| 摘要 |
<p>A power transmission combines a continuously variable belt drive (56,68,70) in series relation with a multi-ratio gear arrangement (84,86;88,90) between the transmission input and output shafts. The gear arrangement can be selectively changed between low and high ratios. In each gear ratio, the belt drive ratio is controlled from an underdrive ratio to an overdrive ratio to thereby provide two continuously variable drive ranges to effect an increase in output speed. A selectively operable transition clutch (34), controlling a chain drive (114,116,118) disposed in parallel with the belt and gear drives, is provided to maintain power transmission between the input and output shafts during a ratio change in the gear arrangement as the belt drive ratio is changed from overdrive to underdrive.</p> |
