To reduce a size and cost by providing a clutch mechanism, which generates a relative rotation to an output shaft by flux of an exciting coil canceling flux of a permanent magnet, between a stationary member and the output shaft.
In this planetary reduction gears with reverse input cutoff mechanism, when a power is transmitted from a drive part side, an armature 24 integrally fixed to an output shaft 14 by flux of an exciting coil 23 is released from a friction plate 22, and when power is transmitted from a driven part side, the armature 24 is absorbed to the friction plate 22 by flux of a permanent magnet 21. Therefore, an output rotation from a speed reduction part 10 is transmitted to the output shaft 14. On the other hand, a reverse input rotation from the output shaft 14 is not transmitted to an input shaft 12. In other words, though driving transmission from the driving part side can be carried out, the driving transmission from the driven part side can not be carried out. A mechanism for switching transmission/cut off of rotation power is more simple than conventional mechanism, reduction in size in a radial direction can be enhanced, cost can be reduced, and it is preferable for a severe case which has limit in size.
MAKINO TOMOAKI
KAWASE TATSUO
