TRANSMISSION CONTROL DEVICE AND METHOD FOR WORKING VEHICLE

摘要

A load increase rate computing means (21) computes an increase rate (ß) of a load on a working vehicle (1)(step (102)). A transmission control means (22), if the load increase rate (ß) is smaller than a load increase rate threshold (ßc) in changing gear from a speed stage (2-speed) at a high speed to a speed stage (1-speed) at a low speed, changes gear from the speed stage (2-speed) at a high speed to the speed stage (1-speed) at a low speed in a lockup state in which a lockup clutch (4a) is engaged (step (103), (105)). Further, the transmission control means (22), if the load increase rate (ß) exceeds the load increase rate threshold (ßc) in changing gear from the speed stage (2-speed) at a high speed to the speed stage (1-speed) at a low speed, changes gear from the speed stage (2-speed) at a high speed to the speed stage (1-speed) at a low speed in a torque converter state in which a lockup clutch (4a) is released (step (103), (104)).