A hydraulic drive unit of a hydraulic excavator is configured to include a first hydraulic pump (P1) that discharges a hydraulic oil for activating a boom cylinder (36) and the like, a first electric motor (M1) that drives the first hydraulic pump (P1), a hydraulic pump for revolution (P2) that discharges a hydraulic oil for activating a revolution motor (26), a second electric motor (M2) that drives the hydraulic pump for revolution (P2), and a motor control device (150) that controls the rotation of the first electric motor (M1) and that of the second electric motor (M2). The motor control device (150) is configured such that when the revolution of the revolving body is not activated by the revolution motor (26), control to deactivate the second electric motor (M2) is performed.

A control arrangement for an arrangement of hydraulically couplable machines has an interface for hydraulic coupling of the machines, and a hydraulic machine for supplying pressure medium to at least one hydraulic consumer of the machines in accordance with requirements. An electronic control device is configured, in accordance with a load of the consumer, to generate an electronic control signal, which can be converted by a transducer of the control arrangement into a hydraulic control signal, in accordance with which the hydraulic machine can be operated.

A hydraulic drive unit of a hydraulic excavator is configured to include a first hydraulic pump (P1) that discharges a hydraulic oil for activating a boom cylinder (36) and the like, a first electric motor (M1) that drives the first hydraulic pump (P1), a hydraulic pump for revolution (P2) that discharges a hydraulic oil for activating a revolution motor (26), a second electric motor (M2) that drives the hydraulic pump for revolution (P2), and a motor control device (150) that controls the rotation of the first electric motor (M1) and that of the second electric motor (M2). The motor control device (150) is configured such that when the revolution of the revolving body is not activated by the revolution motor (26), control to deactivate the second electric motor (M2) is performed.

The construction machine includes: a work implement driven by a first hydraulic actuator and a second hydraulic actuator; a first directional control valve controlling a flow rate and a direction of a hydraulic fluid supplied to the first hydraulic actuator; a first speed-up directional control valve provided in a second pump line and controlling a flow rate and a direction of a hydraulic fluid supplied to the first hydraulic actuator; a second directional control valve controlling a flow rate and a direction of a hydraulic fluid supplied to the second hydraulic actuator; an excavation load sensor that detects an excavation load imposed on the work implement; and a first speed-up control section that drives the first speed-up directional control valve, and the first speed-up control section is configured to control a driving amount of the first speed-up directional control valve in response to the excavation load.

A control system and a method of synchronously operating a plurality of actuators of a work vehicle in a coordinated operation to move an implement. The method includes determining an acceleration parameter for the actuators based at least partly on a control effort associated with the control commands sent to the actuators.

An energy regeneration device capable of controlling flow of a working fluid discharged from an actuator while regenerating energy from the working fluid, and a work machine including the foregoing device, include a boom cylinder, an inertial fluid container, an oil tank, an accumulator, a low-pressure-side opening/closing device, and a high-pressure-side opening/closing device. A calculation unit calculates a duty ratio for opening/closing the low-pressure-side opening/closing device and the high-pressure-side opening/closing device in accordance with a desired flow rate of a hydraulic fluid discharged from the boom cylinder. A regeneration control unit selects alternately the low-pressure-side opening/closing device and the high-pressure-side opening/closing device as a destination with which the inertial fluid container communicates in accordance with the calculated duty ratio, and supplies the discharged hydraulic fluid to an accumulator.

A construction machine includes a hydraulic actuator and a processor. The processor is configured to detect a predetermined object present within a predetermined area around the construction machine, impose a motion restriction on the construction machine by decreasing the flow rate of hydraulic oil supplied to the hydraulic actuator, in response to detection of the object present within the predetermined area, and relax or cancel the motion restriction by increasing the flow rate to a level lower than before a start of the motion restriction or a level substantially same as before the start of the motion restriction, in response to a predetermined operation for relaxing or canceling the motion restriction being performed or in response to the object being no longer detected within the predetermined area, after the start of the motion restriction.

A hydraulic system for construction machinery comprises a regeneration valve unit including a first opening/closing valve installed in a first hydraulic line which connects a head-side chamber of a boom cylinder and a drain tank, to open and close the first hydraulic line, and a second opening/closing valve installed in a second hydraulic line which is branched from the first hydraulic line and is connected to a rod-side chamber of the boom cylinder, to open and close the second hydraulic line, a first check valve installed in the second hydraulic line between the rod-side chamber and the regeneration valve unit and configured to selectively drain a working oil discharged from the rod-side chamber to the drain tank, and a control unit configured to control opening and closing of the first opening/closing valve, the second opening/closing valve and the first check valve according to a control mode.

To provide a hydraulic control system for a working machine with high fuel efficiency and higher versatility to be capable of being adapted to special work. The hydraulic control system for the working machine according to the present invention includes: a plurality of directional control valves (31, 32, . . . ), more than one of which is connected in parallel to each of a plurality of hydraulic pumps (11, 12, 13) to supply hydraulic oil from the hydraulic pump to each of the corresponding actuators (4, 5, 6, 50); operating devices (110, 120, 130, 140) to which an operator inputs manipulated variables; a connection map (182) storing a precedence order for connection between a plurality of hydraulic pumps and a plurality of directional control valves; and a controller (100) controlling the connection conditions of the pumps and the actuators on the basis of the connection amap and operation signals.

A variable displacement pump supplies hydraulic oil to turning motor via a turning control valve; pair of supply/discharge lines connect turning motor and turning control valve; a pair of make-up lines connect pair of supply/discharge lines to tank, each line having check valve; turning operation device including operating lever and outputting operation signal corresponding to inclination angle of operating lever; a flow rate adjuster adjusts tilting angle of pump; and controller controls flow rate adjuster, such that tilting angle of pump increases in accordance with increase in operation signal outputted from turning operation device. Controller: turning acceleration and at time of constant speed turning, controls flow rate adjuster such that discharge flow rate of pump changes on first regulation line; turning deceleration, controls flow rate adjuster such that discharge flow rate of pump changes on second regulation line, second regulation line having slope less than slope of first regulation line.