Patent Application
20060008620
1. Field of the Invention
The invention relates to vehicle parts for use in motor vehicles, and to a method of making such parts.
2. Background Art
Prior vehicle parts and manufacturing methods are disclosed in U.S. Pat. Nos. 3,922,429; 5,082,609; 6,017,617 and 6,544,449, for example.
Under the invention, a method of making a vehicle part is provided. The method includes the steps of spraying material proximate a surface of a tool to form a skin layer; spraying material onto the skin layer to form a resilient layer; removing the skin layer and the resilient layer from the tool; positioning the skin layer and the resilient layer in a mold; and applying material onto the resilient layer to form a rigid substrate on the resilient layer.
Further under the invention, a method of making a vehicle interior trim part includes applying a coating on a tool, the coating comprising aliphatic polyurethane. Next, the method includes spraying material on the coating to form a skin layer, the skin layer comprising aromatic polyurethane. The method further includes spraying material onto the skin layer to form an expanded elastomer layer that comprises expanded polyurethane. The expanded elastomer layer is formed to include a first portion having a first general thickness, and a second portion having a second general thickness greater than the first general thickness. The second portion is also configured to absorb impact energy. Next, the method includes removing the skin layer and the expanded elastomer layer from the tool and positioning those layers in a mold. The method further includes applying material onto the expanded elastomer layer to form a rigid substrate on the expanded elastomer layer that includes rigid polyurethane.
A vehicle part according to the invention includes a sprayed skin layer and a sprayed resilient layer bonded to the skin layer. The resilient layer has a first portion with a first general thickness, and a second portion with a second general thickness different than the first general thickness. Furthermore, the second portion is configured to absorb impact energy. The part also includes a rigid substrate bonded to the resilient layer.
While exemplary embodiments in accordance with the invention are illustrated and disclosed, such disclosure should not be construed to limit the claims. It is anticipated that various modifications and alternative designs may be made without departing from the scope of the invention.
The substrate 12 is a structural member that provides support for the remainder of the panel 10, and may comprise any suitable material. For example, the substrate 12 may be made of reinforced plastic, such as fiberglass reinforced polyurethane. Additional examples of suitable plastics include polypropylene, polyethylene, acrylonitrile butadiene styrene (ABS), polycarbonate (PC), or ABS/PC blends.
The resilient layer 14 is adhered to the substrate 12 and is configured to provide a soft feel and/or an impact management characteristic to the panel 10. For example, as shown in
The resilient layer 14 may comprise any suitable material. For example, the resilient layer 14 may comprise an expanded elastomer such as expanded polyurethane. Furthermore, the density of the resilient layer 14 is preferably, but not necessarily, in the range of 0.3 to 3 grams per cubic centimeter (g/cm3). In one embodiment of the invention, the density of the resilient layer 14 is in the range of 1 to 2.3 g/cm3.
The skin layer 16 is adhered to the resilient layer 14 and coating 18. Moreover, the skin layer 16 is configured to provide a covering over the resilient layer 14 and may comprise any sufficiently dense material. For example, the skin layer 16 may be a solid layer that comprises an aromatic or aliphatic compound. As a more specific example, the skin layer 16 may be made of an elastomer such as polyurethane. Furthermore, the skin layer 16 may have any suitable thickness and density. For example, the skin layer 16 may have a thickness in the range of 0.4 to 2 mm, and a density in the range of 0.15 to 1.5 g/cm3. In one embodiment of the invention, the skin layer 16 has a thickness in the range of 0.5 to 1 mm, and a density in the range of 0.95 to 1 g/cm3.
The coating 18 may be used to protect the skin layer 16 and/or to provide a decorative surface for the panel 10. For example, the coating 18 may be used to inhibit sunlight or other ultraviolet light from reaching the skin layer 16. As another example, the coating 18 may be used as a paint to provide a desired color or texture to the panel 10. While the coating 18 may comprise any suitable material, in one embodiment of the invention the coating 18 is made of an aliphatic polyurethane composition. Furthermore, the coating 18 may have any suitable thickness, such as a thickness of approximately 1 mil.
Alternatively, the coating 18 may be omitted if not required for a particular application. For example, the skin layer 16 may be configured to provide a sufficiently durable and attractive surface such that the coating 18 is not needed.
Referring to
Next, referring to
As mentioned above, the coating 18 may be omitted from the panel 10. In such a case, the skin layer forming material may be sprayed directly onto the tool 26, or onto a mold release agent that is applied on the tool 26, to form the the skin layer 16.
Referring to
Furthermore, the expandable material may be sprayed to achieve any desired thickness at any location, such that the thickness of the resilient layer 14 may vary. Thus, the expandable material may be lightly applied in certain areas where soft feel is a major consideration, and more heavily applied in areas that are designed to absorb impact energy. For example, the expandable material may be applied relatively lightly to form first portion 22, and more heavily applied to form second portion 24.
Next, the method involves removing the coating 18, skin layer 16 and resilient layer 14 from the tool 26 and positioning the layers 14, 16 and 18 in a mold 42 having first and second mold portions 44 and 46, respectively. The mold 42 may also have one or more projections 48 for maintaining or otherwise forming the grooves 20.
Referring to
While the material may comprise any suitable substance or substances, in one embodiment, the material includes polyol and isocyanate such that the substrate 12 is formed of polyurethane. Other suitable materials include polypropylene, polyethylene, ABS, PC, or ABS/PC blends.
Whether the material is injected or poured into the mold 42, such a process may be referred to as reaction injection molding (RIM). Reinforcing material such as milled glass or glass fibers may also be added during the RIM process to provide reinforcement to the substrate 12. As another example, a reinforcing mat or preform, such as a fiberglass preform, may be positioned in the mold 42 prior to the RIM process. This process may be referred to as structural reaction injection molding (SRIM).
With the process described above, panel 10 may be formed with integral localized impact management areas and a soft feel across the entire panel 10. Furthermore, because the resilient layer 14 is combined with the skin layer 16, the thickness of the skin layer 16 may be reduced.
Examples of other vehicle parts that may be manufactured by the above method include door panels, package shelves and pillar trim panels. In a similar manner as described above, such parts may be formed with a resilient layer having integral impact management areas.
Although separate spray assemblies 34 and 38 are shown in the Figures, the spray assemblies 34 and 38 may be provided as a single spray assembly. Furthermore, if the material to be sprayed includes multiple substances, the substances may be mixed at any suitable time. For example, the substances may be mixed upstream of, within, or downstream of associated spray nozzles.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
