Komatsu Corporation

Kabushiki Kaisha Komatsu Seisakusho

Komastsu Ltd.

Hidekazu Nagase

Shigeru Yamamoto

Toshikazu Okada

Nobuhisa Kamikawa

Hiroshi Itogawa

Noriaki Namiki

Norihisa Matsumoto

Naomi Kobayashi

Yasuo Kitahara

Correction for compensating for errors caused by the pitching movement of a vehicle is executed with high accuracy at low cost. The ground speed of the vehicle sensed by a Doppler sensor is corrected with angular velocities with respect to the center of gravity of the vehicle. In this correction, the center of rotation of the vehicle and the rotation of the Doppler sensor itself during the pitching movement of the vehicle are taken into account. In order to mount the Doppler sensor at a high level in the vehicle without increasing the output power of the sensor, arrangement is made such that the relationship between the difference between the actual installation level of the Doppler sensor and a reference installation level and the amount of correction of beam depression angle is stored in a look-up table; the beam depression angle corresponding to the actual installation level of the Doppler sensor is calculated through correction with the corresponding correction amount of the table; and the sensed ground speed of the vehicle is corrected with the calculated beam depression angle.

Vehicle speed detection system

A dozing system for a bulldozer capable of providing high operational efficiency in dozing operation and a smooth excavation face. If it is determined when operation is performed in an automatic digging mode that the load exerted on the blade is stable, a target position for the cutting edge relative to the ground is corrected to the actual position of the cutting edge at that time. According to the ratio of the amount of excavated soil loaded on the front surface of the blade to the loading capacity of the blade front surface and/or the stability of the load exerted on the blade, a switching is performed between a weight characteristic for the operation amount of the load control and a weight characteristic for the operation amount of the smoothing control. Further, a map for correlating actual travel distance with the position of the blade cutting edge is prepared, and stable cutting edge positions are accumulated in each respective cycle and averaged to obtain an optimum target value for the smoothing control.

Dozing device for bulldozer

Hydraulic system for bulldozer

An improved accuracy is ensured for the calculation of the travel distance of a bulldozer by obtaining the accurate vehicle speed and travel direction of the bulldozer. To this end, arrangement is made such that a check is made to determine whether actual tractive force F exerted on the blade exceeds a predetermined shoe slip threshold value F.sub.0 ; switching between vehicle speed detectors (between a Doppler sensor and Sprocket rotating speed detector) is made according to the determination so that suitable one of the vehicle speed detectors detects the vehicle speed of the bulldozer; and the vehicle speed detected by the selected vehicle speed detector is integrated, whereby the travel distance of the bulldozer is calculated.

System for determining the position of a bulldozer

Dozing apparatus of a bulldozer

A dozing system that enables automatic control for all kinds of soil properties and less frequently requires manual control intervention. The system is designed such that the blade is lifted or lowered at a start of excavation in dozing operation in an automatic drive mode such that the actual cutting angle .theta. of a blade detected by an actual cutting angle detector becomes coincident with a target cutting angle (maximum cutting angle) .theta..sub.0 preset by a target cutting angle setting device.

Dozing system for controlling a cutting angle of a bulldozer blade

Tractive force control apparatus and method for construction equipment

During dozing operation, the amount of earth (i.e., load factor) accumulated on the front face of a blade is automatically detected independently of the operator's perception and, based on the detection, the dozing operation is automatically shifted from digging to carrying. The load factor is calculated by obtaining a horizontal reaction force and a vertical reaction force exerted on the blade during digging and by calculating the ratio of the vertical reaction force to the horizontal reaction force. When the load factor reaches a specified value, the blade is automatically controlled to incline backward to hold the earth.

Dozing system for bulldozer

A dozing system for use in a bulldozer, which is capable of performing an automatic dozing operation, according to working conditions and soil properties in the field. In this system, data on the relationships of the actual traveling distance of the bulldozer with actual tractive force exerted on the blade, with the position of the cutting edge of the blade relative to the ground, with the ratio of the amount of excavated soil loaded on the front surface of the blade to the loading capacity of the front surface of the blade, and with the pitch angle of the blade are stored, and based on the stored data, the blade is controlled so as to assume the desired position.

A dozing system for use in a bulldozer, having the capability of estimating a loading ratio (the ratio of soil loaded on the blade to the loading capacity of the blade) with high accuracy so that a mode shift from digging to carrying can be stably performed. Data pieces each representing the digging distance of the bulldozer and the associated loading ratio are obtained from n previous dozing operations and stored. The average of the stored data pieces obtained from n operations is calculated and according to the average, data representative of a digging distance and its associated loading ratio obtained from the present dozing operation is compensated.

Dozing system for use in bulldozer

A hydraulic drive system for the pitch cylinders (4A, 4B) of a bulldozer blade apparatus can include (a) main hydraulic pumps (30A, 30B) and an assistant hydraulic pump (31) to make up the assistant hydraulic circuit, (b) variable displacement hydraulic pumps (21A, 21B), or (c) fixed displacement hydraulic pumps (30A, 30B) and a plurality of solenoid selector valves such that the pitch cylinders can be connected in series. The assistant hydraulic pump (31) is connectable to delivery lines of the main hydraulic pumps through an assistant solenoid selector valve (32) which is controlled by an external signal. The blade (10) can be formed so that a line (14) tangential to the lower edge of the curved panel of the blade is inclined rearwardly with respect to the front face (13) of the blade edge member (12). Earth-moving work can be performed by inclining the blade (10) rearwardly by an angle (.theta..sub.1) with respect to its posture in digging work, and earth-dumping work can be performed by inclining the blade (10) forwardly by an angle (.theta..sub.2) with respect to its posture in digging work. The coupling positions of the two pitch cylinders (4A, 4B) can be in asymmetrical relation to each other. Control signals can be provided by a blade lever (23), tilt/pitch changeover switch (24), and pitch speed changeover switch (25). The tilt/pitch changeover switch (24) and pitch speed changeover switch (25) can be replaced by pitch-dump selector switch (25A) and pitch-back selector switch (24A).

Blade apparatus and its control method in bulldozer

A geared steering device (30) selectively operates rightside and leftside driving mechanisms (2,3) of a crawler vehicle (1) for more efficient operation of the crawler vehicle. The geared steering device (30) comprises a power input drive element (33) for inputting a driving power from a prime mover (7), rightside and leftside steering brakes (38R, 38L), rightside and leftside direct-coupled clutches (36, 44), a turn clutch (46), three arrays of planet gear trains (40, 43 and 48), and power output shafts (32R, 32L) coupled to right and leftside steering brake hubs (34R, 34L). A control unit compares an actual steering ratio of a geared steering device (30) with a designated steering ratio, outputs control signals to respective solenoid valves for controlling the direct-coupled clutches, the turn clutch or a steering brake so as to cause the actual steering ratio to approximate the designated steering ratio. The control unit outputs an engagement signal to the one of the direct-coupled clutches (36 and 44) on the side opposite to a steering direction entered by the steering lever (57).

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Hirakata, Japan

Hidekazu Nagase