To realize an air conditioning duct structure for an air conditioner for a vehicle capable of enhancing a sound absorbing rate characteristic of blowing noise to be a sound absorbing object without increasing plate thickness of a sound absorbing member by disposing the sound absorbing member to form a space between an inner wall surface of an air conditioning duct and the sound absorbing member.
The sound absorbing member 22 made of a porous elastic material for damping vibration energy mainly in a high frequency region of blowing noise generated in an air conditioning unit 10 is provided within the air conditioning duct 20. The sound absorbing rate characteristic in a frequency region lower than the high frequency region is enhanced by providing a projectingly providing part 21b projected to the air conditioning duct 20 and disposing the sound absorbing member 22 to form a prescribed space 25.
KAMIYA TOMOHIRO
ITO KOICHI
KAWASHIMA MASAFUMI
