Nested Composite Brake Drum for Heat Management
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Solution Overview
Problem
Conventional brake drums suffer from brake fade due to heat retention, thermal stress leading to cracks, and excessive weight, with materials like gray iron offering stable friction but low strength and stiffness, and alternative materials failing to adequately address these issues.
Innovation Solution
A brake drum design featuring nested inner and outer drums made from different materials, such as iron for the inner drum and aluminum for the outer drum, with an interference fit and a metal matrix composite flange, to leverage distinct material properties for improved heat management, stress relief, and reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional brake drums are made from gray iron to provide stable friction and wear properties, then friction stability is improved, but weight increases and strength decreases
Solution Approach 1:
The brake drum is divided into two separate drums: an inner drum made of gray iron that contacts the brake lining and provides stable friction, and an outer drum made of aluminum alloy that serves as a heat sink and reduces overall weight. This segmentation allows each component to be optimized for its specific function.
Solution Approach 2:
The invention uses a composite structure combining gray iron and aluminum alloy materials. The gray iron inner drum provides friction stability while the aluminum outer drum provides lightweighting and heat dissipation, creating a composite brake drum system that achieves properties neither material could provide alone.
2Strength
If conventional brake drums use thick sections to resist mechanical stress, then strength is improved, but thermal stress increases due to non-uniform heating and cooling
Solution Approach 1:
The thick brake drum structure is segmented into two thinner concentric drums. This segmentation reduces the thermal mass and allows more uniform heat distribution, reducing thermal gradients and associated thermal stresses while maintaining adequate mechanical strength through the composite structure.
Solution Approach 2:
The invention changes the geometric parameters of the brake drum by dividing it into two thinner concentric layers rather than one thick layer. This parameter change reduces thermal gradients and thermal stress while maintaining structural integrity through the composite configuration.
3Device complexity
If conventional brake drums are designed as single-piece structures for simplicity, then device complexity is reduced, but ease of repair decreases due to inability to replace worn components
Solution Approach 1:
The brake drum is segmented into an inner drum and an outer drum that can be separated. The inner drum, which contacts the brake lining and experiences wear, can be removed and replaced independently from the outer drum, facilitating maintenance and repair without replacing the entire brake drum assembly.
Solution Approach 2:
The brake drum design transitions from a static single-piece structure to a dynamic modular structure where the inner drum can be independently removed and replaced. This enables adaptive maintenance where only the worn component is replaced rather than the entire assembly.
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 reduces brake fade, thermal stress, and weight, while allowing for easy replacement of the inner drum, enhancing durability and performance by utilizing aluminum as a heat sink and metal matrix composite for stiffness and vibration damping.
Implementation Method 1
utilizing aluminum as a heat sink
Implementation Method 2
aluminum as a heat sink to control the temperature
Implementation Method 3
engaged with the inner drum in an interference fit
Implementation Method 4
metal matrix composite for stiffness and vibration damping
Data Source
AI summary
A brake drum is provided having an inner drum defining an outboard, radially inwardly extending flange. The flange defines a first plurality of apertures configured to receive fasteners for coupling the inner drum to a wheel. The inner drum further defines a braking surface. The brake drum further includes an outer drum configured to receive the inner drum therein. The outer drum defines an outboard, radially inwardly extending flange defining a second plurality of apertures aligned with the first plurality of apertures and configured to receive the fasteners for coupling the outer drum to the wheel. The inner drum is comprised of a first material such as iron while the outer drum is comprised of a second material such as aluminum.