Abstract: A slewing-type working machine capable of reducing back pressure generated during slewing. The slewing-type working machine includes: a base carrier; an upper slewing body; a hydraulic motor including first and second ports and slewing the upper slewing body; a hydraulic pump, a slewing operation device including an operating member; a control valve controlling the hydraulic motor based on the operation signal of the slewing operation device; first and second pipe-lines connecting the first and second ports of the hydraulic motor to the control valve; a communication switching device capable of switching communication and cutting of between both pipe-lines and the tank; and a switching command section operating the communication switching devices, when the upper slewing body is slewed, to bring only a pipe-line, which corresponds to a discharge-side pipe-line of the hydraulic motor, of the pipe-lines into communication with the tank, while bypassing the control valve.

Abstract: A slewing-type working machine includes: a hydraulic motor for slewing an upper slewing body; a hydraulic pump; a slewing operation device including an operation member; a control valve controlling the hydraulic motor based on an operation signal of the slewing operation device; first and second pipe-lines connecting first and second ports of the hydraulic motor to the control valve; communication switching devices switching communication and cutoff between both pipe-lines and a tank; an electric motor; an electric storage device; and a controller, which communicates an outlet-side pipe-line to the tank during slewing, makes a brake based on a regenerative action by the electric motor and the electric storage device and causes the electric storage device to store regenerative power, upon deceleration operation. Upon failure occurrence, the controller brings the communication switching devices to a communication-cutoff state and stops the regenerative action to secure slewing.

Abstract: A slewing-type working machine includes: a hydraulic motor having first and second ports and driving an upper slewing body to slew it; a hydraulic pump; a slewing operating device including an operating member; a control valve controlling the hydraulic motor based on an operation signal of the slewing operating device; first and second pipe-lines connecting the first and second ports of the hydraulic motor to the control valve; communication switching devices switchable between communication and cutoff between both pipe-lines and a tank; a slewing electric motor; an electric storage device; and a controller. During a slewing operation, the controller brings the communication switching devices into a communicated state and performs regenerative control by issuing a command on a regeneration amount corresponding to a reduction in back pressure by the communication switching devices in the communicated state to the slewing electric motor.

Abstract: The invention provides a rotation control device capable of reducing a loss of a power of a hydraulic pump in a backward direction operation and also provides a construction machine including the same. The controller controls a capacity of the hydraulic pump such that, in a forward direction operation in which an operating direction detected by the operation sensor and a rotating direction detected by a rotation sensor coincide with each other, the capacity of the hydraulic pump is increased in accordance with an increase in the operation amount detected by an operation sensor, on the other hand, restricts the capacity of the hydraulic pump more in a backward direction operation, in which the operating direction detected by the operation sensor and the rotating direction detected by the rotation sensor are reverse to each other, than in the forward direction operation.

Abstract: A slewing-type working machine, including a base, an upper slewing body, a hydraulic motor slewing the upper slewing body, a hydraulic pump, a slewing operation device, a control valve controlling the hydraulic motor, pipe-lines connecting the hydraulic motor to the control valve, a hydraulic pressure source, communication valves switching communication and cutoff between the pipe-lines and a tank by pilot pressure, an electric motor, an electric storage device, communication selector valves on inlet sides of the communication valves, a switching control valve on an inlet side of the communication selector valves, and a controller. During slewing deceleration, the controller signals to switch the switching control valve to a connecting position and switch the communication selector valves to a pilot pressure supply position. In a slewing stopped state, the controller signals to switch the communication selector valves to a cutoff position and switch the communication valves to a communication cutoff position.

Abstract: A slewing-type working machine capable of reducing back pressure generated during slewing. The slewing-type working machine includes: a base carrier; an upper slewing body; a hydraulic motor including first and second ports and slewing the upper slewing body; a hydraulic pump, a slewing operation device including an operating member; a control valve controlling the hydraulic motor based on the operation signal of the slewing operation device; first and second pipe-lines connecting the first and second ports of the hydraulic motor to the control valve; a communication switching device capable of switching communication and cutting of between both pipe-lines and the tank; and a switching command section operating the communication switching devices, when the upper slewing body is slewed, to bring only a pipe-line, which corresponds to a discharge-side pipe-line of the hydraulic motor, of the pipe-lines into communication with the tank, while bypassing the control valve.

Abstract: A slewing-type working machine includes: a hydraulic motor for slewing an upper slewing body; a hydraulic pump; a slewing operation device including an operation member; a control valve controlling the hydraulic motor based on an operation signal of the slewing operation device; first and second pipe-lines connecting first and second ports of the hydraulic motor to the control valve; communication switching devices switching communication and cutoff between both pipe-lines and a tank; an electric motor; an electric storage device; and a controller, which communicates an outlet-side pipe-line to the tank during slewing, makes a brake based on a regenerative action by the electric motor and the electric storage device and causes the electric storage device to store regenerative power, upon deceleration operation. Upon failure occurrence, the controller brings the communication switching devices to a communication-cutoff state and stops the regenerative action to secure slewing.

Abstract: A slewing-type working machine includes: a hydraulic motor having first and second ports and driving an upper slewing body to slew it; a hydraulic pump; a slewing operating device including an operating member; a control valve controlling the hydraulic motor based on an operation signal of the slewing operating device; first and second pipe-lines connecting the first and second ports of the hydraulic motor to the control valve; communication switching devices switchable between communication and cutoff between both pipe-lines and a tank; a slewing electric motor; an electric storage device; and a controller. During a slewing operation, the controller brings the communication switching devices into a communicated state and performs regenerative control by issuing a command on a regeneration amount corresponding to a reduction in back pressure by the communication switching devices in the communicated state to the slewing electric motor.

Abstract: A slewing-type working machine, including a base, an upper slewing body, a hydraulic motor slewing the upper slewing body, a hydraulic pump, a slewing operation device, a control valve controlling the hydraulic motor, pipe-lines connecting the hydraulic motor to the control valve, a hydraulic pressure source, communication valves switching communication and cutoff between the pipe-lines and a tank by pilot pressure, an electric motor, an electric storage device, communication selector valves on inlet sides of the communication valves, a switching control valve on an inlet side of the communication selector valves, and a controller. During slewing deceleration, the controller signals to switch the switching control valve to a connecting position and switch the communication selector valves to a pilot pressure supply position. In a slewing stopped state, the controller signals to switch the communication selector valves to a cutoff position and switch the communication valves to a communication cutoff position.