| 摘要 |
PURPOSE:To prevent noise from being generated from speed change gears, by providing such a structure that the outer periphery of a nacelle in which the speed change gears are incorporated is covered with a sound-proof material. CONSTITUTION:A gear 13 which is fitted on a rotary shaft 4 supported to a nacelle 3 constitutes a group of speed change gears for increasing the rotational speed of the rotary shaft 4 together with gears 14, 16, 17. The outer peripheries of the nacelle 3 and the rotor hub 6 are covered with cowlings 24, 25, and a soundproof material 25 such as grass fibers, foamed styrene or the like are disposed between the nacelle 3 and the cowling 24. Accordingly, it is possible to shield sound generated from the speed change gears and to prevent the sound from leaking to the outside. |
