DE102022213863A1 - Method and system for producing a bending beam - Google Patents

Abstract

The invention relates to a method for producing a bending beam (15) with a predetermined three-dimensional shape for a roll stabilizer (1), comprising the steps of:- forming a basic framework (16) with a framework-like structure from at least one continuous fiber-reinforced fiber strand (17) in a winding process (30), wherein the fiber strand (17) is formed from a plurality of filaments (33) embedded in a duromer matrix (34), wherein during the formation of the basic framework (16) the at least one fiber strand (17) is laid in unidirectional winding layers (20, 21) and intersecting winding layers (19) with a distance from one another around at least two support elements (23, 24) spaced apart from one another, wherein in areas between the support elements (23, 24) the distance between the winding layers (19, 20) essentially corresponds to the thickness of the at least one fiber strand (17), wherein the unidirectional winding layers (20, 21) and the crossing winding layers (19) are deposited uncompacted in the areas between the support elements (23, 24) during the formation of the basic structure (16); and- embedding (31) the formed basic structure (16) in a fibre-reinforced plastic mass (18).

Description

The invention relates to a method for producing a bending beam according to the preamble of claim 1. Furthermore, a system for producing a bending beam according to the preamble of claim 11 is the subject of the invention.

A bending beam for a roll stabilizer is from the WO 2018/095662 A1 known. The roll stabilizer described therein has two bending beams extending parallel to one another in the longitudinal direction of the vehicle and a torsion bar spring extending in the transverse direction of the vehicle between the two bending beams. The torsion bar spring is connected at both ends to the respective associated one of the two bending beams directly or indirectly in a rotationally fixed manner, with a receptacle for the torsion bar spring and two bearing receptacles for bearings with which the bending beams are connected to a vehicle frame being formed on the bending beams. Both the torsion bar spring and the bending beams are made of metal. The bending beams are solid and consist of a cast material. In the course of electromobility and increased efficiency, there are intensive efforts to significantly reduce the mass of vehicles by using plastics. In the case of commercial vehicles in particular, increasing the payload is of great value, taking into account the high mileage. In addition, the general aim is to achieve a more even weight distribution across the axles of a vehicle, which means that the effort to save mass is more important on the front axle than on the rear axle of a vehicle.

From the EN 10 2018 115 539 A1 A method for producing a vehicle component with a predetermined three-dimensional shape is known. Engine cylinder blocks, transmission housings, pump housings and the like are mentioned as vehicle components. The EN 10 2018 115 539 A1 Known methods include the steps of forming a basic framework with a framework-like structure from at least one continuous fiber-reinforced fiber strand in a winding process, wherein the fiber strand is formed from several filaments embedded in a duromeric matrix, and embedding the formed basic framework in a fiber-reinforced plastic mass. The vehicle components mentioned are subject to a substantially static load or an additional thermal load.

From the EN 10 2019 101 472 A1 A flange component for a wheel bearing of a motor vehicle is known, which is manufactured using the method steps mentioned above.

Based on the prior art described above, it is now the object of the present invention to provide a method for producing a bending beam which is characterized by a reduced mass and at the same time meets existing requirements for mechanical load-bearing capacity.

This problem is solved from a process engineering perspective based on the generic term of claim 1 in conjunction with its characterizing features. From a device engineering perspective, the problem is solved based on the generic term of the co-ordinate claim 11 in conjunction with its characterizing features. The dependent claims that follow each of these represent advantageous developments of the invention.

• - Formen eines Grundgerüsts mit einer fachwerkartigen Struktur aus zumindest einem endlosfaserverstärkten Faserstrang in einem Wickelprozess, wobei der Faserstrang aus mehreren in eine duromere Matrix eingebetteten Filamenten gebildet wird, wobei beim Formen des Grundgerüsts der zumindest eine Faserstrang in unidirektionalen, insbesondere schlaufenförmigen, Wickellagen und sich kreuzenden Wickellagen mit einem Abstand zueinander um zumindest zwei zueinander beabstandete Stützelemente herum abgelegt wird, wobei in Bereichen zwischen den Stützelementen der Abstand der Wickellagen zueinander im Wesentlichen der Stärke des zumindest einen Faserstrangs entspricht, wobei die unidirektionalen Wickellagen und die sich kreuzenden Wickellagen beim Formen des Grundgerüsts unkompaktiert in den Bereichen zwischen den Stützelementen abgelegt werden; und
• - Einbetten des geformten Grundgerüsts in eine faserverstärkte Kunststoffmasse.

According to claim 1, a method for producing a bending beam with a predetermined three-dimensional shape for a roll stabilizer is proposed, comprising the steps:

• - forming a basic framework with a framework-like structure from at least one continuous fiber-reinforced fiber strand in a winding process, wherein the fiber strand is formed from several filaments embedded in a duromer matrix, wherein during the formation of the basic framework the at least one fiber strand is laid in unidirectional, in particular loop-shaped, winding layers and intersecting winding layers with a distance from one another around at least two support elements spaced apart from one another, wherein in areas between the support elements the distance between the winding layers essentially corresponds to the thickness of the at least one fiber strand, wherein the unidirectional winding layers and the intersecting winding layers are laid uncompacted in the areas between the support elements during the formation of the basic framework; and
• - Embedding the formed basic framework in a fibre-reinforced plastic mass.

To date, it has been common practice in previous designs of synthetic fiber-reinforced components to compact the bundles of fiber strands that form the continuous fiber-reinforced basic structure in order to increase the force transmission capacity in the resulting laminate by increasing the force transmission between the fibers.

In contrast to this, the proposed process for producing the bending beam does not involve compacting the winding layers. Instead, the winding layers are uncompacted in a lattice-like structure and arranged at a distance from one another, thereby forming a large number of gaps in order to enable a considerably larger connection surface to the fibre-reinforced plastic mass in order to connect it to the winding layers in a form-fitting and force-fitting manner.

According to a preferred development, the at least one fiber strand used to wind the basic structure can have filaments that are incompletely enclosed by the thermosetting matrix, at least in the outer edge region. The fiber strand is characterized by incomplete resin saturation, i.e. incomplete enclosure or wetting with the thermosetting matrix. For this purpose, the resin saturation can be influenced by means of an impregnation unit as part of an impregnation process. Filaments that are incompletely wetted by the thermosetting matrix are preferably located in an outer edge region of the fiber strand. This is advantageous when bonding the thermoplastic material during the embedding process, since the plastic material can adhere better to dry filaments or filaments that are incompletely wetted by the thermosetting matrix. The resin saturation depends on the fiber volume content of the fiber strand, whereby with increasing fiber volume content the resin saturation increases the number of areas of the fiber strand that remain unwetted during the impregnation process. Alternatively, instead of an increasing fiber volume, a stripping element can be provided which strips the duromer matrix in the outer edge area of the fiber strand at least in sections after the impregnation process.

Alternatively or additionally, a dry fiber strand running parallel in sections can be pressed onto the at least one impregnated fiber strand at least in some areas before the basic structure is wound. In this case, an additional dry fiber strand, i.e. one without impregnation, can be applied to a regularly impregnated fiber strand in order to create direct docking areas for the filaments. A special rewinding device can be used for this, which presses the dry fiber strand onto the regularly impregnated fiber strand as the main strand. This can be done both over the entire length and only in parts of the fiber strand designed as the main strand.

Alternatively or additionally, the at least one fiber strand can be guided through at least one comb element or at least one cutting element before being deposited, by which the at least one fiber strand is fanned out into several sub-strands. The use of at least one comb element or at least one cutting element has the advantage that the surface of the basic structure wound from the fiber strand fanned out into several sub-strands is increased. Several sub-strands is understood to mean a number greater than three.

Alternatively or additionally, the at least one fiber strand can be twisted before being deposited. The at least one fiber strand has a flat, essentially band-like shape, i.e. the width of the fiber strand is several times greater than its height. By twisting the flat fiber strand, it can be converted into an essentially spiral shape. The essentially spiral shape of the fiber strand creates an enlarged contact surface. The enlarged contact surface of the spirally twisted fiber strand improves the form fit when embedding in the plastic mass.

According to a preferred development, the formed basic structure can be subjected to a surface treatment at least in sections before embedding. The surface treatment can be used to clean the surface of the basic structure before it is embedded. Alternatively or additionally, the surface treatment can be used to etch and structure the surface. Partial exposure of filaments can be achieved by removing the upper layer of the duromer matrix, i.e. removing the hardened, dried resin. Cleaning and/or etching and structuring the upper layer of the duromer matrix have the effect of improving the force-fitting connection of the basic structure when embedding it in the plastic mass.

In particular, the surface treatment of the basic structure can be carried out using a plasma process. Preferably, a low-pressure plasma process or an atmospheric pressure plasma process can be used as the surface treatment process. The low-pressure plasma process has the advantage that the activation takes place in a closed space at low pressure, so that even delicately branched areas of the basic structure can be subjected to surface treatment without damage.

By plasma treatment of the thermosetting basic structure, defined functional groups can be created in the thermosetting surface for binding the thermoplastic polymer mass.

Preferably, the basic framework can be produced without a core using the free-form winding process. Preferably, an internal basic framework is used. However, partially internal and external variants of the basic framework are also conceivable.

Preferably, the basic framework can be embedded in the fiber-reinforced plastic mass by means of a pressing process or by means of an injection molding process or by means of a die-casting process.

In particular, the winding process can be carried out by two robots, wherein one of the robots guides the at least one fiber strand and the other robot guides a tool on which the at least two support elements are arranged, around which the at least one fiber strand is deposited.

The object posed at the outset is achieved by a system for producing a bending beam with a predetermined three-dimensional shape for a roll stabilizer according to the independent claim 11.

• - Mittel zum Formen eines Grundgerüsts mit einer fachwerkartigen Struktur aus zumindest einem endlosfaserverstärkten Faserstrang in einem Wickelprozess, wobei der Faserstrang aus mehreren in eine duromere Matrix eingebetteten Filamenten gebildet ist, wobei die Mittel dazu eingerichtet sind, beim Formen des Grundgerüsts den zumindest eine Faserstrang in unidirektionalen, insbesondere schlaufenförmigen, Wickellagen und sich kreuzenden Wickellagen mit einem Abstand zueinander um zumindest zwei zueinander beabstandete Stützelemente herum abzulegen;
• - wobei die Mittel zum Formen des Grundgerüsts zwei Roboter umfassen, von denen ein Roboter den zumindest einen Faserstrang führt und der andere Roboter ein Werkzeug mit den darauf angeordneten Stützelementen;
• - Mittel zum Einbetten des geformten Grundgerüsts in eine faserverstärkte Kunststoffmasse.

According to the independent claim 11, a system for producing a bending beam with a predetermined three-dimensional shape for a roll stabilizer is proposed, which is designed to carry out the method according to one of the preceding claims and/or comprises:

• - Means for forming a basic framework with a framework-like structure from at least one continuous fiber-reinforced fiber strand in a winding process, wherein the fiber strand is formed from several filaments embedded in a duromeric matrix, wherein the means are designed to lay down the at least one fiber strand in unidirectional, in particular loop-shaped, winding layers and intersecting winding layers at a distance from one another around at least two support elements spaced apart from one another during the formation of the basic framework;
• - wherein the means for forming the basic framework comprise two robots, of which one robot guides the at least one fiber strand and the other robot guides a tool with the support elements arranged thereon;
• - Means for embedding the shaped basic structure in a fibre-reinforced plastic mass.

Reference may be made to the advantages of the method according to the invention.

In a further development, the robot guiding the at least one fiber strand can have a thread eye for feeding the at least one fiber strand, which has a means for enlarging the surface of the at least one fiber strand. The means is designed to influence the surface quality and/or the structural design of the at least one fiber strand. This can improve the frictional connection between the basic structure and the plastic mass during embedding, which is advantageous for the overall stability of the bending beam.

For this purpose, the means can be designed as an arcuate or ring-shaped comb element in the thread eye. The fiber strand to be wound runs through the thread eye and is guided through it during the three-dimensional winding process. In this process, at least one fiber strand is fanned out by the comb element in the thread eye and broken down into individual strands, which are then processed when winding the basic structure.

Alternatively, the means can be designed as at least one cutting element. The at least one fiber strand can be cut and broken down into individual partial strands by the at least one cutting element. The cutting element can preferably be designed in the form of a grid.

According to a further development, the robot guiding the at least one fiber strand can have a thread eye for feeding the at least one fiber strand, which comprises an outer frame and an inner part that is relatively movable relative to the outer frame and is driven in rotation, wherein the inner part has a substantially oval opening for guiding the at least one fiber strand. For this purpose, the inner part can be arranged in the outer frame of the thread eye with ball bearings. The rotation can be realized by an electric drive. The drive of the inner part can be carried out indirectly by a belt, for example. The belt can transfer the rotation of a drive shaft of the electric drive to the inner part of the thread eye. The substantially oval opening forms a flat outlet. The rotation of the inner part of the thread eye causes the flat fiber strand fed from a spool or the like to be twisted. The at least one fed flat fiber strand is converted into a spiral shape before it is laid down to form the basic structure. The spiral shape of the at least one fiber strand achieves an increased form fit during later embedding in the plastic mass.

The invention is not limited to the specified combination of features of the independent claims or those dependent thereon. In addition, there are possibilities to to combine individual features with one another, even if they emerge from the claims, the following description of preferred embodiments of the invention or directly from the drawings. The reference of the claims to the drawings by using reference symbols is not intended to limit the scope of protection of the claims.

• 1 eine perspektivische Darstellung eines Wankstabilisators für eine Fahrerhauslagerung gemäß dem Stand der Technik;
• 2 schematisch eine perspektivische, teilweise freigeschnittene Ansicht eines Biegeträgers;
• 3 schematisch ein Grundgerüst des Biegeträgers;
• 4 exemplarisch ein Ablauf des erfindungsgemäßen Verfahrens zur Herstellung des Biegeträgers;
• 5 eine schematische Darstellung eines Faserstrangs im Querschnitt mit teilweise unbenetzten Filamenten;
• 6 eine schematische Darstellung eines Faserstrangs im Querschnitt mit einem zusätzlichen aufgepressten, unbenetzten Faserstrang;
• 7 eine schematische Darstellung des Faserstrangs gemäß 6, der von einem zusätzlichen unbenetzten Faserstrang ummantelt ist;
• 8 schematisch eine Darstellung eines Herstellungskonzepts für den Biegeträger 15;
• 9 schematisch eine Darstellung eines Fadenauges gemäß einer ersten Ausführungsform;
• 10 schematisch eine Darstellung einer alternativen Ausführungsform des Fadenauges;
• 11 schematisch eine Darstellung einer weiteren Ausführungsform des Fadenauges; und
• 12 eine schematische Darstellung eines verdrillten Faserstranges.

An advantageous embodiment of the invention, which is explained below, is shown in the drawings. It shows:

• 1 a perspective view of a roll stabilizer for a driver's cab suspension according to the prior art;
• 2 schematically a perspective, partially cutaway view of a bending beam;
• 3 schematically a basic framework of the bending beam;
• 4 an example of a sequence of the method according to the invention for producing the bending beam;
• 5 a schematic representation of a fiber strand in cross section with partially unwetted filaments;
• 6 a schematic representation of a fiber strand in cross section with an additional pressed-on, unwetted fiber strand;
• 7 a schematic representation of the fibre strand according to 6 which is coated by an additional unwetted fibre strand;
• 8th schematically a representation of a manufacturing concept for the bending beam 15;
• 9 schematically shows a thread eye according to a first embodiment;
• 10 schematically a representation of an alternative embodiment of the thread eye;
• 11 schematically a representation of another embodiment of the thread eye; and
• 12 a schematic representation of a twisted fiber strand.

1 shows a roll stabilizer 1 for a driver's cab suspension according to the prior art. The roll stabilizer 1 has a torsion bar spring 2, to each end of which a bending beam 3 is connected via a non-circular press connection. The torsion bar spring 2 has a first polygonal end section 5 and a second polygonal end section 6, which are suitable for receiving press plugs 4 designed as a polygonal profile, also called a uniform thickness. The torsion bar spring 2 can be designed as a torsion tube, for example. The bending beams 3 have a first end region 7 and a second end region 8. The bending beams 3 are connected in the second end region 8 by means of a bearing 9, here and preferably a rubber bearing, to a vehicle frame 10 (indicated only schematically) and a driver's cab 11 of a motor vehicle. In the first end region 7 of the respective bending beam 3, a receptacle 12 and a bearing receptacle 13 are arranged, and in the second end region 8 of the bending beam 3, a further bearing receptacle 14 for the bearing 9 is arranged. The solid bending beams 3 consist of a cast material, an aluminum cast alloy, a cast steel or a spheroidal graphite cast iron. The term “receptacle 12” describes a geometric structure of the bending beam 3, which serves to receive and fasten the first polygonal end section 5 or the second polygonal end section 6 of the torsion bar spring 2. Accordingly, the term “bearing receptacle 13, 14” describes a geometric structure of the bending beam 3, which serves to receive and fasten the respective bearing 9, regardless of its design.

In the following description, for reasons of simplification and to the extent that it is useful for explaining the objects, the same reference symbols are used for identical or functionally equivalent components or elements.

The representation in 2 shows a schematic perspective, partially cutaway view of a bending beam 15, which serves to accommodate the torsion bar spring 2 and the bearings 9, here and preferably the rubber bearings. The bending beam 15 consists of a wound base frame 16. The base frame 16 consists of at least one continuous fiber strand 17 made of a continuous fiber-reinforced duromer as a winding material. The receptacle 12 and the bearing receptacles 13, 14 are formed by different winding layers 19, 20, 21 of the at least one continuous fiber strand 17. The base frame 16 has a three-dimensional winding structure. The receptacle 12 and the bearing receptacles 13, 14 of the bending beam 1 have a different height profile in the transverse direction y. The wound base frame 16 is embedded in a, in particular thermoplastic, fiber-reinforced, in particular short fiber-reinforced, plastic mass 18. The plastic mass 18 encloses the exposed areas of the basic structure 16 or the different winding layers 19, 20, 21 of the at least one continuous fiber strand 17.

As can be seen from the illustration in 2 and 3 visible, at least the winding surface receptacle 12 has a non-circular outer contour 22. The non-circular outer contour 22 can be designed as a polygonal contour, for example a triangular contour. Corners of the polygonal outer contour 22 are preferably rounded. Furthermore, the sides of the polygonal outer contour 22 can be curved, for example. Alternatively, the non-circular outer contour 22 can also be formed by an oval contour.

In 2 the winding layers 19 and 20 are shown partially visible, with the winding layers 20 being arranged in a loop-like manner between the receptacle 12 and the respective bearing receptacle 13, 14. Connections with loop-like strands of the at least one continuous fiber strand 17 can thus be created between the receptacle 12 and the bearing receptacle 13 in the first end region 7, the bearing receptacle 13 in the first end region 7 and the bearing receptacle 14 in the second end region 8, and the receptacle 12 and the bearing receptacle 14 in the second end region 8 of the bending beam 15. To form the loop-like winding layers 20, the at least one continuous fiber strand 17 is wound with a constant winding direction or unidirectionally, for example only clockwise or only counterclockwise. The holder 12 and the respective bearing holder 13, 14 as well as the two bearing holders 13, 14 of the bending beam 15 each form pairs of deflection points for the at least one continuous fiber strand 17 in order to form the loop-shaped winding layers 20. Several continuous fiber strands 17 with opposite winding directions can also form the loop-shaped winding layers 20.

Furthermore, intersecting winding layers 19 of the winding material are arranged between the bearing holder 14 in the second end region 8 of the bending beam 15 and the opposite holder 12 or bearing holder 13 in the first end region 7. This creates connections with diagonal or intersecting strands of the at least one continuous fiber strand 17 between the holder 12 or the bearing holder 13 in the first end region 7 and the bearing holder 14 in the second end region 8 as well as the holder 12 and the bearing holder 34 of the bending beam 15. For this purpose, the at least one continuous fiber strand 17 is wound with an alternating winding direction. The holder 12 or the bearing holder 13 in the first end region 7 of the bending beam 15 and the bearing holder 14 in the second end region 8 of the bending beam 15 each form a pair of deflection points for the at least one continuous fiber strand 17.

Furthermore, the 2 and 3 It can be seen that the holder 12 and the bearing holders 13, 14 are completely wrapped in the circumferential direction by several winding layers 21. The winding layers 21 are also each wound unidirectionally. The complete circumferential enclosure of the holder 12 or the respective bearing holder 13, 14 by the winding layers 21 of the at least one continuous fiber strand 17 results in an advantageous embodiment of structures in the bending beam 15 that are loaded both by tension and by pressure. A further advantage is that the wear of the fiber-reinforced plastic mass 18 is reduced. The underlying or embedded continuous fiber strand 17 can absorb higher mechanical loads without wear.

In 3 the basic framework 16 of the bending beam 15 according to the invention is shown schematically in plan view. The receptacle 12 and the bearing receptacles 13, 14 can comprise closed profile components 23, 24, which are designed in particular as bushings, sleeves and/or collar sleeves, as support elements. The profile components 23, 24 are preferably made of metal. The profile components 23, 24 can be used during the winding process of the basic framework 16 instead of cores or the like for the formation of the receptacle 12 and the bearing receptacles 13, 14 during winding.

At least the profile component 23 has a non-circular peripheral contour. The profile component 23 of the holder 12 has at least one partially flattened outer side surface 25. The non-circular peripheral contour can correspond to the non-circular outer contour 22 of the holder 12. In particular, the profile component 23 can have the peripheral contour of a Reuleaux triangle.

An example is 3 the introduction of a torque 26, indicated by an arrow, into the bending beam 15 is shown. The torque 26 is introduced into the bending beam 15 by the torsion bar spring 2. The resulting forces that are introduced into the winding layers 19, 20 are visualized with arrows 27 in the case of compressive forces and with arrows 28 in the case of tensile forces. The advantage resulting from the non-circular peripheral contour of the profile component 23 or the non-circular outer contour 22 of the holder 12 is the division of the forces resulting from the torque into compressive forces 27 and tensile forces 28, which are each introduced into the winding layers 19, 20 at an angle. This is achieved by the combination of diagonal and parallel winding layers 19, 20. The winding layers 21, which completely enclose the holder 12 and the bearing holders 13, 14 or the profile components 23, 24, result in an advantageous design of the tensile-compressive loaded structures of the bending beam 15.

In particular, it is provided that the basic framework 16 is completely cured before embedding in the thermoplastic material 18, in particular one reinforced with short fibers. This makes it possible to avoid displacement of the fibers in the continuous fiber strand 17 during the embedding process.

In particular, it is provided that gaps 29 remain between the loop-shaped and/or intersecting winding layers 19, 20 of the basic structure 16, which gaps are filled by the plastic compound 18 when the basic structure 16 is embedded. This is achieved by the uncompacted placement of the unidirectional winding layers 20 and the intersecting winding layers 19 when the basic structure 16 is formed in the areas between the support elements 23, 24. The omission of a solid design of the basic structure 16 by compacting the winding layers 19, 20 in particular has the advantage that the continuous fiber strand 17, which is generally more expensive, only needs to be used to the extent that it is required to bear the loads in the fiber direction. It is essential that gaps 29 of different sizes are formed between the intersecting winding layers 19 and the loop-shaped winding layers 20 of at least one continuous fiber strand. These gaps 29 are filled with plastic compound 18 after embedding. Filling the gaps 29 within and between the winding layers 19, 20 contributes to improving the mechanical stability.

The uncompacted deposition of the winding layers 19, 20 is controlled in such a way that gaps 29 are formed within the intersecting and loop-shaped winding layers, into which the plastic mass 18 can penetrate. Gaps 29 within the intersecting winding layers 19 can form, for example, due to the changing winding direction when they are deposited. In particular, in the crossing areas of the intersecting winding layers 19, these can have distances from one another that correspond at most to the fiber strand thickness. By alternating winding of intersecting and loop-shaped winding layers 19, 20, gaps 29 can be provided between them with distances that correspond at most to the fiber strand thickness.

Thus, larger surfaces are formed between and within the intersecting and loop-shaped uncompacted winding layers 19, 20 compared to a compacted winding and deposit. The gaps 29 enable an improvement in the form fit when embedding the basic structure 16 in the plastic mass 18. The larger surface improves the frictional connection for connecting at least one continuous fiber strand 17 to the plastic mass 18.

In 4 By way of example, a sequence of the method according to the invention for producing the bending beam 15 with a predetermined three-dimensional shape for the roll stabilizer 1 is described. In the first process step 30, the method comprises forming the basic framework 16 with a framework-like structure from at least one continuous fiber-reinforced fiber strand 17 in a winding process, wherein the fiber strand 17 is formed from a plurality of filaments 33 embedded in a duromeric matrix 34, wherein during the formation of the basic framework 16, the at least one fiber strand 17 is laid down in unidirectional winding layers 20, 21 and intersecting winding layers 19 at a distance from one another around at least two support elements which are spaced apart from one another, which can be the profile components 23, 24, wherein in areas between the support elements the distance between the winding layers 19, 20 from one another essentially corresponds to the thickness of the at least one fiber strand 17, wherein the unidirectional winding layers 20 and the intersecting winding layers 19 are laid down uncompacted in the areas between the support elements during the formation of the basic framework 16.

In particular, the winding layers 19, 20 are arranged in a framework-like structure without being compacted, whereby a large number of gaps 29 are formed in order to enable a considerably larger connection surface to the fiber-reinforced plastic mass 18 in order to connect this to the winding layers 19, 20 in a form-fitting and force-fitting manner. In the second process step 31, the shaped basic framework 16 is embedded in the fiber-reinforced plastic mass 18. In the second process step 31, the basic framework 16 is embedded in the fiber-reinforced plastic mass 18 by means of a pressing process or by means of an injection molding process or by means of a die-casting process.

The winding process according to the process step 30 can be preceded by an optional process step 32. The optional process step 32 can involve the process of impregnating the fiber strand 17, ie the embedding of filaments 33 in the duromeric matrix 34. In 5 the fiber strand 17 is shown schematically in cross section.

The at least one fiber strand 17 used for winding the basic structure 16 can have filaments 33 at least in the outer peripheral region, which are incompletely enclosed by the duromer matrix 34. In particular, During the impregnation process in the optional process step 32, at least the filaments 33 located in the outer peripheral region or edge region are not completely wetted with resin as a duromer matrix 34, so that dry regions 35 can form. For illustration purposes, the regions or filaments 33 of the fiber strand 17 that are wetted with the duromer matrix 34 are shown with a dark background, while the unwetted regions 35 or filaments 33 of the fiber strand 17 are shown with a white background. The formation of dry regions 35, in particular in the outer edge region of the fiber strand 17, is advantageous when bonding the plastic mass 18 during the embedding process, since the plastic mass 18 can adhere better to dry or incompletely wetted filaments 33.

For this purpose, the resin saturation can be influenced by means of an impregnation unit as part of the impregnation process in the optional process step 32. Filaments 33 that are incompletely wetted with the resin as a duromeric matrix 34 are preferably located in the outer edge area of the fiber strand 17. The resin saturation can also be influenced by the fiber volume content of the fiber strand 17. As the fiber volume content increases, the number of areas of the fiber strand 17 that remain unwetted during the impregnation process increases, as can be seen by way of example from 5 Alternatively, instead of an increasing fiber volume, a stripping element can be provided which strips the duromer matrix 34 in the outer edge region of the fiber strand 17 after the impregnation process.

Alternatively or additionally, in the optional process step 32 it can be provided that a partially parallel dry fiber strand 36 is pressed onto the at least one impregnated fiber strand 17 at least in partial areas before the winding of the basic structure 16, as in 6 shown as an example. By pressing on the additional dry fiber strand 36, the bonding of the plastic mass 18 during the embedding process is also improved, since the plastic mass 18 can adhere better to the dry, wetted fiber strand 36. The completely wetted fiber strand 17, on the other hand, has all the desired and advantageous properties after curing.

Alternatively or additionally, in the optional process step 32 it can be provided that the at least one impregnated fiber strand 17 is completely covered by at least one further dry fiber strand 36. The at least one impregnated fiber strand 17 is received in a sheath which is formed from at least one further dry fiber strand 36.

Furthermore, the second process step 31 of embedding can be preceded by a further optional process step 37. According to a preferred development, the shaped basic structure 16 can be subjected to a surface treatment as an optional process step 37, at least in sections, before embedding. The surface treatment can be used to clean the surface of the basic structure 16 before it is embedded. Alternatively or additionally, the surface treatment can be used to etch and structure the surface. Partial exposure of filaments 33 can be achieved by removing the upper layer of the duromer matrix 34, i.e. by removing the dried resin. The cleaning and/or etching and structuring of the upper layer of the duromer matrix 34 have the effect of improving the force-fitting connection of the plastic mass 18 to the fiber strand 17 during embedding.

In particular, the surface treatment of the basic structure 16 can be carried out using a plasma process. Preferably, a low-pressure plasma process or an atmospheric pressure plasma process can be used as the surface treatment process. The low-pressure plasma process has the advantage that the activation takes place in a closed space at low pressure, so that even delicately branched areas of the basic structure 16 can be subjected to the surface treatment without damage.

By plasma treatment of the thermosetting basic structure 16, defined functional groups can be generated in the thermosetting surface for binding the thermoplastic polymer mass 18.

8th shows a schematic representation of a manufacturing concept for the bending beam 15. Two multi-axis robots 38, 39 and an exemplary tool 40 are shown. One robot 38 takes over the guidance of the fiber strand 17 and the other robot 39 takes over the movement of the tool 40.

In the tool 40, various support elements (not shown) are arranged around which the fiber strand 17 is laid in order to form the basic structure 16 of the bending beam 15. The support elements are here and preferably designed as the profile components 23, 24, which remain in the basic structure 16 after completion of the winding process. A direction of movement of the tool 40 is indicated with arrows. The manufacturing concept is only shown very schematically here and is not an example of an actual formation of a Production line for the manufacture of the bending beam 15.

According to the exemplary embodiment shown, the second robot 39 guides the support elements or profile components 23, 24, which are arranged in the tool 40, at a variable distance from one another around the guide of the at least one fiber strand 17 by the first robot 38. Alternatively, the fiber strand 17 can be guided by the first robot 38 around the support elements that are arranged in the tool 40. The continuous fiber-reinforced fiber strand 17 is guided in a targeted manner around the support elements that are arranged in the tool 40. The at least one fiber strand 17 is present as wet fiber during the manufacturing process of the basic structure 16.

A thread eye 41 is arranged on the robot 37 to guide the fiber strand 17 to be wound. In addition to the measures already described above to improve the bond between the thermoplastic plastic compound 18 and the thermosetting base frame 16, the thread eye 41 can also be used to further improve the bond during the winding process in process step 30. For this purpose, the robot 38 guiding the at least one fiber strand 17 has a thread eye 41 for feeding the at least one fiber strand 17, which has a means for enlarging the surface of the at least one fiber strand 17. The means is designed to influence the surface quality and/or the structural design of the at least one fiber strand 17. This allows the frictional connection between the base frame 16 and the plastic compound 18 to be improved during embedding, which is advantageous for the overall stability of the bending beam 15.

In 9 the thread eye 41 is shown schematically according to a first embodiment. The thread eye 41 has an outer frame 42 in which an arcuate or annular comb element 43 is arranged. The design of the means as an arcuate or annular comb element 43 in the thread eye 41 makes it possible to divide or fan out the fiber strand 17 to be wound, which runs through the thread eye 41. The fiber strand 17 to be wound runs through the thread eye 41 and is guided through it during the three-dimensional winding process in the first process step 30. The at least one fiber strand 17 is fanned out by the annular comb element 43 in the thread eye 41 and broken down into individual partial strands, which are then processed when winding the basic structure 16.

In 10 an alternative embodiment of the thread eye 41 is shown schematically. According to this embodiment, the means is designed as a cutting element 44. The cutting element 44 can in particular be designed in the form of a grid. The at least one fiber strand 17 can be cut by the cutting element 44 and broken down into individual partial strands before these are processed when winding the basic structure 16.

The use of the comb element 43 or the cutting element 44 has the advantage that the surface of the basic structure 16 wound from the fiber strand 17 fanned out into several sub-strands is increased. The term several sub-strands is understood to mean a number greater than three.

In 11 shows a schematic representation of a further embodiment of the thread eye 41. According to this development, the robot 38 guiding the at least one fiber strand 17 can have a thread eye 41 for feeding the at least one fiber strand 17, which comprises an inner part 45 which is relatively movable relative to the outer frame 42 and is driven in a rotating manner. The inner part 45 also comprises a substantially oval opening 46 for guiding the at least one fiber strand 17. In order to enable the relative movement, the inner part 45 can be arranged in ball bearings in the outer frame 42 of the thread eye 41. The rotation can be realized by an electric drive 47. The drive of the inner part can be carried out indirectly by a belt, for example. The belt can transmit the rotation of a drive shaft of the electric drive 47 to the inner part 45 of the thread eye 41. The substantially oval opening 46 forms a flat outlet. The rotation of the inner part 45 of the thread eye 41 causes a twisting of the flat fiber strand 17 fed from a spool or the like. In this case, the at least one fed flat fiber strand 17 is converted into a spiral shape, as shown in 12 shown schematically before it is laid down to form the basic framework 16. The spiral shape of the at least one fiber strand 17 achieves an increased form fit during later embedding in the plastic mass 18.

The at least one fiber strand 17 has a flat, essentially band-like shape, ie the width of the fiber strand 17 is several times greater than its height. By twisting the flat fiber strand 17, it is converted into a spiral shape, as in 12 shown. The spiral shape of the fiber strand 17 creates an enlarged contact surface. The enlarged contact surface of the spirally twisted fiber strand 17 creates a Improvement of the mold shot during embedding in the plastic mass 18 achieved.

Reference symbols

1

Roll stabilizer

2

Torsion bar spring

3

Bending beam

4

Press plug

5

First final section

6

Second final section

7

First end area

8th

Second end area

9

camp

10

Vehicle frame

11

Driver's cab

12

Recording

13

Stock recording

14

Stock recording

15

Bending beam

16

Basic framework

17

Continuous fiber strand

18

Plastic mass

19

Wrapping position

20

Wrapping position

21

Wrapping position

22

Outer contour

23

Profile component/support element

24

Profile component/support element

25

Outside surface

26

Torque

27

Pressure force

28

traction

29

Space

30

First process step

31

Second process step

32

Optional process step

33

Filament

34

Thermosetting matrix/resin

35

Dry area of 17

36

Dry fiber strand

37

Optional process step

38

robot

39

robot

40

Tool

41

Thread eye

42

Outer frame

43

Comb element

44

Cutting element

45

inner part

46

opening

47

drive

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• WO 2018095662 A1 [0002]
• DE 102018115539 A1 [0003]
• DE 102019101472 A1 [0004]

Claims (15)

Method for producing a bending beam (15) with a predetermined three-dimensional shape for a roll stabilizer (1), comprising the steps: - forming a basic framework (16) with a framework-like structure from at least one continuous fiber-reinforced fiber strand (17) in a winding process (30), wherein the fiber strand (17) is formed from a plurality of filaments (33) embedded in a duromeric matrix (34), wherein during the formation of the basic framework (16) the at least one fiber strand (17) is laid in unidirectional winding layers (20, 21) and intersecting winding layers (19) at a distance from one another around at least two support elements (23, 24) spaced apart from one another, wherein in regions between the support elements (23, 24) the distance between the winding layers (19, 20) essentially corresponds to the thickness of the at least one fiber strand (17), wherein the unidirectional winding layers (20, 21) and the intersecting winding layers (19) crossing winding layers (19) are deposited uncompacted in the areas between the support elements (23, 24) when forming the basic structure (16); and - embedding (31) the formed basic structure (16) in a fiber-reinforced plastic mass (18). Procedure according to Claim 1 , characterized in that the at least one fiber strand (17) used for winding the basic structure (16) has, at least in the outer edge region, filaments (33) which are incompletely enclosed by the duromeric matrix (34). Procedure according to Claim 1 or 2 , characterized in that a partially parallel dry fiber strand (36) is pressed onto the at least one impregnated fiber strand (17) at least in partial areas before the basic structure (16) is wound. Method according to one of the Claims 1 until 3 , characterized in that the at least one fiber strand (17) is guided before deposition through at least one comb element (43) or at least one cutting element (44), by means of which the at least one fiber strand (17) is fanned out into a plurality of partial strands. Method according to one of the Claims 1 until 4 , characterized in that the at least one fiber strand (17) is twisted before deposition. Method according to one of the Claims 1 until 5 , characterized in that the shaped basic framework (16) is subjected to a surface treatment at least in sections before embedding. Procedure according to Claim 6 , characterized in that the surface treatment of the basic structure (16) is carried out by means of a plasma process. Method according to one of the preceding claims, characterized in that the basic structure (16) is produced coreless in the free-form winding process. Method according to one of the preceding claims, characterized in that the basic framework (16) is embedded in the fiber-reinforced plastic mass (18) by means of a pressing process or by means of an injection molding process or by means of a die-casting process. Method according to one of the preceding claims, characterized in that the winding process is carried out by two robots (38, 39), one of the robots (38, 39) guiding the at least one fiber strand (17) and the other robot (38, 39) a tool (40) on which the at least two support elements (23, 24) are arranged, around which the at least one fiber strand (17) is laid down. System for producing a bending beam (15) with a predetermined three-dimensional shape for a roll stabilizer (1), which is designed to carry out the method according to one of the preceding claims and/or has: - means for forming a basic framework (16) with a framework-like structure from at least one continuous fiber-reinforced fiber strand (17) in a winding process (30), wherein the fiber strand (17) is formed from several filaments (33) embedded in a duromeric matrix (34), wherein the means are designed to lay down the at least one fiber strand (17) in unidirectional winding layers (20, 21) and intersecting winding layers (19) at a distance from one another around at least two support elements (23, 24) spaced apart from one another during the formation of the basic framework (16); - wherein the means for forming the basic framework comprise two robots (38, 39), of which one robot (38) guides the at least one fiber strand (17) and the other robot (39) guides a tool (40) with the support elements (23, 24) arranged thereon; - means for embedding the shaped basic framework (16) in a fiber-reinforced plastic mass (18). System according to Claim 11 , characterized in that the robot (38, 39) guiding the at least one fiber strand (17) has a thread eye (41) for feeding the at least one fiber strand (17), which has a means for enlarging the surface of the at least one fiber strand (17). System according to Claim 12 , characterized in that the means is designed as an arcuate or annular comb element (43) in the thread eye (41). System according to Claim 12 , characterized in that the means is designed as at least one cutting element (44) in the thread eye (41). System according to Claim 11 , characterized in that the robot (38, 39) guiding the at least one fiber strand (17) has a thread eye (41) for feeding the at least one fiber strand (17), which comprises an outer frame (42) and an inner part (45) which is relatively movable with respect to the outer frame (42) and which is driven in rotation, wherein the inner part (45) has a substantially oval opening (46) for guiding the at least one fiber strand (17).

Images