Process for Manufacturing a Body Structure for a Convertible

This invention relates to a process for manufacturing a body structure for a vehicle, particularly a convertible, which has a transversely extending rear wall in the area of the rearward wheel houses connected to the bottom and the wheel houses, the rear wall being supported on forward body structure by way of longitudinally directed, laterally exterior members.

In the case of a known body structure of the initially mentioned type (for example, the new Daimler-Benz Roadster, Model 129 described in an article "The New Mercedes-Benz Roadster--Body: Passive Safety" in ATZ 91 (1989)5, Pages 227 to 235), the rear wall, including the two longitudinally directed, laterally exterior members, is mounted during the manufacturing of the shell and is welded to the adjoining body parts. The rear wall and the longitudinally directed members are made of steel plate and therefore have a relatively high weight. After the manufacturing of the shell, the whole body structure is subjected to surface treatments of prime-coating and painting.

It is an object of the invention to provide a process for manufacturing a body structure for a convertible in which cost and weight are saved and the processing time during the shell manufacturing is reduced.

According to the invention, this object is achieved by a process for manufacturing, comprising forming a prefabricated module separate from remaining body structure, which prefabricated module includes the rear wall and two longitudinally directed laterally exterior members, surface treating the remaining body structure, and subsequently connecting the prefabricated module to the remaining body structure.

Principal advantages achieved by means of the invention are that, by separating a part of the structure (rear wall module) from the shell manufacturing and by forming a prefabricated, easily mountable module, costs are reduced in the manufacturing of the shell because high-expenditure welding operations of the rear wall are no longer required. At the same time, the processing time during the manufacturing of the shell is reduced considerably. The investment costs are also reduced. The combining of shell components in a subassembly and the manufacturing in light metal or plastic results in a considerable reduction of weight of up to 25%.

The module containing the rear wall in certain preferred embodiments also contains other components, such as three-point seat belts, rollover protection devices, loudspeakers, cover locks, seals, and the like, in which case the complete module may be furnished as a preassembled unit from an external supplier.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

FIG. 1 is an exploded representation of a body structure with a prefabricated rear wall module, constructed according to a preferred embodiment of the present invention;

FIG. 2 is a lateral schematic view depicting fastening of the module on the B-column of the convertible according to preferred embodiments of the present invention;

FIG. 3 is a lateral schematic view depicting fastening of the module on the floor of the convertible according to preferred embodiments of the present invention;

FIG. 4 is a frontal schematic view of a module formed according to a preferred embodiment of the present invention with an integrated rollover protection device;

FIG. 5 is a diagonal schematic view of another module formed according to a preferred embodiment of the present invention with integrated loudspeakers;

FIG. 6 is a diagonal schematic view of another module formed according to a preferred embodiment of the present invention with an integrated seat belt; and

FIG. 7 is a top schematic view of a longitudinally extending member of a module formed according to a preferred embodiment of the present invention with integrated loudspeakers and a folding-top base fastened therein.

FIG. 1 illustrates a partial area of a body structure 1 for a vehicle which is formed as a convertible and comprises a floor 2, lateral side rails 3, B-columns 4 and rearward wheel houses 5. In the area of the rearward wheel houses 5, a transversely extending rear wall 6 is provided which is connected to the floor 2 and to the wheel houses 5. On both upper laterally exterior areas 7, the rear wall 6 is supported by way of longitudinally directed members 8 on the body structure disposed in front. According to the invention, the rear wall 6, including the provided reinforcements and the two longitudinally directed members 8, are combined to form a prefabricated module 9 which is manufactured outside the shell manufacturing operation for the remaining body structure.

The prefabricated module 9 is not mounted in the vehicle before the surface treatment (prime coating, painting) of the remaining body structure 1 has been carried out in an intermediate station or in the finishing stage. In the embodiment shown, the module 9 is connected with the floor 2 location depicted by at reference number 10 and with the two B-columns 4 at reference number 11. The module 9 is connected with the B-columns 4 and floor 2 with threaded connectors, such as screws, bolts, or the like, in certain contemplated embodiments. In other contemplated embodiments, the module 9 is connected with the B-columns 4 and floor 2 with an adhesive, such as glue. Embodiments are also contemplated where the module 9 is connected with the floor structure 2 and the B-columns by combination of threaded and adhesive connections.

In order to reduce weight, the prefabricated module 9 is preferably manufactured in a light metal construction or is made in one piece of plastic. In order to reduce weight and improve stiffness, the rear wall 6 as well as the longitudinally extending members 8 of the module 9 are constructed as hollow members The module 9 forms a transverse reinforcement of the body structure 1.

In addition, in the area of a longitudinal center plane A--A of the vehicle, the module 9 is connected with the body structure disposed behind it (such as a folding-top compartment). Without the inserted module, the vehicle has such a rigidity that it can be moved without problems through the paint shop to the surface treatment.

Furthermore, a number of add-on pieces may be integrated into the module 9 according to various contemplated embodiments of the invention illustrated in FIGS. 4 to 7. According to FIG. 4, rollover protection devices 12 which can be moved out in the vertical direction are housed in a hollow space of the rear wall 6 of the module 9, only one of these rollover protection devices being shown in the moved-out position B. The rear wall 6 according to FIG. 4 is also provided with diagonally extending reinforcements 13.

In FIG. 5, loudspeakers 14 are housed locally in the area of the approximately horizontally aligned, longitudinally extending members 8 of the module 9. In addition, three-point seat belts 15 or parts thereof (such as belt retractors, belt deflection element) may be provided at the module 9 shown in FIG. 6. Corresponding to FIG. 7, a folding-top base 16 for a folding top or convertible top, which is not shown in detail, is fastened to member 8 of the module 9. In the top view, the members 8 are bent at right angles, the end facing the rear wall 6 being situated farther toward the inside of the vehicle than the end facing the B-column 4.

Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example, and is not to be taken by way of limitation. The spirit and scope of the present invention are to be limited only by the terms of the appended claims.