| 摘要 |
All operating device 1 for controlling an operable control element of a vehicle transmission, eg 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 crankpin 10 to operate a master cylinder piston 12 through rod 11. The rod is biassed by springs 1050, 1052 which act in series on the rod 11 so as to provide a multi-stage characteristic of a compensation force action. Further spring biassing which varies with the movement of the piston 12 is provided by an arrangement 50 comprising a spring-biassed 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.. |
