Abstract: An output command calculating section (40) of an HCU (36) restricts a battery discharge power from an electricity storage device (31) based upon a battery electricity storage rate (SOC) and a current square integrating rate (Risc) of the electricity storage device (31). Thereby, the HCU (36) transfers from a normal mode (NMODE) to a low speed mode (LSMODE) to lower a movement speed of a hydraulic actuator. A monitor display amount calculating section (50) of the HCU (36) calculates a maximum speed reduction rate (DRs) based upon a battery discharge power limit value (Plim0) and an engine output upper limit value (Pemax) from the output command calculating section (40). A monitor device (39) displays a reduction rate of the movement speed of the hydraulic actuator in the low speed mode (LSMODE) based on the maximum speed reduction rate (DRs).

Abstract: A work machine is adapted for reduced fuel consumption in regions where swinging by a hydraulic motor is prone to deterioration in efficiency, such as when the operating stroke of the swinging is small. The work machine includes an engine, a hydraulic pump, a swing structure, an electric motor for driving the swing structure, and a hydraulic motor for driving the swing structure, the hydraulic motor being driven by the hydraulic pump, and includes a swing control lever device that commands the swing structure to be driven. A control device operates in either an electric swing mode in which the swing structure is driven mainly by torque of the electric motor or a hydraulic swing mode in which the swing structure is driven mainly by torque of the hydraulic motor, depending on an operating stroke of the control lever device and/or a swing speed of the swing structure.

Abstract: A construction machine, comprising a hydraulic pump, a swing hydraulic motor, a swing electric motor, a delivery capacity regulating device, and a control unit which controls the driving/braking of the swing structure, is configured to comprise an operation amount detection device for detecting the operation amount of the swing control lever and a speed detection device for detecting the speed of the swing electric motor. The control unit includes a hydraulic pump output reduction control unit which takes in an operation amount signal representing the operation amount of the swing control lever detected by the operation amount detection device and a speed signal representing the speed of the swing electric motor detected by the speed detection device and controls the delivery capacity regulating device by calculating a reduction rate of the output of the hydraulic pump based on the detection signals.

Abstract: A work machine evaluates the fuel consumption for the whole engine running period including the time of operation and the time of non-operation of a work implement and informs an operator of the evaluation in real time to prompt fuel-consumption-savings. The work machine has an engine, a hydraulic pump driven by the engine, an actuator driven by a hydraulic fluid delivered by the hydraulic pump, and an operation device that operates the actuator. A display apparatus for the work machine includes a fuel consumption index calculating section that calculates a first fuel consumption index by dividing the operation time of the operation device by the fuel consumption amount of the engine or dividing the fuel consumption amount of the engine by the operation time of the operation device. The first fuel consumption index calculated by the fuel consumption index calculating section is displayed on a display section in real time.

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: 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: 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 work machine includes a swing hydraulic motor and a swing electric motor for driving an upper swing structure. A capacitor supplies electricity to the swing electric motor and an operating device outputs through one operation, an operating signal for concurrently operating the swing hydraulic motor and the swing electric motor. A main controller switches between a hydraulic-alone drive mode and an electric-alone drive mode, the hydraulic-alone drive mode being a mode to drive only the swing hydraulic motor selected from the swing hydraulic motor and the swing electric motor when the operating device is operated, the electric-alone drive mode being a mode to drive only the swing electric motor selected from the swing hydraulic motor and the swing electric motor when the operating is operated. Therefore, the actuator that malfunctions can easily be specified among the plurality of mounted actuators.

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 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.

Abstract: A hybrid construction machine is capable of performing satisfactory operations even when trouble occurs that disables the electric motor from outputting torque. The hybrid construction has both a hydraulic motor and an electric motor driving the swing structure and a controller for switching between a hydraulic/electric hybrid swing mode (using both the hydraulic motor and the electric motor) and a hydraulic-alone swing mode (using only the hydraulic motor). The switching is executed while achieving satisfactory operability and performance in each mode. Normally, an energy saving operation is performed in the hydraulic/electric hybrid swing mode. When the electric amount of an electricity storage device has gone out of a prescribed range or an abnormality has occurred in an electric system (e.g., failure of an inverter), the swing mode is switched to the hydraulic-alone swing mode so that driving with normal braking torque is possible by the hydraulic motor alone.

Abstract: To rapidly stop an upperstructure even though relief pressure is lowered due to an abnormality in a hydraulic device included in a swing motor driving circuit while intending to stop the upperstructure when a predetermined delay time has passed since a swing operation tool is brought back to a neutral position, provided are: a first choke for controlling a parking brake to apply a braking force to a swing motor when a predetermined delay time has passed since the tool is brought back to a neutral position in a state where the tool is connected to a pilot pump; and an on-off valve and a second choke for controlling the parking brake to apply a braking force to the motor when a delay time shorter than the predetermined delay time has passed since the tool is brought back to the neutral position and disconnected from the pilot pump.

Abstract: A fuel-efficient hydraulic fluid has a lower viscosity than a standard hydraulic fluid, a pressure loss decreases, and thus, when control based on a standard model is exercised, the speeds of various actuators increase. However, the speeds need not be increased beyond the speeds of the standard model. Instead, it is preferred that fuel efficiency be improved. As a result, an engine revolution speed decreases by 50 rpm and a pump torque decreases by 5%. This reduces an engine output. Therefore, when a hydraulic fluid is changed from the standard hydraulic fluid to the fuel-efficient hydraulic fluid, the fuel efficiency can be improved while maintaining operability equivalent to that of the standard model. Hence, the fuel efficiency can be improved while maintaining the operability when an item affecting the fuel consumption is replaced. In addition, the settings can be changed with ease by a service technician.

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 construction machine, comprising a hydraulic pump, a swing hydraulic motor, a swing electric motor, a delivery capacity regulating device, and a control unit which controls the driving/braking of the swing structure, is configured to comprise an operation amount detection device for detecting the operation amount of the swing control lever and a speed detection device for detecting the speed of the swing electric motor. The control unit includes a hydraulic pump output reduction control unit which takes in an operation amount signal representing the operation amount of the swing control lever detected by the operation amount detection device and a speed signal representing the speed of the swing electric motor detected by the speed detection device and controls the delivery capacity regulating device by calculating a reduction rate of the output of the hydraulic pump based on the detection signals.

Abstract: A work machine is adapted for reduced fuel consumption in regions where swinging by a hydraulic motor is prone to deterioration in efficiency, such as when the operating stroke of the swinging is small. The work machine includes an engine, a hydraulic pump, a swing structure, an electric motor for driving the swing structure, and a hydraulic motor for driving the swing structure, the hydraulic motor being driven by the hydraulic pump, and includes a swing control lever device that commands the swing structure to be driven. A control device operates in either an electric swing mode in which the swing structure is driven mainly by torque of the electric motor or a hydraulic swing mode in which the swing structure is driven mainly by torque of the hydraulic motor, depending on an operating stroke of the control lever device and/or a swing speed of the swing structure.

Abstract: The hydraulic fluid energy recovery apparatus includes a fluid communication line for holding a bottom-side hydraulic fluid chamber and a rod-side hydraulic fluid chamber of a hydraulic cylinder in fluid communication with each other, a fluid communication valve connected to the fluid communication line for adjusting the pressure and/or flow rate of a hydraulic fluid passing through the fluid communication line in a manner that allows for adjustment of a degree of opening of the fluid communication valve, first pressure detecting means for detecting a signal indicative of pressure at the bottom-side hydraulic fluid chamber of the hydraulic cylinder, an amount-of-operation detecting means for detecting an amount of operation of the operating means, and a control device for capturing the signal of pressure at the bottom-side hydraulic fluid chamber of the hydraulic cylinder detected by the first pressure detecting means.

Abstract: This invention provides a hybrid construction machine including a swing structure, a hydraulic pump, a hydraulic swing motor driving the swing structure using hydraulic fluid from the hydraulic pump, an electric swing motor driving the swing structure in conjunction with the hydraulic swing motor, a boom cylinder operated simultaneously with the swing structure at times and driven by the hydraulic fluid from the hydraulic pump, a first directional control valve controlling flow of the hydraulic fluid supplied from the hydraulic pump to the hydraulic swing motor, a second directional control valve controlling the flow of the hydraulic fluid returning from the hydraulic swing motor, and a controller and solenoid pressure reducing valves which prevent operation of the second directional control valve when the boom cylinder is operated simultaneously with the swing structure.