Brake Disc Thermal Isolation via Ceramic Intermediates

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Solution Overview

Problem

The existing brake disc systems face challenges in managing high thermal loads generated during braking, particularly with ceramic friction rings, which can lead to material degradation and require efficient cooling while maintaining torque transmission between the friction ring and the brake disc hub.

Innovation Solution

The introduction of intermediate ceramic disks between the friction ring and the brake disc hub, along with anti-rotation features like elongated holes and non-conductive washers, provides thermal and electrical insulation, reducing heat transfer and preventing corrosive attacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the friction ring and brake disc hub are directly connected, then torque transmission is efficient, but thermal load is high and heat is transferred to the shaft

Engineering Contradiction:

Improvethermal load on shaftVSAvoidtorque transmission

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The patent introduces intermediate disks made of ceramic material between the friction ring and brake disc hub. These intermediate disks act as thermal insulators to reduce heat transfer to the shaft while still transmitting torque. The ceramic material provides thermal isolation without significantly compromising the torque transmission capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If intermediate ceramic disks are introduced for thermal isolation, then heat transfer to shaft is reduced, but device complexity increases

Engineering Contradiction:

Improveheat transfer to brake disc chamberVSAvoidnumber of components

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The connection between the friction ring and brake disc hub is segmented by introducing intermediate ceramic disks. This segmentation creates distinct functional zones: the friction ring for braking, the ceramic intermediates for thermal isolation, and the brake disc hub for structural support. This modular approach allows thermal management without completely redesigning the entire assembly.

Inventive Principle:

Principle #1Segmentation

3Reliability

If ceramic friction rings are used, then braking performance is improved, but thermal expansion deformation occurs

Engineering Contradiction:

Improvebraking performanceVSAvoidcylinder ring deformation

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent acknowledges and utilizes the thermal expansion properties of ceramic materials. The intermediate ceramic disks are designed to accommodate thermal expansion differences between the friction ring and brake disc hub. The elastic elements allow for controlled deformation during thermal cycles, preventing permanent distortion of the cylinder ring shape.

Inventive Principle:

Principle #37Thermal expansion

4Reliability

If carbon fiber reinforced ceramic friction rings are used, then braking performance is enhanced, but electrical conductivity increases causing corrosive attack

Engineering Contradiction:

Improvebraking performanceVSAvoidcorrosive attack from salt solutions

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The intermediate ceramic disks serve as electrical insulators between the conductive carbon fiber reinforced ceramic friction ring and the brake disc hub. This intermediary layer prevents electrical conductivity from causing corrosive attacks on the brake disc chamber, while still allowing mechanical torque transmission through the assembly.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration effectively reduces heat transfer between the friction ring and brake disc hub, minimizing thermal stress and maintaining torque transmission, while also preventing corrosion from salt solutions.

Implementation Method 1

intermediate disks made of a preferably sintered ceramic material are arranged between the brake disc hub and the friction ring in such a way that the brake disc chamber and the friction ring do not touch directly

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

the electrical insulation of the ceramic friction rings made of silicon carbide ceramic reinforced with carbon fibers, which are conductive due to the content of carbon reinforcing fibers: the corrosive attack on the friction ring or brake disc chamber that is otherwise observed in the presence of salt solutions is prevented by the electrically non-conductive ceramic washers significantly reduced

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 3

the so-called shielding of the friction ring, a deformation of the cylinder ring in the shape of a cone shell or a cone shell provided with corrugations, is effectively suppressed by the different thermal expansion of the friction ring and the brake disk hub

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP1975451B1Compound brake disc with thermal isolation

Publication Date: 2010.03.24 AUDI AG

Figure 1
Figure 2~3

AI summary

A brake disc (1) comprises a central section (3) and a friction ring (2) connected to it. Intermediate ceramic discs (5) are located between the central section and the friction ring, so the central section and friction ring are not in contact. The friction ring consists of a fibre reinforced ceramic.