Brake Disc Extensions with Recesses for Heat Dissipation

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Solution Overview

Problem

Existing brake discs with ventilated designs face issues such as bending and detachment of connecting links under high torque, thermal stress gradients leading to cracks, and strength problems due to differing material masses and air blockage in cooling channels.

Innovation Solution

The introduction of recesses in the extensions between the brake discs allows for efficient heat dissipation, reducing thermal tension and stress, ensuring mobility and strength by machining these recesses mechanically after casting, which are formed circumferentially between connecting members and brake discs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the friction ring and disk chamber are made of different materials and connected with extensions having through holes or blind holes, then the connecting members can be securely attached, but this results in a large difference in mass between the friction surfaces and extension, causing high temperature gradients and stress gradients that lead to crack formation

Engineering Contradiction:
Improveconnection strengthVSAvoidcrack resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent introduces recesses in the extensions at specific locations to create local variations in mass distribution. This local quality change reduces the mass difference between friction surfaces and extensions, thereby reducing temperature gradients and stress gradients in critical areas, which prevents crack formation while maintaining connection strength

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent modifies the physical parameters of the extensions by introducing recesses that change the mass distribution and thermal characteristics. This parameter change reduces the temperature gradient and stress gradient, preventing crack formation in the friction surfaces

Inventive Principle:
Principle #35Parameter changes

2Strength

If extensions with through holes or blind holes are used to attach connecting members, then secure attachment is achieved, but the size of extensions blocks air from entering cooling channels, preventing effective cooling

Engineering Contradiction:
Improveconnection strengthVSAvoidcooling efficiency
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent segments the extensions by introducing recesses that create channels or pathways. This segmentation allows cooling air to access the cooling channels between friction surfaces, improving cooling efficiency while maintaining the structural integrity and connection strength of the extensions

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If connecting links have free length between support part and friction ring, then they can expand radially without distortion when temperature rises, but under high torque they can bend and become detached

Engineering Contradiction:
Improvethermal expansion stabilityVSAvoidtorque resistance
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent introduces recesses in the extensions that create preliminary constraints on the connecting members. These recesses prevent excessive bending and detachment under high torque while still allowing sufficient radial expansion for thermal growth, effectively countering the harmful effects before they occur

Inventive Principle:
Principle #9Preliminary anti-action

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 prevents crack formation, maintains connecting link mobility across temperature ranges, and ensures uniform heat dissipation and stress reduction, enhancing the brake disc's strength and durability under extreme conditions.

Implementation Method 1

the introduction of recesses in the extensions makes it possible to dissipate the heat that occurs during operation, ie during braking, relatively easily

Methodology Applied
Scientific EffectHeat dissipation: Convection

Implementation Method 2

The connecting links can expand in the radial direction if the temperature rises as a result of the braking process without the risk of distortion

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2425144B1Brake disc
Publication Date: 2013.02.20 ROBERT BOSCH GMBH
  • EP2425144B1 patent drawingFigure 1

AI summary

A brake disc (10) comprises a friction ring (12) and a disc chamber (11) that is connected to the friction ring (12) by means of connecting members (16). A support web (21) having recesses (25) is provided between the two brake discs (12a, 12b). A cooling air flow can enter said recesses (25) and dissipate the heat that is generated in the braking process.