DE10006400A1 - Composite plastic disc wheel for a motor vehicle has SMC layers with unidirectional fibers at various angles - Google Patents

Abstract

The wheel comprises a nave plate(2) and a rim(3) and is compression molded in fiber reinforced plastic sections including SMC(sheet molding compound sections with unidirectional reinforcing fibers. The SMC sections have a resin matrix and two or more stacked fiber layers whose unidirectional parallel fibers are aligned at different according the required load resistance. An independent claim is made for a process for molding the disc wheel in which cut SMC sections with two or more layers of unidirectional fibers in a resin matrix are placed in a molding tool with the fibers oriented to resist the stresses. The assembly is then compression molded while hot.

Description

The invention relates to a disc wheel, which at least in sections fiber-reinforced plastic. The invention further relates to a method for Manufacture of such a disc wheel.

Disc wheels of this type are suitable, for example, for use on motor vehicles. With regard to the improvement of driving dynamics and comfort behavior of Wheel suspensions are of great interest in disc wheels with low Weight since the wheels are effective as unsprung masses on a wheel suspension become. The total weight of one can be achieved by lightweight disc wheels Reduce the vehicle and consequently its fuel consumption. Moreover, at a steered axle, the steering forces are reduced.

Traditionally, disc wheels are made of steel. Increasingly Disc wheels made of light metal, with which a considerable Weight saving can be achieved. Alloy disc wheels are in theirs, however Production is complex and therefore considerably more expensive than steel disc wheels. When looking for inexpensive lightweight alternatives, disc wheels are made fiber-reinforced plastic has been developed, which is Disc wheels have a weight saving potential of another 40 percent exhibit. The solutions known so far are, however, with regard to one Production process ready for series production, the design options on the wheel disc and the mechanical property profile was only optimized to a limited extent. To be considered u. a. that disc wheels especially at higher speeds or Obstacle driving can be exposed to high dynamic loads, and at Brakes are subject to high thermal loads.

DE 42 02 287 A1 discloses a disk wheel made of fiber-reinforced plastic, which is made by injection molding. Furthermore, from DE 42 02 287 A1  known to inject a grid-shaped tissue into the wheel.

However, the achievable component strength is clear in the compression molding process less than in the compression molding process, which is also used to manufacture Disc wheels is used. For this reason, in DE 42 02 287 A1 Wheel disc are manufactured largely without opening. However, this is in view on the ventilation of the wheel, especially in the case of one arranged in the wheel area Brake, as well as in terms of the design options on the wheel disc unsatisfactory.

Disc wheels manufactured in the compression molding process have considerably better ones Strength properties. However, there are greater changes in wall thickness so far only possible to a limited extent.

Against this background, the invention has for its object a disc wheel to create fiber-reinforced plastic, which in addition to a low weight, a high Has design potential and improved strength properties.

This object is achieved by a disk wheel of the type mentioned at the beginning the sections made of fiber-reinforced plastic at least partially with unidirectional fibers reinforced SMC blanks are molded, the with unidirectional fibers reinforced SMC blanks with a resin matrix with at least two superimposed fiber layers made of approximately unidirectional, parallel Has reinforcing fibers that differ in their fiber direction angle.

The solution according to the invention initially has a considerable weight advantage compared to disc wheels made of steel or light metal. Through the targeted use of SMC blanks reinforced with unidirectional fibers can be Manufacture disc wheels with high strength properties with regard to their Wheel disc have a high design potential.

SMC (sheet molding compound) is understood to mean flowable resin mats which are based on an unsaturated polyester resin or vinyl ester resin and generally have a random fiber distribution in the mat plane. The polymer content of an SMC is, for example, about 30 percent. A further 30 percent is contributed by the tangled fibers, for example in the form of glass fibers or carbon fibers. The rest is made up of fillers, for example recycled material made of fiber-reinforced plastic, and additives. Hardeners, dispersants and color pigments are particularly suitable for this.

In the present case, the tangled fiber layer is approximately made up of fiber layers rectified, parallel fibers replaced, with at least two fiber layers are provided, the fibers of which run at an angle to one another. However, it is also possible to add the unidirectional fibers to the tangled fiber layer in the Embed resin matrix.

Due to the layered arrangement of the unidirectional fiber layers, one remains receive sufficiently high flowability of the SMC blanks, so that during production the disc wheel does not cover the entire mold with material got to. Rather, a relatively loose orientation of the blanks to the Form that is essentially with a view to a stress-oriented orientation of the unidirectional fibers is made. This allows the manufacture of the Disc wheel can be kept simple, so that the disc wheel in series production is producible. In addition, the waste of unidirectional fiber SMC material remains low.

In an advantageous embodiment of the invention, the unidirectional Reinforcing fibers multifilament carbon fibers with which optimal Let strength values be achieved. For the fiber material can be conventional Carbon fibers are used, both cable-like fibers and Broadband cables can be used.

The reinforcing fibers in each layer are preferably in their longitudinal extent are cut every 10 to 200 mm, the individual cuts each between 0.5 mm and 20 mm wide and offset to the cuts neighboring fibers. By shortening the endless fibers improves the flowability of the unidirectional fiber SMC. The offset from neighboring fiber groups with each other prevents strength inhomogeneities.

With regard to the thermal stress on the disc wheel, the resin matrix  preferably a thermoset matrix, preferably a vinyl ester resin system.

The unidirectional SMC blanks are preferably aligned stress-oriented. For this, it is advantageous if unidirectional fibers in the Wheel disc are directed radially. The greatest bending strengths and - stiffness at an angle of maximum +/- 30 ° to the radial direction.

In contrast, in the rim well there is a bidirectional alignment of unidirectional Fibers, preferably advantageous in the circumferential direction of the disc wheel, so that the greatest strength and rigidity of the rim bed under bending stress in the Shell surface of the rim base at an angle of maximum +/- 45 ° to the Extent of extent. This can be done with two layers on top of each other with fiber directional angles to the maximum extent of +/- 45 °, but also with multi-layer composites, which also have fiber directions of maximum +/- 90 ° May have circumferential direction.

In a further advantageous embodiment of the invention, the wheel disc is on one Fastening section for coupling the disc wheel to a body provided metallic bushings that are connected to the wheel disc and through extend the wheel disc, the metallic bushings each on one One contact surface for a wheel bolt and one at the other end Have contact surface for direct contact against a wheel flange on the body side. This allows the disc wheel to be damaged without damaging the fiber-reinforced Plastic sections and without excessive loss of preload against one Wheel flange can be clamped. The metallic bushes are already during the Compression molding is molded into the wheel disc so that there is between the metallic Adjusts the bushings and the surrounding plastic sections there is a positive and material connection.

Leave undue tension in the plastic environment of the metallic bushings avoid if the disk wheel, in a preferred embodiment, predominantly with the contact surfaces of the metallic bushings on a wheel flange is supported.

The metallic bushes preferably have a shape for form and / or  cohesive power transmission and are dimensioned in order to Fastening case on a wheel flange with an axial bracing a maximum Compressive stress of 50 MPa on the surrounding areas on the Attachment section to exercise, that of SMC with unidirectional reinforcing fibers is made. This can be achieved, for example, by a sufficiently high rigidity of the metallic sockets can be realized. That from the bracing with the wheel flange resulting compressive stresses in the metallic bushes then remain on one Area near the through opening of the same is limited, while the Outer wall sections that are connected to the plastic environment, a clearly have a lower voltage level.

For thermal decoupling of the wheel disc from a wheel flange on the body and to reduce the surface pressure between a fastening section of the The wheel disc and the wheel flange are in an advantageous development of the invention a support ring from the fastening section on the side toward the wheel flange pressure-resistant material, preferably made of metal or ceramic. The support ring is provided with through openings for wheel bolts. The disc wheel is can only be supported against the body-side wheel flange using the support ring.

The support ring is preferably at least materially integral with the fastening section the wheel disc, the one made of SMC with unidirectional reinforcement fibers is made. The support ring can therefore just like the metallic bushings during the molding with the fastening section or the wheel disc be connected so that additional fastening measures are not required.

In a further advantageous embodiment of the invention, the Fastening section of the wheel disc both metallic bushings and a on-site support ring for connecting the disc wheel to a wheel flange intended. These have coaxial through openings for wheel bolts. The Bushings have a contact surface for a wheel bolt at one end and are included the other end with the wheel bolted on positively and non-positively with the support ring coupled. This creates a fastener with high strength with which any immediate pressure load on fiber-reinforced plastic sections at Bracing the disc wheel with a wheel flange is avoided.  

The positive coupling between the metallic bushings and the support ring can be done in the form of centering shells. This is especially true for the Mounting a disc wheel on a wheel flange cheap when the support ring as separate component is present. However, it is also possible to use the support ring as well metallic bushes with the disc wheel even during compression molding connect. Such an embodiment simplifies assembly on a wheel flange. The positive coupling between the metallic bushes and the support ring then primarily causes a defined positioning between them during of compression molding.

In a further, advantageous embodiment of the invention, the one made of SMC Unidirectional reinforcing fibers manufactured fastening portion of the wheel disc Through holes for wheel bolts. To reduce the surface pressure between the screw heads and in the fastening section is on this on the outside a circular ring with a corresponding hole pattern to support the Heads of the wheel bolts provided. The annulus also has means for material and positive connection with the unidirectional fiber SMC fastening section on. This results in a firm connection between the annulus and the Fastening section, which is already obtained during the compression molding of the wheel disc. The circular ring is preferably in the outer contour of the fastening section integrated. In the present case, metallic bushings can then be dispensed with become. On the other hand, the attachment of a support ring on the side to the wheel flange, d. H. the inside of the disc wheel, possible and advantageous.

Another, particularly stressed and endangered point of the Disc wheel represents the rim flange on the rim bed, against which an on the Tire mounted disc wheel supports. An external one is therefore preferred Section of the outer rim flange formed by a metallic ring, the Wall thickness is 0.1 times to 1 times the wall thickness of the rim flange, whereby the metallic ring completely or partially depicts the outer rim flange depicts its outer contour. The metallic ring has means for material and positive connection with a portion of the disc wheel made of SMC is made with unidirectional reinforcing fibers. This in turn becomes a direct one Heavy pressure load on plastic sections of the disc wheel avoided. Also the metallic ring can already be made of plastic during the compression molding  Formed sections of the disc wheel are consolidated.

In an alternative embodiment, it is also possible to run the wheel disc continuously to form from a metallic material, whereas the rim base at least is partially made from a unidirectional fiber SMC. For fixed coupling points then the wheel disc means for material and positive connection with the Unidirectional fiber SMC made section of the rim well.

The means for a material and positive connection with a unidirectional fiber SMC-made sections include a variety of holes and / or pin-like Protrusions. During molding, the holes or the pin-like ones Projections filled with fiber-reinforced plastic or enclosed so that to a certain extent establishes a positive connection. Between the Plastic material and the surfaces of the holes or the projections occurs in addition, a composite liability, which further increases the strength of the connection.

Furthermore, it is also possible to only make the rim bed from a unidirectional fiber To manufacture SMC. The wheel disc can then be made in one or more parts from a different type Material, preferably a light metal alloy are made, conventional Manufacturing techniques come into use. It is then closed with the rim well screw or also during the pressing process with the fig bed connect.

In a further advantageous embodiment, at least those are off Unidirectional fiber SMC manufactured sections of the disc wheel at least on the Side facing a brake with a heat-resistant and / or reflective coating, preferably with a reflective metal particles based paint.

A particularly light-weight yet stable embodiment results if spokes on a wheel disc made of unidirectional fiber SMC and / or areas of a wheel hub are designed as hollow profiles, the of which Unidirectional fiber-SMC enclosed volumes have a density lower than 1.4 g / ccm having. The hollow profiles can for example in a known manner by Insert lost cores, prefabricated, thin-walled closed ones  Structures or foam cores can be made. You can also use two shells be executed.

In the disc wheel according to the invention can be made of fiber-reinforced at all Plastic-made sections, but preferably on the outer visible side of the Disc wheel area-wide or in sections additional decorative or Functional elements, preferably reflectors, fabric structures, foils or Elements bearing markings are laminated on and / or laminated into them. This is preferably done during the molding by inserting the relevant one Elements in the form.

For the targeted improvement of thermal and possibly also electrical Conductivity in the plastic laminate can fillers or additives in the resin matrix or wire or foil-like structures, all preferably of a metallic type his.

The above object is further achieved by a method of manufacture a disc wheel with a rim well and a wheel disc, at least sectionally consists of fiber-reinforced plastic, in which in a mold Blanks made from a unidirectionally oriented SMC with reinforcing fibers be inserted, each with a resin matrix with at least two superimposed fiber layers made of approximately unidirectional, parallel Reinforcing fibers, preferably carbon fibers or glass fibers, have distinguish the fiber layers by their fiber direction angle, and wherein the Blanks are arranged so that the unidirectional fibers are oriented to stress, and subsequently one in the mold Consolidation of the disc wheel or sections thereof under the influence of Heat and pressure is made.

This method allows the targeted use of unidirectional fiber SMC Cuts with which disc wheels with high strength properties are produced to let. The largely flowable SMC blanks enable a large one Design freedom for the shape of the disc wheel, which is still simple remains producible.  

In an advantageous embodiment of the method is used to manufacture a spoke wheel used a mold with corresponding recesses in the Strip-shaped unidirectional fiber SMC blanks inserted in a radial orientation with the unidirectional fibers in a fiber layer of the SMC extend approximately preferably in the longitudinal direction of the strips. The stripe-shaped Blanks are smaller than the shape of the spoke wheel. They only spread out at one of the heating and closing of the mold into the corresponding mold cavities. However, the radial orientation of the unidirectional fibers becomes essential maintain their orientation a high strength and rigidity on the wheel disc causes.

Preferably, in the area of the wheel disc, the number of spokes coordinated number of blanks inserted into the tool. The number of Cuts with an odd number of spokes smaller than 14 are equal to the number of Spokes. If the number of spokes is even less than 15, the number of Cuts preferably half the number of spokes. In the latter case, the Assembly effort on the molding tool low. By crossing the blanks There can also be an increased accumulation of material in the area of the center of the wheel disc be effected so that in particular a fastening portion of the wheel disc with a larger wall thickness can be formed.

If necessary, an additional cut in the Wheel hub area can be provided.

In a further advantageous embodiment, with regard to the Conserved resources shredded or ground recycled fiber-reinforced Plastic in the total ratio up to 40 percent by weight of the total mass of the Unidirectional fiber SMC added as a filler.

To simplify the production process, all others are preferred Elements, for example metallic or ceramic elements such as support rings, Bushings, circular rings or rim flange rings are placed in the mold and during of the consolidation process with cohesive and form-fitting sections fiber-reinforced plastic. So that is the disc wheel, apart from a possibly required removal of dead press pieces and deburring  as well as any subsequent coating or painting, after Compression molding as a finished component.

The invention is illustrated below with reference to the drawing Exemplary embodiments explained in more detail. The drawing shows in

Fig. 1 is a side view of a first embodiment of a disk wheel of fiber reinforced plastic,

Fig. 2 is a sectional view of the wheel hub according to Fig. 1,

Fig. 3 is a view of a mold for the wheel disc of the disc wheel shown in FIGS. 1 and 2 with inserted SMC blanks,

Fig. 4 is a view of a further molding tool for a wheel disc with six spokes,

Fig. 5 is a sectional view corresponding to FIG. 2, with a recess provided in the wheel disc metallic bushing and a wheel bolt,

Fig. 6 is a sectional view corresponding to FIG. 2 of a further embodiment with an inside support plate,

Fig. 7 is a side view of the support disc according to Fig. 6,

Fig. 8 is a sectional view corresponding to FIG. 2 of a further embodiment with a metal ring in the region of the rim flange of the wheel hub,

Fig. 9 is a side view of the metal rings of FIG. 8,

Fig. 10 is a view of the metallic ring of FIG. 8 in an embodiment with pins for positive connection to the rim well, and in

Fig. 11 is a detailed view of a metallic sleeve for carrying a wheel bolt.

The disc wheel 1 shown in FIGS. 1 and 2 made of a fiber-plastic composite comprises a wheel disc 2 and a rim base 3 which radially surrounds the wheel disc and is connected to it. However, it is also possible to produce only parts of the disk wheel 1 , for example only the rim base 3 or only the wheel disk 2 or sections thereof, from a fiber-plastic composite.

The essentially drum-like rim bed 3 serves to receive a tire and for this purpose has at its axial ends an outside rim flange 4 and an inside rim flange 5 against which side flanks of the tire are supported. The wheel disk 2 adjoins the rim bed 3 radially on the inside in the region of the rim flange 4 and extends essentially in a plane transverse to the axis of rotation X of the disk wheel 1 . In the area of the axis of rotation X, a fastening section 6 is formed on the wheel disc 2 , via which the disc wheel 1 can be coupled to a wheel flange of a body, for example a motor vehicle. For this purpose, the fastening section 6 is provided with three or more through openings 7 , which are preferably arranged equally spaced from one another and concentrically around the axis of rotation X. To fasten the disk wheel 1 to the wheel flange, wheel bolts are inserted from the outside through the through openings 7 and screwed to the wheel flange with corresponding threaded openings while bracing the disk wheel 1 against the same. Furthermore, a center hole 8 is provided on the wheel disc 2 concentrically with the axis of rotation X.

In racing vehicles, the disk wheel 1 is preferably connected via a central nut. For this purpose, the wheel disc 2 is formed with a central hub section which can be shaped, for example, according to the reinforcement around the central hole 8 in FIG. 2. A central opening of large diameter extends through the central hub section and is used to pull the disc wheel onto a stub axle.

In both cases, the wheel disc 2 can be formed with a plurality of spokes 9 which extend radially from the fastening section 6 to the rim base 3 . Breakthroughs 10 between the spokes 9 allow, in addition to saving weight, above all good ventilation of the spoke wheel and a brake arranged inside the same. However, the shape of the wheel disc 2 is not limited to the number of spokes shown in FIG. 1 or the spoke design disclosed there.

However, for reasons of strength, the number of spokes 9 preferably corresponds to the number of through openings 7 for the wheel bolts or is a multiple of the number of through openings 7 . The through openings 7 are each arranged in the region of the radially inner continuation of the spokes 9 on the fastening section 6 .

The geometry of the openings 10 and the spokes 9 is preferably designed such that a suction effect is achieved during a rotary movement of the disk wheel 1 about the axis of rotation X, which transports air out of the wheel disk of the disk wheel 1 to the thermal stress on the wheel, which is generated in particular by a brake arranged near the wheel.

Instead of the spoke design, however, other designs can also be used, for example a lace pattern can be provided.

The sections of the disk wheel 1 consisting of fiber-reinforced plastic are at least partially made of SMC blanks 11 and 12 reinforced with unidirectional fibers, as is indicated in FIG. 3. Fig. 3 shows a part of a compression tool 20 that determines the shape of the wheel disc 2 . The blanks 11 and 12 are inserted into this compression molding tool 20 and consolidated into a wheel disk 2 by compression molding under the action of heat and pressure.

The SMC blanks are obtained from SMC resin mats. These SMC resin mats comprise a resin matrix with at least two superimposed fiber layers made of approximately unidirectional, parallel reinforcing fibers, which are also referred to below as unidirectional fibers. The unidirectional fibers of different fiber layers are arranged at a fiber direction angle to one another, the angle being in a two-layer structure in the range from 10 degrees to 45 degrees. Resin mats with a fiber layer angle of approximately 10 degrees to 30 degrees are preferred for the spokes 9 in order to ensure a high flowability of the SMC blanks.

In the case of a wheel disk made of unidirectional fiber SMC, the spokes 9 or regions of a wheel hub can be designed as hollow profiles. The volume enclosed by the unidirectional fiber SMC then preferably has a density which is less than 1.4 g / ccm.

The resin matrix is a thermoset matrix, preferably a vinyl ester resin system, the Additives and fillers can be added. Can in the SMC resin mats moreover, additional reinforcing fibers can be present in a tangled arrangement. As Tangled fibers are mainly carbon fibers and glass fibers.

Multifilament carbon fibers are used as unidirectional reinforcing fibers used in each layer in the longitudinal extent every 10 mm to 200 mm were cut, the individual cuts between 0.5 mm and 20 Are millimeters wide and offset to the cuts in adjacent fibers exhibit. On the one hand, this ensures sufficient fluidity, on the other hand, high and largely homogeneous strength properties reached.

The orientation of the unidirectional fibers is of great importance for high component strength. The fiber direction angles in the blanks are selected according to the demands. Unidirectional fibers in the wheel disc 2 are therefore directed essentially radially, whereas unidirectional fibers in the rim bed 3 are oriented in the circumferential direction of the disc wheel 1 . Accordingly, blanks with a different layer structure and different fiber direction angles can be used. Preferably, blanks for both the wheel disc 2 and the rim base 3 are made from the same raw material, ie from a type of unidirectional fiber SMC, the blanks being cut stress-oriented to the course of the unidirectional fibers.

As can be seen from FIGS. 3 and 4, strip-shaped blanks 11 are used in the area of the wheel disc 2 , in which the reinforcing fibers run essentially in the longitudinal direction of the strips. For example, the cuts can be made such that their longitudinal extent coincides with the unidirectional fibers of a fiber layer. With small fiber angles of the order of about 10 to 20 degrees, the longitudinal direction of the strips can also be oriented at the bisector of the angle.

For the compression molding, the strips are inserted into the molding tool 20 or 20 'in their main direction of extension, each running radially and point-symmetrically to the center of the wheel disk. In the spoke design shown, the strips are arranged in the area of the shape recesses for the spokes. FIGS. 3 and 4 is further seen that the strips can be made smaller in their dimensions than the mold. This is possible because the unidirectional fiber SMC strips flow under pressure during subsequent thermal stress and fill the mold. Are not shown in Figs. 3 and 4, the blanks for the manufacture of the rim 3, which would be oriented with their fiber direction in the circumferential direction of the disc wheel 1.

The number of blanks to be placed in the mold for the formation of the wheel disc 2 is matched to the number of spokes. In the case of an odd number of spokes smaller than 14, the number of blanks 11 corresponds to the number of spokes, as shown with reference to FIG. 3. Fig. 4, however, shows a mold tool 20 'having an even number of spokes. In this case it is expedient to use strips 11 'which extend over the center of the wheel disc 2 . The number of cuts with an even number of spokes less than 15 is then half the number of spokes. The overlaps in the center of the wheel there lead to an increased accumulation of material, which can be used for a greater wall thickness on the fastening section 6 or to form a wheel hub. If necessary, an additional blank 12 can be provided both in FIG. 3 and in FIG. 4 in the region of the fastening section 6 or the wheel hub.

Shredded or ground recyclate can also be used as filler fiber-reinforced plastic in a total ratio of up to 40 percent by weight Total mass of unidirectional fiber SMC can be added. Besides that, too other known fillers, e.g. B. calcium carbonate compounds are used.

In order to improve the thermal and / or electrical conductivity in a targeted manner, metallic fillers or additives or wire or foil-like structures are introduced into the disk wheel 1 , preferably via the resin matrix.

In general, on the outer visible side of the disk wheel 1, additional decorative or functional elements, preferably reflectors, fabric structures, foils or markings, can be laminated to and / or laminated to sections made of unidirectional fiber SMC on the outer visible side or in sections. This is preferably done by inserting appropriate elements in the mold before consolidating the disc wheel 1 , so that these elements are then integrally present in the disc wheel. For example, it is also possible to laminate a pressure sensor into the rim base 3 to monitor the tire pressure.

As shown in FIG. 5, metallic bushes 13 are provided for coupling the disk wheel 1 to a structure in the fastening section 6 , which is made of SMC with unidirectional reinforcing fibers. In principle, it is possible to insert the bushings 13 into the through openings 7 provided on the fastening section 6 after the compression molding, and to fasten them there. However, the metallic bushes 13 are preferably also inserted into the molding tool 20 or 20 ′ and are thus connected to the surrounding plastic of the fastening section 6 both materially and positively during the molding.

The metallic bushes 13 each have a through opening through which a wheel bolt 14 can be passed. Self-centering wheel bolts 14 are preferably used here, the screw heads of which come into contact with a correspondingly shaped contact surface 15 at one end of the bushing for this purpose. The metallic bushing 13 extends through the fastening section 6 and has at its other end a contact surface 16 for direct abutment against a wheel flange on the body side. In order to avoid an unimpeded and therefore impermissible pressure load on plastic sections of the fastening section 6 , the disk wheel 1 is supported primarily against the wheel flange via the contact surface 16 of the bushes 13 .

The bushes 13 are further dimensioned in such a way that, in the case of fastening, with an axial bracing, a maximum compressive stress of 50 MPa is exerted on the surrounding areas on the fastening section 6 . For this purpose, the outer diameter of the bushings 13 is at least 1.6 times the nominal width of the wheel bolts 14 .

The bushings 13 preferably have an outer contour which, even when subjected to torsional stress by tightening the wheel bolts, ensures a force transmission and a form and material connection. For this purpose, the outer contour z. B. be designed as a polygonal profile, as shown in Fig. 11, or the outer surface has a micro-toothing, for example knurling.

In a further exemplary embodiment, which is explained below with reference to FIGS. 7 and 8, a support ring 17 made of pressure-resistant material, preferably of metal or ceramic, is arranged between a bearing surface of a wheel flange on the body side and the inner wall of the fastening section 6 of the wheel disk 2 . The support ring 17 is provided with through openings 18 for wheel bolts 14 and is formed with a closed cross section. However, a shape which is known from internally ventilated brake disks is preferred in order to reduce the thermal stress through improved heat dissipation.

The support ring 17 is at least integrally connected to the fastening section 6 of the wheel disc 2 , which in turn is made of SMC with unidirectional reinforcing fibers. Furthermore, the disc wheel 1 is supported exclusively against the body-side wheel flange via the support ring 17 .

In addition to the support ring 17 , in the exemplary embodiment of FIGS. 7 and 8, metallic bushings 13 ′ are provided on the fastening section 6 for carrying out wheel bolts 14 . These are essentially designed in accordance with the metallic bushes 13 according to FIG. 5. In contrast to the latter, however, these do not rest with their inside contact surface 16 ′ against a wheel flange, but rather against the support ring 17 . The contact surfaces 16 'are positively and non-positively coupled to the support ring 17 when the wheel is screwed on. In the exemplary embodiment, the contact surface 16 'is conical in order to enable centering between the relevant bush 13 ' and the support ring 17 with respect to a through opening provided on both. The bushings 13 'and the support ring 17 thus result in a fastening arrangement which enables the disc wheel 1 to be braced without an immediate pressure load on plastic parts.

The disc wheel 1 is manufactured with a heated tool. This is preferably made entirely of metal and has a stamp and an at least three-part die. The tool, preferably the stamp, is designed in such a way that support rings 17 with different thicknesses can be inserted in order to vary the press-in depth of the wheel with the thickness of the support ring 17 . The parting plane of the tool segments in the die is arranged in the area of the transition between the wheel disc 2 and the rim base 3 in such a way that by changing the segment that forms the wheel disc 2 and, if appropriate, the stamp, different geometrical designs on the wheel disc or material variations, e.g. B. the insertion of a prefabricated, metallic wheel disc 2 are possible.

In a further embodiment, which is shown in FIGS. 8 to 10, a circular ring 19 is provided in the area of the screw connection or the fastening section 6 , against which the heads of the wheel bolts 14 are supported . The fastening section 6 made of SMC with unidirectional reinforcing fibers and the circular ring 19 have a corresponding number of coaxial through openings for the wheel bolts 14 . The radial extent of the circular ring 19 is at least 1.5 times the nominal wheel bolt diameter. The through openings are each arranged centrally on the circular ring 19 . Furthermore, the circular ring 19 comprises means for material and positive connection with the unidirectional fiber SMC fastening section 6 , which can be designed as bores or as pin-like projections. In the exemplary embodiment shown, bores 21 are preferred which are filled with plastic material of the fastening section 6 during compression molding.

The embodiment of FIGS. 8 to 10 has on its rim bed 3 an outer rim flange 4 , the outer section of which is at least partially formed or reinforced by a metallic ring 22 . The wall thickness of the metallic ring 22 is 0.1 times to 1 times the wall thickness of the rim flange 4 . The metallic ring 22 forms at least part of the outer contour of the rim flange 4 . Furthermore, means for material and positive connection to a unidirectional fiber SMC section of the disk wheel 1 are provided on an inner side of the metallic ring 22 . These can in turn be formed by a large number of bores and / or pin-like projections. In the exemplary embodiment shown, pin-like projections 23 are preferred, which are arranged closely spaced from one another and extend essentially parallel to the axis of rotation X. The metallic ring 22 can also already be inserted into the molding tool and connected to other sections of the disk wheel 1 during the molding.

In a modification of the exemplary embodiments explained above, the wheel disc can also consist entirely of a metallic material, in which case the rim base is at least partially made of a unidirectional fiber SMC. The wheel disc can be connected to the rim bed already during the molding process, for which purpose the wheel disc must be inserted into the mold. In order to reinforce the connection between the wheel disc and the rim base, means for material and positive connection can in turn be provided with the section of the rim base made of unidirectional fiber SMC, which according to the exemplary embodiment in FIGS . 8 to 10 as bores and / or pin-like projections are trained.

Furthermore, it is also possible to make the wheel disc in one or more parts from another To produce material as a unidirectional fiber SMC, preferably from one Light metal alloy, and with one made of unidirectional fiber SMC Screw the rim well.

At least the sections of the disk wheel 1 made of unidirectional fiber SMC are preferably provided with a heat-resistant and / or reflective coating at least on the side facing a brake. For example, a lacquer based on reflective metal particles is used for this.

REFERENCE SIGN LIST

1

Disc wheel

2

Wheel disc

3rd

Rim well

4

external rim flange

5

internal rim flange

6

Fastening section

7

Through opening

8th

Middle hole

9

spoke

10th

breakthrough

11

,

11

'' Unidirectional fiber SMC cutting

12th

Unidirectional fiber SMC cut

13

,

13

'' metallic socket

14

Wheel bolt

15

,

15

'' external contact surface of the socket

16

,

16

'' internal contact surface of the socket

17th

Support disc

18th

Through opening of the support disc

19th

Circular ring

20th

,

20th

'' Mold

21

drilling

22

metallic ring

23

pin-like projection
X axis of rotation of the disc wheel

Claims (28)

1. Disc wheel with a rim base ( 3 ) and a wheel disc ( 2 ), which at least in sections consists of fiber-reinforced plastic, characterized in that the sections consisting of fiber-reinforced plastic are at least partially made of SMC blanks ( 11 , 11 ', reinforced with unidirectional fibers). 12 ) are pressed, the SMC blanks ( 11 , 11 ', 12 ) reinforced with unidirectional fibers each having a resin matrix with at least two superimposed fiber layers made of approximately unidirectional, parallel reinforcing fibers, which differ in their fiber direction angles. 2. Disc wheel according to claim 1, characterized in that the Reinforcing fibers are multifilament carbon fibers. 3. Disc wheel according to one of claims 1 and 2, characterized in that the Reinforcing fibers in each layer in their longitudinal extension every 10 to 200 mm are cut, the individual cuts each between 0.5 mm and 20 mm are wide and offset from the cuts of adjacent fibers. 4. Disc wheel according to one of claims 1 to 3, characterized in that the Resin matrix is a thermoset matrix, preferably a vinyl ester resin system. 5. Disc wheel according to one of claims 1 to 4, characterized in that unidirectional fibers in the wheel disc ( 2 ) are directed so that the greatest bending strengths and stiffness are at an angle of at most +/- 30 ° to the radial direction. 6. Disc wheel according to one of claims 1 to 5, characterized in that unidirectional fibers in the rim base ( 3 ) of the disc wheel ( 1 ) are directed so that the greatest strength and rigidity of the rim base under bending stress in the lateral surface of the rim base at one Angle of maximum +/- 45 ° to the circumferential extent result. 7. Disc wheel according to one of claims 1 to 6, characterized in that the wheel disc ( 2 ) has a fastening section ( 6 ) for coupling the disk wheel ( 1 ) to a structure, the fastening section being provided with metallic bushes ( 13 ) which extend through the fastening section ( 6 ), the metallic bushings ( 13 ) each having at one end a contact surface ( 15 ) for a wheel bolt and at the other end a contact surface ( 16 ) for direct abutment against a wheel flange on the body side. 8. Disc wheel according to claim 7, characterized in that the disc wheel ( 1 ) can only be supported on a wheel flange with the body-side contact surfaces ( 16 ) of the metallic bushes ( 13 ). 9. Disc wheel according to claim 7 or 8, characterized in that the bushes ( 13 ) have a shape for positive and / or integral force transmission and are dimensioned in order to secure a maximum compressive stress of 50 MPa to the surrounding in the event of an axial preload Exercise areas on the attachment portion ( 6 ) made of SMC with unidirectional reinforcing fibers. 10. Disc wheel according to one of claims 1 to 6, characterized in that on a fastening portion ( 6 ) of the wheel disc ( 2 ) for coupling the disc wheel ( 1 ) to a structure, a support ring ( 17 ) made of pressure-resistant material, preferably made of metal or ceramic , is arranged for support against a wheel flange on the body side, the support ring ( 17 ) being provided with through openings ( 18 ) for wheel bolts and the disc wheel ( 1 ) being able to be supported only against the wheel flange on the body side via the support ring ( 17 ). 11. Disc wheel according to claim 10, characterized in that the support ring is at least ( 17 ) integrally connected to the fastening portion ( 6 ) of the wheel disc ( 2 ), which is made of SMC with unidirectional reinforcing fibers. 12. Disc wheel according to one of claims 1 to 6, characterized in that on the fastening portion ( 6 ) of the wheel disc ( 2 ) both metallic bushes ( 13 ') and a support ring ( 17 ) on the side for connecting the disc wheel ( 1 ) with a The wheel flange on the body side is provided, which has coaxial through openings for wheel bolts, the bushings ( 13 ') having a contact surface ( 15 ') for a wheel bolt at one end and with the other end ( 16 ') with the wheel bolted on in a positive and non-positive manner with the Support ring ( 17 ) are coupled. 13. Disc wheel according to one of claims 1 to 12, characterized in that the fastening section ( 6 ) of the wheel disk ( 2 ) made of SMC with unidirectional reinforcing fibers has through-openings ( 7 ) for wheel bolts, and that on the fastening section ( 6 ) a circular ring ( 19 ) is provided with a corresponding hole pattern for supporting the heads of the wheel bolts, the circular ring ( 19 ) having means for material and positive connection with the unidirectional fiber SMC fastening section ( 6 ). 14. Disc wheel according to one of claims 1 to 13, characterized in that the rim base ( 3 ) has an outer rim flange ( 4 ), and that an outer section of the rim flange ( 4 ) is formed by a metallic ring ( 22 ), the wall thickness of which is 0.1 times to 1 times the wall thickness of the rim flange ( 4 ), the metallic ring ( 22 ) completely depicting the outer rim flange ( 4 ) or at least part of its outer contour, and that the metallic ring ( 22 ) means for Has material and positive connection with a portion of the disc wheel ( 1 ), which is made of SMC with unidirectional reinforcing fibers. 15. Disc wheel according to one of claims 1 to 14, characterized in that the wheel disc ( 2 ) consists continuously of a metallic material, whereas the rim base ( 3 ) is at least partially made of a unidirectional fiber SMC, and that the wheel disc ( 2 ) Means for material and positive connection with the section of the rim well ( 3 ) made of unidirectional fiber SMC. 16. Disc wheel according to one of claims 13 to 15, characterized in that the means for material and positive connection with a section made of unidirectional fiber SMC comprise a plurality of bores ( 21 ). 17. Disc wheel according to one of claims 13 to 16, characterized in that the means for material and positive connection with a section made of unidirectional fiber SMC comprise a plurality of pin-like projections ( 23 ). 18. Disc wheel according to one of claims 1 to 17, characterized in that the wheel disc ( 2 ) is made in one or more parts from a material other than unidirectional fiber SMC material, preferably made of a light metal alloy, and the wheel disc ( 2 ) with one Unidirectional fiber SMC manufactured rim base ( 3 ) is screwed. 19. Disc wheel according to one of claims 1 to 18, characterized in that at least the sections of the disc wheel ( 1 ) made of unidirectional fiber SMC ( 1 ) at least on the side facing a brake with a heat-resistant and / or reflective coating, preferably with a reflective metal particles based paint are provided. 20. Disc wheel according to one of claims 1 to 19, characterized in that in a wheel disc made of unidirectional fiber SMC ( 2 ) spokes ( 9 ) and / or areas of a wheel hub are formed as hollow profiles, and that the unidirectional fiber SMC enclosed volume has a lower density than 1.4 g / ccm. 21. Disc wheel according to one of claims 1 to 20, characterized in that on the outer visible side of the disc wheel ( 1 ) area-wide or in sections additional decorative or functional elements, preferably reflectors, fabric structures, foils or markings bearing elements on sections made of unidirectional fiber SMC laminated and / or laminated into them. 22. Disc wheel according to one of claims 1 to 21, characterized in that Fillers or additives or wire or foil-like structures, all preferably metallic type, contained in the resin matrix. 23. A method for producing a disc wheel (1) with a rim base (3) and a wheel disc (2) which consists at least partly of fiber-reinforced plastic (20, 20 ') in which, in a molding tool blanks (11, 11', 12 ) are inserted from an unidirectionally oriented reinforcing fiber having SMC, each of which has a resin matrix with at least two superimposed fiber layers made of approximately unidirectional, parallel reinforcing fibers, preferably carbon fibers or glass fibers, the fiber layers differing in their fiber direction angles, and the blanks ( 11 , 11 ', 12 ) are arranged in such a way that the unidirectional fibers are oriented in a stress-oriented manner, and subsequently the disk wheel ( 1 ) or sections thereof are consolidated in the molding tool ( 20 , 20 ') under the action of heat under pressure. 24. The method according to claim 23, characterized in that for the production of a spoke wheel ( 1 ) a molding tool ( 20 , 20 ') with corresponding shape recesses is used in the strip-shaped unidirectional fiber SMC blanks ( 11 , 11 ') inserted in a radial orientation The unidirectional fibers in a fiber layer of the SMC extend essentially in the longitudinal direction of the strips ( 11 , 11 '). 25. The method according to claim 23 or 24, characterized in that in the region of the wheel disc ( 2 ) a number of blanks ( 11 , 11 ') matched to the number of spokes ( 9 ) is inserted into the mold ( 20 , 20 ') , wherein the number of blanks ( 11 , 11 ') with an odd number of spokes less than 14 is equal to the number of spokes ( 9 ), the number of cuts ( 11 , 11 ') with an even number of spokes less than 15 half the number of spokes is. 26. The method according to claim 25, characterized in that an additional blank ( 12 ) is inserted in the wheel hub area. 27. The method according to any one of claims 23 to 26, characterized in that shredded or ground recyclate made of fiber-reinforced plastic in the Total ratio up to 40 percent by weight of the total mass of the Unidirectional fiber SMC is added as a filler. 28. The method according to any one of claims 23 to 27, characterized in that further elements, in particular metallic or ceramic elements, are inserted into the mold ( 20 , 20 ') and during the consolidation process of the disc wheel ( 1 ) cohesively and positively with sections made of fiber-reinforced plastic.