Automobile assembly

Abstract

A method is provided for making an automobile assembly having a moulded plastics structural member and a reinforcing member in which a polymerisable adhesive is employed to bond the two members together and an automobile assembly having a bonded structural member and a reinforcing member. The assembly is suitably used as a “front end carrier” or a bumper system in an automobile.

Description

BACKGROUND TO THE INVENTION This invention relates to an automobile assembly, in particular to structural assemblies employed at the front end known as a “front end carrier” or rear end of an automobile and also to assemblies for use as bumper systems. The invention is especially concerned with automobile structural assemblies having a reinforcing member and a structural member which are connected together by means of an adhesive. An automobile bumper system typically comprises a “bumper beam” and a “bumper fascia”. Typically the bumper beam is bolted to the chassis of the automobile and the fascia is connected to the body panels. An energy absorption unit is typically disposed between the fascia and beam. A bumper beam is typically made of a rigid material, for example steel and aluminium, to provide structural integrity and an impact reaction surface and may act as a reinforcing member in the bumper system. The “bumper fascia” is shaped so as to abut or to be connectable to the ...

AI Technical Summary

Benefits of technology

We have now found a method by which the reinforcing member may be attached to the plastic structural member in automobile assemblies such as FECs and bumper systems which ameliorates or removes the drawbacks associated with existing methods of producing them. By employing certain types of adhesive which are capable of bonding to low energy surfaces such as plastics materials used in FECs and bumper systems, the need for attachment through mechanical fixing or in situ formation of a plastic moulding around a reinforcing component may be reduced or avoided.

Advantageously, the invention permits the structural member and the reinforcing member to be attached after the structural member has been produced so avoiding the drawbacks of the known process in which the structural member is formed in situ. Thus the risk of having to alter the tools for producing the structural member if the reinforcing member design alters is reduced. Further, the design and hence structural effectiveness of the reinforcing member is not compromised by limitations on the geometry, shape or dimensions of the reinforcing member imposed by the tooling apparatus. The invention accordingly provides advantages as regards enhanced process flexibility, design of the assembly and cost. In addition reinforcements of a complex design may be employed to provide a higher level of reinforcement per unit weight of reinforcement. This arrangement may provide additional benefits as regards design flexibility, reduced weight with the advantages that flow from that.

Problems solved by technology

These prior art documents do not contemplate the use of adhesives to bond reinforcing components to plastic mouldings in automobile applications in which a combination of practical and technical criteria must be met.

In particular, there is no indication in these documents that adhesives may be employed in FECs or bumper systems which, by the nature of their use, are exposed to impact and high stresses and strains.

The known technique of mechanical fixing of the reinforcing member to the plastic structural member has drawbacks as regards structural limitations, and stress concentrations and forming a component, for example an FEC and a bumper system by moulding the plastic in situ, for example through holes in the reinforcement, is costly and inflexible which may limit design options and also increase costs of production.

Producing the components for use in FECs and bumpers by in situ moulding around the reinforcement also requires the moulding tool to have a complementary design to the reinforcing component so any changes in the design of the reinforcing component require modifications to the moulding tool hence introducing further process complication and cost.

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