Abstract: A work machine including a specific actuator that supplies hydraulic fluid from a plurality of hydraulic pumps includes: first and second hydraulic pumps communicating with a first hydraulic actuator; a first control valve returning hydraulic fluid delivered by the first hydraulic pump to a tank; and a load detection section that detects a load on the first hydraulic actuator. A control valve drive section drives the first control valve such that a communication area between the first hydraulic pump and the tank is enlarged corresponding to an increase in the load on the first hydraulic actuator; and a flow rate control section, during supply of the hydraulic fluid from the first and second hydraulic pumps to the first hydraulic actuator, controls to reduce a delivery flow rate of the first hydraulic pump corresponding to an increase in the load on the first hydraulic actuator.

Abstract: The hybrid construction machine includes an engine 11, an electric motor/generator 14, a hydraulic pump unit 17, an electricity storage device 16, an inverter 15, a temperature regulator (16D or 16E), and a hybrid control unit 22. The hybrid control unit 22 executes at least one of first control for controlling a warming-up battery temperature regulator 16D so that it increases a temperature of the electricity storage device 16, second control for controlling the inverter 15 so that it reduces the power output from the inverter 15, and third control for controlling a pump capacity control unit 21 so that it reduces the flow rate of a hydraulic fluid delivered from the hydraulic pump unit 17, according to a charge/discharge history of the electricity storage device 16.

Abstract: To provide a hydraulic drive system for a work machine capable of securing a favorable operability in the case where hydraulic fluid discharged from a hydraulic actuator is regenerated for driving other hydraulic actuator.

Abstract: Provided is a hybrid-type construction machine including a swing device of the hydraulic-electric combined swing type and by which, in a work for which accurate swing operability is demanded like, for example, a crane work, a swing body is driven alone by the electric motor. The hybrid-type construction machine includes an engine, a hydraulic pump driven by the engine, a swing body, an electric motor for driving the swing body, and a hydraulic motor driven by the hydraulic pump for driving the swing body. The swing body is swung by simultaneous drive by the electric motor and the hydraulic motor. The hybrid-type construction machine includes a control apparatus having a work mode changeover unit by which an operator changes over a mode in response to an aspect of a work and an electric alone swing controlling unit configured to control the swing body to be swung by the electric motor alone.

Abstract: A hydraulic control system for a construction machine has a hydraulic actuator that drives an arm, a meter-out channel through which hydraulic fluid discharged from the hydraulic actuator flows, a variable restrictor provided in the meter-out channel, an operating device, and a controller that controls an opening area of the variable restrictor. A posture calculation unit calculates an angle made by the arm with respect to a horizontal direction, a meter-out opening area calculation unit calculates the opening area of the variable restrictor based on the angle made by the arm with respect to the horizontal direction and a time rate of change of the angle, and a meter-out control unit outputs a command signal to a solenoid valve used for adjusting the opening area of the variable restrictor, based on the opening area of the variable restrictor calculated by the meter-out opening area calculation unit.

Abstract: The Construction machinery includes at least two actuators, a main pump that generates hydraulic energy for driving the actuators, control valves disposed between the main pump and the actuators, a hydraulic pump motor driven by the generator motor that generates energy to be added to the hydraulic energy, and a controller that reduces hydraulic energy generated by the main pump when the hydraulic pump motor driven by the generator-motor generates energy. The construction machinery further comprises changeover valves that selectively change a location at which the energy from the hydraulic pump motor driven by the generator-motor is to be added according to the actuators. The controller changes a reduction rate of the hydraulic energy generated by the main pump depending on a specific actuator to which the energy is to be added.

Abstract: Provided is a hybrid work machine capable of performing a warm-up operation on an electric storage device by charging and discharging while suppressing the occurrence of lug-down or over-revolution to an engine. The hybrid work machine includes: an engine; an assist motor mechanically connected to the engine, causing a discharge by generating a drive torque, and generating electric power by generating a brake torque; a hydraulic pump driven by a total torque of the engine and the assist motor; an electric storage device storing the electric power generated by the assist motor and supplying the electric power when the assist motor is discharged; and a controller outputting a torque command signal in order to control the drive torque or the brake torque of the assist motor.

Abstract: Provided is construction machinery that is capable of greatly reducing the amount of fuel consumption by making effective use of recovered energy. The construction machinery has a first hydraulic pump 3 for discharging hydraulic oil for driving an actuator 6, a second hydraulic pump 9, a second prime mover 7 for driving the second hydraulic pump 9, energy storage device 8 for storing energy for driving the second prime mover 7, and a hydraulic oil supply circuit 10 including a hydraulic oil switching section 11c that accepts the hydraulic oil discharged from the first hydraulic pump and the hydraulic oil discharged from the second hydraulic pump and supplies either the mixture of the accepted hydraulic oils or a selected one of the accepted hydraulic oils to the actuator 6.

Abstract: Provided is a hydraulic fluid energy recovery system for a work machine equipped with a hydraulic pump, a hydraulic actuator for driving the work machine, an operating device for operating the hydraulic actuator, and a regenerating device for recovering a return fluid flowing back from the hydraulic actuator.

Abstract: A construction machine includes: a swing structure (20); hydraulic and electric motors (25) mechanically coupled to each other; a hydraulic pump (41) that supplies hydraulic fluid to the hydraulic motor; swing control lever (72) that instructs the swing structure to make a swing motion; and a control device (80) that controls at least either a delivery flow rate of the hydraulic pump or an output torque of the electric motor in such a manner that meter-out and meter-in pressures of the hydraulic motor that is run together with the electric motor approach each other when the demanded torque necessary for the swing motion of the swing structure instructed by the swing control lever can be produced by the electric motor alone.

Abstract: A controller sets a target flow rate of a regenerative hydraulic motor at zero or a low flow rate within an extent in which hydraulic pressure in a regeneration hydraulic line does not become negative pressure when a detected pressure PS detected by a pressure sensor is lower than a first set value previously set by overload relief valves, sets the target flow rate of the regenerative hydraulic motor at a value corresponding to the detected pressure when the detected pressure is higher than or equal to the first set value, and controls the revolution speed of a generator/motor in such a manner that a flow rate through the regenerative hydraulic motor equals the target flow rate. With such features, excellent operability equivalent to that in the conventional technology can be secured.

Abstract: A work machine prevents a fault in a swing electric motor if an uneven coil temperature increase occurs in the swing electric motor during swing press and related operations. An electricity storage device is connected to the electric motor. An inverter drives the electric motor and a swing control lever issues a command to drive the swing structure. A rotational speed detecting device detects swing speed of the swing structure and a controller controls torque of the electric motor. The controller reads the swing speed of the swing structure detected by the rotational speed detecting device to control such that, when the swing speed is zero, the torque of the electric motor is smaller than a maximum torque value and, when the swing speed is a first rotational speed higher than zero, the torque of the electric motor is the maximum torque value.

Abstract: A control device of construction machine that performs tasks by driving a hydraulic pump by means of an electric motor that is driven by electric power of a battery device that is capable to charge and discharge and an engine that is mechanically coupled to the electric motor, includes: a charging/discharging control unit that controls the charging/discharging of the battery device in such a manner that, in case that a heavy load task where an output of the hydraulic pump is large and a light load task where the output of the hydraulic pump is small are alternately performed, when the output of the hydraulic pump during the heavy load task is increased or a time proportion of the heavy load task in the unit period is increased, an average value of charging current of the battery device per the unit period increases, and when the output of the hydraulic pump during the heavy load task is further increased or the time proportion of the heavy load task in the unit period is further increased, then the average va

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: An object of the present invention is to provide a hydraulic control system for a work machine that is capable of reducing the loss caused by flow division while reducing a decrease in the speed of a hydraulic actuator due to a combined operation. The hydraulic control system for a work machine includes a first hydraulic actuator, one hydraulic pump, a second hydraulic actuator, and another hydraulic pump. The hydraulic control system further includes operating instruction detection means and pump flow control means. The operating instruction detection means detects that operating instructions are issued to the first hydraulic actuator and the second hydraulic actuator. The pump flow control means individually adjusts the delivery flow rate of the one hydraulic pump and the another hydraulic pump in accordance with operation amounts designated by the operating instructions for the first and second hydraulic actuators.

Abstract: When option attachment has not been attached, a reserve flow/direction control valve 8 is made to operate as a center bypass cut valve. When an option attachment has been attached, switching control is performed. In the switching control, when the option attachment is not used, the reserve flow/direction control valve 8 is made to operate as a center bypass cut valve for adjusting composite opening area of a center bypass and thereby controlling the flow rate of hydraulic fluid flowing into an actuator. When the option attachment is used, the reserve flow/direction control valve 8 is made to operate so as to supply the hydraulic fluid to an option hydraulic actuator 14.

Abstract: A construction machine is characterized by including: a track structure 10; a swing structure 20 provided on the track structure 10 in a swingable manner; swing motors 25, 27 that drive and swing the swing structure; a boom 31 connected to the swing structure 20; a boom cylinder 32 that moves the boom 31 vertically; a swing operation system 72 that instructs a swing operation of the swing structure 20; a boom operation system 78 that instructs a vertical movement of the boom 31; a detector 74d that detects a bottom pressure of the boom cylinder 32; and a controller 80 that reduces swing speed of the swing structure 20 according to a signal from the detector 74d with respect to a reference swing speed according to a signal of the swing operation, while signals of the swing operation and a boom raising operation are being inputted.

Abstract: A construction machine includes: a swing structure (20); hydraulic and electric motors (25) mechanically coupled to each other; a hydraulic pump (41) that supplies hydraulic fluid to the hydraulic motor; swing control lever (72) that instructs the swing structure to make a swing motion; and a control device (80) that controls at least either a delivery flow rate of the hydraulic pump or an output torque of the electric motor in such a manner that meter-out and meter-in pressures of the hydraulic motor that is run together with the electric motor approach each other when the demanded torque necessary for the swing motion of the swing structure instructed by the swing control lever can be produced by the electric motor alone.

Abstract: Provided is a hybrid-type construction machine including a swing device of the hydraulic-electric combined swing type and by which, in a work for which accurate swing operability is demanded like, for example, a crane work, a swing body is driven alone by the electric motor. The hybrid-type construction machine includes an engine, a hydraulic pump driven by the engine, a swing body, an electric motor for driving the swing body, and a hydraulic motor driven by the hydraulic pump for driving the swing body. The swing body is swung by simultaneous drive by the electric motor and the hydraulic motor. The hybrid-type construction machine includes a control apparatus having a work mode changeover unit by which an operator changes over a mode in response to an aspect of a work and an electric alone swing controlling unit configured to control the swing body to be swung by the electric motor alone.

Abstract: A hybrid work machine has an engine, an assist motor, a hydraulic pump which is driven by the total torque of the engine and the assist motor, and an electric storage device which accumulates electric power generated by the assist motor and supplies the electric power when the assist motor performs electric discharge. The continuous electric discharge from the electric storage device due to continuous operation at high load pressure can be suppressed without an operator experiencing an unusual operational characteristic. To this end, a pump flow rate correction control unit judges whether each hydraulic pump is in a high load operation state or not based on the output horsepower and/or the delivery pressure of each hydraulic pump and performs control such that the delivery flow rate gradually decreases when the hydraulic pump is in the high load operation state and this state continues beyond a predetermined time.