DE102010050874B4 - Motor vehicle structural component made of semi-finished parts connected by means of a node element and manufacturing method - Google Patents

Abstract

Motor vehicle structural component, which consists of at least two semi-finished components (1, 1 ', 1' ') of a fiber-plastic composite pultrudate, which are connected by means of a cast node element (3), wherein the semi-finished components (1, 1', 1 '') have at least one hollow volume (5) lying underneath them, wherein the nodal element (3) consists of a casting material of an aluminum or magnesium alloy on at least one wall (2, 2 ') of a connecting end of each of the at least two semifinished products to be joined. Components (1, 1 ', 1' ') of • a fiber-plastic composite pultrudate is molded positively, wherein the semi-finished components (1, 1', 1 '') outside of the node element (3) are free of casting material, said the cast node element in a region in which it comes to the connecting ends to the system, passage openings (8) for connecting pins, characterized in that the connecting end of the semi-finished components (1, 1 ', 1' ') corresponding through openings (8 ') for receiving the connecting pins and used to form the passage openings (8') in the cast node element (3) inserts are used.

Description

The invention relates to a motor vehicle structural component according to the preamble of claim 1. Furthermore, the invention relates to a corresponding manufacturing method.

So far, structural elements made of fiber composite plastic such as pultrusions or profiles to form a motor vehicle structural component with very time-consuming joining techniques, such as gluing and screwing together. This adds additional component weight and cost. In addition, it is very difficult to fit the FRP structural elements true to size.

From the DE 198 22 731 A1 For example, a method of manufacturing a frame for a vehicle is known in which the node element and the carrier are connected together by magnetic forming. There, the node elements are manufactured in a casting process to form connecting flanges for the carriers. At the flanges, there are sockets, which generate the positive connection by the magnet forming.

The DE 100 26 981 A1 discloses a hollow beam for a motor vehicle body, which is designed so that a load-specific design and, above all, significant weight reduction can be achieved in a simple manufacturing manner. The hollow carrier consists of a prefabricated, shaping inner profile part and an outer, integrally molded with the inner profile part, load-bearing light metal cast body. The light metal cast body is provided at least on one side with an inner profile-free, simultaneously cast with the inner profile end portion, which is formed on a reusable, tool-side, the inner profile part during the casting process-fixing mold core.

DE 10 2005 050 964 A1 describes a structural part for a body of a vehicle and method for its production, wherein the structural part should have an improved energy absorption behavior and can be relatively easily formed. For this purpose, the structural part, which is integrally formed in a casting process, an integrated reinforcing element, which is at least partially formed of reinforcing fibers and is positioned accurately positioned in the structural part. The reinforcing fibers are encapsulated by the metallic material. The manufacturing process therefore involves positionally accurate introduction of the reinforcing element into an open mold, and after closing the mold, pouring a metallic material into the mold so that the reinforcing fibers are encapsulated by the metallic material. Out EP 0 944 472 B1 is a plastic molding having a thermoplastic polymer composition which forms the molding and having a load bearing structure which is integrated into the molding and surrounded by the thermoplastic polymer composition. The load-bearing structure has an endless fiber reinforcement, which consists of several individual, interconnected, high-strength structural elements. In this case, all connection points between the individual structural elements are surrounded by the thermoplastic polymer compound as connecting regions.

In the DE 198 08 392 A1 For example, there is disclosed a method of manufacturing a lightweight alloy alloy casting. The method provides that a casting core is poured or cast to form the cavity.

Based on this prior art, it is desirable to enable the economical joining of fiber composite plastic structures with each other or the joining of fiber composite plastic structures with Leichmetall structures with the correct introduction of force and power transmission. This object is achieved by a motor vehicle structural component with the features of claim 1.

The object of providing a simple method for connecting FRP structures by means of a node element with the smallest possible number of tools and manufacturing steps is achieved by a method having the features of claim 4. Further developments of the objects and the method are disclosed in the subclaims.

A first embodiment relates to a motor vehicle structural component, which consists of two or more semi-finished components, which are connected by means of a cast node element. The semi-finished components consist of a fiber-plastic composite pultrudate, and have at least one internal hollow volume. According to the invention, the node element is molded onto at least one wall of a connecting end of each of the semi-finished components to be connected in a form-fitting manner, while the semi-finished component outside the node element is free of casting material. The essential part of the motor vehicle structural component is thus formed by the FRP components which are simply joined via a node cast on at their connecting ends.

Thus, the advantages of the very high fiber content and the load-oriented structures of the FRP components can be achieved by connection via a cost-effective casting node while compensating component tolerances and maintaining the correct introduction of force and power transmission in the production of Automotive structural components are used and allow an optimization of costs and lightweight construction.

The casting material is an aluminum or magnesium alloy.

The molded node element can penetrate into a cavity portion which is present at the connecting ends of the semi-finished components, alternatively or additionally, the node element can enclose an outer wall of the connecting ends of the semi-finished components, or come to rest there.

It is further provided that the node element and the semi-finished components have passage openings for connecting pins. The node element has the passage openings in the area in which it comes to rest at the connecting ends of the semifinished components; Accordingly, the passage openings of the semifinished components are also present at the connection ends and are congruent with the passage openings of the node element.

Cast-in inserts are used to form the openings in the cast node element. It may be sleeves or internal thread, which are formed for example of metal. This ensures that the knot, which forms a positive fit with the semi-finished products in any case, can additionally be fastened to the semifinished product so that the formed component has the desired stability in the knot region.

A further embodiment provides that in a region in which the node element adjoins the wall of a connection end, there is an adhesive bead.

A method according to the invention for connecting two or more semifinished component parts by means of a node element relates to semifinished component parts made of a fiber-plastic composite pultrudate which has at least one internal hollow volume. The node element is formed from a cast material. For this purpose, the semi-finished components to be joined are first of all placed in a precise position in a casting mold. In each case, the connection end of the semi-finished component parts to be connected is inserted in relation to a cavity of the casting mold such that the connecting end adjoins at least the cavity. The cavity serves to form the shape of the node element.

This is followed by closing the mold and introducing the casting material into the cavity, casting one or more walls of the connection end of the respective semifinished component with the casting material. By solidifying the cast material to form the node element, a positive connection between the wall of the respective connecting ends and the node element is formed. The joining method according to the invention of directly casting a node structure onto the FRP structures significantly reduces the number of tools required and the number of production steps in the production of complex motor vehicle structural components. In addition, a force exerted on the component can be better introduced into the structure and transferred further and thus the material can be better utilized.

In one embodiment, it is also conceivable that the connecting ends of the semi-finished component parts to be joined extend into the cavity of the casting mold so that the formed node element encloses the connecting ends of the semi-finished component parts to be joined. The further component sections are according to the invention free of casting material.

In a variant of the method in which the internal hollow volume of the semifinished component is open at the connection end, so that the semifinished component is arranged in or on the cavity such that the hollow volume opens into the cavity and thus provides a flow path for the casting material, a casting barrier is introduced into the hollow volume before the step of positionally accurate insertion of the semi-finished component, which is arranged near the connecting end and thus prevents further penetration of the casting material into the hollow volume. The cast node element thus remains limited to the area of the connection ends. There, a massive section can be formed.

In a further method embodiment, it is provided that, prior to introduction of the casting material into the cavity, a preform having fibers is arranged in the cavity. The fibers may be metal fibers, carbon fibers, glass fibers and / or textile, in particular aramid fibers. In this case, at least one of the walls of the connecting ends of the semi-finished component parts to be joined comes to rest on the preform, which in the subsequent step is penetrated and / or encapsulated by the casting material when the casting material is introduced. This preform may be a mold core, in particular a fiber preform surrounding a sand core. Due to the preform having reinforcing fibers, the node element is reinforced.

Even without the use of a fiber having preform, it is conceivable that prior to the introduction of the casting material into the cavity, a mold core such as a sand core is introduced into the cavity to the node elements to be formed there with to equip an internal cavity to continue to take into account the lightweight design.

Finally, an embodiment provides that at the connecting end of the semi-finished component dams are provided on an Innewandung while the cavity of the mold is designed such that spacers are formed having a shape to be received between two dams, between the dams, in which no spacer is added, adhesive beads are introduced.

These and other advantages are set forth by the following description with reference to the accompanying figures. The reference to the figures in the description is to aid in the description and understanding of the subject matter. Articles or parts of objects which are substantially the same or similar may be given the same reference numerals. The figures are merely a schematic representation of an embodiment of the invention.

Showing:

1a FIG. 2 a side sectional view of the joining area between two fiber-plastic composite pultrudates and a cast node element, FIG.

1b a view accordingly 1a , but with a fiber-containing preform in the node element,

2 a perspective top view of the joining region between a further FRP pultrudate and a node element according to a further embodiment of the invention,

3 3 is a perspective top view of a further embodiment of two FRP structures connected by means of a node element,

4 a perspective view of a motor vehicle structural component according to an embodiment of the invention, in which three FRP structures are connected by means of a node element,

5 a perspective view of three FRP structures, which are connected via two node elements,

6 a perspective sectional view through a connecting end of a FVK structure with cast node element part, in the means of spacers, the realization of defined Kleberaupen between Gussknotenelement and the FVK structure is enabled.

The motor vehicle structural component according to the invention consists of several, but at least two semifinished components and at least one cast node element. The semifinished components used can be a fiber-plastic composite pultrudate, hereinafter also referred to as FRP structure, which corresponds in particular to the desired lightweight construction of a motor vehicle through an internal hollow volume and through the force flow-oriented arrangement of the reinforcing fibers. For the production of more complex motor vehicle structures several such FRP structures must be joined together, a time-consuming adhesive technique increases the weight of the component as well as the costs and is difficult due to the production-related deviations in the FRP structures.

The manufacturing method according to the invention enables the economical joining by direct pouring of the FRP structures into the knots in exact positioning to each other while compensating component distortions. It ensures the correct introduction of force and power transmission. Due to the very high fiber content of the pultrusion profiles, load-optimized structures can be realized by means of this simplified joining technique with maximum material utilization and consistent lightweight construction.

1a shows the connection region of a motor vehicle structural component, in which a FVK pultrudate by means of a casting node 3 approximately at an angle with another FVK pultrudate 1' is joined together. From the FVK pultrudates 1 . 1' only the connection ends are represented by the node element 3 are poured around. However, the main part of the FRP profiles is (not shown figuratively) outside the enveloping casting node 3 , In this way, the motor vehicle structural component is provided with optimum strength with the greatest possible weight saving.

The casting material is an aluminum or magnesium alloy. Since only the connecting ends of the FRP structures 1 . 1' are molded, the temperature entry in the FRP profile is lower than when the FRP pultrudate is completely encapsulated. To get a good bond between FVK pultrudates 1 . 1' and the casting node 3 It is conceivable to ensure the FRP profiles 1 . 1' for example, with additional fiber windings 10 equip the profiles 1 . 1' on the outside wall 2 give a certain roughness.

Alternatively, on the outside wall 2 an adhesion-promoting coating may be provided.

Since the semi-finished parts 1 . 1' fiber-reinforced, they must, despite their internal hollow volume 5 not during the casting process Internal pressure to be applied. However, it is beneficial to have a cast barrier before the casting process 4 near the connection end in the hollow volume 5 to arrange the casting material only to a certain extent in the internal hollow volume 5 along the inner wall 2 ' to let penetrate and thus provide a particularly good fit and the unwanted pouring of the semi-finished component 1 . 1' to prevent.

Conceivable, however, are variants in which the FRP pultrudate is formed in this joining region solid or at least with thicker wall thickness in order to better withstand the die casting process or to form a casting barrier.

1b shows a joint of two FVK pultrudates 1 . 1' by means of a node element 3 which are essentially the ones out 1a corresponds, but here is an amplification of the casting node 3 with a fiber preform 6 in front.

The fibers may be metal fibers, carbon fibers, glass fibers, aramid or other common reinforcing fibers. At the preform 6 It may be a prefabricated, for example, on a sand core kraftschlussgerecht wound textile preform 6 Act together with the FVK pultrudates 1 . 1' in a mold to form the node element 3 is inserted so that not only the Verbindungsendbereiche the FVK pultrudate 1 . 1' , but also the textile preform 6 is cast around the aluminum or magnesium casting material.

The mold is equipped with a cavity corresponding to the shape of the knot to be formed. At the in 1a and 1b illustrated node elements 3 ' The FRP pultrudates will extend into the cavity of the mold so that they can be poured over. In this case, the FRP pultrusions can be fixed during the casting process, this can be done via appropriate tool parts or, for example, by a mold core piece, which also represents the casting barrier.

2 shows an alternative node element 3 which is not molded around the connection end of the FRP pultrudate, but forms a pin in a through the inner wall 2 ' limited recess of the FRP pultrudate extends into it.

This recess can through a cast barrier 4 be limited, which may be created for example by an adhesive. To the connection between the FVK pultrudate 1 and the node 3 To reinforce both the FRP pultrudate 1 . 1' as well as the node element 3 corresponding passage openings 8th . 8th' have, in which pins or screws can be inserted. The passages 8th' at the FVK pultrudate 1 . 1' can thereby with radially and concentrically around the passage opening 8th' arranged reinforcing structures may be provided, which is an interruption of the power flow in the FRP pultrudate 1 . 1' through the passages 8th' Stop and reinforce in the area of the openings.

3 shows another alternative joint line between node element 3 and FRP pultrudate 1 . 1' , here is the connecting wall 2 Stepped dar. Here are openings 8th in the node element 3 and here not visible through openings in the FVK pultrudate 1 . 1' provided to strengthen the connection. In general, it is also conceivable that the contact area between node element 3 and the wall 2 of the FRP pultrudate is provided with an adhesive.

4 shows a section of a motor vehicle structural component, in which three semi-finished components 1 . 1' . 1'' a node element 3 are connected. Here is the form fit between the respective FVK pultrudates 1 . 1' . 1'' and the node element via a node element 3 extending peg-shaped section instead, extending into one through the inner wall 2 ' limited recess of the respective Pultrudats 1 . 1' . 1'' extends.

The fiber composite plastic pultrudate may exhibit fibers deposited at 0 °, 90 °, and ± 45 °, as shown, around the apertures 8th' in which screws 11 can be arranged, radial and circumferentially concentric fiber reinforcement structures are provided. Again, to limit the recess in the FRP pultrudate a cast barrier 4 , which can also be made of adhesive, be provided.

5 shows three FRP pultrudate structures 1 . 1' . 1'' each of which two by means of a node element 3 are connected. The node elements 3 allow any, angled arrangement of the various FRP pultrudates to each other, and therefore can also be designed differently even in their design and, for example, to save weight cavities 12 or footbridges 13 have to connect further structures. At the contact points between the respective FRP pultrudates 1 . 1' . 1'' and the node 3 is a glue bead 9 intended. Also is to secure the connection here a screw 11 provided in the joining area.

6 shows a particular embodiment of the connection between node element 3 and FRP pultrudate 1 , with which a defined bead of glue 9 between the node element 3 and the FVK structure 1 with the help of spacers 7 . 7 ' can be realized. On the inner wall 2 ' of the FRP profile 1 are dams 7 provided as a spacer, while the cast-in node 3 with present four spacers 7 ' is poured, which are each recorded between two dams. Between the other dams 7 becomes the glue bead 9 brought in.

Finally, it is conceivable that the node element comprises a fiber reinforcement, which also has a fiber composite plastic powder rutate with fiber directions in 0 °, 90 °, ± 45 °, ± 60 °, etc. quasi-isotropic. There can of course also hole reinforcements, be provided radially and concentrically circular around the passage openings. This preform is inserted together with the pultruded semi-finished components in the cavity of the mold and encapsulated by a casting material in the manner described.

To form a cavity in the node member to make the node lighter, a removable mandrel, such as a sand core, may be used.

Thus, the object according to the invention provides an economically joined motor vehicle structural component made of fiber composite plastic structures, which satisfies the lightweight construction concept and nevertheless allows a correct introduction of force and power transmission.

Claims (10)

Motor vehicle structural component comprising at least two semifinished components ( 1 . 1' . 1'' ) consists of a fiber-plastic composite pultrudate, which by means of a cast node element ( 3 ), the semifinished components ( 1 . 1' . 1'' ) at least one hollow volume lying to them ( 5 ), wherein the node element ( 3 ) of a casting material of an aluminum or magnesium alloy on at least one wall ( 2 . 2 ' ) a connecting end of each of the at least two semi-finished components to be joined ( 1 . 1' . 1'' ) is molded from a fiber-plastic composite pultrudate form fit, wherein the semifinished components ( 1 . 1' . 1'' ) outside the node element ( 3 ) are free of casting material, wherein the cast node element in a region in which it comes to the connection ends to the system, passages ( 8th ) for connecting pins, characterized in that the connecting end of the semi-finished components ( 1 . 1' . 1'' ) corresponding passage openings ( 8th' ) for receiving the connecting pins and for forming the passage openings ( 8th' ) in the cast node element ( 3 ) cast inserts. Motor vehicle structural component according to claim 1, characterized in that the node element ( 3 ) in at the connecting ends of the semifinished components ( 1 . 1' . 1 ) present cavity sections and / or around a wall of the connecting ends of the semifinished components ( 1 . 1' . 1'' ) comes to the plant. Motor vehicle structural component according to claim 1 or 2, characterized in that at least one adhesive bead ( 9 ) in an area between the cast node element ( 3 ) and the wall ( 2 . 2 ' ) is provided one of the connection ends. Method for joining at least two semifinished components ( 1 . 1' . 1'' ) from a fiber-plastic composite pultrudate, by means of a node element ( 3 ) of a casting material, to a motor vehicle structural component, wherein the semi-finished component parts ( 1 . 1' . 1'' ) at least one internal hollow volume ( 5 ), comprising the steps of a) inserting the semi-finished component parts to be joined ( 1 . 1' . 1'' ) positionally accurate in a mold, wherein in each case a connecting end of the semi-finished component parts to be joined ( 1 . 1' . 1'' ) adjoins at least one cavity of the mold, wherein the cavity has a shape for forming the node element ( 3 b) closing the casting mold, c) introducing the cast material from an aluminum or magnesium alloy into the cavity, at least on one wall ( 2 . 2 ' ) of the connection end of the semifinished components to be connected ( 1 . 1' . 1'' ) casting the casting material from a fiber-plastic composite pultrudate, d) allowing the casting material to solidify, the node element ( 3 ) and wherein a positive connection between the wall ( 2 . 2 ' ) and the node element ( 3 ), wherein the cast node element in a region in which it comes to the connection ends to the plant, passages ( 8th ) and the connecting end of the semifinished components ( 1 . 1' . 1'' ) corresponding passage openings ( 8th' ), are introduced through which pins or screws, characterized in that inserts are molded from sleeves or internal threads to form the passage openings in the cast node element. Method according to claim 4, wherein the connecting ends of the semifinished components ( 1 . 1' . 1'' ) extend into the cavity of the mold. Method according to claim 4 or 5, wherein at least one semifinished component ( 1 . 1 . 1'' ) with internal hollow volume ( 5 ) is arranged in or on the cavity such that the hollow volume ( 5 ) extends into the cavity and provides a flow path for the casting material, comprising the steps - before step a), the positionally accurate insertion of the semifinished component ( 1 . 1' . 1'' ) with internal hollow volume ( 5 ), Introducing a casting barrier ( 4 ) in the hollow volume ( 5 ) near the connection end. Method according to one of claims 4 to 6, comprising the steps - before step b), before introducing the casting material into the cavity, arranging a preform comprising fiber ( 6 ) in the cavity, wherein at least one of the walls ( 2 . 2 ' ) of the connecting ends of the semi-finished components to be joined ( 1 . 1' . 1'' ) at the preform ( 6 ) and in step c) the preform ( 6 ) is penetrated and / or encapsulated by the casting material. Method according to claim 7, wherein the preform ( 6 ) surrounds a mold core. Method according to one of claims 4 to 6 comprising the steps - Before step b), before introducing the casting material into the cavity, inserting a mold core in the cavity. Method according to one of claims 4 to 6, wherein at the connecting end of the semifinished component ( 1 . 1' . 1'' ) on an inner wall a plurality of dams ( 7 ) and wherein the cavity of the mold has a shape for providing spacers ( 7 ' ), wherein a spacer ( 7 ' ) has a shape between two dams ( 7 ) and between the dams ( 7 ) at the connection end Kleberaupen ( 9 ) to be provided.

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