Gradient Heat-Conduction Brake Disk for Thermal Stress Control
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Solution Overview
Problem
Conventional brake disks face issues with inadequate heat dissipation and thermal stress, particularly in brakes for electromobility, leading to worsened braking performance and potential failure. Additionally, existing coatings require costly and inconvenient adaptations with brake linings, and thermal input causes warpage and cracking.
Innovation Solution
A brake disk design featuring a metallic main body with a ring-shaped securing element, a first friction region facing the rotating axis, and a second friction region diametrically opposite. The design includes a heat conduction layer with gradated thermal conductivity and specific heat resistance, applied via laser buildup welding, and a tribologically stressable hard material layer on top. The heat conduction layer consists of multiple materials with varying thermal conductivities, and its thickness is gradated to optimize heat dissipation and reduce thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional brake disks are used with uniform material composition, then manufacturing is simple, but heat dissipation is inadequate and thermal stress causes warpage and cracking
Solution Approach 1:
The brake disk employs a composite material structure where different regions have different material compositions optimized for their specific functions. The friction regions contain ceramic particles for wear resistance, while intermediate regions have different ceramic concentrations for stress management, and core regions are optimized for heat dissipation. This local differentiation resolves the contradiction by improving heat dissipation and thermal stress resistance without requiring complete redesign of the entire structure.
Solution Approach 2:
The brake disk uses a composite material system combining metallic matrix (cast iron or steel) with ceramic particles (oxides, carbides, nitrides). This composite structure enables simultaneous achievement of wear resistance, heat dissipation, and thermal stress resistance by leveraging the complementary properties of different materials in different regions, directly addressing the heat dissipation inadequacy of conventional uniform materials.
2Reliability
If ceramic particles are added to improve wear resistance, then friction surface durability increases, but manufacturing complexity and cost increase
Solution Approach 1:
Ceramic particles are selectively concentrated in the friction regions where wear resistance is most critical, while the concentration decreases in intermediate and core regions. This local quality approach ensures maximum durability where needed while minimizing manufacturing complexity and material cost in regions where wear resistance is less critical.
3Temperature
If thermal conductivity is increased to improve heat dissipation, then temperature control improves, but thermal stress resistance may decrease
Solution Approach 1:
The brake disk creates a thermal conductivity gradient where regions closer to the friction surfaces have higher thermal conductivity for rapid heat dissipation, while intermediate regions have lower thermal conductivity to act as thermal barriers and reduce thermal stress transmission to the core. This spatial differentiation resolves the contradiction between heat dissipation and thermal stress resistance.
Solution Approach 2:
The composite material structure with varying ceramic particle concentrations creates natural thermal conductivity variation throughout the brake disk. Regions with different ceramic content provide different thermal properties, enabling simultaneous heat dissipation and thermal stress management through material composition rather than requiring separate structural elements.
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
The solution achieves efficient thermal management and homogeneous temperature distribution within the brake disk, improving braking performance and preventing thermal stresses and cracking. It also allows for rapid readiness for use, especially in vehicles with energy recuperation systems, and extends the service life of the brake disk.
Implementation Method 1
a heat conduction layer with gradated thermal conductivity and specific heat resistance
Implementation Method 2
the at least one heat conduction layer is disposed atop the metallic main body and the tribologically stressable hard material layer atop the heat conduction layer by means of laser buildup welding
Data Source
AI summary
The invention relates to a brake disk (3), which has at least one thermal conduction layer (4, 6) with a thermal conductivity and specific thermal resistivity that can be graduated, the thermal conduction layer consisting of at least two different materials or of a varying layer thickness, thereby graduating the thermal conductivity or the thermal resistivity within the thermal conduction layer.