and method that converts the kinetic energy generated by the operation of a swing motor into hydraulic potential energy and reuses the hydraulic potential energy for swing motor acceleration. An accumulator can be provided for storing exit oil from the swing motor that is pressurized by the inertia torque applied on the moving motor via movement of an upper structure of a machine. The pressurized oil in the accumulator can be reused to accelerate the swing motor by supplying pressurized oil to the swing motor.

Abstract: A hydraulic system has a valve assembly with two workports coupled to chambers of first and second cylinders which are connected mechanically in parallel to a machine component. A separation control valve is connected between first chambers of both cylinders, and a shunt control valve is connected between the workports. A recovery control valve couples an accumulator to the first chamber of the second cylinder. Opening and closing the valves in different combinations routes fluid from one or both cylinders into the accumulator where the fluid is stored under pressure, and thereafter enables stored fluid to be used to power one or both cylinders. The shunt control valve is used to route fluid exhausting from one chamber of each cylinder to the other chambers of those cylinders. Thus the hydraulic system recovers and reuses energy in various manners.

Abstract: A power supply for powering a hydraulic implement includes: an electric storage unit; an electric motor, an electric generator, a hydraulic pump and a control unit; the electric motor adapted for receiving electric power and driving the hydraulic pump to power the hydraulic implement; the electric generator adapted for translating mechanical energy into the electric power; the electric storage unit also being adapted for providing the electric power; and the control unit for selecting a source of the electric power from one of the generator and the electric storage unit. A method for operating the power supply and a vehicle are also provided.

Abstract: A hydraulic unit, in particular for lifting and lowering loads in stacking trucks, has at least one working cylinder (10). The piston/rod unit (12) of the cylinder is guided movably in a housing (22). By a hydraulic pump (25), the piston/rod unit can be extended in its one drive direction (30) and can be retracted in its other opposite drive direction (32). A control device (20) actuates the displacement movements to that effect. A storage device (38) is fed energy in one drive direction (32). The energy fed in can be called up from the storage device (38) to assist a displacement movement in an opposite drive direction (30).

Abstract: A method of controlling a hydrostatic drive is provided. The hydrostatic drive has a hydraulic pump and a hydraulic engine. The hydrostatic drive further has a first and a second hydraulic reservoir for storing and recuperating energy. Pressure energy is stored in the first reservoir. For the purpose of recuperating the pressure energy stored in the first reservoir, the first reservoir is connected to a suction side of the hydraulic pump. A downstream working line of the hydraulic engine is connected to the second reservoir. In addition, the downstream working-line connection of the hydraulic engine is disconnected from the suction side of the hydraulic pump.

Abstract: A hydraulic drive system for an actuator uses a pair of pressure compensated hydraulic machines to control flow to and from the drive chambers of the actuator by varying the controlled pressure of one of the machines. The machines are mechanically coupled to permit energy recovery and charge an accumulator to store supplies energy. The drive system may be combined with other services including a transmission for incorporation in a vehicle. The transmission uses a pressure compensated supply and torque control of the wheels.

Abstract: A hydraulic drive system for storing and releasing hydraulic fluid includes a high pressure storage device, a low pressure storage device, a pump operating at a range of pump speeds for converting between mechanical energy and hydraulic energy, and a motor operating at a range of motor speeds for converting between hydraulic energy and mechanical energy. The pump and motor are both fluidly connected to the high and low pressure storage devices. The hydraulic drive system further includes a control valve fluidly connected to the high pressure storage device, the pump and the motor, the control valve being operable to selectively distribute high pressure fluid between the pump, motor and high pressure storage device.

Abstract: A pressure accumulator, in particular a pulsation damper, having an accumulator homing (1) which defines a longitudinal axis (3) and has an inflow opening (15), and an outflow opening (17) for a fluid, wherein two working spaces, in particular a gas space (23) for a working gas and a fluid space (33), are separated from one another inside the accumulator housing (1) in a fluid-tight manner, in particular in a gas-tight manner, by a bellows-like separating member (21), and the separating member (21) is connected at its one end (25), to a lid (27), forming a fixed termination of the gas space (23) in relation to the housing, and at its other end (29) to a piston pan (31) which is axially movable in the accumulator housing (1) and forms a movable termination of the gas space (23), such that working movements of the piston part (31) bring about changes in volume of the working spaces adjoining the separating member (21), is characterized in that inflow opening (15) and outflow opening (17) are respectively provid

Abstract: The invention relates to a drive system (1) having a travel drive, a working hydraulic system (3) and a device for hydrostatic braking (4). The device for hydrostatic braking has a first hydrostatic piston machine (12) which is connected to a drive train (2), wherein the first hydrostatic piston machine (12) is connected via an accumulator line (14) to a pressure accumulator (15) and the accumulator line (14) is connected via an accumulator pressure line (16) to the working hydraulic system (3). As an alternative, the drive system (100) additionally has a second hydrostatic piston machine (13) which is connected mechanically to the first hydrostatic piston machine (12), wherein the first hydrostatic piston machine (12) is connected in the closed circuit via the accumulator line (14) to the pressure accumulator (15), and the second hydrostatic piston machine is connected in the open circuit via a working line (16) to the working hydraulic system (3).

Abstract: A ground engaging vehicle including a movable member, a hydraulically driven actuator, a hydraulic pump, a plurality of valves and at least one hydraulic conduit. The hydraulically driven actuator is coupled to the movable member and the actuator has a first chamber and a second chamber. The plurality of non-proportional valves include a first valve, a second valve, a third valve and a fourth valve. The at least one hydraulic conduit couples the pump with the first valve and the second valve. The first valve is in direct fluid communication with the first chamber. The second valve is in direct fluid communication with the second chamber. The third valve is in direct fluid communication with the first chamber and the fourth valve is in direct fluid communication with the second chamber. The first valve and the second valve each include an open position and a closed position.

Abstract: An energy storage system for a hybrid vehicle, with an internal combustion engine having an output shaft, includes a reservoir containing working fluid, a reversible pump/motor in fluid communication with the reservoir, and an accumulator containing working fluid and gas. The accumulator is in selective fluid communication with the reversible pump/motor to deliver pressurized working fluid to the reversible pump/motor when operating as a motor, and to receive pressurized working fluid discharged by the reversible pump/motor when operating as a pump. The energy storage system also includes an electric motor having a rotor selectively coupled to the output shaft to transfer torque to the output shaft. The reversible pump/motor is coupled to the rotor to transfer torque to the rotor when operating as a motor, and to receive torque from the rotor when operating as a pump.

Abstract: A method provides several modes for recovering hydraulic energy produced by an overrunning load acting on cylinders connected in parallel to a machine component. In one mode, fluid from first chambers in both cylinders is routed into the accumulator, while other fluid is directed into second chambers of those cylinders. In a different mode, fluid is routed from the first chamber of only one cylinder into the accumulator, and fluid from the first chamber of the other cylinder goes into the second chambers of both cylinders. Yet another mode comprises routing fluid from the first chambers of both cylinders into the second chambers of both cylinders. In still another mode, fluid from the first chambers of both cylinders goes into the return conduit while the second chambers of both cylinders receive fluid from a supply conduit. Several modes of reusing the recovered energy are described.

Abstract: In conventional ram-driven presses, the downward stroke of the ram into a tool causes acceleration of the tool, thereby facilitating an operation on a workpiece by the tip of the tool. While the ram stroke is found to impart sufficient dynamic energy to the tool to facilitate the necessitated operation by the tool tip, there are other more efficient, and in turn, more effective, means and methods of actuating the tool tip, with such means and methods being facilitated from energy derived from the tool's acceleration or from energy from other external sources.

Abstract: An infinitely variable transmission for use with an internal combustion engine is provided. Specifically, a prime mover is provided for driving a first hydraulic machine. The first hydraulic machine is arranged to drive a second hydraulic machine via a fluid line that connects the first and second hydraulic machines. The second hydraulic machine is operatively connected with an output element, such as a wheel to drive a vehicle. Each of the first and second hydraulic machines have electronically controllable valves for varying the speed and/or the torque of the first and second hydraulic machines thereby providing an infinitely variable transmission.

Abstract: A hydraulic drive system for storing and releasing hydraulic fluid includes a high pressure storage device, a low pressure storage device, and a pump-motor operating at a range of pump-motor speeds for converting between hydraulic energy and mechanical energy. The pump-motor is disposed between the high pressure device and the low pressure device. In normal operation, the hydraulic drive system enters a motoring mode where hydraulic energy is released from the high pressure storage device and converted to mechanical energy using the pump-motor. It also enters a pumping mode where mechanical energy is converted into hydraulic energy. A neutral state exists where hydraulic energy is neither stored nor released from the high pressure storage device. An approach for compensating for temperature changes using varying pressure limits helps to maintain the hydraulic drive system in normal operation, thereby promoting efficiency within the hydraulic drive system.