Co-cast Brake Disc Protrusions for Stress Management
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Solution Overview
Problem
Co-cast disc brake systems face issues with performance and safety due to thermal shrinkage and stress concentration at the interface between the metal bell and composite friction disc, leading to suboptimal braking torque transmission and thermal stress management.
Innovation Solution
The design incorporates tapering protrusions on the composite external braking band that radially inwardly extend towards the symmetry axis, allowing for an intimate metal connection during co-casting and reducing stress concentrations by optimizing the interaction between the composite material and melted metal, thereby enhancing wettability, shrinkage management, and stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If co-casting process is used to manufacture brake discs, then manufacturing simplicity and cost are improved, but interface reliability and stress distribution deteriorate due to thermal shrinkage and stress concentration at the metal bell-composite friction disc interface
Solution Approach 1:
The invention applies local quality by creating protrusions with specific geometric features (tapered shape, specific height and diameter ratios) at the critical interface zone between the metal bell and composite friction disc. These localized structural modifications optimize the co-casting process in the critical area, improving metal flow, reducing shrinkage defects, and enhancing stress distribution precisely where needed, without complicating the overall manufacturing process.
Solution Approach 2:
The invention employs parameter changes by specifying precise geometric parameters for the protrusions (height-to-diameter ratio between 0.5-2.0, taper angles between 10-45 degrees) that optimize the interface formation during co-casting. These parameter optimizations control the solidification process, metal shrinkage behavior, and stress distribution, resolving the contradiction between manufacturing simplicity and interface reliability.
2Ease of manufacture
If co-casting process is used to manufacture brake discs, then manufacturing cost is reduced, but stress concentration and thermal stress management worsen at the connection interface
Solution Approach 1:
The protrusions create localized structural variations at the interface that modify stress distribution patterns. The tapered geometry and specific dimensions of these protrusions concentrate reinforcement precisely at the high-stress interface zone, improving stress management locally without adding complexity or cost to the overall co-casting process.
Solution Approach 2:
The invention utilizes the composite nature of the friction disc (carbon fiber reinforced ceramic matrix) in combination with the metal bell, creating a bimetallic composite structure. The protrusions optimize the bonding interface between these two different materials, leveraging their complementary properties to reduce stress concentration while maintaining the cost benefits of co-casting.
3Reliability
If traditional assembled brake discs are used, then performance and safety are improved through precise interface control, but manufacturing complexity and cost increase due to multiple working steps and assembly requirements
Solution Approach 1:
The invention merges the metal bell and composite friction disc into a single co-casted component, eliminating the need for separate assembly steps, mounting hardware, and multiple working steps. The protrusions ensure that this merged structure achieves interface quality comparable to traditional assembled discs, thereby reducing manufacturing complexity without sacrificing performance and safety.
Solution Approach 2:
The protrusions are pre-formed in the composite friction disc before the co-casting process, creating optimized interface geometry in advance. This preliminary action ensures proper metal flow and bonding during co-casting, achieving reliable interface formation without requiring complex post-processing or assembly operations.
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 improves the reliability and performance of co-cast composite brake discs by ensuring a secure connection, efficient torque transmission, and reduced stress levels during both braking and cooling phases, while simplifying the manufacturing process and reducing costs.
Implementation Method 1
during cooling of the melted metal, the thermal shrinkage of the same tends to make the bell depart from the originally matching shape of the radially external band
Implementation Method 2
optimizing the interaction between the composite material and melted metal, thereby enhancing wettability
Data Source
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AI summary
A disc for disc brakes comprising a metallic bell (2) and a radially external band (3) in composite material comprising carbon fibers. The bell (2) is co-casted on the radially external band (3). The radially external band (3) presents side braking surfaces (4) suitable to cooperate with brake calipers to exert a braking action on a vehicle. The radially external band (3) is shaped to form a plurality of protrusions (8) of composite material, which protrusions (8) are placed around a symmetry axis (X-X). In a radial plane, a terminal portion (20) of each protrusion (8) juts radially inwards and tapers towards the symmetry axis (X-X) and the co-casted bell (2) incorporates the terminal portions (20).