Abstract: A hydraulic circuit that enables smooth absorption of the energy of a return fluid from a hydraulic actuator by means of an energy recovery motor. A return fluid passage to which the fluid discharged from a boom cylinder is branched is provided at the tank passage side of a solenoid valve of a boom control circuit. The return fluid passage comprises two return passages, which are provided with a flow rate ratio control valve for controlling a ratio of fluid that branches off into the return passages. The flow rate ratio control valve is comprised of a solenoid valve disposed in the return passage, which is provided with an energy recovery motor, and a solenoid valve disposed in the return passage, which branches off the upstream side of the solenoid valve.

Abstract: A work machine enabling a hybrid drive system to be directly driven by energy contained in a return fluid discharged from a hydraulic actuator. The work machine includes a hydraulic actuator control circuit and a swing control circuit. The hydraulic actuator control circuit serves to control hydraulic fluid supplied from pumps of a hybrid drive system to travel motors and work actuators. The swing control circuit serves to control a swing motor generator, which functions as an electric motor and, during braking of rotating motion of the upper structure, functions as a generator. The hydraulic actuator control circuit includes an energy recovery motor provided in a return passage, though which return fluid recovered from a work actuator flows. The energy recovery motor is adapted to be driven by return fluid and thereby drive a motor generator of the hybrid drive system.

Abstract: A swing control circuit is provided separately from a hydraulic actuator control circuit. The swing control circuit includes a swing pump motor connected to closed circuits of a swing motor through a solenoid valve that serves as a directional control valve. A swing motor generator is connected to the swing pump motor. The swing motor generator is connected to an electric power storage device of a hybrid type drive system. An exterior-connecting passage for feeding hydraulic fluid to hydraulic actuators of a lower structure and a work equipment is drawn from a pipeline between the swing pump motor and the solenoid valve. A connecting passage solenoid valve is disposed in the exterior-connecting passage. The invention enables hydraulic energy generated in the swing system to be directly fed to the outside of the swing system.

Abstract: A boom control circuit for controlling hydraulic fluid fed to a boom cylinder is provided separately and independently from a travel/stick/bucket control circuit, which serves to control hydraulic fluid fed to travel motors, a stick cylinder, and a bucket cylinder. The boom control circuit includes a boom pump, an energy recovery motor disposed in a return passage through which return fluid from the boom cylinder 8bmc passes, and a boom motor generator connected to the energy recovery motor. The aforementioned boom pump is connected through a clutch to the boom motor generator. The invention is capable of providing a work machine of which a boom control circuit is adapted to function independently so that the flow rate required by the boom control circuit can be easily ensured.

Abstract: A boom control circuit for controlling hydraulic fluid fed to a boom cylinder is provided separately and independently from a travel/stick/bucket control circuit, which serves to control hydraulic fluid fed to travel motors, a stick cylinder, and a bucket cylinder. The boom control circuit includes a boom pump, an energy recovery motor disposed in a return passage through which return fluid from the boom cylinder 8bmc passes, and a boom motor generator connected to the energy recovery motor. The aforementioned boom pump is connected through a clutch to the boom motor generator. The invention is capable of providing a work machine of which a boom control circuit is adapted to function independently so that the flow rate required by the boom control circuit can be easily ensured.

Abstract: A work machine enabling a hybrid drive system to be directly driven by energy contained in a return fluid discharged from a hydraulic actuator. The work machine includes a hydraulic actuator control circuit and a swing control circuit. The hydraulic actuator control circuit serves to control hydraulic fluid supplied from pumps of a hybrid drive system to travel motors and work actuators. The swing control circuit serves to control a swing motor generator, which functions as an electric motor and, during braking of rotating motion of the upper structure, functions as a generator. The hydraulic actuator control circuit includes an energy recovery motor provided in a return passage, through which return fluid recovered from a work actuator flows. The energy recovery motor is adapted to be driven by return fluid and thereby drive a motor generator of the hybrid drive system.

Abstract: A swing control circuit is provided separately from a hydraulic actuator control circuit. The swing control circuit includes a swing pump motor connected to closed circuits of a swing motor through a solenoid valve that serves as a directional control valve. A swing motor generator is connected to the swing pump motor. The swing motor generator is connected to an electric power storage device of a hybrid type drive system. An exterior-connecting passage for feeding hydraulic fluid to hydraulic actuators of a lower structure and a work equipment is drawn from a pipeline between the swing pump motor and the solenoid valve. A connecting passage solenoid valve is disposed in the exterior-connecting passage. The invention enables hydraulic energy generated in the swing system to be directly fed to the outside of the swing system.

Abstract: Actual temperatures of intake air, hydraulic oil, and coolant, to be cooled by a cooling fan, are detected. Target fan revolution speeds are determined by PI control units based on differences between the actual temperatures and target temperatures. The cooling fan is controlled based on the target fan revolution speeds. To restrict accumulation of negative integral elements when performing integration by the PI control units an integration start control system adapted to control the timing for each PI control unit to initiate integration is provided. Target temperatures for initiating integration are respectively set, and control is performed so that integral elements of each PI control unit are kept invalid until the actual temperature of the corresponding cooling target fluid, i.e. the intake air, the hydraulic oil, or the coolant, reaches the corresponding target temperature. Delay in rise of fan revolution speed is prevented.

Abstract: Temperature of each cooling target fluid is detected. When the flow rate of a cooling target fluid passing through a cooling system is high, the fan revolution speed of a cooling fan of the cooling system is controlled to achieve a target fan revolution speed so that the detected temperature of the cooling target fluid reaches a preset target temperature. In cases where the engine is in a low idling state, the flow rate of each cooling target fluid passing through the cooling system is reduced. The fan revolution speed of the cooling fan is controlled to achieve a new target fan revolution speed that is lower than the target fan revolution speed.

Abstract: The invention is a fan revolution control method for controlling a pump-motor system, by controlling the fan revolution speed of a cooling fan adapted to be rotated by a fan motor to cool cooling target fluids. The pump-motor system drives the fan motor by a hydraulic fluid fed from a fan pump driven by an engine. The pump-motor system is controlled so the fan revolution speed starts from the minimum fan revolution speed when the engine is started up; the minimum fan revolution speed is maintained for at least several seconds; after the elapse of several seconds, the fan revolution speed is gradually increased from the minimum fan revolution speed. The fan revolution speed reaches a target fan revolution speed over a period of at least several seconds. The method prevents generation of peak pressure or pressure hunting.

Abstract: A voice attachment control apparatus (1) for a construction machine (80) is provided. The voice attachment control apparatus (1) includes speech analysis means (1a) for speech-analyzing a voice command representative of an instruction by voice regarding a movement of an attachment (401), speech discrimination means (1b) connected to the speech analysis means (1a) for discriminating the instruction of the voice command, machine body control means (1c) connected to the speech discrimination means (1b) and operable of controlling movement of the attachment (401) based on the instruction, and speech synthesis means (1d) for conveying a working situation of the attachment (401) to an operator of the machine body (80). The voice attachment control apparatus (1) uses voice to control starting, stopping and speed adjustment of the attachment (401) to improve the safety of the working person.

Abstract: A voice-actuated machine body control apparatus for a construction machine is provided. The voice-actuated machine body control apparatus comprises speech recognition means (1a) capable of speech-recognizing a voice command representative of an instruction by voice regarding a movement of a machine body (80), machine body control means (1e) capable of controlling the machine body movement based on a result of the recognition by the speech recognition means (1a), obstacle recognition means (1b) capable of detecting the presence of an object outside the machine body which may possibly make an obstacle to the machine body movement, and avoidance means (1c) capable of inhibiting, when the presence of an object outside of the machine body is detected by the obstacle recognition means (1b), the machine body movement in accordance with the voice command preferentially to the control by the machine body control means (1e) thereby to avoid an inappropriate movement of the machine body (80).

Abstract: Temperature of each cooling target fluid is detected. When the flow rate of a cooling target fluid passing through a cooling system is high, the fan revolution speed of a cooling fan of the cooling system is controlled to achieve a target fan revolution speed so that the detected temperature of the cooling target fluid reaches a preset target temperature. In cases where the engine is in a low idling state, the flow rate of each cooling target fluid passing through the cooling system is reduced. The fan revolution speed of the cooling fan is controlled to achieve a new target fan revolution speed that is lower than the target fan revolution speed.

Abstract: The invention is a fan revolution control method for controlling a pump-motor system, by controlling the fan revolution speed of a cooling fan adapted to be rotated by a fan motor to cool cooling target fluids. The pump-motor system drives the fan motor by a hydraulic fluid fed from a fan pump driven by an engine. The pump-motor system is controlled so the fan revolution speed starts from the minimum fan revolution speed when the engine is started up; the minimum fan revolution speed is maintained for at least several seconds; after the elapse of several seconds, the fan revolution speed is gradually increased from the minimum fan revolution speed. The fan revolution speed reaches a target fan revolution speed over a period of at least several seconds. The method prevents generation of peak pressure or pressure hunting.

Abstract: Actual temperatures of intake air, hydraulic oil, and coolant, to be cooled by a cooling fan, are detected. Target fan revolution speeds are determined by PI control units based on differences between the actual temperatures and target temperatures. The cooling fan is controlled based on the target fan revolution speeds. To restrict accumulation of negative integral elements when performing integration by the PI control units an integration start control system adapted to control the timing for each PI control unit to initiate integration is provided. Target temperatures for initiating integration are respectively set, and control is performed so that integral elements of each PI control unit are kept invalid until the actual temperature of the corresponding cooling target fluid, i.e. the intake air, the hydraulic oil, or the coolant, reaches the corresponding target temperature. Delay in rise of fan revolution speed is prevented.

Abstract: In the construction machinery equipped with an engine, a hydraulic control unit and a machine controller, there is provided an antitheft device for the construction machinery, which can prevent the engine from starting and the hydraulic control unit from working with reliability no matter how the starter circuit of the engine is modified. The initial state of the machine controller is so set that the fuel injection by a fuel injection unit of the engine is halted and that the operations of control units in the hydraulic control unit are halted, and an antitheft control unit is provided to release the initial state of the machine controller upon receiving a release signal from the antitheft control unit.

Abstract: The detectors, which are adapted to detect operation signals from operating devices for inputting actuation commands to a work machine, and hydraulic system locking switch, which is adapted to command locking so as to halt the work machine or unlocking to enable the work machine to resume working, are connected to a logic circuit adapted to compute the method of locking the work machine based on signals input from these components. A hydraulic system locking electromagnetic selector valve adapted to maintain or release the work machine at or from the locked state is connected to the logic circuit. In case an unlocking command is sent in the situation where there is an outstanding operation signal input to the work machine, the logic circuit maintains the work machine at the locked state until a safety check is performed.

Abstract: A voice attachment control apparatus (1) for a construction machine (80) is provided. The voice attachment control apparatus (1) includes speech analysis means (1a) for speech-analyzing a voice command representative of an instruction by voice regarding a movement of an attachment (401), speech discrimination means (1b) connected to the speech analysis means (1a) for discriminating the instruction of the voice command, machine body control means (1c) connected to the speech discrimination means (1b) and operable of controlling movement of the attachment (401) based on the instruction, and speech synthesis means (1d) for conveying a working situation of the attachment (401) to an operator of the machine body (80). The voice attachment control apparatus (1) uses voice to control starting, stopping and speed adjustment of the attachment (401) to improve the safety of the working person.

Abstract: A voice-actuated machine body control apparatus for a construction machine is provided. The voice-actuated machine body control apparatus comprises speech recognition means (1a) capable of speech-recognizing a voice command representative of an instruction by voice regarding a movement of a machine body (80), machine body control means (1e) capable of controlling the machine body movement based on a result of the recognition by the speech recognition means (1a), obstacle recognition means (1b) capable of detecting the presence of an object outside the machine body which may possibly make an obstacle to the machine body movement, and avoidance means (1c) capable of inhibiting, when the presence of an object outside of the machine body is detected by the obstacle recognition means (1b), the machine body movement in accordance with the voice command preferentially to the control by the machine body control means (1e) thereby to avoid an inappropriate movement of the machine body (80).

Abstract: An electro-hydraulic transducing valve (3a) and other elements associated with cylinder-controlling components, such as a control valve (3), are connected to the output end of a controller (23) adapted to perform control computation based on electric manipulation signals send from and electric joy stick (12a) or the like. Control valve return pressure (PT) and load-sensing pressure (PL) are detected by the first and second detectors (18), (19) so that start-up of a hydraulic cylinder (7) or the like is detected based on rise of the differential pressure (&Dgr;P) between the two types of pressures. The controller (23) is provided with a function generating unit (14a) and a calibration computing unit (20). The function generating unit (14a) has a reference function (F) that determines the relationship between electric manipulation signals and command values for commanding the electro-hydraulic transducing valve (3a) and other similar elements.