| 摘要 |
<p>A continually variable transmission includes a fluid coupling (20) having an impeller (22) driven from a power source and a turbine (24) adapted to be driven hydrodynamically from the impeller (22) or to be connected mechanically to the impeller (22) by a lockup clutch (26). The turbine (24) drives the shaft (28) on which a sprocket wheel (38) of a constant speed ratio chain drive mechanism (38, 40, 42) and a sheave (30) of a variable ratio belt drive mechanism (30, 36, 32) are rotatably carried. The output sprocket (42) of the chain drive mechanism (38, 40, 42) is connected through a regeneration mode clutch (48) to the ring gear (50) of a dual planetary gearset. The output sheave (32) of the belt drive mechanism (30, 36, 32) is connected directly to the sun gear (58) of the planetary gearset or through a first mode clutch (52) to the carrier (54) of the gearset, on which the first and second sets of planetary pinions (56, 60) are rotatably mounted. The reverse brake (70) selectively holds the ring gear (50) to produce reverse drive. The transmission accelerates the vehicle from rest by disengaging the regeneration clutch (48) and engaging the first mode clutch (52). The mode of operation can be shifted by reversing the engagement of these clutches when the speeds of their components become substantially synchronous upon changing the belt ratio to the ratio of the fixed chain drive mechanism. A one-way clutch (46) permits the chain drive mechanism (38, 40, 42) to overrun in the first mode and to become locked in the second mode. The belt drive mechanism (30, 36, 32) drives the ring gear (58) from the fluid coupling turbine (24) in the first mode and drives the input sprocket (38) of the chain drive mechanism (38, 40, 42) from the ring gear (50) in the regeneration mode.</p> |
