| 摘要 |
PROBLEM TO BE SOLVED: To provide a grommet for underfloor of a vehicle capable of making mutually contradictory elements such as water draining property and reduction of aerodynamic noise compatible. SOLUTION: This grommet 10 is composed of a base part 11 attached liquid-tightly to a water draining hole 2 formed on underfloor 1 of a vehicle body, a through hole 12 formed by communicating the inside and the outside of a vehicle compartment with the base part 11 and having a water draining function, and a valve mechanism 13 holding a valve opened condition for communicating the through hole 12 usually and closed by blocking the through hole 12 by difference in pressure generated in the outside and the inside of the underfloor 1 when the vehicle runs at predetermined speed or more. The valve mechanism 13 is in a valve opened condition at predetermined speed or less, and water collected on the underfloor 1 is drained to the outside of the vehicle from the through hole 12. The through hole 12 is closed by the valve mechanism 13 by reducing underfloor pressure at predetermined speed or more, and a Helmholtz resonance system is removed to reduce aerodynamic noise in a middle low frequency region efficiently. COPYRIGHT: (C)2006,JPO&NCIPI
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