摘要 |
A power transmission apparatus (1) comprises a case (2,102) defining a cavity, moveable parts arranged within the cavity, fixed parts arranged within the cavity, the fixed parts including parts moveably supporting the moveable parts, a wall at least partly constituting said case, and a thin wall portion formed in the wall, the thin wall portion (3c) being constantly pressed in an outward direction of the cavity by one of the fixed parts, so as to increase its rigidity. Membranous vibration of the case wall may be effectively controlled and the radiation noise from the transmission apparatus can be reduced without increasing the thickness of the transmission case wall or arranging ribs on it. |