Abstract: A rotation detecting device which detects the rotational state of a rotary shaft, is structured to be a device in which the number of parts is small, and the incorporation is simple. The structure is such that a long holder receiving part is formed on the channel back side in an opening part of a motor shaft case body of a casing which contains a reduction mechanism part, and a sensor holder in which a hall device, the rotation detecting device, is incorporated, is slid in the longitudinal direction of the motor shaft, and is incorporated in the holder receiving part in the lightly pressed state, similarly to the incorporation of the motor shaft.

Abstract: When providing a rotation detecting device which detects the rotational state of a rotary shaft, it is constructed to be a device in which the number of parts is small, and the incorporation is simple.

Abstract: A speed reducing device employs dampers which are provided for power transmission from a worm wheel engaged with a worm gear to an output shaft of the device so as to absorb shocks. The device does not require a metallic plate to which the dampers are adhered nor a bearing which specifically supports the output shaft. A first wheel is engaged with the worm gear and has protrusions on its plate surface facing a second wheel. The second wheel is rigidly connected to the output shaft and has protrusions on its plate surface facing the first wheel. The protrusions of the first and second wheels take complementary positions, in which each protrusion of one wheel is apart from the adjacent protrusion of the other wheel a predetermined distance with respect to the rotational direction. The dampers are provided between neighboring protrusions of the first and second wheels so that the dampers are pressed and contracted to elastically transmit power from the first wheel to the second wheel.

Abstract: In a small-sized motor with a worm reduction gear wherein a worm, an armature and the like are coupled onto the outer periphery of an intermediate portion of a motor shaft and fixed thereto; the motor shaft is inserted into a gear case, whereby a worm wheel is meshed with the worm; a journal member having the outer diameter larger than that of the worm is projectingly provided at a position close to the worm of the motor shaft; a bearing in the intermediate portion is fixed to the gear case; and the journal member is supported by this bearing in the intermediate portion.