AIR BLOWING PORT DEVICE OF VENTILATION AND AIR CONDITIONING DEVICE

PURPOSE:To prevent occurrence of air blowing sound, eliminate any noisy sound and provide a silent sound by a method wherein a wall thickness part at an inner circumference of a cylinder part is provided with a curved line inner surface contacting along an outer circumference of a damper in the same degree as that of a sealing member along an outer circumference of a damper and then a circular damper is made such that a contact starting part starting a contact at the curved line inner surface of the thickened part at a certain inclination and a contact completed part are arranged at the thickened part at a certain angle. CONSTITUTION:When a damper 7 performs a closing operation and a sealing member 8 at an outer circumference of the damper 7 under a certain angle is contacted with a thickened part 10, a contact starting part 17 is arranged in such a way as the sealing member 8 is concurrently contacted with another semi-circular thickened part 11. When the damper 7 performs an opening operation and the sealing member 8 completes a contact at a certain angle with the thickened part 10, the contact completion part 18 is provided in such a way as the sealing member 8 may complete its contact at the other semi-circular thickened part 11. A thickened part 16 near a damper shaft 6 may always contact with the sealing member 8. Accordingly, a gradual narrowing or gradual widening of the aeration passage does not occur, so that an occurrence of air blowing sound is restricted.