PROCEDURE FOR THE PRODUCTION OF A MULTI-CELLULAR VEHICLE CHASSIS AND THUS MANUFACTURE VEHICLE CHASSIS

DEVICE AND PROCEDURE FOR THE PRODUCTION OF GRP COMPONENTS CONSTRUCTION UNITS

The invention is on the area of the GRP components technology and concerns a procedure and a device for the production of construction units from GRP components materials (fiber-reinforced plastics), in particular hollow parts or parts with Hinterschnitten.

Procedures for the production of GRP components construction units are well-known since longer, are suitable however only limited for the production of hollow bodies. These procedures are directed from there toward the production of dish-shaped, open construction units, which exhibit no Hinterschnitte and are simply release from formable. Further procedures are well-known, with which aids are used, in order to press fibers against a wall of a cavity. Likewise procedures are well-known, with which auxiliary layers are used, which remain at the construction unit or again are removed.

WO2006/1 22987 the same Anmelderin concerns a procedure for the production of a fiber of composite construction part. A foil is preformed e.g. by means of a deep-drawing or a blast pipe process in a first tool. This foil can be occupied outside of the actual production tool with fibers. Subsequently, the foil with the fibers is inserted into the production tool, where then the connection of the fibers with that takes place it surrounding resin. An advantage of this procedure consists of the fact that the proof pro zess within the production tool does not take place, so that this is available for the actual production process further. Likewise it is not necessary to cool the production tool down but it can be held on a constant temperature.

From the state of the art that is RTM VE so called rfahren well-known, which for the production of open or only slightly hinterschnittigen shaped parts from thermosetting polymers and Elasto meren serves. In the comparison to pressing here the molding material is pumped by means of pistons by a usually heated pre-chamber over distributor channels to the cavity (forming nest), into which the fibers were previous inserted. Disadvantages of this procedure are the long cycle times and by heating and cooling of the form caused high energy consumption. , If it concerns the production from hollow and/or hinterschnittigen construction units, is not special conventional RTM VE well-known from the state of the art rfahren suitably. Such construction units require a very complex, multipart tool concept.

A task of the invention consists pointing of it a procedure and a device to the Herstel lung at least bereichsweise a hollow or hinterschnittigen construction unit from GRP components materials. This task is solved by the independent patent claims.

The invention been based in an execution form on the employment of suitable, three-dimensional preformed, or multi-layer at least bereichsweise hollow blowing cores, wel che outside of the actual production form on the one hand as proof tool for the drying fibers and/or prepregs which can be processed and on the other hand during the actual processing process with that the fibers to be connected, when serve printing diaphragm. Good results are obtained, as the blowing cores are made by blast pipes, injection moulding or an equivalent a procedure of one or more parts. If necessary the blowing cores exhibit one or more or work-connected with one another chambers from each other locked. The blowing cores are preferably made of one application adapted comparatively thin material, which exhibits a certain natural stability, so that occupying with the fibers which can be processed becomes possible. The blowing cores used as auxiliary tools are occupied usually outside of the tool with fibers, tape or braided. If necessary they can be subjected for the increase of the stability of the structure with occupying with pressure or be filled with a runable material, e.g. sand, which is then again removed. Likewise the possibility exists to connect it temporarly with an auxiliary construction in the form of supports or other holding devices, so that occupying with fibers is simplified.

Blowing cores are made efficiently of a thermally ductile material. Depending upon area of application the following materials are suitable: Polypropylene (PP), polyethylenes Terephthalate (PET), polycarbonates (PC), PP (Pa), polymethyl metacrylate (PMMA), Polybutylenterephthalat (PBT, PBTP), PU (PURE), Acryli foils. Used depending upon material will other H first 11 muddled. Blasformverfahren are suitable, with which liquid plastic (e.g. PP) is pressed circularly from a nozzle, so that a hose develops. This hose is squeezed, after it achieved a certain length, at the lower end and blown up then, after it was brought into a closed blast pipe planned for it. For the increase of the adhesive strength of the fibers and the auxiliary of materials (e.g. adhesive, etc.) at the surface of the blowing core, the inner wall of the cavity of the blowing core can exhibit a raue or structured surface, which will transfer with blast pipes to the surface of the blowing core. If necessary a blowing core can be composed also of several parts.

Hollow or strongly hinterschnittige construction units are usually manufactured today in the prepreg technology by means of mini autoclave or autoclave hardening. With this procedure maximally four construction units per working day can be manufactured per tool, since mA nuell complex proof process can take place only in the cooled down tools. A further disadvantage consists of the fact that the surface quality is comparatively bad and an additional rework required. Besides these procedures are suitable only limited for a series production, since they are very time intensive and require high tooling expenses. In contrast to it the procedure according to invention is suitable substantially better for the employment in series production and leads to a substantial reduction of the Werkzeugkos ten over up to 30%. By the use of a blowing core as proof tool can besides without the use of Preform devices are to a large extent done.

The fibers can be interconnected very efficiently by means of an optimized, new RTM procedure. Thus it will manufacture possible hollow and/or hinterschnittige company server federal construction units e.g. for applications within the automobile range. With erfin RTM procedure (Resin transfer Moulding) dungsgemässen in contrast to the state of the art dry fibers not into an opened, at least two-piece production tool are inserted, but on a blowing core according to invention presented or temporarly fastened. Subsequently, the fibers as well as the blowing core are brought into a cavity or multipart production form. Afterwards the tool is closed and resin hardeners are injected a mixture from a mixture and a proportioning plant between the external wall of the cavity and the blowing core, in such a manner that the fibers are impregnated. The fibers are pressed by producing a difference of pressure against the external wall of the cavity, so that the building essentially formed by the fibers receives part its final geometry. The difference of pressure is produced by filling the blowing core from the outside, e.g. by means of compressed air. Alternatively or in addition the blowing core with a defined volume gas can be filled and locked then. By a vacuum IE it ren the external area is likewise reached that the blowing core expands inside the form and presses the fibers in such a way against the external wall. Additional pressure can be obtained by a chemical reaction. The pressure can be discharged by a small drilling again.

By temperature influence the injected resin (e.g. Epoxy) arrives accelerated at the hardening by precipitation. An advantage of the RTM procedure according to invention are the manufacturing suitable for series production of hollow and/or hinterschnittigen GRP components construction units by means of short cycle times. A further advantage exists in the possibility of manufacturing construction units with complex geometry and of integrating many functions into the construction unit (e.g. metal insertion hurry as connecting of elements). Depending upon area of application and need also open dish-shaped construction units can be manufactured in the same style, as the blowing core only bereichsweise is occupied. Further preformed auxiliary layers between blowing core and fibers are if necessary possible.

By means of the procedure according to invention the possibility, a construction unit exists to manufacture in such a way that all outside sides of the hollow and/or hinterschnittigen GRP components construction unit exhibit a perfect, in the tool condition and the manufacturing process defined surface quality. By the RTM procedure according to invention exists besides the possibility the actual production tool isothermally to operate, which affects pre partful the energy consumption and the construction unit costs, since this no more does not have to be cooled down and heated again. Likewise the turn-around times are affected favourably due to the isotherms of the enterprise of the tool.

In the comparison to the state of the art with the RTM procedure according to invention at an auxiliary body appropriate, preformed fiber things (Preforms) are already put together with the auxiliary body into the open, if necessary warm tool. The advantage is in the comparison to the state of the art in substantially faster bringing of the fibers into the tool, as well as the cooling which is void if necessary. Likewise it is to be manufactured for the first time possible completely closed construction units. So that textiles fiber semi-finished material can be brought with three-dimensional curved construction units as simply as possible into the form, it is favourable, if the individual cuts are interconnected first to a Preform. For this the among other things following procedures proved as favorable: a) Temperature influence and thermoplastic binders; b) Sewing or verse ticking of the cuts (situations); c) manual laying of a spraying adhesive on.

Compared with a conventional RTM procedure, with which excluding solid tools are used, as well as no hollow or only slightly hinterschnittige parts to be manufactured to be able, result besides substantial advantages regarding the tool concept. So for example Hinterschnitte in the construction unit can be illustrated less complex. By be void the multipart internal tool are reduced the tool Cesamtkosten around approximately 30 - 40%.

Depending upon area of application the blowing cores (auxiliary bodies) can remain with the procedure according to invention in the construction unit or remove e.g. by or an later brought in opening already existing again. Is the material of the auxiliary body, to select respectively the coating of the surface in such a way that an easy release from the construction unit is possible. Parts and building groups can be inserted at the beginning into the tool and/or be connected later with the finished construction unit, e.g. by sticking, welding together or by mechanical attachments.

For the production of the Preform it is necessarily, the dry fibers and/or the position structure on one essentially later geometry according to preformed to apply sufficiently sturdy auxiliary body. Since perhaps the auxiliary body can remain in the closed construction unit, it is necessary that this does not affect unfavorably the later intended purpose. Good results are obtained by means of membranförmigen Hilfskörpem, which are easy and sufficiently thin-walled, as well as if necessary by means of a fluid and/or a rieselfähigen solid, e.g. sand, fill themselves, respectively blow up to let, so that they achieve a certain inherent stability. Depending upon area of application materials for the auxiliary bodies are used, which exhibit a certain elasticity, so that the auxiliary body can be increased by admission with pressure. Auxiliary bodies are well suitable by blast pipes, e.g. in the extruding blow moulding, a thermoplastic polymer to be made or auxiliary bodies of adhesive or sewn fabric are manufactured. The individual Gewebelagen in the resin are injected by later application of pressure of this closed diaphragm. If the auxiliary body is to remain inside the construction unit, a permanent gluing with the construction unit should be ensured, in order to avoid a release during the enterprise.

If necessary as auxiliary bodies serving the blowing cores can be coated forwards or during occupying with fiber semi-finished material or taping with endless fibers additionally or submitted of a surface treatment. Likewise the possibility exists of subjecting the blowing core before inserting into the production form, provided finished with fibers, to a further processing step. Examples for this are thermal treatments, drying processes, etc. There is the possibility of providing the auxiliary bodies with a layer which penetrates the presented fibers during the production process and which Mat form rix or at least a part of it.

Fibers are occupied on the blowing core usually as semi-finished material in the form of drying fibers or previous with resin soaked fibers, e.g. prepreg (Preimpregnated Fibres) or tape. The descriptive procedure is suitable for the processing of different fiber types or a combination of it.

Depending upon area of application the blowing cores become consciously smaller (undersize) or made available with by geometry desired deviating in a defined measure, so that the application of the fibers on the blowing cores and/or inserting the same into the cavity of the production tool are e.g. simplified. As the blowing core in the production form is blown up, the fibers by the blowing core against the outside wound the cavity pressed and the part receives thereby its final geometry. With the RTM procedure exists the possibility to introduce in which the fibers and a provided a blowing core with undersize into the production form was inserted, resin before the blowing core is blown up. It is reached that the fibers would flow through more simply from the resin become. By the following thing, in a step or multi-level blowing up the blowing core, surplus resin through for it intended discharge opening channels from the cavity of the per duktionsform is pressed. Thus hollow or strongly hinterschnittige parts of high quality can be manufactured.

As the blowing core is only partly occupied with fibers, also open construction units can be manufactured. The production form can exhibit an appropriate simplified, i.e. the construction unit not completely enclosing structure.

A procedure according to invention for the production of a body from GRP components material essentially exhibits the following process steps:

a) Attach from fibers at the surface one directly or indirectly inflatable auxiliary body in the form of Cewebelagen and/or by winding technology;

b) It brings the auxiliary body into the cavity of a production form in such a manner that those

Fibers at least bereichsweise along the inner surface of the cavity are arranged;

c) It subjects the auxiliary body by means of pressure, in such a manner that the fibers are pressed against the inner surface of the cavity of the production form;

d) If necessary bringing in a Martixwerkstoffes by supplying from the outside;

e) Stick together the fibers to a construction unit;

f) Withdrawal of the construction unit after the fibers with one another stuck together.

If necessary, the auxiliary body before applying the fibers can be coated, in such a manner that the fibers can stick after the production process firmly to the surface of the auxiliary body or be solved from it. This can be achieved, as the auxiliary body is treated with a bonding agent, e.g. in the form of adhesive or with parting agent.

If necessary, the fibers on the exterior (i.e. the auxiliary body opposite side) with a further auxiliary body, e.g. in form a deep-drawing, can Spritzgies be sen or blast pipes of a manufactured thermoplastic foil be provided.

Likewise the possibility exists, at the same time or in several work procedures successively several with fibers totally or partly covered auxiliary bodies in or several production tool to interconnect or adapt together.

The production tool can be multipart out-arranged or, so that the auxiliary body and the brought in fibers are completely or only partly enclosed during the production process.

Pressure on the laminate is applied when hardening by the internal pressure (air) in the core. With a hollow construction unit the possibility exists of arranging this tool-falling so that it is completely surrounded by the tool. This has the advantage that later no outline trimming is necessary.

When production tools are suitable particularly tools with cavities made of metal, e.g. steel or aluminum, which result in a particularly high surface quality and a high reproduction accuracy. Depending upon area of application other materials are possible.

In an area of application good results are obtained, as the enterprise of a work of zeuges for the execution RTM VE according to invention rfahrens with approximately 900C takes place. The curing time amounts to thereby approx. 30 minutes. Depending upon geometry and structure, as well as the kind and thickness of the materials which can be processed these values can deviate. If necessary the Clastemperatur (Tg) can be increased by means of a thermal treatment downstream.

The procedure revealed here is suitable for the production of structure parts, e.g. for vehicles or airplanes, which are exposed to a high demand a small weight to exhibit however nevertheless are. The procedure makes possible for example vehicle chassis with a complicated, if necessary more-cellular, to manufacture structure in very short time and with high quality. There is the possibility of combining open and closed structures in a processing step. Several blowing cores are combined, in order to develop the structure. Likewise the possibility exists of combining a blowing core with other manufacture procedures. In order to obtain an optimal result, prefabricated structure parts from fibers or other materials can be inserted into the production form. The production form can exhibit for this purpose retaining means e.g. in the form of openings or projections/leads.

In principle the possibility exists to insert further parts into the production form, which is a late component of the finished GRP components construction unit. E.G. a basic can be composed or more-cellular chassis of a vehicle or a Bestanteile of it of one or more Hilfskörpem. Further components can be work-connected in the same work procedure. E.G. fittings or honeycomb structures from metal or another honeycomb material, in addition, foam made of plastic or metal can be inserted and enclosed totally or partly by fibers. Thus highly complex parts with a multiplicity of functions can be manufactured very economically.

During the production of a hollow body as for example a Tankes for gas, liquids of the solids, the blowing core can remain inside the tank over after the production as sealing layer for the fluid which can be kept inside the tank to serve. Even if exists the possibility of integrating at the same time that or the necessary connections in a processing step which serves or the removal of the fluid later. For special on idioms the blowing core can be developed out several layers, which take over them assigned special tasks. As an internal layer is very flexibly trained e.g., so that it pulls itself with an emptying together, the possibility exists of realizing tanks which do not exhibit dead volume within the range of the fluid. A further example of use are printing bottles for compressed gas. Usual printing bottles exhibit a comparatively high weight, which affects itself negatively among other things in the case of transport.

An execution form of the procedure according to invention for the production of a GRP components construction unit essentially exhibits the following process steps:

a) Make available, a closed auxiliary body made of a foil;

b) Attach from fibers on the auxiliary body outside of a production form;

c) Bring the auxiliary body with the fibers into a cavity of a production form;

d) Latches of the production form in such a manner that the auxiliary body and the fibers are enclosed inside the cavity;

e) It produces for a difference of pressure between the inside of the auxiliary body and the environment, in such a manner that the volume of the auxiliary body becomes larger, in such a manner that the fibers are pressed by means of the auxiliary body against an inner wall of the cavity;

f) Stick together the fibers;

g) Withdrawal of the construction unit from the production form.

The auxiliary body can exhibit if necessary for the enlargement of the volume an opening for bringing in a fluid. Alternatively or in addition the auxiliary body can exhibit for the enlargement of the volume inside a propellant. E.G. a liquid with according to low boiling point can be brought in, with reaches a certain temperature level evaporated and thus the pressure increased. Depending upon area of application the auxiliary body exhibits geometry, which is constantly or essentially place-dependently variable 1% to 20% smaller than the cavity of the production form. Thus bringing into the production form or the attachment of the fibers can be facilitated.

The invention described on the basis by, into that following figures remark with shown play more near. Show schematically and simplifies:

Fig. 1 the production of a blowing core;

Fig. 2 the attachment of fibers at a blowing core;

Fig. 3 bringing in one with fibers occupied blowing core into a production form;

Fig. 4 a sectional view by a production form;

Figure 1 shows schematically and strongly simplified like a blowing core 1 by blast pipes (Extru sionsblasen) in a processing step in a here two-piece blast pipe tool 2 is manufactured. The blast pipe tool 2 exhibits a lower part 3 and an upper section 4, which one half exhibit each of a cavity 5. First continuously or also intermittent a hose (more near not represented) from hot, ductile plastic from ange flanged tool as preform under assistance of the force of gravity perpendicularly downward extruded. Material thickness in the hose is regulated thereby according to the form of the finished workpiece. Then a thorn (more near not represented) from above or down brings in into the hose. At this time still opened split blast pipe work drives then to and coats the hose with the thorn inside the cavity 5. by the thorn compressed air into the hose is then pressed, with which this is blown up and pressed and cooled down to the outer contour of the cavity inside the blow tool. The plastic adapts so to the given form and hardens. By variation of material thickness in the hose the thickness of the plastic in the finished product can be steered purposefully. The blowing cores are made depending upon area of application of different materials. Among other things the following materials for the blast pipes are suitable: Polyolefins, above all polyethylene (PE) and polypropylene (PP); Plexiglass (PMMA); Polycarbonate (PC); PP (Pa); thermoplastic PU; thermoplastic elastomers (TPU).

Blowing cores can be made depending upon area of application also on other way and of other materials or combinations of it, be welded together or stuck e.g. in that them from several spraying pouring hurrying. Likewise the possibility exists to make the blowing core of fabric, which is impregnated before or afterwards or coated, so that it receives the necessary characteristics. The fabric can be joined by sewing, sticking or welding.

Figure 2 shows like a blowing core 1 with fibers 10 is occupied. Alternatively or supplementing the blowing core 1 can also with fibers tapes to become. Likewise the possibility insists of processing more than a kind of fiber of attaching respectable on the blowing core. In principle all well-known fibers can be processed in accordance with the procedure described here. Likewise stands the possibility of integrating prefabricated parts or building groups or of attaching inscriptions.

The blowing core 1 is provided and closely locked with a valve 1 1. For the attachment of the fibers 10 blowing core 1 was fastened here to a supporting device 12. Other mounting plates are possible.

Figure 3 shows a production form 14 in opened condition with a cavity 1 5 on the inside into the one blowing core 1 provided with fibers 10 is inserted. The production form shown is suitable for the RTM procedure according to invention and consists here of a lower part 16 and an upper section 1 7, which can be opened and closed over a hinge connection 18. The production form 14 exhibits in or several first and second connections 19, 20 for and the removal of resin. Likewise is present in or several third connections 21, by means of which a blowing core 1 can be blown up with closed production form on the inside with compressed air or another fluid. With a RTM process the production form is usually heated, so that the reaction of the resin is accelerated. For this purpose the production form points inside means for heating and connections to the energy input to (more near not represented).

The cavity 1 5 exhibits here geometry of the final construction unit. If necessary aids can e.g. in the form of intermediate foils or layers, which remain later at the construction unit or again from this are removed. Good results are obtained with in the WO2006/122987 described procedure the same Aπmelderin. A foil is brought thereby previous by deep-drawing, blast pipes or injection moulding into defined geometry and serves as intermediate layer or auxiliary layer, which into the cavity 15 of the production form 14 is inserted separately before the blowing core 1 into these is inserted. If necessary this intermediate layer can be occupied alternatively or supplementing likewise with fibers (more near not represented).

In the execution form shown the blowing core 1 exhibits geometry, which in a defined measure of geometry of the cavity 15, respectively, the finished construction unit (not represented), deviates. This facilitates the attachment of the fibers, respectively inserting into the cavity 15. Only by blowing the blowing core 1 up with closed production form the fibers are pressed against the wall of the cavity 15 and achieve so its final geometry (see for this figure 4).

Figure 4 shows a cut by a production form 14 in accordance with figure 3 in closed

Condition. Inside the cavity 15 are a blast pipe 1, which is blown up from the outside by a compressed air connection 21 with compressed air. Fibers 10 of a construction unit are pressed thereby controlled against the wall 22 of the cavity 1 5. Depending upon Anwendungsge

CORRECTED SHEET (RULE 91) to ISA/EP offer takes place blowing the blowing core up before during or after resin was led by the appropriate connections 19, 20 by the fibers 10. The pressure inside the blowing core is stopped depending upon application and applied in one or more stages. Concerning the process parameters is a comparatively large range too fin that; e.g. a construction unit is hardened depending upon geometry and injection time between 800C and 1200C. In an example of use blowing cores are filled when injecting with 0 to 8 bar positive pressure. When hardening and pressing out of resin the pressure is increased to 6 to 12 bar. By variation of the pressure and/or the temperature according to a pre-defined profile by gradual or continuous increasing and/or making smaller impregnating the fibers with resin can be optimized. In place of the RTM VE rfahrens also prepregs can be used. The production form 14 is dimensioned accordingly. In order to obtain completely closed bodies, the blowing core before bringing into the production form with a certain Casvolumen can be filled and locked then. After bringing into the production form that is miert external area vakuu. It is reached that the blowing core expands inside the cavity 1 5 and is pressed the fibers against the external wall 22. Supporting a increased tool temperature affects itself.

BEZUGSZEICHENUSTE

1 blowing core

2 blast pipe tool

3 lower part

4 upper section

5 cavity

10 fibers

1 1 valve

12 supporting device

14 production form

15 cavity

16 lower part production form

17 upper section production form

18 hinge connection

19 Aπschluss for resin supply

20 connection for resin removal

21 connection for filling the blowing core

22 inner wall of the cavity

23 heating

CORRECTED SHEET (RULE 91) ISA/EP