Patent Application
20070248797
The subject invention is directed to a vehicle door construction and more particularly to viscoelastic dampers for a water deflector for use therein.
Vehicle doors typically include a first outer sheet metal panel which defines the door exterior. A spaced inner sheet metal door panel reinforces the outer panel and defines a chamber or cavity which houses various mechanisms, including window operators, latches, and the like. Openings through the inner door panel allow access to such mechanisms. A trim panel covers the inner door panel and provides the decorative interior for the door.
Generally, water deflectors or protectors are joined to a face of the inner door panel. The water deflector protects the inner door trim panel, as well as components mounted thereon, from being damaged by water entering the interior of the doors. The water deflector also prevents the intrusion of air, dust and water from the inner door cavity into the passenger cabin. A permanently plastic and permanently tacky pressure-sensitive adhesive can be applied to selected areas of the deflector sheet to permit attachment to the inner door panel.
Water deflector sheets of the general type under consideration are shown and described, for example, in commonly assigned U.S. Pat. No. 5,482,343 for “Vehicle Door and Water Deflector” and U.S. Pat. No. 5,560,967 for “Sound Absorbing Automotive Water Deflector.” The disclosures of these patents are incorporated herein by reference. As shown therein, the deflector sheets generally include a layer of polyethylene foam sandwiched between one or more relatively thin flexible sheets of a suitable plastic such as polyethylene or polypropylene. This sheet construction can be processed using standard techniques and performs satisfactorily in its water deflecting function.
Water deflectors or protectors are commonly used in the automotive industry to protect inner door trim panels, as well as components mounted thereon, from being damaged by water entering the interior of the doors. Vehicle manufacturers have also been interested in achieving sound insulation through the use of such deflectors.
One type of water deflector which has been in use for some time comprises a layer of closed cell polyethylene foam sandwiched between thin layers of polyethylene film. This sheet construction can be processed using standard techniques and performs satisfactorily in its water deflecting function; however, it does not contribute significantly in terms of sound insulating qualities.
While various material combinations have been proposed for use as sound insulating water deflectors, these combinations have typically had significant drawbacks in terms of cost and/or processing difficulties. For example, it is often desirable to provide the deflectors with pocket-like bulges or non-planar sections to better conform to the surface to be protected or to accommodate mechanisms and components within the doors. Some combinations can be given such configuration only by slow and comparatively expensive thermoforming and vacuum forming techniques. Relatively inexpensive and rapid mechanical forming techniques such as described in commonly assigned U.S. Pat. Nos. 4,696,848; 4,865,791; and 4,873,132 cannot be used for certain of the proposed combinations.
As interior acoustics became important, vehicle manufacturers have also been interested in achieving sound insulation through the use of such water deflectors to restrict sound from traveling into the passenger cabin from the inner door cavity. Traditional water deflectors can help reduce sound transmission from the inner door to the passenger cabin by blocking and reflecting sound energy.
However, recently, automotive manufacturers have begun installing sound systems with increased power capabilities. As driven speaker power is increased and speakers with low frequency are used, the sound systems have become a potential contributor to noise generation. With increasing power and the ability to generate strong low frequency response, the sound systems can induce sympathetic vibration in the deflectors. This induced vibration can result in a very noticeable buzz or noise from the water deflectors. In cases such as this, the water deflectors can thus become undesired noise generators.
In light of the foregoing, it has become evident that a need exists for a water deflector sheet design that will permit obtaining both water deflecting and sound insulating/dampening characteristics and overcome the above-mentioned deficiencies and others while obtaining better and more advantageous results.
In accordance with the subject disclosure, a water deflector is provided which has improved sound absorbing/dampening qualities. The deflector is comprised of at least one sheet or layer of high strength linear low density polyethylene, polypropylene film or foam. To be effective, the viscoelastic properties of the polyethylene, polypropylene film or foam are then modified with softer, more elastic or rubbery resins to impart dampening characteristics. The deflector may be used alone or as a composite with an open cell foam or non-woven absorber.
The use of the foregoing sheet bonded to a planar face of an open or closed celled foam produces a water deflector sheet which has a significant increase in sound absorbing/dampening qualities as compared to prior sheet constructions.
A primary object of the invention is the provision of an improved water deflector sheet construction.
Yet another object of the invention is the provision of a water deflector sheet which has significantly increased sound absorbing and dampening qualities together with characteristics which allow processing of the sheets using known techniques.
A still further object is the provision of a water deflector sheet construction which has the advantages described but which is comparatively inexpensive.
Still other non-limiting objectives and/or aspects of the present disclosure will become apparent from a reading and understanding of the description of the embodiment hereinbelow.
The present disclosure may take physical form in certain parts and arrangements of parts, a preferred embodiment of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part of the disclosure and wherein:
Referring more particularly to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the disclosure only, and not for the purpose of limiting same,
The door structure thus far described is fairly typical and it is possible that the door of the subject invention could have a variety of other configurations and access openings through the inner panel provided at a variety of different locations.
Extending over the inner door panel 12 and joined thereto is a door trim panel structure 22. The door trim panel provides a decorative cover and overlay for the inner door panel and is formed from a variety of different materials, including metal and fabric combinations, molded plastic, and the like as is well known. The inner door panel 22 in such door structures is releasably connected to the sheet metal inner door panel so that access can be had to the interior of the door for maintenance and/or repair of the various mechanisms and components mounted therein. Generally, it has been the practice to provide the trim panel with hook or hook-like fastener elements on its rear surface which can enter into and engage into suitable openings formed through the inner door panel 12.
The presence of the noted openings 18, 20 and passages through the inner door panel require that steps be taken to prevent water, dust and the like from entering the interior of the door through these openings and into engagement with the door trim panel, thus potentially damaging the trim panel. For this reason, it has been the practice to use water deflector sheets which are placed on an interior surface of the door inner panel 12 to overlie and effectively close the various openings 18, 20 and the like.
The water deflector sheet is formed to have the desired peripheral shape to suitably overlie the inner door panel 12 and is releasably joined thereto by the use, for example, of a pressure sensitive adhesive located in bands or strips 24 about the outer periphery of the sheet. In
With reference to
As shown in
To dampen vibrations in the sheet which may be caused by a vehicle sound system, viscoelastic properties of the film 56, 58 are modified with softer, more elastic or rubbery resins to impart desired dampening characteristics. By softening the film, it displays fewer tendencies to induced vibration thereby transforming vibrational energy into thermal energy. For example, an ethylene vinyl acetate (EVA) modified foam has an improved vibrational resistance compared to a conventional open celled or closed cell foam. In this particular example, a three millimeter (3 mm) thick, four pound (4 lb) density EVA foam was laminated to modified 0.0006 inch thick film. When tested on an actual vehicle, this deflector sheet eliminated vibration induced by high power audio speakers. The dampening effect can be further enhanced by employing a modified foam.
It should be appreciated that the above deflector is only an example of the present disclosure and that other modified foams and films can be used to obtain both water deflecting and sound insulating/dampening characteristics. Also, other combinations of sheet material and foam could be advantageously employed using its concept with the development including, for example, a sheet processed to have the desired characteristics affixed to the opposed side face faces of the foamed material.
The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
This application claims priority from Provisional Application Ser. No. 60/787,337, filed on Mar. 30, 2006.
| Number | Date | Country | |
|---|---|---|---|
| 60787337 | Mar 2006 | US |
