Abstract: A pump control device and a valve control device each includes: an instruction calculator that calculates a control instruction of causing a controlled object to operate by using a manipulation amount of a manipulation and at least one control parameter, and inputs the calculated control instruction to the controlled object; and an ideal output calculator that calculates an ideal output of an actuator, the ideal output being associated with the manipulation amount of the manipulation. The pump control device adjusts at least one pump control parameter to reduce a difference between a control output and the ideal output when an operation of a movable part is a power running operation. The valve control device adjusts at least one valve control parameter to reduce a difference between a control output and the ideal output when the operation of the movable part is a non-power running operation.

Abstract: A speed compensation part included in a construction machine executes a feedback control of regulating an opening degree of a second control valve to an opening degree obtained by subtracting a correction amount from a second target opening degree of the second control valve, when a combined manipulation is performed and a preset load determination condition is satisfied. The correction amount is calculated by the speed compensation part so as to be larger as a speed difference between a first target speed and a first actual speed becomes larger, the first target speed being a target speed of a first actuator and determined on the basis of a manipulation amount of a first instructive manipulation, the first actual speed being an actual speed of the first actuator.

Abstract: A notification system includes: a notifier which notifies an operator of a state of a lifting magnet; a sensor which detects at least one of a voltage, an electric current, and an electric power supplied for exciting the lifting magnet; a determination part which determines, based on detection data from the sensor, whether an attraction quantity of the lifting magnet reaches a maximum attraction quantity after excitation of the lifting magnet is started; and a notification control part which causes the notifier to notify that the attraction quantity reaches the maximum attraction quantity when the determination part determines that the attraction quantity reaches the maximum attraction quantity.

Abstract: A turn-drive apparatus capable of securing high acceleration at the time of turning start with a reduced relief loss includes a hydraulic pump of a variable capacity type, a turning motor, a turning control device, a relief valve, and a flow rate control device that controls a pump flow rate. The flow rate control device calculates a relief-cut-control target pump flow rate on the basis of the sum of a minimum relief flow rate and a turning-speed flow rate, and inputs a pump capacity command to the variable capacity-type hydraulic pump based thereon. The flow rate control device makes the relief-cut-control target pump flow rate larger than the sum of the minimum relief flow rate and the turning-speed flow rate at the time of turning start.

Abstract: A turn-drive apparatus capable of securing high acceleration at the time of turning start with a reduced relief loss includes a hydraulic pump of a variable capacity type, a turning motor, a turning control device, a relief valve, and a flow rate control device that controls a pump flow rate. The flow rate control device calculates a relief-cut-control target pump flow rate on the basis of the sum of a minimum relief flow rate and a turning-speed flow rate, and inputs a pump capacity command to the variable capacity-type hydraulic pump based thereon. The flow rate control device makes the relief-cut-control target pump flow rate larger than the sum of the minimum relief flow rate and the turning-speed flow rate at the time of turning start.

Abstract: Provided is a hydraulic drive apparatus of a work machine capable of reducing a surge pressure. The hydraulic drive apparatus includes a control valve interposed between the hydraulic pump and a hydraulic actuator, an operation device moving the control valve in response to an actuator operation, an unload valve, an unload operation valve changing a pilot pressure of the unload valve in response to an input of an unload operation command, a target pressure calculation part, and an unload operation command part. The target pressure calculation part calculates a target pressure that increases with an increase in the holding pressure of the hydraulic actuator. The unload operation command part inputs an unload operation command to the unload operation valve to make the pump pressure of the hydraulic pump follow the target pressure.

Abstract: Provided is a hydraulic drive apparatus of a work machine capable of reducing a surge pressure. The hydraulic drive apparatus includes a control valve interposed between the hydraulic pump and a hydraulic actuator, an operation device moving the control valve in response to an actuator operation, an unload valve, an unload operation valve changing a pilot pressure of the unload valve in response to an input of an unload operation command, a target pressure calculation part, and an unload operation command part. The target pressure calculation part calculates a target pressure that increases with an increase in the holding pressure of the hydraulic actuator. The unload operation command part inputs an unload operation command to the unload operation valve to make the pump pressure of the hydraulic pump follow the target pressure.

Abstract: An opening and closing motion control section controls an optional control valve so as to reduce opening degree of the optional control valve in a case where a first opening reduction condition is satisfied that a slewing operation detection section detects an operation amount equal to or more than a reference operation amount set in advance so that the reference operation amount is larger than a minimum operation amount of a slewing operation member for causing slewing motion of an upper slewing body and that an optional operation detection section detects operation received by an optional operation member.

Abstract: When at least one of a value a detected output current to a magnet and a magnet load defined by the following formula is equal to or larger than a threshold value predetermined for the value of the detected output current or a threshold value predetermined for the magnet load, a controller constituting a control device outputs, to a control circuit, a command to decrease voltage applied to the magnet from next attracting operation. Magnet load=excitation ratio×I×V . . . ; wherein excitation ratio: excitation time/(excitation time+non-excitation time); I: value of the output current; V: voltage applied to a lifting magnet.

Abstract: Provided is a hydraulic driving apparatus capable of operating hydraulic actuators that actuate a boom, an arm, and a tip attachment at respective suitable speeds. The hydraulic driving apparatus includes a first hydraulic pump connected to a first main actuator, a second hydraulic pump connected to a second main actuator and an attachment actuator, a first merging selector valve that allows hydraulic fluid to be supplied from the first hydraulic pump to the second main actuator, and a power distribution control device that operates displacement of the first and second hydraulic pumps so as to decrease power distribution from a pump drive source to the second hydraulic pump and increase power distribution from the pump drive source to the first hydraulic pump when a specified combined operational action is performed on the second main actuator and the attachment actuator.

Abstract: Provided is a hydraulic driving apparatus capable of operating hydraulic actuators that actuate a boom, an arm, and a tip attachment at respective suitable speeds. The hydraulic driving apparatus includes a first hydraulic pump connected to a first main actuator, a second hydraulic pump connected to a second main actuator and an attachment actuator, a first merging selector valve that allows hydraulic fluid to be supplied from the first hydraulic pump to the second main actuator, and a power distribution control device that operates displacement of the first and second hydraulic pumps so as to decrease power distribution from a pump drive source to the second hydraulic pump and increase power distribution from the pump drive source to the first hydraulic pump when a specified combined operational action is performed on the second main actuator and the attachment actuator.

Abstract: An opening and closing motion control section controls an optional control valve so as to reduce opening degree of the optional control valve in a case where a first opening reduction condition is satisfied that a slewing operation detection section detects an operation amount equal to or more than a reference operation amount set in advance so that the reference operation amount is larger than a minimum operation amount of a slewing operation member for causing slewing motion of an upper slewing body and that an optional operation detection section detects operation received by an optional operation member.

Abstract: When at least one of a value a detected output current to a magnet and a magnet load defined by the following formula (1) is equal to or larger than a threshold value predetermined for the value of the detected output current or a threshold value predetermined for the magnet load, a controller constituting a control device outputs, to a control circuit, a command to decrease voltage applied to the magnet from next attracting operation. Magnet load=excitation ratio×I×V . . . (1); in which excitation ratio: excitation time/(excitation time+non-excitation time); I: value of the output current; V: voltage applied to a lifting magnet.

Abstract: Simplification of a device configuration and control is realized, which enables attraction and release by a magnet without using a battery. A magnet work machine includes a generator motor (8) driven by an engine (7); and an inverter (10) which controls a magnet (6) and the generator motor (8) such that the magnet (6) is energized by electric power from the generator motor (8) to attract metal scraps or the like, and during demagnetization for releasing metal scraps or the like, electric power applied to the magnet (6) is transmitted to the generator motor (8) as regenerative power so as to be consumed. The inverter (10) determines a torque of the generator motor (8) as a motor according to a voltage change of a main circuit based on a detected main circuit voltage so as to suppress the voltage change, and gives the torque as a command.

Abstract: Simplification of a device configuration and control is realized, which enables attraction and release by a magnet without using a battery. A magnet work machine includes a generator motor (8) driven by an engine (7); and an inverter (10) which controls a magnet (6) and the generator motor (8) such that the magnet (6) is energized by electric power from the generator motor (8) to attract metal scraps or the like, and during demagnetization for releasing metal scraps or the like, electric power applied to the magnet (6) is transmitted to the generator motor (8) as regenerative power so as to be consumed. The inverter (10) determines a torque of the generator motor (8) as a motor according to a voltage change of a main circuit based on a detected main circuit voltage so as to suppress the voltage change, and gives the torque as a command.

Abstract: A construction machine including: a lower propelling body; an upper slewing body having a rear region with an engine room; a slewing device for slewing the upper slewing body; and a platform cover. The slewing device includes a slewing electric motor having an electric-motor output shaft, and a speed reducer having a speed-reducer output shaft rotated more slowly than the electric-motor output shaft, the speed reducer installed forward of the engine room such that the speed-reducer output shaft points downward, the slewing electric motor disposed just above the speed reducer. The platform cover is provided on a top of the slewing electric motor, having an upper surface serving as a platform for maintenance of equipment in the engine room. The platform cover is lower than the engine cover and adjacent to a front side of the engine room.

Abstract: There is provided a slewing control device that enables to detect breakdown of a driving system of a mechanical brake, and generate a torque for holding a slewing body in a stopped state to thereby prevent movement of the slewing body when an anomaly has occurred. In a working machine for driving a slewing body by an electric motor 1, judgment is made as to whether a mechanical brake 4 is in an inconsistent state, based on a command to be outputted to a brake circuit B, and a pressure detected by a brake pressure sensor 17. The inconsistent state is a state that the mechanical brake 4 is in a brake released state when an activation command for switching the mechanical brake 4 to a brake activated state is outputted. If it is judged that the mechanical brake 4 is in the inconsistent state, a command for obtaining a braking torque for holding the slewing body in a stopped state is outputted to the electric motor 1.

Abstract: A construction machine including: a lower propelling body; an upper slewing body having a rear region with an engine room; a slewing device for slewing the upper slewing body; and a platform cover. The slewing device includes a slewing electric motor having an electric-motor output shaft, and a speed reducer having a speed-reducer output shaft rotated more slowly than the electric-motor output shaft, the speed reducer installed forward of the engine room such that the speed-reducer output shaft points downward, the slewing electric motor disposed just above the speed reducer. The platform cover is provided on a top of the slewing electric motor, having an upper surface serving as a platform for maintenance of equipment in the engine room. The platform cover is lower than the engine cover and adjacent to a front side of the engine room.

Abstract: There is provided a slewing control device that enables to detect breakdown of a driving system of a mechanical brake, and generate a torque for holding a slewing body in a stopped state to thereby prevent movement of the slewing body when an anomaly has occurred. In a working machine for driving a slewing body by an electric motor 1, judgment is made as to whether a mechanical brake 4 is in an inconsistent state, based on a command to be outputted to a brake circuit B, and a pressure detected by a brake pressure sensor 17. The inconsistent state is a state that the mechanical brake 4 is in a brake released state when an activation command for switching the mechanical brake 4 to a brake activated state is outputted. If it is judged that the mechanical brake 4 is in the inconsistent state, a command for obtaining a braking torque for holding the slewing body in a stopped state is outputted to the electric motor 1.