Working Vehicle Travel Control Apparatus

A working vehicle travel control apparatus, comprising:

• a variable displacement hydraulic pump that is driven by an engine;
• a variable displacement hydraulic motor that is connected in a closed circuit to the hydraulic pump and driven upon pressure oil from the hydraulic pump;
• a first control unit that controls a motor displacement angle of the hydraulic motor by an electrical signal;
• a constant mesh transmission that includes a clutch device that includes a High clutch section that transmits power at a first transmission gear ratio and a Low clutch section that transmits power at a second transmission gear ratio, which is greater than the first transmission gear ratio, the constant mesh transmission that transmits or interrupts power from the hydraulic motor;
• and
• a second control unit that controls the first control unit so as to reduce the motor displacement angle to a predetermined value when the transmission is switched from the first transmission gear ratio to the second transmission gear ratio.