Ventilated Brake Disc Geometry for Thermal Coning Reduction
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Solution Overview
Problem
Disc brakes in commercial vehicles experience uneven heat dissipation leading to thermal coning, where temperature gradients cause differential expansion and susceptibility to thermal juddering and heat cracking, which is not effectively addressed in existing ventilated brake discs with parallel-sided friction plates and constant-width cooling channels.
Innovation Solution
The brake disc design features differential material distribution and ventilation channel geometry between inboard and outboard plates, with varying thickness and expanding channel width, creating a 'nozzle effect' for enhanced cooling air flow and reduced temperature gradients, minimizing coning without radially-inner region thinning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional parallel-sided friction plates with constant-width cooling channels are used, then manufacturing is simple, but temperature gradients cause thermal coning and differential expansion
Solution Approach 1:
The brake disc employs differential material distribution where the inboard friction plate has variable thickness (thinner at inner radius, thicker at outer radius) while the outboard friction plate has constant thickness. The cooling channels also have variable width (narrower at inner radius, wider at outer radius). This local variation in geometric properties creates a nozzle effect that directs cooling air to specific regions, achieving more uniform temperature distribution and reducing thermal coning without compromising manufacturing feasibility
Solution Approach 2:
The invention changes the geometric parameters of the brake disc components - specifically varying the thickness of the inboard friction plate and the width of cooling channels along the radial direction. These parameter changes create a nozzle effect that enhances cooling air flow to regions with higher heat generation, balancing the temperature distribution between inboard and outboard plates and eliminating thermal coning
2Temperature
If cooling channels are made wider to improve cooling, then heat dissipation improves, but disc structure becomes less stable
Solution Approach 1:
The cooling channel width is varied locally along the radial direction - narrower at the inner radius and wider at the outer radius. This local variation creates a nozzle effect that directs and accelerates cooling air flow to the outer regions where heat dissipation is most needed, achieving effective cooling while maintaining structural integrity through optimized material distribution
Solution Approach 2:
The brake disc employs asymmetric cooling channel geometry where the channel width differs at different radial positions. The channels are narrower near the hub and wider toward the outer radius, creating an asymmetric flow path that optimizes cooling efficiency while maintaining structural balance and reducing thermal coning
3Stability of the object's composition
If differential material distribution is used to reduce coning, then temperature uniformity improves, but manufacturing complexity increases
Solution Approach 1:
The invention implements local quality variations in the inboard friction plate thickness and cooling channel width to achieve uniform temperature distribution. The variable thickness design of the inboard plate, combined with variable-width cooling channels, creates a nozzle effect that directs cooling air to high-heat regions. While this increases manufacturing complexity compared to constant-thickness designs, the complexity is localized and manageable through standard manufacturing processes
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 design achieves more even temperature distribution across the disc, reducing thermal expansion differences and coning, while also lowering stress at the disc-hub connection and potentially reducing material usage and costs.
Implementation Method 1
creating a 'nozzle effect' for enhanced cooling air flow
Implementation Method 2
by conduction and radiation to other portions of the brake disc and adjacent components and/or by convection via cooling air
Implementation Method 3
by conduction and radiation to other portions of the brake disc and adjacent components and/or by convection via cooling air
Implementation Method 4
by conduction and radiation to other portions of the brake disc and adjacent components and/or by convection via cooling air
Implementation Method 5
Due to gradients in temperature distribution, different regions of the disc will exhibit different amounts of thermal expansion
Data Source
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AI summary
An internally ventilated brake disc with a disc coning reducing arrangement is provided in which temperature differences between inboard and outboard sides of the brake disc are minimized in order to reduce coning-causing differential thermal expansion. Between a radially inner region of a brake disc that includes brake disc-to-axle hub mounting features and a radially outer region the mass of the inboard side of the brake disc is distributed in a manner that reduces the amount of differential thermal expansion occurring during brake application between the inboard and outboard sides of the brake disc, thereby minimizing thermally-induced coning effects. The inboard side disc plate portion may having an increasing axial thickness in the direction from the radially outer region to the radially inner region, providing additional material mass to receive and dissipate heat energy received during a braking event.