A work machine management apparatus includes: a working element identification information acquiring unit acquiring working element identification information indicating replacement of a working element; a flow rate setpoint acquiring unit acquiring a flow rate setpoint of a hydraulic oil for the working element; a pressure setpoint acquiring unit acquiring a pressure setpoint of the hydraulic oil for the working element; a working element operation information acquiring unit acquiring the acquired flow rate setpoint, the acquired pressure setpoint and operation information of the working element; and a working element actual operation information calculator calculating actual operation information containing an actual operation duration of the working element based on the information acquired by each of the working element identification information acquiring unit, the flow rate setpoint acquiring unit, the pressure setpoint acquiring unit and the working element operation information acquiring unit.

A work machine includes an operation intention determining section that determines whether or not an operator has an intention of operating an operation member based on a state change of the operation member, a current supply section that supplies a current to a solenoid valve device based on an operation of the operation member, and a current control section that permits supply of a standby current from the current supply section to the solenoid valve device when it has been determined by an operation position determining section that the operation member is disposed within a preset neutral range and it has been determined by the operation intention determining section that there is an intention of operating the operation member, the standby current being lower than a current of the time when a hydraulic actuator starts driving.

Provided are an energy regeneration device which can regenerate energy of a working fluid discharged from an actuator while controlling a flow rate of the working fluid, and a work machine including the foregoing device. The regeneration device (100) includes a boom cylinder (20), an inertial fluid container (102), an oil tank (110), an accumulator (105), a low-pressure-side opening/closing device (103), and a high-pressure-side opening/closing device (104). A calculation unit (151) calculates a duty ratio for opening/closing the low-pressure-side opening/closing device (103) and the high-pressure-side opening/closing device (104) in accordance with a desired flow rate of a working fluid discharged from the boom cylinder (20). A regeneration control unit (153) selects alternately the low-pressure-side opening/closing device (103) and the high-pressure-side opening/closing device (104) as a destination with which the inertial fluid container (102) communicates in accordance with the calculated duty ratio, and supplies a discharged working fluid to an accumulator (105).

An excavator includes a hydraulic oil holding circuit that is provided in an oil passage between a bottom-side oil chamber of a boom cylinder and a control valve and is closed when the boom is not lowered, and a controller. The controller releases a closed state of the hydraulic oil holding circuit when the excavator is in a predetermined unstable state, and controls a released state so that an acting velocity in a lowering direction of the boom becomes less than or equal to a predetermined reference.

A construction machine comprises a machine frame and an articulated boom pivotably mounted to the machine frame. An electric motor is connected to a battery for operating a component of the construction machine. The construction machine is configured to be operated in a loader mode in which a first tool is mounted to the articulated boom, and in an excavator mode in which a second tool is mounted to the articulated boom. The construction machine comprises a tool storage for storing the first tool and/or the second tool. The construction machine is configured to replace one of the first tool and second tool when mounted to the articulated boom with the other one of the first tool and the second tool when stored in the tool storage. A method of changing an operational mode and a method of selecting an operational mode of a construction machine are also described.

A hydraulic system for a working machine, includes a first hydraulic pump to output an operation fluid, a hydraulic device to be operated by the operation fluid, an operation member to be operated, a control valve to control the hydraulic device based on an operation extent of the operation member, a holding member to set a held operation extent that is the operation extent held in the operation of the operation member, and a pedal to be operated to change the held operation extent set by the holding member.

A shovel includes a traveling lower body; a revolving upper body rotatably installed on the traveling lower body; an object detection device provided on the revolving upper body; a control device provided in the revolving upper body; and an actuator configured to move a driven object, wherein the object detection device is configured to detect an object in a detection space set in surroundings of the shovel, and wherein the control device is configured to allow a motion of the driven object in a direction other than a direction heading for the detected object.

An excavator attachment is attached to an excavator rotating platform. During normal operation, a drive means drives the attachment according to operator input into a manipulation device. A sensor detects motion of the excavator. Based on output of the sensor, a slip suppression unit detects slipping of the excavator undercarriage in an extension direction of the attachment, and corrects operation of the attachment performed by the drive means.

A hydraulic drive system for a hydraulic excavator that enables leveling work and a jack-up operation by a blade in a float state, that can prevent a body from falling even when an operator has falsely operated the hydraulic excavator during the jack-up operation by the blade, and that yet can perform favorable leveling work with the blade turned into the float state is provided. A float switch 37, a float valve 38, and a controller 34 are provided, the float valve 38 is changed over to a float position VI upon operating the float switch 37 when the blade is not in a jack-up state, the float valve 38 is changed over from the float position VI to a normal position V when the float valve 38 is in a state of being at the float position VI and an operation lever device 22 has been operated, and the float valve 38 is kept at the normal position V when the float valve 38 is at the normal position V and the float switch 37 has been operated in the jack-up state.

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.