Sound-damping air-conducting duct and method for the production of a sound-damping air-conducting duct

Abstract

A sound-damping air-conducting duct that has at least one exit opening for air, and is provided, in the region of the exit opening, with a lining made of a sound-absorbing material, which lining is surrounded, at least on its outside, by a wall made of plastic, provided with holes, and the lining is attached to this wall, whereby the lining is immediately, preferably directly, connected with the wall, with material fit and/or shape fit, and/or is connected with it in a single work step with the wall that is produced using a primary shaping method. A method for the production of a sound-absorbing air-conducting duct is also provided.

1 . A sound-damping air-conducting duct for an air conditioning or ventilation system comprising:
 (a) at least one exit opening for air;   (b) a lining made of a sound-absorbing material provided near said at least one exit opening, said lining having an outside portion;   (c) a wall made of plastic attached to said lining and surrounding at least an outside portion of said lining, said wall being provided with a plurality of holes at least near said lining;   wherein said lining is immediately connected with the wall with a material fit or shape fit or is connected with the wall in a single work step when the wall is formed.   
   
   
       2 . The sound-damping air-conducting duct according to  claim 1 , wherein the air conditioning or ventilation system is in a vehicle, said lining comprises a non-woven fabric, said wall forms a self-supporting line segment, and said lining is directly connected with the wall. 
   
   
       3 . The sound-damping air-conducting duct according to  claim 1 , wherein the lining has a profiled surface or a surface provided with nubs on an inside portion of said lining or on the outside portion. 
   
   
       4 . The sound-damping air-conducting duct according to  claim 1 , wherein the plastic is a thermoplastic plastic and the lining is porous or open-celled at least on the outside portion such that the thermoplastic plastic of the wall passes through the lining at least in partial regions of the lining or at least in part. 
   
   
       5 . The sound-damping air-conducting duct according to  claim 4 , wherein the lining is not completely infiltrated or penetrated by the thermoplastic plastic of the wall so that the surface of an inside portion of the lining is essentially free or completely free of the thermoplastic plastic of the wall. 
   
   
       6 . The sound-damping air-conducting duct according to  claim 4 , wherein the lining comprises internal material structures and the thermoplastic plastic of the wall engages behind said internal material structures. 
   
   
       7 . The sound-damping air-conducting duct according to  claim 6 , wherein the internal material structures comprise fibers. 
   
   
       8 . The sound-damping air-conducting duct according to  claim 1 , wherein the lining has a thickness that is less than 1.0 mm. 
   
   
       9 . The sound-damping air-conducting duct according to  claim 1 , wherein the lining has a thickness of approximately 0.5 mm. 
   
   
       10 . The sound-damping air-conducting duct according to  claim 1 , wherein the lining has an original thickness and the lining is compressed to a compressed thickness that amounts to only a fraction of the original thickness. 
   
   
       11 . The sound-damping air-conducting duct according to  claim 1 , wherein the holes of the wall comprise passage holes. 
   
   
       12 . The sound-damping air-conducting duct according to  claim 1 , wherein the holes of the wall have an average diameter or a minimal diameter of 1 to 3 mm. 
   
   
       13 . The sound-damping air-conducting duct according to  claim 1 , wherein the holes have an average diameter or a minimal diameter of 1.5 to 2.5 mm. 
   
   
       14 . The sound-damping air-conducting duct according to  claim 1 , wherein the holes have an average diameter or a minimal diameter of 1.8 to 2.2 mm. 
   
   
       15 . The sound-damping air-conducting duct according to  claim 1 , wherein the holes of the wall are conical. 
   
   
       16 . The sound-damping air-conducting duct according to  claim 1 , wherein at least the holes of the wall provided near the lining narrow in cross-section towards the lining. 
   
   
       17 . The sound-damping air-conducting duct according to  claim 16 , wherein the holes narrow continuously toward the lining. 
   
   
       18 . The sound-damping air-conducting duct according to  claim 1 , wherein the holes of the wall provided near the lining are covered by the lining. 
   
   
       19 . The sound-damping air-conducting duct according to  claim 18 , wherein the holes are immediately delimited by the lining. 
   
   
       20 . A method for producing a sound-damping air conducting duct for air conditioning or ventilation system comprising the steps of:
 (a) producing a wall from thermoplastic using a primary shaping method selected from the group consisting of an injection-molding method, a transfer-molding method, and an impact-extrusion method; and   (b) connecting a lining made of sound-absorbing material with the wall in one work step during formation or shaping of the wall;   wherein the duct has at least one exit opening for air and is provided with the lining;   wherein the lining is surrounded at least on an outside portion of the lining by the wall; and   wherein the wall is provided with holes.   
   
   
       21 . The method accordingly to  claim 20 , wherein
 the lining is immediately connected with the wall with a material fit or a shape-fit;   the air conditioning or ventilation system is in a vehicle;   the lining comprises a non-woven fabric; and   the wall forms a self-supporting line segment.   
   
   
       22 . The method according to  claim 21 , wherein the vehicle is a motor vehicle and the lining is directly connected with the wall. 
   
   
       23 . The method according to  claim 20 , wherein the lining has an original thickness and the lining is compressed to a fraction of the original thickness before or during the formation or shaping of the wall, at least in partial regions of the lining. 
   
   
       24 . The method according to  claim 20 , wherein the lining is compressed by mechanical forces of die structures of a mold die that determine configuration or shape of the holes of the wall at local pressure points. 
   
   
       25 . The method according to  claim 20 , wherein during the formation or shaping of the wall, the thermoplastic plastic is provided in a molten or viscous state and the lining is compressed during the formation or shaping of the wall, at least in partial regions by the internal pressure forces exerted by the thermoplastic plastic in the molten or viscous state. 
   
   
       26 . The method according to  claim 20 , wherein during the formation or shaping of the wall, the thermoplastic plastic is provided in a molten or viscous state and the lining is compressed by mechanical forces of die structures of a mold die that determine the configuration or the shape of the holes of the wall, at local pressure points and, at the same time or subsequently, in regions disposed adjacent to or between the local pressure points by internal pressure forces of the thermoplastic plastic in the molten or viscous state that occur during formation or shaping of the wall. 
   
   
       27 . The method according to  claim 20 , wherein the lining is compressed before or during the formation or shaping of the wall, in such a manner that the holes of the wall of the sound-damping air-conducting duct in a finished condition are immediately delimited, at least in part by the lining. 
   
   
       28 . The method according to  claim 27 , wherein the holes of the wall of the sound-damping air conditioning duct in the finished condition are immediately delimited essentially by the lining. 
   
   
       29 . The method according to  claim 24 , wherein the lining in the sound-damping air-conducting duct in a finished condition, near or at the local pressure points, has a first thickness that approximately corresponds to a second thickness of the lining in regions that immediately follow the local pressure points or in regions disposed adjacent to or between the local pressure points. 
   
   
       30 . The method according to  claim 26 , wherein the lining in the sound-damping air-conducting duct in a finished condition, near or at the local pressure points, has a first thickness that approximately corresponds to a second thickness of the lining in regions that immediately follow the local pressure points or in regions disposed adjacent to or between the local pressure points. 
   
   
       31 . The method according to  claim 24 , wherein the lining, in the sound-damping air-conducting duct in a finished condition, near or at the local pressure points, has a thickness that is different as compared with adjacent regions of the lining. 
   
   
       32 . The method according to  claim 26 , wherein the lining, in the sound-damping air-conducting duct in a finished condition, near or at the local pressure points, has a thickness that is different as compared with adjacent regions of the lining. 
   
   
       33 . The method according to  claim 31 , wherein the thickness is smaller as compared with the regions adjacent to the lining. 
   
   
       34 . The method according to  claim 32 , wherein the thickness is smaller as compared with the regions adjacent to the lining. 
   
   
       35 . The method according to  claim 20 , wherein:
 (a) the lining is introduced into an open mold die having a die core;   (b) the lining is held on or on top of the die core, to prevent detachment from the die core or to prevent displacement relative to the die core by at least one holding or fixation device; and   (c) the plastic material for the wall is introduced into the open mold die, the open mold die is subsequently closed, whereby or whereupon the wall is formed and connected with the lining in one work step,   or   the open mold die is closed and the plastic material for the wall is injected or pressed into the closed mold die, whereby or whereupon the wall is formed and connected with the lining, in one work step.