| 摘要 |
PROBLEM TO BE SOLVED: To drain water through a drain hole without varying noise reduction characteristics.SOLUTION: A resonator 10 includes: a drain hole 20 formed vertically penetrating a bottom part of a resonance chamber 12; and an opening/closing member 30 which is swingably supported on the resonance chamber 12 through a shaft part to swing, and displaced between a closing attitude for closing the drain hole 20 and an opening attitude for opening the drain hole. The opening/closing member 30 has one swing end part formed to be heavier than the other swing end part and is held in the closing attitude with the weight the one swing end part, and the other swing end part has a water reservoir recessed part formed to receive water flowing down from the resonance chamber 12 and to reserve the water by such an amount that the other swing end part becomes heavier than the one swing end part. |
