Molded article designed to absorb airborne sound

• US 5,652,415 A
• Filed: 05/02/1995
• Issued: 07/29/1997
• Est. Priority Date: 11/07/1992
• Status: Expired due to Fees

• Current Assignee: Helmut Pelzer
• Original Assignee: Helmut Pelzer
• Inventors: Pelzer, Helmut, Akyol, Tarik, Guenzel, Rolf, Keller, Hans Peter
• Primary Examiner(s): Dang, Khanh
• Application Number:
  US08/433,875
• Time in Patent Office: 819 Days
• Field of Search: 181/286, 181/295, 181/290, 181/291, 181/294, 181/207, 181/208
• US Class Current: 181/286
• CPC Class Codes: B32B 2266/0278 Polyurethane
• CPC Class Codes: B32B 2266/06 Open cell foam
• CPC Class Codes: B32B 2605/08 Cars
• CPC Class Codes: B32B 2607/00 Walls, panels
• CPC Class Codes: B32B 27/065 of foam
• CPC Class Codes: B32B 27/40 comprising polyurethanes
• CPC Class Codes: B32B 3/12 characterised by a layer of regularly- arranged cells, e.g. a honeycomb structure
• CPC Class Codes: B32B 3/20 of hollow pieces, e.g. tubes; of pieces with channels or cavities
• CPC Class Codes: B32B 3/28 characterised by a layer comprising a deformed thin sheet , i.e. the layer having its entire thickness deformed out of the plane, e.g. corrugated, crumpled B32B29/08 takes precedence
• CPC Class Codes: B32B 5/18 characterised by features of a layer of foamed material
• CPC Class Codes: B32B 7/08 by mechanical means
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: B60R 13/08 Insulating elements, e.g. for sound insulation sound insulating linings for trains B61D17/185; drivers' cabs for load-carrying vehicles insulated against vibrations or noise B62D33/0604; thermal or acoustic insulation of engines F02B77/11; damping of sounds using compensation by electro-acoustic methods G10K11/178
• CPC Class Codes: B60R 13/0838 for engine compartments
• CPC Class Codes: F02B 77/13 Acoustic insulation
• CPC Class Codes: G10K 11/172 using resonance effects

Abstract

A molded article for the absorption of airborne sound, to be used principally in the engine compartment of motor vehicles and particularly as a sound absorber inside partial and complete motor encapsulations, is formed by a porous absorber (1) of which the core (6), being sealed on both sides (7,8) over its complete surface by a respective PU film of a thickness less than 90 μm, is made from an open-pored PU (polyurethane) foam of a thickness of at least 3 mm and about 15 mm at the most. The core comprises cavities (2-4) originating on the bottom face and formed by the injection molding process, said cavities being open only towards the bottom face (5) and having different cavity volumes and different heights (11) measured from the bottom face (5).

Claims

1. A molded article for absorbing airborne sound, comprising:

a porous absorber core having at least two sides and comprising an open-pored polyurethane foam having a thickness between about 3 mm and about 15 mm,

a polyurethane film covering each of the at least two sides of the porous absorber, the polyurethane film having a thickness not greater than about 90 μ

m,

the porous absorber core being configured to define a plurality of cavities aligned along and opening toward a common plane, the plurality of cavities comprising at least a first cavity and a second cavity, the first cavity having an end wall spaced a first distance from the common plane, the second cavity having an end wall spaced a second distance from the common plane, the first distance and the second distance being unequal, the first cavity defining a first volume, the second cavity defining a second volume, the first volume and the second volume being unequal.

2. The article of claim 1, wherein at least one of the cavities has a side wall having a truncated conical shape and an end wall spaced from the common plane by a distance of between about 8 mm and about 60 mm.

3. The article of claim 2, wherein the end wall is spaced from the common plane by a distance of between about 15 mm and about 50 mm.

4. The article of claim 1, wherein the cavity defines a substantially polygonal cross section having not more than eight edges.

5. The article of claim 4, wherein the edges of the polygonal cross section coincide with an imaginary envelope circle having a diameter between about 20 mm and about 200 mm.

6. The article of claim 5, wherein the cavity defines a substantially circular cross section having a diameter between about 60 mm and about 120 mm.

7. The article of claim 1, wherein at least one of the cavities has a side wall and the side wall and a line perpendicular to the common plane define an angle between about 10°

and about 60°

.

8. The article of claim 1, wherein the polyurethane film covering each of the at least two sides of the porous absorber has a thickness between about 20 μ

m and about 80 μ

m.

9. The article of claim 8, wherein the polyurethane film covering each of the at least two sides of the porous absorber has a thickness between about 20 μ

m and about 60 μ

m.

10. The article of claim 1, comprising a carrier on which the article can be mounted by at least one of a bonding connection and a clip connection.

11. The article of claim 10, wherein the carrier comprises an engine capsule.