Vehicular structural members and method of making the members

#The present invention relates to lightweight inserts for improving the structural integrity or dampen the sound of vehicular structural members, such as a car's frame rail or pillar.

#Reducing automotive vehicle weight is and continues to be important to meet ever more stringent fuel economy and environmental standards. All the while, automobiles are expected to be quieter and safer. To meet these contradictory desires, automotive engineers have introduced foams into vehicular cavities to primarily reduce noise (acoustic foams). These foams have generally been introduced into a hollow area of the structural member after the member has been formed. The foam has also been introduced by inserting a foamable material in the hollow member as the member is being formed and subsequently foaming the foamable material during, for example, E-coating.

#Because foams have been difficult to locate precisely and contain within a certain area of a hollow structural member, from one vehicle to another, they have not been used for improving, for example, the rigidity of structural members. This inability to know exactly where the foam is and to what extent the foam fills the cavity leads to unpredictability and variability of the crash worthiness of one automobile to another. For example, crush zones designed into the structural member may contain unwanted foam resulting in excessive energy being delivered to a vehicle occupant in an accident, whereas a foam that does not sufficiently fill the cavity could result in a similar problem.

#FIG. 1 is a cross-sectional view of the vehicular hollow member having the insert therein prior to enclosing the hollow member.

#FIG. 2 is a cross-sectional view of the vehicular hollow member having the insert therein after enclosing the hollow member, but prior to expansion of the heat expandable adhesive. FIG. 3 is a cross-sectional view of the vehicular hollow member having the insert therein after expanding the heat expandable adhesive.

#FIG. 4 illustrates another embodiment of an insert of the invention.

#Hollow member as used herein means an empty cavity formed by the parts of the apparatus, such as an automobile, which cavity is typically enclosed. The apparatus may exhibit structural weakness at the point of the location of the hollow member. At least a portion with respect to the location of the adhesive on the shaped foam article means that the shaped foam article has adhesive on some or all of its outer surface. Integral locating means is a means for locating and holding the shaped part in the location it is meant to be placed wherein the locating means is integrated into the shaped part. The integral locating means can be a shaped indentation or protrusion made from the foam used to form the shaped part. Alternatively, the integral locating means is made of another material wherein a portion of the locating means is molded into the shaped foam part or permanently affixed post molding so as to permanently lock the integral locating means in place. The integral locating means can be a metal tab used to weld the part in place, a threaded insert adapted to receive a screw designed to hold the part in place. The integral locating means can be any part wherein a portion is molded in the rigid foam part and the portion outside of the part has a mechanical affixing means adapted for mechanically holding the part in a location, such as a snap fit clip or a clip. Mechanical affixing means is any known mechanical device used to hold a part in its proper location including a snap fit clip, bolt, screw or the like. All or a portion of the integral locating means can be a magnet. The integral locating means can also be a molded part which has a pressure sensitive adhesive on the external portion.

#In one embodiment the integral locating means is a locating pin extending from a surface of the rigid foam. The locating pin can have a portion molded into the rigid foam insert or be formed from the rigid foam when the rigid foam insert is fabricated. Preferably, the hollow member has a matching locating hole that the locating pin fits in to locate the rigid foam insert in place. When the rigid foam insert is placed in the hollow member, the locating pin is inserted into the locating hole for the purpose of locating the rigid foam in the proper location.

#The term “engaging” as used herein means using the locating means to place the rigid foam insert at the proper location in the hollow member. In a preferred embodiment, the locating means also can be used to hold the rigid foam insert in place either permanently or until the foamable adhesive expands to meet the walls of the hollow member and thereby hold the rigid foam insert in place. Engaging can also mean applying the integral locating means to hold the rigid foam insert in place. This can be achieved by welding metal tabs to the hollow member, placing a locating means having a pressure sensitive adhesive or magnet thereon in a position that the adhesive or magnet come into contact with the hollow member, or by applying the mechanically affixing means to proper part of the hollow member to hold the rigid foam insert in place. Where the integral locating means is a threaded receptacle for a screw, an external screw may be engaged. “Shaped” as used herein means having a three dimensional form adapted to fit into a hollow member. “Integral” as used in integral locating means, means that the locating means is not merely temporarily attached to the foam insert, but that it is attached such that, if it was removed, the locating means would either be broken or the insert foam would be damaged. Generally, this means that the locating means is a continuous part of the insert foam, the part is molded in the insert foam or is adhesively bonded to the insert foam.