| 摘要 |
PROBLEM TO BE SOLVED: To guarantee stable noise elimination work ranging a long term by protecting a noise elimination deviation detector and a speaker from intense heat of exhaust gas. SOLUTION: This device is provided with a noise detector 7 detecting a noise of an engine 2, a sound absorption duct 1 guiding the noise, the noise elimination deviation detector 6 provided in the vicinity of an opening end 1b of a side opposite to the noise source side, and detecting a noise elimination deviation level and a noise elimination signal generating device 9 receiving the output of the noise detector 7 and the output of the noise elimination deviation detector 6, and forming a noise elimination signal for generating a sound wave with a size equal to the noise flowing through the sound absorption duct 1 and with a phase opposite to the noise from the speaker 4 toward the inside of the sound absorption duct 1. In such a case, the noise elimination deviation detector 6 and the speaker 4 are attached to the bottom wall part of the sound absorption duct 1. The noise elimination deviation detector 6 and the speaker 4 hardly be in contact with the exhaust gas of a high temp., to be protected from a damage and deterioration due to the high temp. |
