| 摘要 |
An electric actuator comprising a coil 22 mounted to turn on a rotary spindle 20 between flat permanent magnets 24 carried by yokes, e.g. plates 26, 28, and a means for feeding electricity to the coil 22. The yokes 26, 28 comprise top and bottom flat plates 26, 28 each carrying a flat permanent magnet 24 with the coil 22 being placed between them. The coil 22 is centred on the rotary spindle 20 and has an angular stroke lying in a range 90{ to 180{. The rotary spindle 20 is connected to stepdown gearing 40, 42, 46 and 48 for connection to an output member such as a gearbox selector shaft (50, fig 4). Stepdown gearing 40, 42, 46 and 48 have outlines that are not circular in shape, thus making it possible to have a non-linear relationship between angular stroke and force. The magnets 24 are circular disks are mounted with clearance about the spindle 20. Coil 22 comprises turns of electrical wire forming parallel conductors wound on a disk or bar shaped support (34). A manual control (54) is provided so that in event of a breakdown, the selector shaft (50) can put a gearbox in neutral by pulling cable (52). |
