| 摘要 |
PURPOSE:To manufacture the captioned duct for vehicles which is excellent in heat- insulating and vibration-proof properties by inserting a pair of foamed skins of the heat-insulating duct with bellows into a pair of hollow molding metal dies, introducing a parison and performing blow molding. CONSTITUTION:A foamed sheet 1 of plasticized synthetic resin is fitted to a duct- shaped female-type simple vacuum molding die 2 having wave-shaped concave- convexes and subjected to vacuum molding, whereby a pair of foamed skins 1A and 1B of the heat-insulating duct with bellows parted in two along a parting line is obtained. Next, after a bonding agent is applied on the inside surfaces of the skins 1A and 1B and bonding-agent layers 3 are formed thereby, the skins are inserted into the inside of the right and left hollow molding metal dies 4, the parison 5 is introduced into the dies 4, the dies are closed to form spaces 8 and 9 for forming waste bags at both upper and lower ends of the dies 4, the parison 5 is expanded by blowing air in from a blow-in port 6, and thereby a hollow tube 7 is formed monolithically with the skins 1A and 1B. After that, the dies being opened, the tube is cut closs-wise along the cut lines 14 and 15 of the waste bags 12 and 13. |
