| 摘要 |
PURPOSE:To aim at muffling effects ranging from a low frequency region to a high frequency region, by installing a sound-absorbing material so as to surround a perforated pipe material passing through the inside of an airtight sectioned chamber and forming it with low and high density materials arranged in the axial direction of a pipe. CONSTITUTION:A soundabsorbing material is installed around a perforated pipe material 5 which passes through the inside of an airtight sectioned chamber 6 of a muffler 1 in structure, and this sound-absorber is made up with a low sensity sound-absorbing material 8, e.g., low density glass wool and wire netting being arranged in the axial direction of pipe 5 and a high density material 9 consisting of high density glass wool and foam glass. With this, acoustic waves in a low frequency region are radiated out of a lot of holes, diffracting and osmosing them into the low density sound-absorbing material 8 while the acoustic waves in the high density frequency region bump against the high density sound-absorbing material 9 and are attenuated thereof; since the pipe 5 is continuous, back pressure to the engine is as little as possible and, what is more, there is no cause for a lowering of engine power. |
