A hydraulic transmission mechanism (57) and a transmission gear (74) for transmitting the driving force of the engine (2) are provided, and the respective outputs of the hydraulic transmission mechanism (57) and the transmission gear (74) are synthesized to form a transmission output. (74), to obtain the output of high
power transmission efficiency, use the above-mentioned hydraulic transmission mechanism (57), obtain the output of the stepless speed change that can advance zero position, with simple speed change operation, carry out speed adjustment according to the situation, seek the speed change function To improve and improve
operability, etc., at the same time, through each output of forward rotation or reverse rotation of the hydraulic transmission mechanism (57), the composite output shaft (84) is rotated in one direction, and the composite output shaft (84) composite hydraulic transmission mechanism (57) and transmission gear (74) each output, carry out variable speed output, ensure the output torque when zero position advances easily, improve microspeed driving performance easily, and effectively utilize the high power of transmission gear (74) at working speed The output of transmission efficiency seeks to improve the working ability on
dirt roads, etc.