DE102010042752A1 - Novel construction for passenger car / commercial vehicle lightweight frame rims including construction, material concept, design features and manufacturing process - Google Patents

Abstract

Rotating wheel masses have a major impact on the acceleration performance of cars and commercial vehicles. To reduce CO2 emissions and fuel consumption, rims are made available that are lighter than the usual sheet steel or cast aluminum designs. In addition to the reduction in weight, the reduction in the moment of inertia is also achieved. In the case of electric vehicles, the use of lightweight rims with the same range can make the battery smaller, lighter and more cost-effective. With the same battery size, the range increases.

Description

Field of the invention

Rotating wheel masses have a great influence on the acceleration performance of cars and commercial vehicles. To reduce CO ₂ emissions and fuel consumption, rims are made available that are lighter than today's standard sheet steel or cast aluminum designs. In addition to the weight reduction, the reduction of the moment of inertia is achieved. In electric vehicles, the use of lightweight rims with the same range, the battery can be made smaller, lighter and more cost-effective. With the same battery size, the range increases.

State of the art

Car rims are usually made of rolled steel. Weight savings can be partially achieved by the rim geometry. However, even optimized geometries still carry a relevant high weight. Alternatively, in recent years rims made of lighter materials such as aluminum or fiber composites, especially Kevlar or carbon based established. With such less stable materials, however, the rim geometries are limited and typically a relatively large mass is needed to provide minimum stability.

There is great interest in new types of lightweight wheels in the automotive industry. A well-known technique is the production of such rims with U-shaped spokes of light metal like those in DE 4013603 are described. Disadvantage of such rims is that due to the U-shape thicker wall thicknesses of the spokes and thus a higher weight must be taken into account.

In DE 102 28 052 Lightweight lightweight alloy rims that partially contain textile hybrid materials are disclosed. Even such systems are lighter than pure aluminum rims. Nevertheless, the weight savings with these rims is only slight.

In DE 10 2005 041 940 is a lightweight rim described which consist entirely or in large part of textile-reinforced matrix materials, so a textile-resin hybrid system. These rims must, in order to ensure the required stability have correspondingly large wall thicknesses. However, the required amount of material in turn leads to a non-irrelevant minimum weight of these rims. In DE 10 2007 045 108 Further developments of these rims are revealed. In these optimized systems, the rim is partially made of textile tubes. This brings a further weight saving and improved stability. But even these systems are still optimized in terms of weight and stability.

The use of polymer foams in the manufacture of lightweight rims is also known. In WO 2007035076 For example, PU foams are used to make and assemble elastomeric molds from two part polyurethanes. The foam is removed afterwards.

From racing and motorsport fiber composite rims are known. The manufacturing process is designed for individual production and not suitable for mass production of car / NFZ rims. In US 6,398,313 Rims for lightweight bicycles are described, which are composed of two parts of a fiber composite material and optionally glued to a foam core. The foam material is only included in the rim and not in the spokes. In DE 4010326 Among other things, foam materials for spoke-free disc wheels, as used in racing bikes, described. A similar method is according to JP 05229229 also described for tennis rackets.

In US 4,030,754 are filled with polymer foam filled lightweight wheels for the automotive industry. Even with these rims only composed of two shell parts rim is filled with the foam material. Thus, the weight saving is only relatively low. It is known to the person skilled in the art that in the case of automobile rims, in particular the spokes make up a large part of the weight. Here, weight savings according to the prior art, however, are hardly possible because in particular the spokes for the stability of the rim and thus the vehicle safety are of great importance.

In addition, the latter systems all have the disadvantage that they have joining elements or joints, which are disadvantageous in terms of stability, especially with lateral loads as they occur when cornering.

task

It is an object of the present invention, in view of the prior art, to provide a novel lightweight rim having an improved combination of weight, durability and strength.

Moreover, it was an object of the present invention to provide a lightweight rim available that has no joining elements or joints.

Moreover, it was an object of the present invention to provide lightweight rims with a material concept that allows a high degree of freedom in the design of the outer shape of the rim.

Task was also to provide a design and manufacturing process available, which allows the production of very lightweight rims with good strength and durability and in cycle times of less than 10 minutes - largely automated.

solution

The tasks are solved by means of a new type of construction for car / commercial vehicle (light commercial vehicle) lightweight chamber rims and the method for producing these. These novel lightweight chamber rims sit down analogously to known rims from a rim base and a rim star, containing the hub, together. The lightweight rim according to the invention is characterized by special material combinations.

In particular, the tasks are solved with the help of a novel lightweight rim, which consists of a rim and a rim star hub. The rim well and the rim star according to the invention each consist of an outer and at least three of four sides of the outer region enclosed inner region. The outer region is made of a reinforced hybrid material containing a reinforcing material and a matrix material. The inner region, as stated above, encompassed by at least three out of four sides of the hybrid material, consists of a core material which is a foamed polymer.

In a preferred embodiment, the core material is enclosed on all four sides by the hybrid material. In a second, alternative embodiment, three of the four sides of the core material are enclosed with the hybrid material, and as the fourth side, the wheel inner side is not enclosed by the hybrid material, but with a protective layer, such. B. a glued protective film coated. This is thus a filled with nuclear material U-profile.

In both alternative embodiments, the inside may be additionally provided with a heat reflecting layer, e.g. B. in the form of a glued metal foil, be coated. In the second embodiment, this metal foil and the protective layer may be identical.

The rim bed

The rim base according to the invention consists of a reinforced hybrid material. The reinforcing material used is carbon fiber, aramid fiber or glass fiber. Fibers may be unidirectional in fabrics, mats or nonwoven fabrics. The fiber content makes up between 30 and 70% by volume, preferably between 50 and 65% by volume of the hybrid material.

The matrix material used is epoxy resin. The epoxy resin formulation is adjusted to a viscosity of 10 to 2000 mPa.s at 23 ° C. The wall thickness can be between 2 and 20 mm, preferably between 2 and 10 mm.

In the rim well, one or more circumferential chambers are provided. These chambers serve to stiffen and simultaneously reduce the required fiber composite mass and thus the rim weight. For the transmission of shear and compressive forces, the chambers are completely filled with a core material. For the transmission of shear and compressive forces, the chambers are completely filled with a core material. The core material has a density of 25 to 200 kg / m ² , preferably a density of 51 to 71 kg / m ³ . The compressive strength is 0.3 to 10 MPa. The shear strength is in the range of 0.3 to 6.0 MPa.

As the core material, polymer foams such as polyurethane, polymethyl methacrylate (PMMA) or poly (meth) acrylimide (PMI) foams are used. Preference is given to using PMMA or PMI foams.

The rim star with hub

The reinforcing material and the matrix material of the rim star and the hub contained correspond to the reinforcing material or the matrix material of the rim well. This applies with respect to the fiber material, the shape of the fiber material and the epoxy resin.

The rim star is made in sandwich construction, regardless of the design. The rim design may include single or multiple spoke and a disc shape with and without cooling air openings. Thus, with the structure according to the invention all common rim designs can be implemented. The cross-sections of the spokes and the disc are designed with an outer fiber composite layers and a foam core located between them. This structure is analogous to the construction of the rim base.

The hub consists of centering and holes for the wheel mounting, which is usually done with bolts or screws. The execution of the centering and the holes can be carried out with or without metal inserts. The cavities between holes and centering are completely filled with foam cores according to the comments on the rim base.

The rim star can have different shapes. In addition to a disc, rim stars with one, two, three, four, five or more recesses can be produced. Thus, rims with several wide spokes can be realized. The spokes may in turn be closed to the outside or U-shaped, d. H. be hollow towards the vehicle interior. Other shapes, such as an x-shaped cross section are conceivable.

Preferred are star wheels, which have between 3 and 12 spokes. Particularly preferred are rim stars, which have between 3 and 7 spokes.

Preferably, the spokes have a chamber profile or a U-profile.

The core material

The core material is a polymer foam. In particular, preferably, the core material is a PMMA or PMI foam, very particularly preferably a PMI foam as it is to relate, for example, from the company Röhm under the trade name ROHACELL ^®. The composition and preparation of such PMI foams can be found in EP 0 874 019 . EP 1 444 293 or EP 1 678 244 be read. Such PMI foams are typically foamed, crosslinked materials prepared from a mixture containing (meth) acrylic acid, (meth) acrylonitrile, crosslinkers, blowing agents and polymerization initiators.

The formulation (meth) acrylic acid stands for methacrylic acid, acrylic acid or mixtures of both. The formulation (meth) acrylonitrile is methacrylonitrile, acrylonitrile or mixtures of both.

PMMA foams are correspondingly foamed PMMA molding compounds.

An important aspect of the present invention is that the polymer foam is a closed pore material. This is the case in particular for the listed PMMA and PMI foams. Closed pores prevent penetration of the foam core with epoxy resin. In this way, the foam core is not penetrated when impregnating the reinforcing material with the epoxy resin and the low density of the rim interior is maintained. Superficial penetration into superficial open pores is even desired because it increases the strength of the rim.

The rim may additionally have an aluminum or iron ring around the tread. Such reinforcement prevents damage to the rim when mounting or operating a tire, which has metal elements directed mostly to the rim.

• – Sehr geringes Gewicht, deutlich leichter als Stahl-, Aluminium-, oder einschichtige Faserverbundlösungen. Die gewichtsoptimierten Kammerquerschnitte des Felgenbetts und die Sandwich Konstruktion des Felgensterns mit Nabe ergeben eine gegenüber dem Stand der Technik deutlich verbesserte Kombination aus Gewicht und Festigkeit.
• – Die mit der Reduzierung des Gewichts einhergehende Reduzierung des Trägheitsmoments von über 50% ermöglicht eine deutliche CO₂-Emissions- und Kraftstoffverbrauchsminderung für Fahrzeuge mit konventionellem Antrieb.
• – Bei Elektrofahrzeugen sinkt der Energieverbrauch entsprechend. Hinzu kommt die Möglichkeit die Batteriekosten zu reduzieren oder die Reichweite zu vergrößern.
• – Eine Lackierung der Felgen kann entfallen. Damit entfallen auch die für die Lackierung und Lacktrocknung anfallende CO₂-Emissionen.
• – Die erfindungsgemäßen Felgen zeigen eine besonders gute Witterungsbeständigkeit, sowie keine Korrosion durch Feuchtigkeit oder Streusalz.
• – Felgen sind mit normierten Befestigungssystemen ausgeführt und damit für Neufahrzeuge und im Servicemarkt einsetzbar. Damit sind die Felgen ohne Umbauten auf bestehende Radaufhängungen übertragbar.
• – Im Nachrüstfall ergibt sich die gleiche CO₂-Einsparung wie beim Neufahrzeug.
• – Im Crash/Impact Verhalten ist zunächst von einer Schädigung des Faserverbundes in Form von einer Rissbildung auszugehen. Größere Ausbrüche wie bei gegossenen Aluminiumfelgen sind jedoch nicht zu erwarten. Das Entweichen der Luft aus dem Reifeninneren erfolgt bei der Leichtbau-Kammerfelge langsam und erlaubt eine Unfall vermeidende Fahrerreaktion. Der analoge Schadenverlauf der Aluminiumfelge führt in der Regel zum Ausbruch eines größeren Teils des Felgenhorns verbunden mit einem schlagartigen Druckverlust im Reifen. Assistenzsysteme und Fahrer sind bei hohen Geschwindigkeiten mit diesem Schadenverlauf oft überfordert. Somit tragen die erfindungsgemäßen Felgen zu einer Verbesserung der Sicherheit im Straßenverkehr bei.

The rims according to the invention have a number of advantages:

• - Very light weight, significantly lighter than steel, aluminum, or single-layer fiber composite solutions. The weight-optimized chamber cross-sections of the rim bed and the sandwich construction of the rim star with hub result in a comparison with the prior art significantly improved combination of weight and strength.
• - Reducing the moment of inertia of more than 50% associated with weight reduction provides significant CO ₂ emission and fuel economy reduction for conventional drive vehicles.
• - For electric vehicles, the energy consumption decreases accordingly. Added to this is the possibility of reducing battery costs or increasing the range.
• - A painting of the rims can be omitted. This also eliminates the CO ₂ emissions incurred for the coating and paint drying.
• - The rims of the invention show a particularly good weather resistance, and no corrosion by moisture or road salt.
• - Rims are designed with standardized fastening systems and can therefore be used for new vehicles and in the service market. Thus, the rims are transferable without modifications to existing suspension.
• - In the retrofit case results in the same CO ₂ savings as the new vehicle.
• - In the crash / impact behavior, damage to the fiber composite in the form of crack formation must initially be assumed. Larger outbreaks such as cast aluminum rims are not expected. The escape of air from the inside of the tire takes place slowly in the lightweight chamber rim and allows an accident-avoiding driver reaction. The similar damage profile of the aluminum rim usually leads to the eruption of a larger part of the rim flange combined with a sudden pressure loss in the tire. Assistance systems and drivers are often overstrained at high speeds with this loss experience. Thus, the rims according to the invention contribute to an improvement in road safety.

Likewise, a component of the present invention is a novel process for the production of the lightweight rims described above. In this case, the production process for the production of the rim base, the rim spider and the hub, as well as the complete rim comprises the process steps production of the cores, production of the reinforcing material blanks and production of the rim prefabricated part.

Production of the cores

The starting material for producing the cores is a blank cut from the foam sheet or a mold-foamed blank made of PMMA or PMI. The shaping can be done by sawing, milling or a combination of sawing and milling. Alternatively or as an additional processing step, thermoforming can also be used. The blank is heated and then formed and cooled in a suitable tool. The molding takes place, for example, by bending, rolling or pressing.

In a particularly preferred embodiment, starting material is roughly preformed as unfoamed semi-finished product, containing at least one blowing agent. This polymer blank or more polymer blanks are positioned in a two- or multi-part form. The mold is closed and heated to the material-specific foaming temperature. The blanks foam and fill the cavity of the mold. The finished cores are removed after opening the mold.

Production of the reinforcing material blanks

The fibers for producing the hybrid material contained in the rim base, rim star and hub are processed into woven fabrics, nonwoven fabrics, knitted or wound fiber blanks. These are brought into a shape that corresponds to the later rim base or the rim star with hub.

Production of the wheel finished part

By coating the mold to produce the finished rim part, a coating can be applied to the later rim as a surface finish. For the representation of the desired color and surface structure, for example, in a first operation, a sunlight- and weather-resistant layer with a thickness of 10 to 100 .mu.m can be applied to the mold surface. The method used for this purpose may be, for example, a spray painting. This layer can be transparent, colored or set with a metallic effect. In addition, the layer may be additized such that scratch resistance, additional UV or weathering protection and / or antisoiling properties are achieved.

The actual manufacturing process is carried out in a first process step by inserting the reinforcing material blanks and the cores in the manufacturing mold of the rim. This mold is preferably in two parts, consisting of a mold bottom and a mold lid and has additional radially movable mold segments.

For this purpose, single or multi-part reinforcing material blanks and cores can be inserted, draped and finally end-positioned. Locally bonding of reinforcing material blanks and cores can be done to ensure dimensional stability during manufacture.

In a second process step, conditioning and closing of the mold take place. The mold can already be preheated during the loading process to the temperature later set for the curing of the epoxy resin formulation. After inserting, draping and positioning all components, the mold is closed. The clamping forces are generated by a press or mechanical clamping of the upper and lower mold halves.

The third process step is the resin injection. After closing the two- or multi-part mold, an epoxy resin system consisting of a mixture of epoxy resin (A component) and an amine hardener component (B component) is injected under pressure into the mold. The component A consists of a mixture of components with OH groups such as. As bisphenol A, and components with oxirane groups, such as. B. epichlorohydrin. Component B are usually acid anhydrides, di- or triamines. The compositions of the epoxy resins are well known in the art and may, for. In H.-G. Elias, macromolecules (Volumes 1-4, Wiley-VCH, Weinheim, 6th edition, 1999-2003) be read. A rapid cure begins as soon as the resin wets the preheated mold. The formulation and viscosity of the resin with the hardener system, injection pressure, in-mold pressure, mold internal temperature and curing time are process parameters which are optimized for the application. If necessary, injection takes place at several points simultaneously; This achieves the best possible distribution of the resin. The epoxy resins are preferably heat-curing systems having a temperature resistance of at least 200 ° C.

After curing takes place in the fourth step, the removal of the finished rim. After removal, first possible pins are removed at the injection or venting points of the rim by cutting and / or polishing.

Optionally, in particular, if no previous internal coating of the mold has taken place, then the rim can be degreased and painted. Protective coatings, color layers and / or clearcoats can be applied. The coating can be done by spray, dip or powder coating.

In a preferred embodiment, the rim is made in one piece. This means that the shape of the rim, including rim base, rim star and hub, is laid out in one step with reinforcing material blanks and foam core material. In an alternative, non-preferred embodiment, various rim components -. B. rim base and rim star - made separately and later, z. B. by gluing, connected to each other. In such a procedure, however, a rim would be molded with joints.

In a further alternative embodiment, which is also conceivable in the preferred production of the rim in one piece, the reinforcing material blanks and / or the foam core are differently composed in rim base and rim star. The inventive method makes it possible to make material variations in different areas when laying out the mold.

The automation of steps 1 to 4 results in a repeatable, consistent component quality. In addition, very economical cycle times are possible under 10 min.

The examples given below are given for a better illustration of the present invention, but are not intended to limit the invention to the features disclosed herein.

Examples

Reference and thus comparative example of the present examples is the standard rear wheel of a Lotus Exige. This affects the shape, diameter and width of the rim. The reference rim is Comparative Example 1 made of pure aluminum. The rim according to Comparative Example 2 is made of a carbon fiber-epoxy composite material analogous to the examples (hereinafter CF-EP for short) and has a spoke solid profile. Example 1 represents a chamber profile filled with foam material. Example 2 shows an inwardly open U-profile.

The following results were determined in a simulation calculation.

• • Maximal auftretende Quer- und Bremskräfte sind auf Grund des Reibwerts Straße-Reifen gleich. Die Speichenquerschnitte sind so dimensioniert, dass bei maximalen Quer- und Bremskräften die Biegespannung gleich ist. Dabei verteilt sich die Bremskraft B auf alle Speichen, die Querkraft Q nur auf 60% der Speichen.
• • Bremsmoment ”Mb” (Rad) = Bremskraft × Radius Rad
• • Die Summe Umfangskraft Speichen ”B” ist auf den Radius der Krafteinleitung ins Felgenbett zu beziehen und ist: Mb/Radius Krafteinleitung
• • Radius Kraft Einleitung Felgenbett ”ru” = Radius Einspannung + Speichenlänge
• • Die Speiche wird als Biegebalken gerechnet, Einspannung in der Nabe
• • B wirkt tangential in Umfangsrichtung, Q wirkt orthogonal auf die Speiche mit der Folge einer seitlicher Auslenkung, Krafteinleitung ebenfalls am Felgenbett.
• • Biegelänge = Speichenlänge
• • Der Balkenquerschnitt ist der Querschnitt an der Einspannung (b × t)
• • Der Balkenquerschnitt ist konstant
• • Die Stelle der höchsten Belastung ist die Einspannstelle
• • Aluminium Referenz und Composite Varianten werden nach dem gleichen Prinzip gerechnet

With regard to the calculation parameters, the following assumptions were made:

• • Maximum transverse and braking forces are equal due to the road-tire coefficient of friction. The spoke cross-sections are dimensioned so that the bending stress is equal at maximum transverse and braking forces. The braking force B is distributed to all spokes, the lateral force Q only to 60% of the spokes.
• • Braking torque "Mb" (wheel) = braking force × radius wheel
• • The sum of peripheral force spokes "B" is related to the radius of the force introduction into the rim well and is: Mb / radius force transmission
• • Radius force Introduction rim bed "ru" = radius clamping + spoke length
• • The spoke is calculated as a bending beam, clamping in the hub
• • B acts tangentially in the circumferential direction, Q acts orthogonally on the spoke with the consequence of a lateral deflection, force also on the rim base.
• • Bend length = Spoke length
• • The beam cross section is the cross section at the clamping (b × t)
• • The beam cross-section is constant
• • The point of highest load is the clamping point
• • Aluminum reference and composite variants are calculated according to the same principle

With respect to the comparative examples, two commercially available systems were compared. This also gave the dimensions for the model calculations for Comparative Example 1 and Examples 1 and 2: Table 1 vehicle model Lotus Exige 2008 rim lotus Pro Race 1, 2 tires A048 LTS (90 W) ASPIRE (91 W) Weight rim 7.9 kg 8.8 kg tire width 225 mm H / W 45 Radius rim 215.9 mm Wide rim 190.5 mm Height of tires 101.25 mm Radius wheel 317.2 mm Circumference wheel 1992 mm Maximum wheel load 372 kg Maximum braking and lateral force 4378 N Hub diameter (clamping point of the spoke) 170 mm Radius clamping 95 mm Spoke length "I" 100 mm Number of spokes 12 b (clamping point spokes) 22 mm t (clamping point) 25 mm F (cross-sectional area: Σ clamping points) 6600 mm ²

For better calculation, a replacement model was created on the basis of these real rims. It is a 5-spoke rim with an identical sum of spoke cross sections. Table 2 Number of spokes 5 b (clamping point spokes) 52.8 mm t (clamping point) 25 mm F (transverse surface: Σ stress points) 6600 mm ² This results in the following parameters: mb 1388 Nm ru 195 mm Sum B 7120 N B / spoke 1424 N

The assumed values for the materials are shown below: Table 3 Die-cast aluminum DG-AL-MG9 CF-EP with 60% by volume fiber; Fabric 90 & 45 ° Tensile strength (δ) 20 kg / mm ² or 196 N / mm ² 705 N / mm ² elongation 1-3% nb E-module (E) 75000 N / mm ² 74000 N / mm ² Density (D) 2.7 g / cm ³ 1.5 g / cm ²

The following relationships were used to calculate the braking force for solid sections. For better illustration reference is made to the drawings 2 to 4. J _x = t b · ^3/12 moment of inertia [mm ^4] W _x = t · b ^2/6 moment of resistance [mm ³ ] δ = B × I / W _× tensile strength [N / mm ² ] f = B * I ³ / (E * J * 3) deflection [mm]

For chamber profiles, the following formulas were used: (d = wall thickness in mm) J _x = (t * b ³ - ((t - 2d) * (b - 2d) ³ ) / 12 W _x = (t * b ³ - ((t - 2d) * (b - 2d) ³ ) / 6b δ = B × I / W _× f = B * I ³ / (E * J * 3)

For U-profiles, the following formulas were used: J _x = (t · b ³ - ((t - d) · (b - 2d) ³ ) / 12 W _x = (t · b ³ - ((t - d) · (b - 2d) ³ ) / 6b δ = B × I / W _× f = B * I ³ / (E * J * 3)

The following relationships were used to calculate the lateral force for solid sections: J _x = b · t ^3/12 W _x = b · t ^2/6 δ = Q · I / W _x f = Q * I ³ / (E * J * 3) For chamber profiles the following formulas were used: J _x = (b * t ³ - ((b-2d) * (t-2d) ³ ) / 12 W _x = (b * t ³ - ((b - 2d) * (t - 2d) ³ ) / 6t δ = Q · I / W _x f = Q * I ³ / (E * J * 3)

For U-profiles, the following formulas were used:
Dimensions e denote the distance of the profile cross-section (e1 from the outside, e2 from the inside) e1 = (2dt ² + (b - 2d) d ² / (4dt + 2d (b - 2d)) e2 = t - e1 W _x = J _x / e 2 δ = Q · I / W _x f = Q * I ³ / (E * J * 3)

In the following model calculation, the dimensioning of the rims according to comparative examples (V examples) 1 and 2 or Examples 1 and 2 were carried out in such a way that identical deformation results with the same braking and transverse forces. (Design for equal rigidity) The model calculation was made for 5 spokes. Table 4 V Example 1 V example 2 example 1 Example 2 Material, shape Aluminum solid profile CF-EP solid profile CF-EP chamber profile CF-EP U-profile Braking force B 7120 N t 31 mm 31 mm 32 mm 32 mm b 28.5 mm 28 mm 30 mm 27 mm d - - 4.5 mm 10 mm e1 - - - 15 mm e2 - - - 17 mm J _x [mm ² × mm ² ] 59802 56709 54250 51859 W _x [mm ³ ] 4197 4051 3617 3841 δ 34 N / mm ² 35 N / mm ² 39 N / mm ² 37 N / mm ² Security against breakage 6 21 19 20 f 0.11 mm 0.11 mm 0.12 mm 0.12 mm Weight spokes 1193 g 651 g 358 g 533 g Ratio to V-Example 1 100% 55% 30% 45%

The numerical values stated under "Safety against breakage" result from the quotient of tensile strength of the material against tensile stress in the load case.

The corresponding calculation was also carried out for comparable lateral forces Q. This led to the following results. The values for t, b, d, e1 and e2 correspond to the values listed in Table 4. Table 5 V Example 3 V example 4 Example 3 Example 4 Material, shape Aluminum solid profile CF-EP solid profile CF-EP chamber profile CF-EP U-profile Transverse force Q 4378 N J _x [mm ² × mm ² ] 70754 69512 60628 62832 W _x [mm ³ ] 4565 4485 3789 3678 δ 32 N / mm ² 33 N / mm ² 39 N / mm ² 40 N / mm ² Security against breakage 6 23 19 19 f 0.09 mm 0.09 mm 0.11 mm 0.10 mm

It can be seen from the examples that rims can be constructed with the material concept according to the invention, which are characterized by a significantly lower weight with the same rigidity and at the same time have a significantly increased safety against breakage.

The drawings serve to illustrate the examples.

1 Rim in landscape format

2 Schematic representation of solid profile

3 Schematic representation of chamber profile

4 Schematic diagram U-profile Following the numbering from Fig.1: 1 rim flange 2 rim 3 Wheel width 4 Wheel Size 5 centering 6 Counterforce Axis (lateral force and Br diagonal) 7 Clamping the spoke in the hub Cross section Full spoke aluminum [b × t] 8th Transverse force, initiation in rim bed braking force orthogonal 9 offset 10 Spoke, tread depth t

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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 assumes no liability for any errors or omissions.

Cited patent literature

• DE 4013603 [0003]
• DE 10228052 [0004]
• DE 102005041940 [0005]
• DE 102007045108 [0005]
• WO 2007035076 [0006]
• US 6398313 [0007]
• DE 4010326 [0007]
• JP 05229229 [0007]
• US 4030754 [0008]
• EP 0874019 [0028]
• EP 1444293 [0028]
• EP 1678244 [0028]

Cited non-patent literature

• H.-G. Elias, Macromolecules (Volumes 1-4, Wiley-VCH, Weinheim, 6th Edition, 1999-2003) [0042]

Claims (15)

Lightweight rim for automobile wheels consisting of a rim base and a rim star with hub, characterized in that the rim base and the rim star each enclosed in the outer region of a reinforced hybrid material containing a reinforcing material and a matrix material, and in the inner region, at least three out of four sides of the hybrid material, a core material consisting of a foamed polymer. Lightweight rim according to claim 1, characterized in that the Kermaterial is enclosed on four sides of the hybrid material. Lightweight rim according to claim 1, characterized in that the core material is enclosed on three sides by the hybrid material, that the fourth side is the inner side of the wheel, and that this inner side of the wheel is provided with a protective layer. Lightweight rim according to at least one of claims 1 to 3, characterized in that the wheel inner side is provided with a heat-reflecting metal layer. Lightweight rim according to at least one of Claims 1 to 4, characterized in that the matrix material is an epoxy resin and the reinforcing material is a woven fabric, nonwoven fabric, knitted fabric or a wound fiber blank made of carbon fiber, aramid fiber or glass fiber. Lightweight rim according to claim 5, characterized in that the epoxy resin before curing has a viscosity at 23 ° C between 10 and 2000 mPa · s. Lightweight rim according to at least one of claims 1 to 6, characterized in that it is the Kermaterial is a poly (meth) acrylimide or a PMMA foam. Lightweight rim according to claim 7, characterized in that the core material has a density between 25 and 200 kg / m ³ , a compressive strength between 0.3 and 10.0 MPa and a shear strength between 0.3 and 6.0 MPa. Lightweight rim according to at least one of claims 1 to 8, characterized in that the rim star has between 3 and 12 spokes. Lightweight construction rim according to claim 9, characterized in that the spokes have a chamber profile or a U-profile. Lightweight construction rim according to at least one of claims 1 to 10, characterized in that the lightweight rim was manufactured in one piece and has no joining or splices. A method for producing a lightweight rim according to any one of claims 1 to 11, characterized in that In a first process step, reinforcing material blanks and the core material are placed in a rim-imaging form, which in a second process step conditions the inserted substances, closes the mold and preheats to a curing temperature of the matrix material In a third process step, a mixture of a crude resin and hardener mixture are injected into the mold, this mixture is cured in the mold and the finished rim is then cooled, and the in a fourth Vefahrensschritt the rim, consisting of rim and rim star with hub is removed from the mold. A method according to claim 12, characterized in that the matrix material is an epoxide, wherein the reinforcing material is a woven fabric, nonwoven fabric, knitted fabric or a wound fiber blank of carbon fiber, aramid fiber or glass fiber and the core material is a poly (meth) acrylimide or a PMMA foam. A method according to any one of claims 12 or 13, characterized in that the mold has been sprayed with a coating formulation prior to the first process step. Method according to at least one of claims 12 to 14, characterized in that after removal of the rim at this possibly existing pin are removed, the rim is then polished, degreased and painted.

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