Asymmetric Carbon Fiber Brake Rotor Preforms
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Solution Overview
Problem
Brake rotor preforms and rotors experience fractures and failures due to uneven compression and shear forces at the butt joints, leading to mechanical instability and failure during braking.
Innovation Solution
The brake rotor preforms and pads are designed with a spiral annular structure and asymmetrical segments with carbon fiber precursor tow oriented in specific directions, and brake pads with non-coplanar ends, which distribute axial forces across both segments, reducing the likelihood of fractures at the butt joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If brake rotor preforms are formed from segments laid end-to-end to form an annular spiral structure, then the brake rotor can be manufactured with carbon fiber composite material, but the butt joints between segments become vulnerable to shear forces and fractures during braking
Solution Approach 1:
The patent applies asymmetry by configuring the spiral structure such that the butt joints between segments are not coplanar with the friction surfaces of the brake rotor. This asymmetric arrangement ensures that when axial compression forces are applied during braking, the shear forces do not concentrate at the butt joints, thereby preventing fractures while maintaining the structural strength of the carbon fiber composite brake rotor
Solution Approach 2:
The patent resolves the contradiction by introducing a dimensional consideration - the spatial arrangement of butt joints relative to the friction surfaces. By ensuring that butt joints are not coplanar with friction surfaces (a relationship in the radial dimension), the design distributes shear forces across multiple segments rather than concentrating them at joint interfaces, thus improving reliability without compromising strength
2Force
If axial compression force is applied to the brake rotor during braking, then friction is generated for braking, but uneven compression causes shear force within the carbon-carbon brake rotor leading to fracture
Solution Approach 1:
The patent applies segmentation by dividing the brake rotor into multiple segments that are laid end-to-end to form an annular spiral structure. This segmentation allows the design to distribute the axial compression forces across multiple segments and their interfaces, preventing concentration of shear forces at any single location. The segmented structure maintains overall structural strength while resisting fracture under braking loads
Solution Approach 2:
The asymmetric configuration of butt joints relative to friction surfaces ensures that axial compression forces are distributed evenly across segments during braking. This asymmetric arrangement prevents the development of concentrated shear forces that would otherwise lead to fracture, thereby maintaining the brake rotor's resistance to shear force while enabling effective friction-based braking
3Strength
If segments are arranged with carbon fiber precursor tow oriented in chordal or radial directions, then mechanical and structural properties are improved, but the preform remains vulnerable to fracture at butt joints under shear force
Solution Approach 1:
The patent applies asymmetry by arranging the spiral structure such that butt joints between segments are not coplanar with the friction surfaces. This asymmetric spatial arrangement ensures that even though carbon fiber precursor tow is oriented in chordal or radial directions to optimize mechanical properties, the shear forces generated during braking do not concentrate at the butt joints, thereby preventing fractures while maintaining improved mechanical and structural properties
Data Source
AI summary
The present disclosure describes brake rotor preforms and brake pads configured to reduce fracturing and failure of brake rotors by distributing the axial force applied during braking across butt joints between abutting segments of preforms and rotors manufactured therefrom. The preforms comprise a spiral annular structure formed about a longitudinal axis from a plurality of carbon fiber precursor tow segments having a partial annular shape. Each segment is asymmetrical when viewed in the longitudinal axis direction and configured so planes defined by the segment's ends are never coplanar with planes extending radially from the longitudinal axis. The brake pads have a partial annular shape and ends adapted to prevent planes defined by the ends from being coplanar during use with a plane extending radially from a brake rotor longitudinal axis.