Shin Caterpillar Mitsubishi Ltd.

Caterpillar Japan Ltd.

Hideto Furuta

Naoyuki Moriya

Shoji Tozawa

Madoka Binnaka

Kazushige Okamoto

Nobuaki Matoba

Nobumi Toyoura

Noriyuki Adachi

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.

Work machine

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.

Swing drive device and work machine

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 cylinderpasses, 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.

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.

Fan revolution speed control method

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.

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.

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

Method and apparatus for voice-activated control of attachment of construction machine

A voice-actuated machine body control apparatus for a construction machine is provided. The voice-actuated machine body control apparatus comprises speech recognition means () capable of speech-recognizing a voice command representative of an instruction by voice regarding a movement of a machine body (), machine body control means () capable of controlling the machine body movement based on a result of the recognition by the speech recognition means (), obstacle recognition means () 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 () capable of inhibiting, when the presence of an object outside of the machine body is detected by the obstacle recognition means (), the machine body movement in accordance with the voice command preferentially to the control by the machine body control means () thereby to avoid an inappropriate movement of the machine body (). Thus, the construction machine () can be operated appropriately with voice uttered by the operator while the operator does not operate an joystick, a pedal or the like and does not perform an inputting operation using a switch or the like.

Voice-actuated machine body control apparatus for construction machine

Antitheft device for construction machinery

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. By commanding unlocking of the work machine after commanding its locking in the state where there is no outstanding operation signal input to the work machine, the work machine is released from the locked state.

Method and device for locking work machine

An electro-hydraulic transducing valve ( ) and other elements associated with cylinder-controlling components, such as a control valve ( ), are connected to the output end of a controller ( ) adapted to perform control computation based on electric manipulation signals send from and electric joy stick ( ) or the like. Control valve return pressure (P ) and load-sensing pressure (P ) are detected by the first and second detectors ( ), ( ) so that start-up of a hydraulic cylinder ( ) or the like is detected based on rise of the differential pressure (&Dgr;P) between the two types of pressures. The controller ( ) is provided with a function generating unit ( ) and a calibration computing unit ( ). The function generating unit ( ) has a reference function (F) that determines the relationship between electric manipulation signals and command values for commanding the electro-hydraulic transducing valve ( ) and other similar elements. The calibration computing unit ( ) is adapted to correct the reference function (F) by computing the calibration deviation (&Dgr;S) between the actual command value stored at the moment with the cylinder actually started and the provisional command value that corresponds to an imaginary start-up moment of the cylinder and has been set beforehand according to the reference function (F), and adding the calibration (&Dgr;S) to the reference function (F).

Method and device for controlling work machine

The composite operation efficiency can be improved in a work machine with a plurality of hydraulic actuators. In the control section the flows to be shared to the respective hydraulic actuators are calculated on the basis of the permissible flow in compliance with an operating quantity of an operating tool, and control commands are outputted to an electromagnetic pressure valve so that the corresponding shared flows are supplied to the respective hydraulic actuators.

Hydraulic control device for working machines

Construction machine

In a construction machine including a control unit for receiving operating signals from operating members and outputting operation commands to actuators, by using a monitor and control levers, correlations between the control levers or switches and the actuators, i.e., an input/output relationship between any of the control levers and corresponding one of electro-hydraulic conversion valves, can be freely set. The set input/output relationships are registered in a memory in a rewritable manner.

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Tokyo, Japan

Hideto Furuta