| 摘要 |
PURPOSE:To prevent the noise generated by an engine and the noise generated when air is taken into a cowling from spreading to the passengers of a ship by providing a thick wall which is thicker than other sections at a part including at least the front part of a top cowl wall face and by suppressing the increase in weight of an outboard motor as much as possible. CONSTITUTION:A top cowl 38 has a shape of a box whose lower section is opened as a whole, and a part of the wall faces includes at least the front face 46 and is formed so as to be thicker than the other wall faces. In this case, the front face 46, the front side of the top panel 48, and the front parts of both sides 50 are thick parts. In this case, the transmission of the sound from an engine 10 and air-intake sound introduced from an air-intake port 44 to the inside of a cowling is prevented in the tick parts and effectively shut off. In addition, even if the vibration of the engine 10 is transmitted to the top cowl 38, because the rigidity of the thick parts is high, the vibration of the thick parts is limited, and the generation of noise is restricted. Since the passengers stay in the ship, that is, are positioned at the front part of the ship far from the outboard motor, noise is effectively prevented from spreading. |
