Abstract: A load control unit for a bulldozer, comprising an actual tractive force detector for detecting the actual tractive force of a vehicle body; target tractive force setting switch for setting a target tractive force for an automatic blade control mode in dozing operation; and blade controller for controlling a blade to be lifted or lowered such that if there is a difference between the actual tractive force detected by the actual tractive force detector and the target tractive force set by the target tractive force setting switch when digging is started with the automatic blade control mode in dozing operation, the actual tractive force gradually comes closer to the target tractive force.

Abstract: A blade control system for use in a bulldozer comprising: a driving mode setting device which can set an automatic blade control mode during dozing operation; a running condition detector for detecting whether a transmission is placed in forward range or reverse range; and a blade controller for controlling tilting and lowering of a blade such that when the speed range detector has detected that the transmission is placed in forward range and the driving mode setting device has set the automatic blade control mode to start digging, the lower end of the blade becomes horizontal in relation to a vehicle body and is brought into contact with the ground.

Abstract: A dozing control unit for a bulldozer, comprising an actual tractive force detector for detecting the actual tractive force of a vehicle body; a driving mode selector button capable of switching a manual operation mode to an automatic driving mode in dozing operation; and a blade controller for controlling a blade to be lifted or lowered such that if there is a difference between the actual tractive force detected by the actual tractive force detector and a target tractive force set for the automatic driving mode when the manual operation mode is switched to the automatic driving mode by the driving mode selector button, the actual tractive force gradually comes closer to the target tractive force.

Abstract: A control unit for controlling load on a bulldozer in the case of manual intervention, comprising: an actual tractive force detector for detecting the actual tractive force of a vehicle body; a target tractive force setting device for setting a target tractive force for an automatic blade control mode in dozing operation according to the actual tractive force detected by the actual tractive force detector; and a blade controller for controlling a blade to be lifted or lowered such that, if there is a difference between the target tractive force set by the target tractive force setting device when switching from the automatic blade control mode to a manual operation mode takes place in dozing operation and the actual tractive force detected by the actual tractive force detector when return from the manual operation mode to the automatic blade control mode takes place, the actual tractive force gradually comes closer to the target tractive force set when switching to the manual operation mode takes place.

Abstract: A steering system for a bulldozer, comprising a steering direction indicating device for indicating a lateral direction in which a vehicle body is to be steered, a dozing operation detector for judging by detection whether the bulldozer is in dozing operation, a steering controller for controlling the vehicle body to be steered in the lateral direction indicated by the steering direction indicating device when the dozing operation detector judges that the bulldozer is in dozing operation, by tilting a blade in the indicated lateral direction in order to impose offset load on the vehicle body, and by causing a difference between the relative travel speeds of right and left crawler belts attached to the vehicle body at least when light load occurs in the dozing operation.

Abstract: A dozing system for a bulldozer, comprising an actual tractive force detector for detecting an actual tractive force of a vehicle body; a target tractive force setting device for setting a target tractive force for a vehicle body; a tractive force deviation calculator for calculating the deviation between the actual tractive force detected by the actual tractive force detector and the target tractive force set by the target tractive force setting device; and a comparison control unit for controlling a blade to be lifted or lowered such that the absolute value of the deviation is increased, when at least the absolute value of the deviation is less than a preset value and tile actual tractive force is approaching the target tractive force.

Abstract: An automatic drive control system for a bulldozer comprising a digging start detector for detecting that the bulldozer is in a digging start position, a digging end detector for detecting that the bulldozer is in a digging end position, a driving direction detector for detecting the momentarily varying driving direction of the bulldozer, and a drive controller for shifting a transmission into a forward gear when the digging start detector detects that the bulldozer is presently in the digging start position; shifting the transmission into a reverse gear when the digging end detector detects that the bulldozer is presently in the digging end position; and controlling the bulldozer such that the driving direction detected by the driving direction detector is made coincident with a target driving direction when the bulldozer is moving from the digging start position towards the digging end position.