| 摘要 |
An electric motor 12 operates a transmission 12a, 12b having an output element which is biassed by energy storing means, eg a spring, that when the electric motor 12 is in an idle condition, eg turned-off at least partially engages a clutch so as to transmit a nominal torque which is less than a nominal torque produced by a power train. The electric motor 12 is electronically controlled and may have a transmission in the form of multi-stage gearing, such as worm and crank gearing 12a, 12b operating the clutch through a fluid column 8 or alternatively through linkwork (fig 1b) or directly (fig 27). The single or multi-stage gearing may include toothed gearing, eg epicyclic gearing (fig 30) or swashplate gearing (fig 33) or cam gearing (figs 18, 19) or rack-and-pinion gearing (fig 21). The gearing may be such that the ratio between the electric motor 12 and the clutch operating member will vary, eg by using non-circular gears (fig 22), the electronic control responds to signals such as engine speed, vehicle speed and an intent of a driver to change ratio. |
