METHOD AND FIXING FOR JOINING BODY MODULES

Field of the invention

The invention relates to a method and a fixing for joining body modules, in particular plastics body modules of a motor vehicle.

Background of the invention

It is known from EP-OS 01 80 554 that different variants of a vehicle can be manufactured by a modular technique. A frame is manufactured, which is common to the variants, and different modules are attached to the frame to form the different variants, for example a hatchback or an estate car version of the same vehicle.

It is also known that such modules can be manufactured from plastics material and joined to one another by means of an adhesive. Such adhesive joints with plastics compounds, which are designed to be permanently elastic to avoid noise generation and the like, necessitate suitable fixing of the body modules to be joined together, during the curing time of this plastics compound.

Description of the known prior art

A fixing for fitting a vehicle door to a body part is known from DE-PS 33 40 634, in which a solid plug provided on one component is received with clearance in a socket mounted in the other component. The space between the plug and the socket is subsequently filled with a relatively fast curing plastics compound which is injected into the cavity under pressure from the end of the socket opposite to the end froi: which the plug is introduced into the socket.

There are two disadvantages with the above proposal. First, access is required to both ends of the socket to allow the plug to be introduced from one end and the curable plastics material to be injected from the other. Second, if a module has several such plug and socket fixings along the adhesive joint, it is difficult to manoeuvre the modules to locate all the plugs at the same time within theirs respective sockets and this difficulty is compounded by the fact that there will inevitably be tolerance errors in the location of the plugs and sockets on their respective modules.

DE-PS-26 02 433 described the securing of a wall mounting plug in a wall to enable a screw to be fixed to the wall. The plug is placed in a hole pre-drilled into the wall and a curable plastics material is injected through the plug into the gap between the plug and the wall. In this way, the plug is held firmly in the wall and one does not rely on the expansion of the plug, which occurs when a screw is driven into the plug, to grip the wall.

Object of the invention

The invention seeks to provide a method and a fixing which enable plastics body modules of motor vehicles to be joined together more simply and in which it is sufficient to have access to only one side of the modules which are to be joined.

Summary of the invention

According to one aspect of the invention, there is provided a method of joining two components, such as plastics body modules of a motor vehicle, characterised by the steps of providing inserts recessed into the mating surfaces between the two components, the inserts being opposite one another when the components are in the position in which they are to be joined, there being in

each pair of facing inserts a first insert having the form of a socket open at only one end and a second insert having the form of a sleeve open at both ends, holding the components together in the position in which they are to be joined, inserting into each pair of aligned inserts a hollow plug which is received with clearance in the two inserts, and injecting a curable plastics material through the hollow plug into the space between the plug and the two inserts, the plastics material being injected from the same side of the modules as the plug is introduced into the aligned inserts.

Because there are no protrusions from either of the modules to be joined to one another, the latter can readily be position relative to one another, if necessary after the application of a permanently elastic jointing compound. The insertion of the plugs and the injection of the plastics material into the inserts can be carried out in a manner corresponding to tack welding of conventional sheet metal body parts.

According to a second aspect of the invention, there is provided a fixing for joining two components, such as plastics body modules of a motor vehicle, characterised by two inserts to be arranged opposite one another in the two components along the mating surface between the two components, a first insert having the form of a socket open at only one end and the second insert having the form of a sleeve open at both ends, and a hollow plug having an inner end capable of being received with clearance in the two inserts, the outer end of the hollow plug being adapted for connection to a plastics material injection unit to enable a curable plastics material to be injected through the hollow plug into the space between the plug and the two inserts.

Because there is clearance between the plugs and each of the aligned inserts, a substantial degree of misalignment

between the inserts in each pair can be tolerated without impairing the insertion of the plugs and the injection of the fast curing plastics material.

By suitably shaping of the free end of the hollow plug to form a tight fit with an injection unit, the hollow plug can be used directly as an injection nozzle which allows rapid and deep penetration of the plastics material into the inserts and their complete filling.

If the walls of the inserts are provided with annular grooves, thread-like grooves or similar keying formations, not only is the common surface between socket and plastics material increased for better adhesion, but a positive keying is also produced.

Advantageously, the hollow plug may also be provided with annular grooves, thread-type grooves or transverse openings, to improve the adhesion of the plastics material and its distribution in the inserts.

Conveniently, the inserts may be formed as tubular inserts of metal or plastics material set into into the plastics body modules. In this case, they can be constructed in a desirable manner without the need for cores in the plastics body modules.

If an annular seal is arranged in the region between the inserts, undesirable escape of the curable plastics material can be avoided.

The curable plastics compound may suitably consist of a reaction plastics material (a multi-component thermo- setting plastics material) which hardens in a load-bearing manner after a predetermined short period of time, or can consist of a fusible plastics material (thermoplastic material) which solidifies in a load-bearing manner after a predetermined short period of time.

Brief description of the drawinσs

The invention will now be described further, by way of. example, with reference to the accompanying drawings, in which:

Figure 1 shows a partial section through a joint between a plastics roof module and a plastics side wall module at the moment of injection of the curable plastics material,

Figure 2 shows a similar joint to Figure 1, at a different position and without introduced plastics jointing compound, on completion of injection of the curable plastics material,

Figure 3 shows an exploded view of a joint between a plastics floor pan module and the door threshold region of a plastics side wall module with the necessary individual parts prior to assembly, and

Figure 4 shows a partial section through the joint between the plastics floor pan module and the door threshold region of the plastics side wall module.

Detailed description of the preferred embodiments

In the joint between two plastics body modules, shown in Figures l and 2, a plastics roof module 1 is constructed as a sandwich component with an external surface layer 2, an internal surface layer 3 and a filling core 4.

A plastics side wall module 5 is similarly constructed as a sandwich component with an external surface layer 6, an internal surface layer 7 and a core layer 8.

A vehicle door 9, also designed as a plastics component, co-operates with the plastics side wall module 5 in the usual way via a seal if

The two plastics body modules, the roof module 1 and the side wall module 5, have overlapping 11 and 12 as well as 13 and 14 into which a permanently elastic plastics joining compound 15 requiring a relatively long curing time is introduced.

At strategic points in the roof module 1 as well as in the side wall module 5 there are provided plug and socket fixings. The sockets of the fixings are formed in two initially separate parts constituted by inserts which are arranged in the plastics modules. In particular, inserts

18 are formed in the roof module 1 which have through bores defining cavities 16 open at both ends and inserts

19 are formed in the side wall module 5 which define cavities 17 open at only one end.

In the embodiment illustrated in Figure 1, the inserts 18 and 19 are additionally formed with annular or thread-like grooves 20 and 21. The inserts 18 and 19 can be prefabricated from either metal and plastics material and can be integrally set into the plastics body modules at the strategic points without the need to resort to pull cores in order to prepare the cavities.

A hollow plug 22 with an undulating outer contour 23, an open tip 24 at its inner end and an open outer end 25, which is preferably constructed such that it can be loaded with the rapidly curing plastics compound 27 directly by an injection unit 26, is inserted into the mutually aligned cavities 16 and 17. The outer end 25 of the hollow plug 22 is preferably constructed such that it can be covered by superimposed components, for example a blanking cap 37 or a handle 38 (shown in dot-dash lines) .

As shown in Figure 2, the fixings at different strategic points between the roof module 1 and the side wall module 5 can have different dimensions in order to allow for the local conditions. In the illustrated section through the

roof frame of a plastics motor vehicle body, the cavity 17' in the roof module 1 is relatively short while the 16' in the side wall module 5 is kept larger. The corresponding hollow plug 22' is adapted accordingly.

In the joint between a plastics floor pan module 28 and the door threshold region of the side wall module 5 shown in Figures 3 and 4, other advantageous developments of the invention can be seen.

The plastics floor pan module 28 is again constructed as a sandwich component having an external surface layer 29, an internal surface layer 30 and a core layer 31, reinforcing layers 32 and 33 being in this case added in other areas as required.

The plastics side wall module 5 still has an external surface layer 6, an internal surface layer 7 and a core layer 8 but is additionally provided with reinforcing layers 34 and 35.

The reinforcing layers 32 and 33 or 34 and 35 can be formed by corresponding reinforcing fabric inlays or by sheet metal inlays. The blind cavity 17" constructed in the floor pan module 28 is formed in this case by an insert 19" and the through cavity 16" provided in the side wall module 5 is formed by a tubular insert 18". The important feature of this arrangement, however, is that these tubular inserts 19" and 18" are appropriately surrounded and supported by the corresponding reinforcing layers 32 and 33 or 34 and 35.

A tubular plug 22" of suitable length is provided to join together the two inserts. Between the regions of the two plastics body modules which, under certain circumstances, may fail to lie completely on one another, there can be arranged an annular seal 36 which prevents an undesirable escape of the curable plastics material 27. The free end

of the hollow plug 22" can again be sealed by a blanking cap 37".

As shown, in particular, in Figures 2 and 4, it is not absolutely essential for two plastics body modules which are to be joined together also to be joined over broad surface regions by a permanently elastic plastics jointing compound.