| 摘要 |
PURPOSE:To enable a driver to hear securely alarm sound, and to miniaturize an alarm and widen its directivity by forming a resonance box having a penetrat ing hole in an instrument panel so that an alarm is fitted in the interior thereof, and constituting it so that the vibrational sounds are amplified and output through the penetrating hole. CONSTITUTION:A resonance box 5 is integrally formed so as to be projected on the dash-upper-panel 4 side of the inner wall 1a of an instrument panel 1, and the inner space of this resonance box 5 is communicated with a space behind a meter 3 via a penetrating hole 6. And, an alarm 8 is closedly fixed to the resonance box 5 by means of screws in the state that a vibrating body is arranged. Then, by setting the cross-sectional areas are lengths of the reso nance box 5 and the penetrating hole 6 on the basis of the frequency of the vibrating body, resonant sounds in which the vibrational sounds of the vibrating body are amplified are radiated through the penetrating hole 6. As a result, alarm sounds radiated through the penetrating hole 6, even if the vibrational energy of the alarm 8 is small, are made securely audible to a driver, enabling the alarm 8 to be miniaturized and its directivity to be widened.
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