| 摘要 |
PURPOSE:To improve a drip-proof property and protection capacity sufficiently satisfying a cooling effect by making the depth of a rib near to an outer diameter section larger than that of the rib at the inner diameter section side in the concentric circular rib, which is mounted to a bracket and forms ventilating voids. CONSTITUTION:In a concentric circular rib 3, which is installed between a bearing box 8 and an outer circumferential section 1a of a bearing bracket 1 and builds up openings 2 for ventilation, the depth of a rib 7 near to the outer circumferential section 1a is made larger than the depth (b) of the rib 3 at the inner diameter side only by DELTAb. DELTAb Shall be 12mm. or shorter, and is selected in length which can prevent the infiltration of waterdrops falling at the angles of 15 deg. or less in the vertical direction from the outer circumferential section 1a. Thus, a drip-proof property and protection capacity can be improved making the most of the characteristics of the concentric circular rib and sufficiently holding a cooling effect. |
