| 摘要 |
A continuously variable transmission has an endless V belt (15) running across a driving pulley (11) and a driven pulley (21), a transmission ratio changing mechanism for changing the running diameters of the belt around the pulleys radially in opposite directions to each other, and a tension-adjusting unit (50) for pressing the belt to obtain belt tension. The tension-adjusting unit (50) includes a tension roller (51) coming into pressure contact with the slack side of the belt (15) from outside, a swing arm (53) having an end rotatably supported on a transmission case (6), a link member (52) having an end rotatably supporting a shaft of the tension roller (51) and another end rotatably coupled with another end of the swing arm (53), and urging means (54, 55) for swingingly urging the swing arm (53) so that the tension roller (51) presses the belt (15). A linkage structure having two degrees of freedom is used for supporting the tension roller (51), so that the tension roller (51) can automatically move to a position where it does not interfere with either pulley (11, 21) at any transmission ratio.
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