SPEED CHANGE CONTROLLER AND SPEED CHANGE RATIO CONTROL METHOD OF WORKING TRUCK

摘要

A working truck using the output from an internal combustion engine (30) for working power and traveling power comprises an accelerator pedal (1) for raising the rotational speed of the internal combustion engine (30) depending on a stepping-on operation, and a gearbox (40) for changing the speed of rotation of the internal combustion engine (30) for use as traveling power. The speed change ratio controller of the gearbox (40) calculates a first target vehicle speed (Wne) dependent on the rotational speed of the internal combustion engine (30), calculates a second target vehicle speed (Wu) dependent on the stepping-on amount of the accelerator pedal (1), and controls speed change ratio of the gearbox (40) based on the lower one of these target vehicle speeds, thus attaining a vehicle speed dependent on the stepping-on amount of the accelerator pedal (1) for traveling even during high speed rotation of the internal combustion engine (30).