Komatsu Corporation

Koji Uematsu

Kazuhiro Hatake

Yuya Kusumoto

Azumi Nomura

Nobuki Hasegawa

Seiichi Abe

A traction control device of a six-wheel drive construction machine, the drive construction machine including: right and left front wheels connected to each other via an axle, right and left center wheels connected to each other via an axle, and right and left rear wheels connected to each other via an axle, the right and left front, center and rear wheels being driven as driving wheels; a braking mechanism provided to each of the wheels; and a differential adjusting mechanism for adjusting a differential between the front and rear driving wheels, the traction control device controls the braking mechanisms only for the driving wheels related to any two of axles while controlling the differential adjusting mechanism.

Traction control device

An object of the invention is to provide a traction control apparatus capable of suitably controlling an error, if it occurs, between an estimation of a vehicle speed and an actual vehicle speed. A traction control apparatus according to the invention includes a vehicle speed estimator and a driving-force controller. The traction control apparatus includes a vehicle state determiner that determines whether the vehicle speed of the construction vehicle estimated by the vehicle speed estimator and the driving-force control by the driving-force controller are balanced, and a driving-force control changer that changes a driving-force control by the driving-force controller when the vehicle state determiner determines the vehicle speed and the driving-force control to be unbalanced.

Traction control apparatus

A traction control device includes: rotation speed detectors provided to wheels; a control-start determiner that determines whether or not to control a braking mechanism and a differential adjusting mechanism based on rotation speeds; a braking mechanism controller that controls the braking mechanism based on a result of the determination of the control-start determiner; and a differential adjusting mechanism controller that controls the differential adjusting mechanism based on the result of the determination of the control-start determiner, in which the control-start determiner includes: a right-left-wheel rotation speed difference calculating section; a front-rear-wheel rotation speed difference calculating section; and a control-start determining section that determines whether or not to start controlling at least one of the braking mechanism and the differential adjusting mechanism when one of rotation speed differences reaches or exceeds a predetermined threshold.

The invention provides a traction control device capable of ensuring a sufficient acceleration and course traceability during the turning of a vehicle irrespective of the type of driving system or a road surface condition. A traction control device of the invention includes: a control-start determiner that determines whether or not to control a braking mechanism; and a traction force estimating section that estimates a traction force between each of wheels and the road surface. The traction force estimating section includes: a control condition determining section that determines a control condition of the braking mechanism based on a result of the determination of the control-start determiner; a traction force initial value setting section that sets an initial value in accordance with a result of the determination of the control condition determining section; and a traction force modifying section that modifies the traction force based on a control deviation.

A vehicle speed estimator includes a unit that selects a minimum rotation speed among rotation speeds of wheels detected by a rotation speed detector and calculates a reference wheel speed of a construction vehicle at every predetermined time. The unit includes: a variable filter processor that performs a low-pass filter processing to the minimum rotation speed, the variable filter processor having a variable time constant; and a time constant changer that changes the time constant of the variable filter processor in accordance with travel conditions of the construction vehicle.

Vehicle speed estimator and traction control device

An object of the invention is to provide a traction control device capable of preventing a reduction in acceleration. A traction control device of the invention includes a braking mechanism controller that controls a braking mechanism. The braking mechanism controller includes: a target brake torque calculating section that calculates a target brake torque to each of wheels based on the rotation speed of the wheel and an estimated vehicle speed; a target brake torque determining section that determines whether or not the target brake torque reaches or exceeds a per-stored threshold; a reference wheel determining section that selects a reference wheel used as a reference for controlling the braking mechanism based on the target brake torque to each of the wheels; and a target brake torque reducing section that reduces the target brake torque in accordance with a difference between the target brake torque to the reference wheel and the threshold when the target brake torque to one of the wheels reaches or exceeds the threshold.

An object of the present invention is to provide an antilock brake system control device that can realize an accurate constant speed running control by cooperating an ABS control and a constant speed running. The control device includes: an ABS control hydraulic circuit that controls an ABS of each wheel; constant speed running controllersthat supply hydraulic pressure to a rear brakewhen a vehicle runs down a slope; wheel rotation speed detectorsFL,FR,RL,RR; a monitorthat monitors a set speed under constant speed running control; a monitorthat monitors actual speed of the vehicle; a judging unitthat judges whether running speed is being kept constant or not based on the set speed and the actual speed; and a regulatorthat regulates decompression by the ABS control when it is judged that the running speed is not being kept constant.

Antilock brake system control device and method

A retarder control system for a working vehicle includes: an input shaft revolution speed detector () for detecting an input shaft revolution speed of a transmission; a running state acquirer () for acquiring a running state of the working vehicle; a threshold map storage () for storing a plurality of threshold maps of an input shaft revolution speed at which the retarder braking control starts or ends in accordance with a predetermined running state of the working vehicle; a threshold map selector () for selecting a threshold map from the threshold maps stored in the threshold map storage based on the running state acquired by the running state acquirer; and a braking controller () for retarder braking control based on the input shaft revolution speed of the transmission detected by the input revolution speed detector () and the threshold map selected by the threshold map selector ().

Retarder control device for working vehicle

In a vehicle in which an engine output power is transmitted to front and rear wheels through a transmission and an inter axle differential, a wheel lock prevention device is provided. The wheel lock prevention device comprises a differential lock mechanism for locking the inter axle differential, a detection element for detecting a wheel lock state of the front and rear wheels, and an operation element for operating the differential lock mechanism so as to lock the inter axle differential by operating the differential lock mechanism upon the detection of the wheel lock state.

Device for preventing wheel lock of vehicle

A system for controlling an operation of a cylinder comprises: a hoist cylinder displacing a member to be driven such as vessel of a dump truck in a vertical direction; a directional control valve for switching the cylinder so as to take a first position performing an expansion motion of the hoist cylinder and a second position performing a contraction motion thereof; an electromagnetic proportional pressure control valve for throttling a meter-out area at a time when the directional control valve takes the second position; a potentiometer for outputting a signal in response to the vertical displacement of the vessel; and a controller. When the controller detects that the vessel is just before the descending end position, the controller controls to reduce the output pressure as optimum current from the electromagnetic proportional pressure control valve to thereby make slow the descending speed by throttling the meter-out area of a hoist valve of the hoist cylinder. Thereafter, the vessel descending speed is detected by the controller, and in the case where this descending speed differs from the set descending speed, the current from the electromagnetic proportional pressure control valve is amended to thereby amend the descending speed through the control of the meter-out area of the hoist valve.

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Oyama, Japan

Koji Uematsu