Composite Brake Disc Hub and Ring Joining

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Solution Overview

Problem

Composite brake discs face issues with high unsprung weight due to different thermal expansion coefficients of materials used in brake disc hubs and rings, leading to inefficiencies in heat dissipation and stress management under torque loads.

Innovation Solution

A composite brake disc design featuring a brake disc hub with an outwardly directed tooth profile and a brake ring with an involute tooth profile, allowing for elastic-plastic deformation during joining, which enables simple component-centered positioning and efficient torque transmission through flank centering, with a gap between tooth tips and roots to distribute stress evenly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a one-piece cast brake disc is used, then the structural simplicity is maintained, but the unsprung weight becomes excessively high

Engineering Contradiction:
Improveunsprung weightVSAvoidstructural complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The brake disc is divided into two separate components: a brake disc hub made of lightweight aluminum material and a brake ring made of friction material. These segments are joined together to form the complete brake disc assembly, reducing overall weight while maintaining functional integrity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention employs composite construction by combining aluminum material for the brake disc hub with friction material for the brake ring. This composite approach leverages the lightweight properties of aluminum while incorporating the necessary friction characteristics of the braking surface

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If composite brake discs with aluminum hubs are used to reduce weight, then weight reduction is achieved, but different thermal expansion coefficients cause positioning and stress distribution problems

Engineering Contradiction:
ImproveweightVSAvoidpositioning accuracy
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The invention addresses thermal expansion differences by designing the joining mechanism to accommodate parameter changes during operation. The tooth profile geometry and joining structure allow for controlled movement and stress distribution as temperatures vary, maintaining reliable positioning despite material expansion differences

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If traditional joining methods are used for composite brake discs, then assembly is simplified, but stress distribution under torque loads becomes inefficient

Engineering Contradiction:
Improveassembly simplicityVSAvoidstress distribution
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention employs curved tooth profiles with specific geometric characteristics that optimize stress distribution. The circular arc and involute profiles create favorable contact patterns that distribute loads more evenly across the joining interface, improving strength while maintaining manufacturability

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 design achieves a weight reduction while ensuring effective stress distribution and material efficiency, allowing for better thermal expansion compensation and improved performance under varying torque loads.

Implementation Method 1

at least the brake disk hub (2) undergoes elastic and elastic-plastic deformation in the joining area (6)

Methodology Applied
Scientific EffectElastic-plastic deformation: Deformation

Data Source

PatentEP2673525B1Composite brake disc
Publication Date: 2016.09.07 MERCEDES BENZ GROUP AG
  • EP2673525B1 patent drawingFigure 1~3
  • EP2673525B1 patent drawingFigure 4~5

AI summary

The invention relates to a composite brake disc, in particular for a motor vehicle, comprising a brake disc hub (2) and an associated brake ring (3,3') which are connected to one another by means of a joining process, wherein in a joining region (6) an internal brake ring tooth profile (8) engages in a brake disc hub tooth profile (7). The brake disc hub tooth profile (7) has circular arc brake disc hub tooth flanks (10), whereas the brake ring tooth profile (8) has involute brake ring tooth flanks (11). Because of the special paired design with two different toothings a firm, load-bearing connection between the brake disc hub (2) and the brake ring (3) can be achieved.