Abstract: A work machine includes: a multi-joint type work implement; a plurality of hydraulic actuators driving the work implement; an operation device outputting an operation signal to the plurality of hydraulic actuators; a storage section storing a target configuration defined by connecting a plurality of target surfaces; a control object surface selection section that in the case where a control point set at a claw tip of a bucket is under the target configuration, uses a target surface closest to the control point on the target configuration as a control object surface; and a target operation control section that controls the plurality of hydraulic actuators such that the operational range of the control point is limited to the control object surface and a region above the same in the case where an excavation operation is input from an operator via the operation device.

Abstract: Provided is a work machine that is equipped with a control unit that executes area limiting control with respect to a work device. The control unit includes: a position computing section that calculates the position, on an operation plane, of the forward end (first reference point) of a bucket and the rear end (second reference point) of the bucket; and a first distance computing section that calculates the distances in the operating plane from the first reference point and the second reference point to the target face A to be controlled. When the smaller one of the two distances is equal to or lower than a threshold during area limiting control, the control unit corrects an operation signal output from an operation lever device so as to reduce the operating speed of a hydraulic actuator that is a control target of the operation signal.

Abstract: A work machine has a controller which has an area limiting control section correcting the pilot pressures of pilot lines, a regeneration control section adjusting the flow rate of the hydraulic fluid caused to flow from a tank side line of an arm cylinder into a pump side line thereof between zero and a predetermined upper limit value, and a regeneration control switching section that issues an order to the regeneration control section to set the predetermined upper limit value to a first set value when the function of the area limiting control section is invalid and that issues an order to the regeneration control section to set the predetermined upper limit value to a second set value that is smaller than the first set value when the function of the area limiting control section is effective.

Abstract: A work machine (1) having a controller (40) that can perform area limiting control, the work machine further includes a machine control ON/OFF switch (17) that alternatively selects an ON position permitting execution of the area limiting control and an OFF position prohibiting execution of the area limiting control. The controller (40) has an engine control section (63) that performs automatic idling control when a predetermined period of time (T1) has elapsed after a point in time when all of operation levers (1, 23) have attained a neutral state. The engine control section (63) is configured to execute the automatic idling control during when the switch (17) is in the OFF position and not to execute the automatic idling control during when the switch (17) is in the ON position.

Abstract: When a work implement is actuated in such a manner that a work point is located at each of a plurality of positions on a datum line, a first work point position computing section calculates a position of the work point at each of the plurality of positions. A calibration value computing section calculates calibration values of angle conversion parameters (?bm, ?bm, ?am, ?am, ?bk, ?bk), dimension parameters (Lbm, Lam, Lbk), and line parameters (tilt tan ?, intercept Zline) using the fact that the positions of the work point at each of the plurality of positions calculated by the first work point position computing section can satisfy a linear equation indicating a datum line. A parameter update section reflects the calibration values calculated by the calibration value computing section in computation by a corresponding computing section that is one of the angle computing section and the first work point position computing section.

Abstract: A hydraulic excavator includes: a hydraulic pump driven by power generated by an engine; a work device that operates by a plurality of hydraulic cylinders driven by power generated by the hydraulic pump; an actuator control section that controls the boom cylinder in such a manner that a tip end of a bucket is located on or above a target surface; a control point position calculation section that calculates a bucket claw tip position on the basis of angle sensors; and a power generator control section that imposes more limitations on output power ranges of the engine and the hydraulic pump when a distance between the claw tip position and the target surface is equal to or smaller than a threshold D than those when the distance between the claw tip position and the target surface is larger than the threshold D.

Abstract: The energy efficiency is increased by reducing the throttle/relief loss in the delivery flow of the hydraulic pump caused by the bleed-off control, while also making it possible to control the delivery pressure of the hydraulic pump according to the operation amount of the control lever unit and improving the operational performance. A controller 6 includes a target pump pressure setting unit 32 which calculates a target pump delivery pressure which increases with the increase in an operation amount signal from an operation amount detector 20A/20B based on the operation amount signal and a pump flow rate upper limit setting unit 33 which calculates a pump flow rate upper limit which increases with the increase in the operation amount signal based on the operation amount signal.

Abstract: A work machine that can prevent restarting of an engine against a will of an operator from an idle stop state is provided. A hydraulic excavator includes a display device 52 that displays a confirmation screen image 58 for allowing an operator to confirm whether or not an engine 32 is to be restarted from an idle stop state, and an inputting device 54 that allows the operator to input a restart instruction for the engine in an interlocked relationship with the display of the confirmation screen image 58. A machine controller 100 includes a restart controlling section 118 that restarts the engine 32 based on the restart instruction for the engine inputted by the inputting device 54.

Abstract: A construction machine includes: a swing structure (50); a hydraulic pump (1); a hydraulic motor (3) for driving the swing structure (50) using hydraulic fluid from the hydraulic pump (1); an electric motor (14) for driving the swing structure (50) with or without the aid of the hydraulic motor (3); and a hydraulic actuator (16) driven by the hydraulic fluid from the hydraulic pump 1, the hydraulic actuator can be operated together with the swing structure (50). When the swing structure (50) is operated together with the hydraulic actuator (16), only the electric motor (14) is used to swing the swing structure (50).

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.

Abstract: A hydraulic system for a work machine includes a first hydraulic pump driving a swing hydraulic motor; a second hydraulic pumps driving a boom cylinder; a first pump displacement increase valve controlling a volume of the first hydraulic pump; a swing pilot pressure sensor detecting a swing operation amount; a boom raising pilot pressure sensor detecting a boom raising operation amount; and a controller controlling a control signal to the first pump displacement increase valve on the basis of the swing operation amount and the boom raising operation amount. The controller controls the control signal in such a manner that a delivery rate of the first hydraulic pump becomes higher as the swing operation amount is larger and an increasing rate of the delivery rate of the first hydraulic pump becomes lower as the boom raising operation amount is larger during a swing boom raising operation.

Abstract: A display system for a construction machine includes: a moving direction computing section for computing a predictive moving direction of a bucket; a work-tool display control section that, if the moving direction computing section predicts a movement of the bucket, changes the display position of a bucket image based on the predictive moving direction such that the area of a region located on the predictive moving direction side from the bucket image on the display screen of a monitor is displayed wider than when the bucket image is displayed at a reference position and that displays the bucket image at the reference position if a movement of the bucket cannot be predicted. A target-surface display control section displays on the display screen an image of a target surface when the bucket image is displayed at the display position determined by the work-tool display control section.

Abstract: A motor-generator (27) is connected mechanically to an engine (21) and a hydraulic pump (23). The hydraulic pump (23) delivers pressurized oil to cylinders (12D) to (12F) in a working mechanism (12), a traveling hydraulic motor (25) and a revolving hydraulic motor (26). The revolving hydraulic motor (26) drives a revolving device (3) in cooperation with a revolving electric motor (33). An HCU (36) reduces outputs of the revolving electric motor (33), the revolving hydraulic motor (26), the boom cylinder (12D) and the like such that a ratio of a revolving speed of an upper revolving structure (4) and a movement speed of raising a boom (12A) is held to a ratio in a normal mode (NMODE) at the time of performing a compound movement of a revolving movement and a boom-raising movement in a low speed mode (LSMODE).

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: 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 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: Both a hydraulic motor and an electric motor are provided for driving an upper swing structure. When the amount of electricity stored in a capacitor is appropriate, the upper swing structure is driven by both the hydraulic motor and the electric motor. When the amount of electricity stored in the capacitor exceeds an appropriate value, the mode is changed over to a mode in which the upper swing structure is driven only by the hydraulic motor, and an assist electric generation motor is assist-driven or engine-driven to thereby rapidly return the amount of electricity stored in the capacitor to an appropriate range. The capacity of the capacitor can be reduced, and the amount of electricity stored in the capacitor can be managed without losing the operability of swing motion.

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.