Title of Invention

AUTOMOBILE ASSEMBLY

Abstract

The present invention relates to a method 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.

Full Text

AUTOMOBILE ASSEMBLY 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 energy absorption unit and also to have aesthetic appeal, it being part of the external part of the bumper system. A "bumper fascia" may typically be made of or comprise a moulded plastics material. Energy absorption units (EAU) may be made of metal, for example steel and aluminium, or may be made of plastics material. The EAU compresses or distorts on impact so absorbing the energy of the impact. Conventional plastic bumper EAUs may be assembled for example by heating staking points so as to weld the plastics material of the EAU and the fascia together. This process may however leave undesirable visible marks on the fascia. 1 he fascia may also be attached to the EAU using mechanical fixing means. The EAU may be connected to the bumper beam or may be located close to but spaced from the beam. Typically, the EAU may be connected to the beam using mechanical fixing means. When this fascia and EAU or the EAU and bumper beam are connected at localised points, large stresses may be encountered at those points leading to failure in the event of a collision and less efficient absorption of energy along the length o1 the bumper system. A "front end carrier (hereafter FEC) for an automobile Is that part of the body of the automobile which joins the two sides of the front of the automobile together and is aligned transversely so as to enclose a front, typically engine, cornpart-nenl. The FEC is shaped for aesthetic and functional purposes, and typicaliy houses or is otherwise used to carry one or more of the lighting assemblies. the cooling system and the latch by which the bonnet is secured when -Icsed. FEC's conventionally are made of at least two parts, a structural member and a reinforcing member. Usualy, the structural member, whether in an FEC or a bumper system, comprisss a plastics material, for example polypropylene, glass filled polypropylene or polyamides, which lends itself to shaping in the desired form. The plastics part of the FEC or bumper system is conventionally produced by moulding using known techniques including compression moulding and injection moulding. In an FE:C, the reinforcing member is employed to provide impact resistance, as WEII as providing structural benefits such as improved durability and stiffness. The reinforcement is typically made of a metal, for example steel and aluminium, but may be made from other materials capable of providing reinforcement. The reinforcing member is typically attacned to the structural member by mechanical fixing, for example using bolts and screws. However mechanical fixing causes concentrations of stress at the fixing points between the plastic moulding and the rainforcement, which may cause the FEC to fall mechanically during durability testing. As an alternative to mechanical fixing In FEC's, the plastic moulding may be moulded around and interlock with the reinforcement for instance by way of providing holes in the reinforcements and forming the plastio moulding in situ so as to secure the two parts together. This process nevertheless is more expensive than assembling the plastic moulding and reinforcement using mechanical fixing olgomers or polymers having olefinic unsaturation. Where a compound which causes the complex to disassociate is employed, it is kept separate from the complex until initiation of polymerisation is desired. The polymerisable composition which contains the disassociating agent may be cured at any desired Figures 5 to 8 show cross-section views of different examples of bumper systems; according to the invention. either or both the structural member (14) and reinforcing member (15) at all points at which they are in contact. Alternatively, the reinforcing member (15) may have lips (18) to which adhesive (16) is applied and which are then contacted with the structural member (14) as illustrated in Figure 6 or, as shown in Figure 7, neither the reinforcing member (15) nor the structural member (14) need have lips. Figures 9 to 11 show a structural member (14) connected to a reinforcing number (15) by means of an adhesive (16) which preferably is employed along the length of the members (14) and (15). In Figure 9, the structural member (14) is an EAU and is made of a polypropylene moulding. The bumper fascia (19) is spaced apart from member (14) and connected through conventional means to another part of the vehicle (not shown). In Figures 10 and 11, the bumper fascia is the structural member (14). The 'C" shaped EAU is the reinforcing member (15) and is made of steel. The member (15) is spaced apart from the bumper beam (20). The member (15) Isbonded to te bumper fascia (14). Suitably, the generally "C" shaped component as illustrated in Figure 9 structural number (14)) and Figures 10 and 11 (reinforcing member (15)) priovides excellent impact resistance properties. Once assembled, the open end of the "C" section is closed by being bonded to the bumper beam (20) in Figure 9, the bumper fascia (19) in Figure 10 and is located next to, but not bonded to, the bumper Deam (20) in Figure 11 so creating a closed box section. The thickness of the box section and the thickness of the walls defining the box section determine the stiffness of the assembly and the performance of the assembly under Impact. The horizontal walls, that is the top and bottom part of the "C" shaped component may be designed to buckle under a certain load. This enables the impact resistance of the assembly to be tailored according to the intended use. The height of the bctx sectiion, that is the length of the back part of the "C" shaped component may be tailored to provide desired properties according to the intended use Use of an EAU having a "C" shaped cross section is especially advantageous in that the box shaped cross section formed on assembling the bumper system possesses excellent strength characteristics when subjected to impact. Claims 1 a method for producing an automobile assembly comprising a structural number made of a moulded plastics material having a low energy surface and a reinforcing member attached to the structural member, the members having complementary suffaces, which comprises applying an adhesive to the complementary surface of the structural member and/or reinforcing member, bringing the complementary surfaces of the reinforcing member and structural member into contact and allowing the adhesive to set so as to bond the structural member and reinforcing member together wherein the adheslve is capable of bonding to a low energy surface plastic and the structural member is not subjected to treatment to Improve adhesion prior to application of the adhesive. 2. A method according to claim 1 In which the low energy surface plastics mateial has a surface energy of less than 45 mJ/m2 742. A method for producing an automobile assembly comprising a structural number made of a moulded plastics material having a low energy surface and a reinforcing member attached to the structural member, the members having complmentary surfaces, which comprises providing an adhesive comprising a polymerisation composition, contacting together the components of the composition under conditions to initiate polymerisation, applying the adhesive to the cornplemontary surface of the structural and/or reinforcing member, bringing the complementary surfaces of the reinforcing member and structural member into contact and curing the adhesive whereby the said members bond together and wherein the structural member is not subjected to treatment to improve adhesion prior to application of the adhesive. 11. A method for producing an automobile assembly substantially as herein above described with reference to the accompanying drawings. 12. An automobile assembly substantially as herein above described with reference to the accompanying drawings.

Documents:

1992-chenp-2003 abstract.pdf

1992-chenp-2003 claims granted.pdf

1992-chenp-2003-abstract.pdf

1992-chenp-2003-claims.pdf

1992-chenp-2003-correspondance others.pdf

1992-chenp-2003-correspondance po.pdf

1992-chenp-2003-description complete.pdf

1992-chenp-2003-drawings.pdf

1992-chenp-2003-form 1.pdf

1992-chenp-2003-form 18.pdf

1992-chenp-2003-form 3.pdf

1992-chenp-2003-form 5.pdf

1992-chenp-2003-pct.pdf