Brake Disc Connecting Elements Form-Fit Attachment

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Solution Overview

Problem

Conventional brake discs experience unsatisfactory attachment quality and position between the friction ring and connecting elements due to integral material connections, leading to deformation, uneven wear, and 'brake judder' at high temperatures, compromising driving comfort and safety.

Innovation Solution

The brake disc features a form-fitting connection between the support part and friction ring via composite casting with recesses and projections on connecting elements, ensuring a defined and strong attachment, reducing heat transfer, and preventing deformation, with connecting elements designed as hollow bodies for internal ventilation and solid materials for cost-effective production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If material connections (welding or soldering) are used to attach the friction ring to the connecting elements, then a firm connection is achieved, but the connection quality and position become undefined, and the connection becomes loose at high temperatures

Engineering Contradiction:
Improveconnection strengthVSAvoidconnection position precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The connection is segmented into two independent functions: the connecting elements provide mechanical support and positioning (form-fit connection), while the adhesive provides thermal bonding. This segmentation allows each component to optimize its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention merges two connection methods (form-fit mechanical connection and adhesive bonding) into a hybrid system. The form-fit connection ensures precise positioning and structural strength, while the adhesive provides thermal resistance and additional bonding, creating a comprehensive solution that addresses both mechanical and thermal requirements.

Inventive Principle:
Principle #5Merging (Combining)

2Strength

If material connections are used to connect the friction ring to the connecting elements, then a firm attachment is achieved, but heat transfer from the friction ring to the supporting part increases

Engineering Contradiction:
Improveattachment firmnessVSAvoidheat transfer loss
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The adhesive layer acts as a thermal intermediary with low thermal conductivity between the friction ring and the connecting elements. This intermediary reduces heat transfer from the friction ring to the supporting part while maintaining mechanical attachment firmness, effectively decoupling the thermal and mechanical functions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If soldered joints are used to connect the friction ring to the connecting elements, then a material bond is achieved, but the joints become loose at temperatures above the melting temperature of the solder

Engineering Contradiction:
Improvematerial bond strengthVSAvoidconnection reliability at high temperature
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention changes the thermal parameter (melting temperature) of the bonding material by selecting an adhesive with a glass transition temperature suitable for brake disc operating conditions. This parameter change ensures the connection remains reliable at high temperatures where traditional solder would fail.

Inventive Principle:
Principle #35Parameter changes

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 solution provides a stable and secure connection at high temperatures, preventing deformation and wear, enhancing driving comfort and safety by minimizing heat transfer and maintaining structural integrity, while allowing efficient cooling and simplified production.

Implementation Method 1

Since material connections are also known to be characterized by good thermal conductivity, they promote high heat transfer from the friction ring to the connecting elements. This in turn has the consequence that an increased heat input into the supporting part also takes place via the contact points of the connecting elements to the supporting part. The resulting temperature differences between the contact points and the rest of the supporting part can also lead to a distortion of the supporting part

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The resulting temperature differences between the contact points and the rest of the supporting part can also lead to a distortion of the supporting part, since the outer area of the supporting part expands more than the inner area. Undesirable thermal distortion can therefore occur, which distorts the supporting part in the sense of a 'ripple' and leads to a wobble that is transferred to the friction ring

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2765324B1Brake disc for a disc brake in a motor vehicle
Publication Date: 2017.10.04 AUDI AG
  • EP2765324B1 patent drawingFigure 1~4

AI summary

A brake disc (10) for a disc brake of a motor vehicle, comprising a cup-shaped support part (12) and a friction ring (14), in which the support part (12) and the friction ring (14) are firmly connected to each other in the radial direction (r) via several connecting elements (20) arranged in the circumferential direction (u) and extending in the radial direction (r), designed as separate components, wherein the connecting elements (20) are positively connected to the support part (12), and the connecting elements (20) are positively connected to the friction ring (14).