Abstract: To rotate a rotary body at a constant velocity, a swing control device of an electric rotary excavator controls rotation of the rotary body with a small first torque command value. By contrast, when operating a swing lever for acceleration, the rotation is controlled with a larger second torque command value. The first torque command value is generated based on a deviation between a velocity command value for an electric motor that rotates the rotary body and a measured velocity of the rotary body, and the second torque command value has a larger absolute value than the first torque command value and is obtained by adding a feed-forward torque command value to the first torque command value.

Abstract: An engine control apparatus includes an engine target speed set unit 51 setting a first target speed through a throttle dial, a relief engine maximum speed calculation unit 52 calculating a second target speed limiting a maximum target speed in a relief operation according to a load pressure of a hydraulic pump, a speed control means controlling an engine speed such that the engine speed is equal to lower one of the first target speed and the second target speed, a determination means determining whether an engine torque assist action of a generator motor is performed, based on a deviation between an target speed and a real speed of the engine. When the determination means determines that the engine torque assist action is performed, the speed control means controls the engine speed to be equal to the target speed through the engine torque assist action of the generator motor.

Abstract: A power generation control method of a hybrid construction machine capable of maintaining voltage of a capacitor in an appropriate range while minimizing capacitance of the capacitor and of surely preventing a system from being rendered inoperative, and the hybrid construction machine are provided. For this purpose, swing power corresponding to electric power consumed by a swing motor for swinging a part of a body relative to other parts is sequentially calculated, a value of the calculated swing power is converted to a smaller value, a power generation command of a generator motor is sequentially generated using the converted value, and the generated power generation command is output to an inverter for driving the generator motor.

Abstract: A method of controlling a hybrid construction machine capable of preventing a system from being rendered inoperative without increasing a capacitance of a capacitor and of inhibiting delay of a swing operation relative to an operation command at the time of swing operation, and the hybrid construction machine are provided. For this purpose, at the time of discharge of the capacitor, actual torque command values are respectively generated by referring to an assist torque limit value corresponding to capacitor voltage of a generator motor and a swing power running torque limit value corresponding to the capacitor voltage of a swing motor, as well as, at the time of charge of the capacitor, an actual target output value of the generator motor is generated.

Abstract: A work machine includes: hydraulic actuators 21, 22, 23, 31, and 32; a capacitor 61 for storing electric power when a generator motor 44 operates as a generator and for supplying electric power when the generator motor 44 operates as a motor; and a swing electric motor 10, the hydraulic actuators 21, 22, 23, 31, and 32 and the swing electric motor 10 are operated by operation of operating levers 50, 70. The work machine includes an idling stop control unit 110 for stopping the idling of an engine 40 and retains the swing electric motor 10 in an operation prohibited state at least on the condition that stored voltage of the capacitor 61 is predetermined voltage or higher when the neutral states of the operating levers 50, 70 continue for a predetermined stop time during operation of the engine 40.

Abstract: The present invention provides a construction machine where overheating of mounted electric devices can be prevented properly with a simple structure and a method of controlling the construction machine. For this purpose, a pump target discharge flow rate of a hydraulic pump is calculated based on an operated amount of an operating unit, a temperature of an electric device mounted on the construction machine is detected, an engine minimum speed, which is a minimum possible speed of an engine in carrying out low-speed matching for matching output of the engine and pump absorbing horsepower of the hydraulic pump to each other in a low-speed region where speed of the engine is lower than set speed, is calculated by using the detected temperature of the electric device, and a maximum value out of a corresponding speed of the pump target discharge flow rate and the engine minimum speed is generated as a candidate for an engine target speed.

Abstract: An object of the present invention is to operate the working machine etc. with satisfactory responsiveness as intended by the operator while enhancing engine efficiency, pump efficiency, and the like, where a first engine target revolution ncom1 adapted to a current pump target discharge flow rate Qsum is set, and when determined that the current pump target discharge flow rate Qsum is greater than a predetermined flow rate (10 (L/min)), a revolution nM (e.g., 1400 rpm) greater than an engine low idle revolution nL is set as a second engine target revolution ncom2 determining that operation levers 41 to 44 switched from a non-operation state to an operation state. The engine revolution is controlled so that the second engine target revolution ncom2 is obtained if the second engine target revolution ncom2 is equal to or greater than the first engine target revolution ncom1.

Abstract: A speed of a hydraulic actuator is matched with that of an electric actuator when the hydraulic actuator and the electric actuator are concurrently actuated. When determination units (71, 72) determine that a boom hydraulic cylinder (31) and a rotation generator motor (11) are concurrently actuated based on a controlled variable of a boom control lever (41) and a controlled variable of a rotation control lever (42), a torque of the rotation generator motor (11) is restricted based on a pump discharge pressure (Pp). Therefore, for example, a torque limit command is generated and output such that a torque limit value (TL2) of the rotation generator motor (11) is decreased with a decrease in discharge pressure (Pp) of a hydraulic pump (3).

Abstract: A control device 50 of an electric rotary excavator generates a rotation speed coefficient in accordance with a setting condition of a fuel dial 13 and a selection condition of a mode selection switch 14 and changes a value of a target speed command value based on the rotation speed coefficient to change a rotation speed of a rotary body 4. Accordingly, when the engine speed becomes low through operation of the fuel dial 13 or the mode selection switch 14, the rotation speed of the rotary body 4 can be decreased accordingly, while when the engine speed becomes high, the rotation speed can be increased accordingly. Therefore, the operation feeling substantially similar to a conventional arrangement for hydraulically rotating the rotary body 4 can be obtained, so that the operator is not confused when the operator shifts excavators from the conventional hydraulic excavator to the electric rotary excavator.

Abstract: In stopping a rotary body of an electric rotary excavator (a construction machine), a control-system changing unit of a rotation control device changes a control law from a speed control law to a position control law when a target speed is judged to be smaller than a speed threshold value. By changing to the position control, a larger braking torque can be output to an electric motor as compared with that in the speed control, thereby reliably maintaining the rotary body in a stationary state.

Abstract: A rotation controller of an electric rotary excavator is provided with a gear drive controller that includes a backlash determination device and a torque limit setting device. With the arrangement, since an output torque of an electric motor is limited by a torque limit when a backlash is eliminated, an excessive torque is prevented from being output. After that, the output torque is gradually changed by an output control device of the gear drive controller. Accordingly, since acceleration and deceleration of a rotary body is performed without causing an operator to feel uncomfortableness, a shock generated when the backlash is eliminated can be suppressed. As a result, smooth rotation operation free from an influence of the backlash can be realized.

Abstract: To rotate a rotary body at a constant velocity, a swing control device 50 of an electric rotary excavator controls the rotation of the rotary body with a small first torque command value T1. Thus, when inertia moment of the rotary body is changed due to extension or retraction of a boom and an arm, the change of the inertia moment affects the rotation velocity of the rotary body, and an operator can perform a rotation operation with the same feeling as in a hydraulically-driven excavator. In contrast, when operating a swing lever 10 for acceleration, the rotation is controlled with a large second torque command value T2. Accordingly, a good and quick operational feeling is obtained without a delay in acceleration or deceleration, and the degradation of workability can be avoided.

Abstract: In an electric rotary excavator (construction machine) 1, when earth pressure acts on a rotary body 4 in an opposite direction to an instructed direction of a lever, a control-system changing means 150 of a rotation control device 100 increases a torque output of an electric motor 5 that drives the rotary body 4. Accordingly, the torque output can properly react against the acting earth pressure, thereby preventing the rotary body from continuing to be rotated in the opposite direction. Therefore, even when the earth pressure becomes large, the work will not be affected. In addition, when the rotary body is rotated on a slope, the rotary body can be prevented from being rotated back greatly due to the weights of the boom and the arm.

Abstract: A control device 50 of an electric rotary excavator generates a rotation speed coefficient in accordance with a setting condition of a fuel dial 13 and a selection condition of a mode selection switch 14 and changes a value of a target speed command value based on the rotation speed coefficient to change a rotation speed of a rotary body 4. Accordingly, when the engine speed becomes low through operation of the fuel dial 13 or the mode selection switch 14, the rotation speed of the rotary body 4 can be decreased accordingly, while when the engine speed becomes high, the rotation speed can be increased accordingly. Therefore, the operation feeling substantially similar to a conventional arrangement for hydraulically rotating the rotary body 4 can be obtained, so that the operator is not confused when the operator shifts excavators from the conventional hydraulic excavator to the electric rotary excavator.

Abstract: In a swing control device installed in an electric rotary excavator (a construction machine), when a leading edge or a trailing edge of a lever signal is sharp due to a quick operation of a swing lever, a gradient as a rise time Ta1 or a fall time Tb1 is provided to the leading edge or the trailing edge of the torque output and the acceleration that are output based on the lever signal so as to somewhat ease the edge. With the arrangement, an impact in acceleration or deceleration of a rotary body can be suppressed. Specifically, a gradient in the acceleration operation is provided such that the rise time Ta1 becomes 0.15 seconds or more, while a gradient in the stop deceleration operation is provided such that the fall time Tb1 becomes 0.1 seconds or more.

Abstract: In stopping a rotary body 4 of an electric rotary excavator (a construction machine), a control-system changing means 150 of a rotation control device 100 changes a control law from a speed control to a position control when a target speed is judged to be smaller than a speed threshold value. By changing to the position control, a larger braking torque can be output to an electric motor 5 as compared with that in the speed control, thereby reliably maintaining the rotary body 4 in a stationary state.

Abstract: In an electric rotary excavator (construction machine) 1, when earth pressure acts on a rotary body 4 in an opposite direction to an instructed direction of a lever, a control-system changing means 150 of a rotation control device 100 increases a torque output of an electric motor 5 that drives the rotary body 4. Accordingly, the torque output can properly react against the acting earth pressure, thereby preventing the rotary body from continuing to be rotated in the opposite direction. Therefore, even when the earth pressure becomes large, the work will not be affected. In addition, when the rotary body is rotated on a slope, the rotary body can be prevented from being rotated back greatly due to the weights of the boom and the arm.

Abstract: An engine control device capable of improving engine efficiency by operating the engine in an area where fuel consumption is small (good) while allowing high responsivity of the engine to be maintained. The object can be achieved by operating to match at a point on a target torque line of a torque diagram and operating an electric motor when a matching point moves on the target torque line in a direction in which a load applied to the engine output shaft becomes large.

Abstract: The present invention relates to an engine control device and aims to improve engine efficiency by operating the engine in an area where fuel consumption is small (good) and to allow keeping high responsivity of the engine. The object can be achieved by operating to match at a point on a target torque line of a torque diagram and operating an electric motor when a matching point moves on the target torque line in a direction that a load applied to the engine output shaft becomes large.