To provide a rotation detecting device capable of miniaturizing while keeping high precision in detection of rotational angle.
The rotation detection device comprises a warm gear 4 which is rotatively driven by a steering shaft, a main gear 13 and a sub gear 14 which rotate coaxially, engaging with the warm gear 4, a twisted coil spring 17 for giving reverse rotational force to the main gear 13 and the sub gear 14 to each other, and a magnet 15 fixed on the main gear 13 for detecting the rotation. A columnar engaging part 13j is protrusively provided on the surface of the main gear 13 opposite to the sub gear 14, the first and the second columnar parts 14e, 14g are provided on the bottom of the recess 14d of the sub gear 14, the engaging part 13j is inserted slidably into the long hole 14c, at the same time the turning part 17a of the twisted coil spring 17 is supported by the first columnar part 14e, and both the arm parts 17b, 17c of the twisted coil spring 17 are hooked respectively on the fixing parts 13j and the second columnar part 14g.
OKUMURA HIROBUMI
Ichiro Suzuki
Hirohiro Ichimura
Kazuo Kobayashi