| 摘要 |
PURPOSE:To accurately perform power transmission and reduce the size of the captioned device by forming a speed increasing gear by means of an intermediate gear and a clutch gear and pressing a clutch plate to closely touch the speed increasing end of the speed increasing gear. CONSTITUTION:A speed increasing gear is formed by an intermediate gear 4, engaged with a gear part provided on the inner peripheral face of a driven rotary body 13, and a clutch gear 5, engaged with said gear 4, while clutch plates 6, 7 rotating in one body with a main driving rotary body 2 are pressed to closely touch a disc part of the clutch gear 5 which is the speed changing end of the speed changing gear, and the clutch force is obtained. Thus, self-rotation of the intermediate gear 4 is obstructed by this clutch force during expanding/contracting operation of an antenna and driving force of the main driving rotaty body 2 is directly transmitted to the driven rotary body 13 through the intermediate gear 4, therefore, the driving force for the motor side to the antenna side can be accurately transmittged. Further, since a small force suffices to press the clutch part, the captioned device can be reduced in its size.
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