Patent ID: 8733496

Claim:
An acoustic damper fixed to a vibration source along an outer surface of a vibration source which generates air vibration, the acoustic damper comprising: a housing for surrounding a part of the outer surface; a compartment wall for partitioning space of the housing; a partition wall for defining at least two adjacent passages with the housing and the compartment wall, the partition wall being provided along the outer surface in the housing, wherein each of the at least two adjacent passages communicates with the vibration source and take in the air vibration; and at least two partition members respectively provided for the at least two adjacent passages each of which closes the downstream side of the passage with respect to the propagation of the air vibration to serve as resistance against the air vibration, wherein directions from an inlet to the at least two partition members are opposed to each other for the at least two adjacent passages, the inlet being communicating to the vibration source.