| 摘要 |
An operating device 1 for controlling an operable control element of a vehicle transmission, for example for shifting and/or selecting the transmission ratio of a gearbox and/or for operating a clutch 2, has an electric motor 3 which rotates a shaft through worm gearing to cause a crankpin 10 to operate a master cylinder piston 12 through a rod 11. The rod 11 is biassed by a spring 25. Further spring biassing which varies with the movement of the piston is provided by an arrangement 50 comprising a spring-bissed roller acting on a cam 30 which rotates with the crank. In alternative arrangements the variable spring bias uses a linearly-moving surface with transversely-acting rollers or the roller may instead act on a rotary face cam. |
