Abstract: A system and method for storing potential energy for a material handler. The system and method involves actuating a machine element using hydraulic cylinders; measuring a position of the machine element; controlling the hydraulic cylinders with a hydraulic circuit by an electronic control unit; determining a maximum target pressure for at least one gas actuator coupled to the machine element; calculating a target pressure for the at least one gas actuator at the position; measuring a gas pressure measurement from the at least one gas actuator; comparing the target pressure to the gas pressure measurement; and adjusting a hydraulic adjustment valve to increase or decrease an amount of hydraulic fluid within a hydraulic chamber of an accumulator thereby changing a gas pressure within the at least one gas actuator to correspond to the target pressure.

Abstract: An electrohydrostatic actuator system comprising: a volume- and/or speed-variable hydraulic machine which is driven by an electric motor, for providing a volumetric flow of a hydraulic fluid; a differential cylinder with a piston side and a ring side; and at least one pretensioning source. The actuator system has a closed hydraulic circuit, wherein, during operation, the hydraulic fluid in the hydraulic circuit is pressurized by means of the hydraulic machine and/or the pretensioning source. Furthermore, according to the invention, the differential cylinder provides a power motion operating mode and a rapid motion operating mode. In order to balance a volume of the hydraulic fluid in the closed hydraulic circuit, according to the invention an expansion reservoir is connected to the piston side of the differential cylinder via a valve.

Abstract: A renewable energy and waste heat harvesting system is disclosed. The system includes an accumulator unit having a high pressure accumulator and a low pressure accumulator. At least one piston is mounted for reciprocation in the high pressure accumulator. The accumulator unit is configured to receive, store, and transfer energy from the hydraulic fluid to the energy storage media. The system collects energy from a renewable energy source and transfers the collected energy using the pressurized hydraulic fluid. The system further includes one or more rotational directional control valves, in which at least one rotational directional control valve is positioned on each side of the accumulator unit. Each rotational directional control valve includes multiple ports. The system also includes one or more variable displacement hydraulic rotational units. At least one variable displacement hydraulic rotational unit is positioned adjacent each of the rotational directional control valves.

Abstract: A swing drive system for an excavator is provided which utilizes a prime mover mechanically connected to a first hydraulic pump/motor and a second hydraulic pump/motor mechanically connected to a swing mechanism. The system includes a hydraulic circuit connecting a hydraulic fluid reservoir, a hydraulic accumulator, the first hydraulic pump/motor, and the second hydraulic pump/motor. The system is operable in one mode where the second hydraulic pump/motor acts as a pump to retard movement of the swing mechanism and pressurized hydraulic fluid from the second hydraulic pump/motor is pumped into the hydraulic accumulator. The system is operable in another mode where the pressurized fluid from the hydraulic accumulator is used to assist the prime mover in driving hydraulic consumers, including the swing drive.

Abstract: The present disclosure relates to a motion control unit that is capable of receiving electrical power from an electrical power source and hydraulic power from a hydraulic power source. The motion control is configured to produce a blended power output derived from the electrical and hydraulic power which can be used to power a hydraulic actuator. The motion control unit can also split hydraulic power recovered from hydraulic actuator to the electrical power source and the hydraulic power source.

Abstract: An embodiment of the present invention provides a regeneration system of energy released from a working implement, which includes an actuator configured to move up and down the working implement, an accumulator configured to communicate with the actuator, and a controller configured to receive a pressure value of the actuator and a pressure value of the accumulator to control a discharge operation of the accumulator based on a pressure difference value between the actuator and the accumulator.

Abstract: The electrohydrostatic actuator system according to the invention comprises a volume-variable and/or rotational-speed-variable hydro machine, which is driven by an electric motor, for providing a volume flow of a hydraulic fluid, and a main shaft which is movable by the hydraulic fluid and which has at least one first chamber, wherein the first chamber, with at least one first main hydraulic line and a first main valve, is hydraulically connected to the hydro machine via a connection line. The actuator system according to the invention further comprises a secondary shaft which is movable by the hydraulic fluid and which has at least one first chamber, wherein the first chamber, with at least one first secondary hydraulic line and a first secondary valve, is hydraulically connected to the hydro machine via a connection line.

Abstract: The present disclosure relates to a hydraulic circuit, comprising: a hydraulic displacement unit for driving an implement; a hydraulic machine fluidly connected or selectively fluidly connected with the hydraulic displacement unit the hydraulic machine having a fixed hydraulic displacement; an electric machine drivingly engaged or selectively drivingly engaged with the hydraulic machine; a hydraulic pump fluidly connected or selectively fluidly connected with the hydraulic displacement unit, the hydraulic pump having a variable hydraulic displacement; and an electric motor drivingly engaged or selectively drivingly engaged with the hydraulic pump.

Abstract: An electric generator motor system for powering a vehicle and generating power includes a plurality of batteries and an electric converter in operational communication with the plurality of batteries. An electric drive motor is in operational communication with the electric converter. The electric drive motor propels a vehicle. A compressor is in operational communication with the electric converter. A plurality of air tanks is in operational communication with the compressor. An air motor is in operational communication with the plurality of air tanks. An alternator is in operational communication with the air motor and is in operational communication with the plurality of batteries to charge each battery.

Abstract: Provided is a hydraulic circuit of construction equipment, including a boom cylinder for controlling ascending and descending movement of a boom, which includes a valve unit having a first control valve configured to control a large chamber of the boom cylinder to selectively communicate with a small chamber of the boom cylinder, a second control valve configured to control the large chamber to selectively communicate with an oil tank, a third control valve configured to control the large chamber to selectively communicate with an accumulator, and a fourth control valve configured to control a part of hydraulic oil flowing to the accumulator to selectively flow to an assist motor.

Abstract: A hydraulic drive system of a construction machine includes: a boom control valve connected to a boom cylinder by a boom raising supply line and a boom lowering supply line; a pump that sucks hydraulic oil through a suction line, and delivers the hydraulic oil through a delivery line; a regenerative valve that brings the boom raising supply line and the suction line into communication with each other through a regenerative line when a boom lowering operation is performed; and a controller that controls an accumulator switching valve. The controller: switches the accumulator switching valve to a pressure accumulation position when a pressure accumulation condition is satisfied; switches the accumulator switching valve to a pressure release position when a pressure release condition is satisfied; and switches the accumulator switching valve to a neutral position when neither the pressure accumulation condition nor the pressure release condition is satisfied.

Abstract: An excavator with a boom comprises a main electrical drive system with an electrical power storage unit. The excavator comprises an electrical drive configured to actuate movement of the boom to raise and/or lower part of the boom. The excavator comprises a separate fluid-operated, auxiliary actuation system for storing potential energy of the part of the boom during lowering thereof and for using the stored potential energy to support raising of the part of the boom. The auxiliary actuation system is configured to store the potential energy and to support raising the part of the boom autonomously without interaction with the main electrical drive system.

Abstract: A hydraulic system for recovering potential energy of a load implement of a mobile construction vehicle. The hydraulic system includes first and second actuators and control valving. The first and second actuators are configured to be coupled to the load implement for controlling raising and lowering of the load element. The control valving is operable between a first position at which, during a lowering of the load implement, the control valving directs hydraulic fluid from one of the first and second actuators to an accumulator to charge the accumulator, and a second position at which the control valving directs hydraulic fluid from the accumulator to one or more of the first and second actuators to power the one or more of the first and second actuators to raise the load element.

Abstract: A single-rod hydrostatic actuator or pump-controlled actuator, comprises a hydrostatic pump connected in a closed circuit to a single-rod hydraulic cylinder where the cylinder velocity is directly controlled by the pump flow, without the need of intermediary valves. Due to the absence of throttling losses, the efficiency of hydrostatic actuators is considerably superior to the efficiency of conventional valve-controlled circuits. However, because of the differential areas at the cap and rod sides of the cylinder, the flows coming into and out of the cylinder do not match. Several attempts have been made to this date to produce a stable, robust and reliable circuit that can be used in everyday applications but no circuit has ever been conceived to reach the high standards of reliability and robustness required by industry. The current invention solves the problem of the differential flows with a design that is reliable, oscillation-free and robust.

Abstract: A servohydraulic drive includes a hydrostatic displacement machine, an electric machine that is mechanically speed-coupled with the displacement machine, a hydraulic cylinder that is fluidically connected to the displacement machine via first and second working lines, a hydraulic accumulator, and a supply unit. The displacement machine has a stroke that is adjustable via a hydraulic adjustment device. The cylinder is configured to be activated by reversal of the fluid flow through the displacement machine in opposite directions. The accumulator is preset to a low pressure and is fluidically connected via a valve assembly in each case to the lower pressure working line. The supply unit is configured to supply the adjustment device with pressurized fluid under the necessary pressure for the adjustment regardless of the present pressure in the working lines such that the displacement machine is configured for an active and load pressure-independent adjustment of its stroke volume.

Abstract: A valve includes a valve housing (33), which has at least one service connection (A, B), a pressure supply connection (P) and a return connection (T). In the valve housing (33), a control slide (STS) is guided so as to be movable longitudinally to control these individual connections. The supply pressure, which is applied to the pressure connection (P) to control a consumer (10, 12), connected to the service connection (A; B), is guided across at least one control side (56) of the control slide (STS) via an orifice plate (54) and a control channel (50). The control side (56) is positioned in a control chamber (58) in the valve housing (33) such that it can move. The control chamber (58) is connected to the return connection (T) via an additional orifice plate (59).

Abstract: A operator supporting electrohydraulic drive and control system based on, position sensors (8) (9), a electronic control unite ECU (2), a recovery, storing and re-use system for energy, and with actuator (3) (4) and the drive control valve (6) (7) bolted together in one (3+6) (4+7) unite and with the valve (6) (7) independently of the ECU (2) is controlling effective use of pump capacity and recovery of energy and with control of speed for low speeds, or prevented speed by valves (6) (7) or pump (10) (10a) (11) (11a) displacement and for higher speed with control of deplacement of pumps and motors and with valves (6) (7) at the same time controlled to be fully open.

Abstract: A hydraulic system for recovering potential energy of a load implement of a mobile construction vehicle. The hydraulic system includes first and second actuators and control valving. The first and second actuators are configured to be coupled to the load implement for controlling raising and lowering of the load element. The control valving is operable between a first position at which, during a lowering of the load implement, the control valving directs hydraulic fluid from one of the first and second actuators to an accumulator to charge the accumulator, and a second position at which the control valving directs hydraulic fluid from the accumulator to one or more of the first and second actuators to power the one or more of the first and second actuators to raise the load element.

Abstract: An apparatus for recuperating hydraulic energy in a working machine includes at least one first differential cylinder piston device with a differential cylinder and separate rod and bottom sides, and at least one hydraulic accumulator which is hydraulically connectable with the differential cylinder piston device. The potential energy of the differential cylinder piston device retracting under pressing load is at least partly storable in the hydraulic accumulator. The rod and bottom sides are connectable with each other via at least one brake valve for recirculating hydraulic fluid from the bottom side into the rod side.

Abstract: The invention concerns a device for the direct recovery of hydraulic energy in a machine, comprising at least one single-acting storage cylinder-piston device with a storage cylinder, a storage cylinder-piston and a storage cylinder chamber, with at least one differential cylinder-piston device with a differential cylinder comprising a separate rod side and base side, and with at least one hydraulic accumulator, which may be connected to the storage cylinder-piston device and/or the differential cylinder-piston device, wherein the potential energy of the storage cylinder-piston device, which retracts under a compressive load, may be at least partially stored in the hydraulic accumulator.

Abstract: A hydraulic system for recovering potential energy of a load implement of a mobile construction vehicle. The hydraulic system includes first and second actuators and control valving. The first and second actuators are configured to be coupled to the load implement for controlling raising and lowering of the load element. The control valving is operable between a first position at which, during a lowering of the load implement, the control valving directs hydraulic fluid from one of the first and second actuators to an accumulator to charge the accumulator, and a second position at which the control valving directs hydraulic fluid from the accumulator to one or more of the first and second actuators to power the one or more of the first and second actuators to raise the load element.

Abstract: Provided is a work machine capable of regenerating a return hydraulic fluid from a hydraulic actuator while preventing a drag loss of a regeneration hydraulic motor and a hydraulic pump from increasing and preventing the regeneration efficiency of the regeneration hydraulic motor from decreasing. A controller 100 computes a required regeneration hydraulic motor revolution speed from a displacement of a regeneration hydraulic motor 13 and a regeneration flow rate of the regeneration hydraulic motor, computes a required first hydraulic pump revolution speed from a displacement of a first hydraulic pump 15 and a target assist flow rate of the first hydraulic pump, and selects a greater one of the required regeneration hydraulic motor revolution speed and the required first hydraulic pump revolution speed as a target revolution speed of an electric motor 14.

Abstract: A hydraulic system for construction machinery includes a boom cylinder, a main control valve including a boom control spool that is configured to selectively supply a hydraulic oil from a hydraulic pump to a boom head chamber and a boom rod chamber of the boom cylinder, a regeneration device connected to the boom head chamber of the boom cylinder through a hydraulic regeneration line, a regeneration valve unit installed in the regeneration line, and a control unit connected to the main control valve and the regeneration valve unit, wherein in a boom down low speed mode the hydraulic oil is drained through the regeneration device to lower the boom at a first speed, and in a boom down high speed mode the hydraulic oil is drained through the regeneration device and the main control valve to lower the boom at a second speed greater than the first speed.

Abstract: Provided is a construction machine allowing regeneration of a return hydraulic fluid at the time of both a boom raising operation and a boom lowering operation with a small number of valves, making it possible to secure a satisfactory operability at the time of both the boom raising operation and the boom lowering operation.

Abstract: A urea water tank (27) is formed as a box body that includes a rear inclined surface (28A) that inclines so as to be parallel with a left inclined surface (7C) of a counterweight (7), a front inclined surface (28B) that inclines with a space being left apart from the rear inclined surface (28A) and in substantially parallel with the rear inclined surface (28A) and a front surface (28C) that is formed on front ends of the rear inclined surface (28A) and the front inclined surface (28B) and is formed into a flat surface that is parallel with a left-right direction of an upper revolving body (4). The rear inclined surface (28A) of the urea water tank (27) is disposed along and facing the left inclined surface (7C) of the counterweight (7) and the front inclined surface (28B) is disposed with a gap being left apart from and facing the heat exchanger (9).

Abstract: A hydraulic boom control system for a forestry machine includes a pump for pressurizing a hydraulic fluid on a high pressure side, a reservoir for storing hydraulic fluid on a low pressure side, and a first hydraulic cylinder including a cap end and a rod end. The first hydraulic cylinder is configured to actuate the hoist of the boom. A second hydraulic cylinder includes a cap end and a rod end and is configured to actuate the stick of the boom. A first control valve is operable to control the first hydraulic cylinder. A second control valve is operable to control the second hydraulic cylinder. A variable return metering valve is fluidly connected to at least one of the first or second control valves. The variable return metering valve is operable to modulate shared hydraulic fluid flow between the first hydraulic cylinder and the second hydraulic cylinder.

Abstract: Provided is a hydraulic drive system for a work machine configured with a single solenoid proportional valve for a regeneration circuit, wherein substantially the same actuator speed can be secured irrespective of whether or not hydraulic fluid discharged from a hydraulic actuator is regenerated for driving of another hydraulic actuator.

Abstract: Provided are a hydraulic circuit and a work machine capable of improving an initial motion speed of a hydraulic cylinder during a contraction of the hydraulic cylinder and securing a necessary pump flow rate while hydraulic fluid is being accumulated in an accumulator. Hydraulic oil from a head side of a second boom cylinder is regenerated in a first boom cylinder and the second boom cylinder through a second control valve of a regeneration circuit. At the same time, oil from the head side of the first boom cylinder is accumulated to a first accumulator by a pressure accumulating circuit through a first control valve. The hydraulic oil supplied under pressure from a main pump is fed to a rod side of the first boom cylinder by a boom control valve. A bleed-off valve of a bleed-off circuit communicates the first control valve to a tank at the time of initial operation of the first control valve, thereby releasing hydraulic oil from the head end of the first boom cylinder to improve an initial motion speed.

Abstract: A control device for suppressing engine load fluctuation according to main pump circuit conditions, wherein an assist torque calculation task includes a target engine torque calculation task separating smooth torque components from main pump load torque and setting a minimum value of either smooth torque component or engine setting torque as target engine torque, and a subtractor calculating target assist torque based on a difference between the main pump load torque and the target engine torque, the assist torque calculation task controlling a capacity of an assist pump based on the target assist torque and controlling switching between an assist mode and a charge mode.

Abstract: A hydraulic system for a mobile work vehicle is configurable in a hybrid mode and a hydrostatic mode. The hydraulic system includes a pump/motor, a propel circuit, a pump, a hydraulic accumulator, and an accessory circuit. The pump/motor is adapted to exchange power with a drive train of the mobile work vehicle. The propel circuit is adapted to exchange hydraulic fluid power with the pump/motor. The pump is adapted to transfer power from a prime mover of the mobile work vehicle to the propel circuit. The hydraulic accumulator is adapted to exchange hydraulic fluid power via an accumulator isolation valve with the propel circuit when the hydraulic system is configured in the hybrid mode. The accessory circuit is adapted to receive hydraulic fluid power from the hydraulic accumulator, at least when the hydraulic system is configured in the hydrostatic mode and the accumulator isolation valve is closed.

Abstract: A hydraulic drive device includes a pump, a hydraulic machine, and a tank. The hydraulic machine is connected fluidically to first and second fluid lines, which are configured to be connected fluidically to the tank or the pump via an adjustable main valve. The device further includes a first valve with a continuously adjustable first orifice. Pressure fluid is configured to be conducted out of the second fluid line via the first orifice and into the tank. The first valve is acted upon in the closing direction of the first orifice by a first spring and acted upon in the opposite direction by the pressure at a control point. The control point is connected fluidically to the tank via a first throttle device, connected via a second throttle device to the first fluid line, and connected to the first fluid line via a third throttle device and a second valve.

Abstract: A hydraulic system for recovering potential energy of a load implement of a mobile construction vehicle. The hydraulic system includes first and second actuators and control valving. The first and second actuators are configured to be coupled to the load implement for controlling raising and lowering of the load element. The control valving is operable between a first position at which, during a lowering of the load implement, the control valving directs hydraulic fluid from one of the first and second actuators to an accumulator to charge the accumulator, and a second position at which the control valving directs hydraulic fluid from the accumulator to one or more of the first and second actuators to power the one or more of the first and second actuators to raise the load element.

Abstract: The invention is directed to controlling a hydraulic actuation system having at least one degree of freedom, a prime mover, at least one actuation module and a controller, with each actuation module including: an over-center variable displacement pump having a power input connection configured to power the pump from the prime mover and a displacement varying input for varying the displacement of the pump; a displacement varying actuator configured to modulate the displacement varying input of the pump; an output actuator in direct communication with the pump, the output actuator configured to drive a corresponding degree of freedom; and at least one sensor establishing a feedback measurement that represents a force or motion of the output actuator. Based on a value of each feedback measurement, the force or motion of the output actuator is regulated by controlling the prime mover and the displacement actuator for the output actuator.

Abstract: A shovel includes a first pump 14L; a second pump 14R; a hydraulic swing motor 21; a pump/motor 14A configured to generate an engine-assist torque in response to hydraulic oil from the hydraulic swing motor 21 during swing deceleration; an accumulator 80 configured to accumulate the hydraulic oil flowing out of the hydraulic swing motor 21 during swing deceleration; a regeneration valve 22G configured to switch open/close of transfer from a discharge port 21L to the pump/motor 14A and the accumulator 80; and a controller configured to control the regeneration valve 22G. During swing deceleration, the controller adjusts an open area of the regeneration valve 22G in such a way that a swing flowing-out pressure becomes a swing braking target pressure, and causes the hydraulic oil flowing out of the hydraulic swing motor 21 to flow into the pump/motor 14A and the accumulator 80 at the same pressure.

Abstract: Provided is a system and method to generate and control hydraulic fluid flow that exceeds the fluid flow capacity of an electrically driven pump to achieve high actuator retraction/extension speeds and/or electrical flow capacity of an electrical storage system to better control electrical storage. Electric machines and hydraulic pumps generally have a maximum speed beyond which they cannot be operated at. Further, electrical storage systems typically have storage capacities and rates beyond which they cannot be operated at. While an alternate approach could be to increase the hydraulic pump displacement, thus lowering the required electric machine and pump speed to generate a certain flow, it is typically desirable to reduce pump displacement in order to reduce required electric machine torque and minimize component size and losses.

Abstract: Provided is a hydraulic fluid energy regeneration device for a work machine, including: a regeneration hydraulic motor driven by discharged return hydraulic fluid; a first hydraulic pump mechanically connected to the regeneration hydraulic motor; a second hydraulic pump that delivers an hydraulic fluid for driving a first hydraulic actuator and/or a second hydraulic actuator; a junction line that allows the hydraulic fluid delivered by the second hydraulic pump to be joined; a second regulator that regulates the delivery flow rate of the second hydraulic pump; and a first regulator that regulates the flow rate of the hydraulic fluid coming from the first hydraulic pump and flowing through the junction line.

Abstract: Provided is a hydraulic drive apparatus for a construction machine capable of achieving both of cavitation prevention and improvement of regeneration efficiency. The apparatus includes a regenerative motor configured to regenerate energy of hydraulic fluid discharged from a slewing motor, a first regeneration tank line for returning regeneration discharge fluid from the regenerative motor to a tank through a back pressure valve which is provided in a makeup line, a second regeneration tank line for returning the regeneration discharge fluid directly to the tank so as to bypass the back pressure valve, a regeneration-tank-line selector valve, and a regeneration-tank-line-selection control section configured to shift the regeneration-tank-line selector valve to pass the regeneration discharge fluid through the first regeneration tank line during slewing deceleration and otherwise through the second regeneration tank line.

Abstract: A hydraulic fluid energy regeneration system for a work machine capable of securely maintaining a brake pressure even when a solenoid valve or the like is erroneously rendered open by an electrical failure is provided.

Abstract: A header comprising an inlet line, a check valve, an accumulator and a hydromechanical transmission system is disclosed. The inlet line is used to receive a first pressure of hydraulic fluid and be in communication with the check valve. The accumulator is located downstream the check valve and in communication with the inlet valve. The hydromechanical transmission system includes a pressure line in communication with the inlet line that is downstream the accumulator and a closed hydraulic circuit in communication with the pressure line having a hydrostatic pump and a variable speed motor.

Abstract: The construction machine includes: a control valve that switchingly supplies hydraulic fluid from a hydraulic pump to a hydraulic actuator; a control valve drive device that supplies pilot secondary hydraulic fluid to the control valve in accordance with an operation of an operation lever device; a pilot hydraulic pump that supplies pilot primary hydraulic fluid to the control valve drive device; a pressure accumulation device that recovers return hydraulic fluid returned from the hydraulic actuator. The construction machine further includes: a check valve provided in a line between the pilot hydraulic pump and the control valve drive device; a pressure reducing valve that supplied the hydraulic fluid accumulated in the pressure accumulation device; a flow rate reduction device; and a controller that controls the flow rate reduction device in accordance with the pressure in the line between the check valve and the control valve drive device.

Abstract: A variable-speed volume-control direct-drive all-electric hydraulic excavator drive and energy recover system the control drive circuit of which includes the A, B, C energy source, boom cylinder control valve group, arm cylinder control valve group, bucket control valve, swing control valve, swing motor control valve group, left travel control valve, right travel control valve, eight 2-position 2-way valve, I and II 2-position 3-way valve, I and II accumulator. The drive control circuit adopts open control independent-cavity variable-speed pump-control volume direct-drive circuit. Each of the cavities of cylinder is controlled by an energy source and the pressure and flow rate of the cavities are adjusted by the rotational speed and torque control of the generator independently. The present invention is four-quadrant running and have advantages of high efficiency, high integrity, low consumption, redundancy energy source, no need for pilot supply, low noise, integrate recovery of kinetic and potential energy.

Abstract: A series hydraulic hybrid system for a vehicle is described. The system has a hydraulic circuit, a hydraulic working assembly, and a hydraulic accumulator assembly. The hydraulic circuit has a first hydraulic displacement unit in fluid communication with a second hydraulic displacement unit. The first hydraulic displacement unit is drivingly engaged with a power source. The hydraulic working assembly has a hydraulic implement and a hydraulic working pump in fluid communication with the hydraulic implement, the hydraulic working pump drivingly engaged with the power source. The hydraulic accumulator assembly has a high pressure hydraulic accumulator and a low pressure hydraulic accumulator. The hydraulic accumulator assembly selectively fluidly connects to the hydraulic circuit and the hydraulic accumulator assembly selectively fluidly connects to the hydraulic working assembly.

Abstract: A pump that supplies hydraulic oil to a boom cylinder and a turning hydraulic motor; a regenerative hydraulic motor is coupled to the pump and to which the hydraulic oil discharged from the boom cylinder at a time of boom lowering and/or the hydraulic oil discharged from the turning hydraulic motor at a time of turning deceleration is/are led; an engine drives the pump; an alternator mounted to the engine and operable to rotate an output shaft of the engine when electric power is supplied to the alternator; an electrical storage device connected to the alternator; a power converter interposed between the alternator and the electrical storage device; and a controller that switches the power converter to either a servo-on state or a servo-off state and that controls the power converter either in a charging mode or in a discharging mode when switching the power converter to the servo-on state.

Abstract: A hybrid work machine includes: an engine controller (14) that controls rotational speed of an engine (7) in accordance with a target rotational speed input from an EC dial (31); an assist motor (10) that generates electricity using power of the engine (7); a hydraulic pump (6) operated using power of the engine and/or of the assist motor; and a vehicle body controller (11) that estimates power (Pe) the engine is required to output when a request to generate electricity is sent to the assist motor and permits the assist motor to generate electricity only when the engine power requirement is not greater than an electricity generation threshold value (Eth1). The electricity generation threshold value (Eth1) is determined based on the power and characteristics of energy loss of the engine (7).

Abstract: A turning control apparatus includes a turning body and a hydraulic motor to turn the turning body. A high-pressure relief circuit relieves hydraulic pressure of a first hydraulic line at a first relief pressure, the first hydraulic line supplying an operating oil to drive the hydraulic motor. A hunting reduction circuit relieves a hydraulic pressure of a second hydraulic line at a pressure lower than the first relief pressure, the second hydraulic line being connected to a deceleration-side hydraulic port from which the operating oil is discharged when the hydraulic motor is being driven. The hunting reduction circuit connected to the deceleration-side hydraulic port is caused to open before an operation lever to operate turning of the turning body returns to a neutral position.

Abstract: Provided is a working machine capable of regenerating and utilizing surplus energy. The working machine related to the present invention is provided with a branching flow path (150) through which hydraulic oil flows between a hydraulic actuator (24) and a hydraulic pump-motor (14), an accumulator (30) arranged in the branching flow path, a first opening/closing valve (31) arranged between the accumulator and the hydraulic pump-motor, and a second opening/closing valve (32) arranged between the accumulator and the hydraulic actuator. A control device (41) selectively introduces the hydraulic oil from the hydraulic actuator and the hydraulic oil from the hydraulic pump-motor to the accumulator and accumulates the same by controlling opening/closing of the first opening/closing valve and the second opening/closing valve.

Abstract: A hydraulic circuit architecture for a work vehicle includes a pump, a work circuit, a propel circuit, and a circuit selector. The work circuit is connected to an actuator for driving a work component of the work vehicle. The propel circuit includes a motor that is adapted to be connected to a drive train of the work vehicle. The propel circuit also includes an accumulator. The circuit selector selectively connects the pump to the work circuit and the propel circuit. The hydraulic circuit architecture is operable in a first mode and a second mode. In the first mode, the propel circuit is connected to the pump and the work circuit is disconnected from the pump. In the second mode, the work circuit is connected to the pump and the propel circuit is disconnected from the pump. When the hydraulic circuit architecture is in the second mode, stored energy from the accumulator can be used to drive the motor to cause propulsion of the work vehicle.

Abstract: Engine anti-idling and restart may be implemented in a machine having a power source, a movable work tool, a pump driven by the power source, an actuator receiving fluid from the pump and moving the work tool, a high-pressure fluid reservoir, and an assist motor operatively connected to the power source. Engine restart may include detecting operator input to start the power source, and fluidly connecting the fluid reservoir to the assist motor to assist in starting the power source in response to detecting the operator input. Prior to shutting down the power source during anti-idling, fluid from the pump may be input to the assist motor, pressurized and communicated to the high-pressure fluid reservoir in response to determining that idle condition exists and a reservoir charge pressure is less than a reservoir minimum restart pressure needed to restart the power source.

Abstract: A hydraulic control system for a machine is provided. The hydraulic control system includes a fluid reservoir, a pump motor and an accumulator. The pump motor is configured to provide pressurized fluid and to receive fluid to provide a power output. The hydraulic control system further includes a hydraulic actuator having a first and a second chamber, a first valve, a regenerative valve, and a controller. The controller is in communication with the first valve and the regenerative valve to selectively actuate the regenerative valve to allow flow of a first portion of the fluid from the first chamber to the second chamber. The controller is further configured to selectively actuate the first valve to allow flow of a second portion of the fluid from the first chamber through the pump motor to provide the power output to a shaft of a power source.

Abstract: Energy regeneration system does not affect operation of a hydraulic actuator except when a relief valve is operating, by connecting an actuator hydraulic line to a regeneration hydraulic motor with a small pressure loss during regeneration, and ensures holding pressure when the energy cannot be regenerated. A first valve device disposed between actuator hydraulic lines and a regeneration hydraulic motor, has a throttle passage capable of increasing pressure in the higher pressure side actuator hydraulic line to a set pressure of the relief valves. A second valve device disposed in parallel with the first valve device between the actuator hydraulic lines and the regeneration hydraulic motor, is switched from a close to an open position by pressure between the first valve device and the regeneration hydraulic motor when pressure between the first valve device and the regeneration hydraulic motor increases to approach the set pressure of the swing relief valve.