Composite Brake Disc Joint Structure for Strength and Cooling
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Solution Overview
Problem
Brake discs made of different materials at the joint of a hat part and a disc part face challenges in maintaining coupling strength and heat dissipation, particularly due to material differences and the generation of red rust on gray cast iron surfaces, which affects vehicle weight reduction and performance.
Innovation Solution
A brake disc design featuring a hat part made of ductile cast iron with protruding bridges and a disc part made of common cast iron, incorporating curved joint surfaces and air-flow channels formed by vanes, which enhances coupling strength and heat dissipation by exposing bridge ends to air channels and using specific vane configurations for improved airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a hat part made of ductile cast iron is used to reduce weight, then weight reduction is achieved, but coupling strength with the disc part becomes difficult to maintain
Solution Approach 1:
The front ends of the bridges are formed with a curved surface having a radius of curvature of 2.0R to 3.0R. This curvature distributes the contact stress more evenly across the coupling interface between the ductile cast iron bridge and the gray cast iron disc part, preventing stress concentration that would lead to coupling failure. The curved surface allows the heterogeneous joint to maintain sufficient coupling strength while enabling weight reduction through the ductile cast iron hat part.
2Strength
If gray cast iron is used for the hat part, then coupling strength is maintained, but red rust is generated on the surface deteriorating appearance and causing judder
Solution Approach 1:
The patent applies different materials to different parts of the brake disc based on local functional requirements. The hat part is made of ductile cast iron for weight reduction and corrosion resistance, while the disc part remains gray cast iron for friction performance. The curved surface at the bridge front ends specifically addresses the coupling interface to maintain strength despite the material change in the hat part.
3Ease of manufacture
If gray cast iron is used for both hat part and disc part, then manufacturing simplicity is maintained, but heat dissipation is insufficient due to material limitations
Solution Approach 1:
The brake disc employs a composite structure where the hat part is made of ductile cast iron and the disc part is made of gray cast iron. This composite material approach allows optimization of each part for its specific function: ductile cast iron provides better weight reduction and corrosion resistance for the hat part, while gray cast iron maintains excellent friction characteristics for the disc part. The curved surface at the bridge front ends ensures effective heat transfer across the material interface.
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 design stabilizes coupling strength and improves heat dissipation, maintaining yield strength and reducing temperature within the disc plates, as demonstrated by comparative examples showing enhanced heat dissipation and thermal capacity.
Implementation Method 1
the coupling pillars are fixed in contact with both sides of the bridges while exposing front ends of the bridges. Joint surfaces of the front ends of the bridges and the front ends of the coupling pillars are curved surfaces. The radius of curvature (R) of the joint surfaces of the front ends of the bridges and the front ends of the coupling pillars is 2.0R ̃3.0R.
Implementation Method 2
a plurality of vanes defining a channel for air flow are arranged between a pair of disc plates
Data Source
AI summary
A brake disc, in which a hat part that is mounted on a hub and a disc part that provides friction surfaces with brake pads are made of different materials and are combined, includes: a plurality of bridges protruding and circumferentially arranged around an edge of the hat part for coupling to the disc part; a plurality of vanes defining a channel for air flow; and a plurality of coupling pillars, which are fixedly in contact with the bridges, respectively, arranged between a pair of disc plates. The coupling pillars are fixedly in contact with both sides of the bridges while exposing front ends of the bridges.