Molded body
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- BAYERISCHE MOTOREN WERKE AG
- Filing Date
- 2014-11-11
- Publication Date
- 2026-07-09
AI Technical Summary
Existing brake discs and calipers in vehicles face challenges in achieving optimal weight and braking performance while managing heat dissipation and unsprung inertia forces.
The use of a shaped body made entirely of gamma titanium aluminide, which offers high modulus of elasticity, low density, and high heat resistance, is proposed for brake discs and calipers, with production methods including centrifugal casting to create one-piece or multi-part designs with or without cooling channels.
This solution provides superior material properties, reducing unsprung inertia forces and enhancing braking performance through the use of gamma titanium aluminide, which is lighter and more resistant to heat, thus improving vehicle performance.
Abstract
Description
[0001] The invention relates to a shaped body made of titanium aluminide. Titanium aluminides (TiAl) are intermetallic compounds of titanium and aluminum. They can be produced both as structural materials and as coating materials. In the binary phase diagram of titanium-aluminum according to Murray, McCullough, and Huang, at least four intermetallic phases exist. The two most important are the hexagonal α2-Ti3Al, which can contain approximately 25 to 35% aluminum at room temperature, and γ-TiAl (here gamma-titanium aluminide) with 50 to 55% aluminum, an L10 superstructure, and a tetragonally distorted face-centered cubic unit cell. Some of the technically important Ti-Al alloys, with aluminum contents between 35 and 50%, also consist of a mixture of these two phases.
[0002] An intermetallic compound (more precisely, an intermetallic phase) is a homogeneous chemical compound consisting of two or more metals. Unlike alloys, they exhibit lattice structures that differ from those of the constituent metals. Their lattice contains mixed bonding, consisting of a metallic bonding component and smaller covalent or ionic bonding components, resulting in superstructures.
[0003] Against the backdrop of the continued strong growth in private car use, the automotive industry is striving to reduce the pollutant emissions of its vehicles. One known approach is the use of lightweight materials, utilizing material-optimized design. In this context, it has already been proposed to replace the currently standard materials of steel or cast iron in brake discs with composite materials made of intermetallic phases and ceramics.
[0004] For example, German patent DE 103 39 315 A1 describes a brake disc made of a ceramic / intermetallic composite material. For improved heat dissipation, this brake disc is internally ventilated, meaning it features radial cooling channels or ribs located between two friction surfaces. As the brake disc rotates, this creates a centrifugal force that draws air from the hub through the radial cooling openings to the outside, thus promoting heat dissipation. Despite its greater width and weight, this internally ventilated brake disc design has become standard in many passenger cars.
[0005] Based on this prior art, the object of the present invention is to create a molded body, in particular a brake disc or a brake caliper, which is an optimal solution with regard to its weight and the braking effect of a vehicle brake.
[0006] The problem is solved by the features of the first claim. Further embodiments of the invention are described in the dependent claims.
[0007] According to the invention, a shaped body made of titanium aluminide is characterized in that it consists exclusively of gamma titanium aluminide.
[0008] It has been found that such a shaped component, used in a brake disc (at least as a friction ring) or in a brake caliper, particularly for use in motor vehicles, possesses outstanding specific material properties, such as a high modulus of elasticity, low density, high hot strength and yield strength, and is superior to known aluminum, magnesium, and titanium alloys and composite materials made of intermetallic phases and ceramics. The use of gamma titanium aluminide brake discs and / or brake calipers also leads to a reduction in unsprung mass forces on the chassis.
[0009] Further advantageous embodiments of the invention provide that the molded body is characterized in that it is a brake disc for a disc brake, comprising a friction ring with two adjacent friction surfaces and a brake disc hub, wherein the friction ring and brake disc hub are manufactured in one piece by casting. Such a one-piece brake disc, preferably manufactured by centrifugal casting with or without cooling channels, has a simple design and is easy to produce.
[0010] Alternatively, the molded part can also be designed as a one-piece friction ring produced by casting, with one or two friction surfaces for a disc brake. In the first case, for example, a brake disc hub can be connected to the friction ring, and in the second case, two friction rings can be connected to a brake disc hub with integrated cooling channels. For these multi-part brake discs, only the friction rings need to be manufactured, preferably by centrifugal casting, with or without cooling channels. A brake disc is thus advantageously constructed from parts made of different materials according to the stresses on the parts, with the friction rings being made of gamma titanium aluminide. This material is also used in a third advantageous embodiment of the vehicle brake for a molded part, which in this case is a one-piece brake caliper for a disc brake, either cast or built.It is self-evident that the embodiments according to the invention can also be combined in such a way that both the brake caliper and the brake disc consist at least partially of molded parts made of pure gamma-titanium aluminide. Advantageously, these molded parts are produced by centrifugal casting. QUOTES INCLUDED IN THE DESCRIPTION
[0011] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. 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
[0012] DE 10339315 A1
[0004]
Claims
[1] Molded body made of titanium aluminide, characterized by that it consists exclusively of gamma titanium aluminide. [2] Molded body according to claim 1, characterized by that this is a brake disc for a disc brake comprising a friction ring with two adjacent friction surfaces and a brake disc pot, wherein the friction ring and brake disc pot are manufactured in one piece by casting. [3] Molded body according to claim 1, characterized by that this is a one-piece brake caliper for a disc brake, manufactured by casting or construction. [4] Molded body according to claim 1, characterized by that this is a friction ring manufactured in one piece by casting, with one or two friction surfaces for a disc brake. [5] Molded body according to any one of claims 1 to 4 for use in a motor vehicle. [6] Molded body according to any one of claims 1 to 5 characterized by that it is manufactured using the centrifugal casting process.