STEPLESS SPEED CHANGE UNIT

摘要

A stepless speed change unit comprising a driving pulley (11), a driven pulley (21), a belt (15) entrained between the driving and driven pulleys, a speed change ratio changing mechanism for changing the belt-entraining diameters of both pulleys mutually in opposite directions, and a tensioner device (50) pressing the belt to obtain a belt tension. The tensioner device (50) is provided with a tension roller (51) pressing the slack side of the belt (15) from outside, a swing arm (53) swingably supported by a speed change unit case (6), a link (52) connecting the tension roller (51) to the arm (53), an urging means (54, 55) for urging the arm (53) to swing in a direction for the tension roller (51) to press the belt (15). A support mechanism for the tension roller (51) is of link construction having two or more degrees of freedom, whereby in all speed change ratios, the tension roller (51) can be automatically moved to a position where it does not interfere with the pulleys (11, 21).