Hitachi Construction Machinery Co., Ltd.

Toshikazu Minoshima

Takao Kurosawa

Kichio Nakajima

Takanobu Ikari

Takayoshi Murahashi

Katsumi Tamura

Tomohiko Yasuda

Akira Kikuchi

Takashi Yagyu

Michio Fushiki

Yoshifumi Nabeshima

Takashi Yagyuu

Yudai Itai

Motoo Futami

Takashi Ikimi

Takayuki Sato

Yutaka Watanabe

Keizo Shimada

Shinji Akino

Takashi Sasaki

Yohei Nakate

Hirokazu Shimomura

Yuusuke Shibue

Akira Ohno

The load measuring apparatus for a working machine includes a front load acquisition unit that acquires a front load applied to front suspension cylindersAl,Ar, a rear load acquisition unit that acquires a rear load applied to rear suspension cylindersBl,Br, a surface resistance detection unitthat detects a surface resistance of a travel road for a dump truck, an adderthat based on the front load acquired by the front load acquisition unit and the rear load acquired by the rear load acquisition unit, computes a total load acting on the suspension cylindersAl,Ar,Bl,Br to determine the load of a cargoA, and a total load correction unitthat corrects the total load, which has been computed by the adder, according to the surface resistance detected by the surface resistance detection unit

Load measuring apparatus for a working machine

An object of the present invention is to provide a new load measuring apparatus for a construction machine that enables more enhancing measurement precision by monitoring a condition of a suspension cylinder. The load measuring apparatus for a construction machine according to the present invention is provided with a loading weight arithmetic modulethat calculates a loading weight on the basis of loads of plural suspension cylindersand a loading weight confirmation modulethat outputs the calculated loading weight when the loads of the suspension cylindersare all equal to or larger than a specified value and makes the calculated loading weight ineffective without outputting the loading weight when any one of the loads is below the specified value.

Load measuring apparatus for construction machine

An object is to restrain a hoist shaft and a bushing of a hoist cylinder from abrading. A haulage vehicle with a pivoting vessel has a telescoping hoist cylinder provided between the vessel and the vehicle. Supply of hydraulic oil to the hoist cylinder is controlled by a valve provided between the hydraulic power source and the hoist cylinder. The haulage vehicle is provided with a bushing at one end portion of the hoist cylinder; a hoist shaft is mounted in a through bore of the bushing; a lubricant supplier supplies lubricant to a clearance between a surface of the hoist shaft and an internal surface of the through bore of the bushing; and when the vessel is seated on the vehicle, a controller controls the valve to make the hoist cylinder contract and also supply lubricant to the clearance.

Transportation vehicle

A parking brake control device for a transport vehicle is attached to a vehicle body including a parking brake () of a negative control type for maintaining a state in which rotation of wheels is stopped, the parking brake control device including a control unit () for controlling movement of a spool () for magnetizing or demagnetizing a solenoid valve () to release or actuate the parking brake (). The control unit () includes a stop determining section () that determines whether the vehicle body stops traveling, an actuation command section () that actuates the parking brake () when the stop determining section () determines that the vehicle body is stopped, and a release command section () that releases the parking brake () after elapse of a preset setting time after the actuation of the parking brake () is started by the actuation command section ().

Parking brake control device for transport vehicle

Front wheels (L,R) a steering operation of which is possible by a steering mechanism () are mounted on a vehicle body (). Steering cylinders (L,R) of the steering mechanism () extend and contract in response to an operation of a steering handle () provided in a cab () to perform the steering operation of the front wheels (L,R). The steering mechanism () is provided with a rotation angle sensor () for detecting a steering angle &#x3b8; of the left front wheel (L) and a proximity switch () for detecting whether or not the front wheel (L) is in a straight-ahead state. A controller () determines that the rotation angle sensor () or the proximity switch () is abnormal when the steering angle (&#x3b8;) detected by the rotation angle sensor () is different from the detection result by the proximity switch ().

Steering device for vehicle

A body hoisting state display device to be mounted on a dump truck includes: an angle detection unit that detects a rotation angle of the body with respect to the frame; a seating detection unit that detects whether or not the body is seated on the frame; a calculation unit that causes an inclination angle of the body at which the body is rotated with respect to the frame from a seated state of the body to be calculated, based on the rotation angle detected by the angle detection unit, as a ratio to an angle of a rotatable range that is defined between the seated state and a state in which the hydraulic cylinder is stopped at the position short of the position at which the hydraulic cylinder is extended to the maximal extent; and a display control unit that causes the ratio of the inclination angle of the body that is calculated by the calculation unit to be displayed on a display screen.

Dump truck body hoisting state display device

A loading platform is capable of tilting on a vehicle body. In accordance with a position of an operating lever for operating a hoist cylinder for tilting the loading platform and ON/OFF of a limit change switch operated by an operator, a running speed of the vehicle body is limited. If the loading platform is not seated and the limit change switch is OFF, the running speed is limited to a first speed limit or less which is low speed running. If the loading platform is not seated and the limit change switch is ON, when the operating lever is at a lowering position or a floating position, change of the speed limit to a second speed limit faster than the first speed limit is allowed. When the operating lever is at a raising or holding position, the change of the speed limit from the first speed limit is prohibited.

Conveyance vehicle

Wheel drive motors () constituted of electric motors for driving rear wheels () are provided on a vehicle body () of a dump truck (). Each wheel drive motor () is connected to a main power generator () through a bidirectional converter () and the like and driven by power supplied from the main power generator (). A resistor () that consumes regenerative power from each wheel drive motor () is connected to the bidirectional converter (). Cooling air is supplied to the resistor () from a blower (). Operations of a switch () of the resistor () and the blower () are controlled by a controller (). A mode selecting switch () for selecting a heating mode (A), a blowing mode (B), and a heating and blowing mode (C) is connected to the controller ().

Electric working vehicle

In case a burden is discharged from a vessel (), the vessel () is raised obliquely backward with respect to a vehicle body () by a hoist cylinder (). However, when discharging work is stopped on the way, the vessel () is temporarily lowered to a position at which this sits on the vehicle body (). When the vessel () lowers, a weight of the burden left loaded thereon acts on the hoist cylinder () as a load in addition to the weight of the vessel (). A controller () determines whether the vessel () lowers in a burden loading state based on various detection signals. When the vessel () lowers in the burden loading state, switching of directional control valves () and () is controlled so as to decrease a contracting speed of the hoist cylinder (), thereby prevent the vessel () from colliding against the vehicle body ().

Transporter vehicle

A control valve device comprises two direction control valves. The direction control valve includes an expansion side variable throttle portion and a contraction side variable throttle portion. The direction control valve includes an expansion side variable throttle portion and a contraction side variable throttle portion. When a hoist cylinder is telescopically operated to raise or lower a vessel, as the hoist cylinder approaches a stop position, a controller determines that the hoist cylinder gets close to the stop position. Based upon this determination, the controller variably adjusts a flow passage area of the direction control valve using the variable throttle portions or variably adjusts a flow passage area of the direction control valve using the variable throttle portions in such a manner as to slow down or speed up the telescopic speed of the hoist cylinder corresponding to the weight in the side of vessel.

A load measuring device for a construction machine includes a processing unit for acquiring signals indicative of cylinder pressure of front and rear suspension cylinders via pressure sensors and computing a weight value of a load put on a dump body of the construction machine. When the construction machine is traveling on a curvilinear route, the construction machine makes the output of the weight value ineffective. In particular, when the differential speed value between the rear wheels, received from a speed difference detector, is below a preset value, the arithmetic unit outputs a loading weight W computed by the processing unit, as final loading weight, and so that when the differential speed exceeds the preset value, the arithmetic unit makes ineffective the computed loading weight W as the final loading weight output.

Apparatus for measuring load of construction machine

When the drive of a lubricant pump () is stopped to prevent the lubricant pump () from assuming an idling state, a determination is made as to whether or not a temperature difference (&#x394;T) between the temperature (T) of a lubricant oil detected earlier by a temperature sensor () and a warning temperature (Toh) is equal to or lower than a predetermined threshold value (&#x3b1;). When the temperature difference (&#x394;T) is within the threshold value (&#x3b1;), an 'overheat' warning is issued to an operator of a dump truck (). In consequence, even in a case where a temperature sensor () is provided on the output side of the lubricant pump () by being located on an outer side of a wheel mounting case (), planetary gear reduction mechanisms (), () inside the wheel mounting case () can be prevented from overheating by warning the operator of the vehicle.

Lubricant oil state warning device for a working vehicle

A vehicle which evaluates tire wear properly even in a road condition that tires easily slip or lock up. The vehicle, which has a driven wheel and a driving wheel with tires attached thereto, includes: a revolution speed detector for detecting revolution speeds of the driven and driving wheels; a wheel speed detector for detecting wheel speeds of the driven and driving wheels based on the detected revolution speed data of the driven and driving wheels; a wheel speed ratio detector for detecting a wheel speed ratio between the driven and driving wheels based on the detected wheel speed data of the driven and driving wheels; and a tire condition evaluator for outputting an evaluation result indicating that the tire(s) attached to the driven wheel and/or driving wheel is(are) worn when the wheel speed ratio is higher than a preset threshold.

Vehicle having tire wear evaluation system

In case a temperature (T) of a lubricant oil (G) cannot be detected by an oil temperature sensor () provided on an output side of a lubricant pump (), the temperature (Tm) of a wheel drive motor () is detected by using a motor temperature sensor () provided on the wheel drive motor (). By estimating the temperature (T) of the lubricant oil (G) from the temperature (Tm) of the wheel drive motor (), monitoring is carried out as to whether or not the temperature (Tm) has risen to a predetermined temperature (Tms) at which the cooling of the lubricant oil (G) by forced circulation is deemed necessary. The drive of a lubricant pump () by a pump drive motor () is stopped until the motor temperature (Tm) rises to a level exceeding the predetermined temperature (Tms).

Travel drive apparatus for a working vehicle

An electric drive vehicle having a power generator coupled to an engine, a first power converter connected with the power generator for converting the AC power generated by the power generator to DC power, a second power converter connected with the first power converter, for converting the DC power to AC power, a power consuming device for consuming the DC power, connected to a DC circuit between the first and second power converters, an electric motor connected with the second power converter, and at least one wheel driven by the electric motor, wherein the vehicle has a first control mode for controlling the output of the electric motor and a second control mode for controlling the power consumed by the power consuming device, and the second control mode performs such control that the operations of the second power converter and the electric motor in the first control mode are simulated.

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Kasumigaura, Japan

Toshikazu Minoshima