Drum-in-hat Brake Bell Weight Reduction via Segmented Materials
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Solution Overview
Problem
High-performance brake discs with integrated auxiliary brakes, known as 'drum-in-hat' type, have larger and heavier bells due to the need to accommodate auxiliary braking systems, which increases unsprung mass inertia and weight, conflicting with customer preferences for lighter systems.
Innovation Solution
A bell design for 'drum-in-hat' brake discs comprising an annular flange made of a lighter material, such as aluminum, and a drum made of steel or cast iron, where the annular flange and drum are separate elements that reduce overall weight and inertia while maintaining the necessary interface area for effective braking, allowing for easy substitution in existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the bell is designed to accommodate an auxiliary brake in drum-in-hat type brake discs, then the auxiliary braking function is integrated, but the weight and size of the bell increase
Solution Approach 1:
The bell is divided into two separate parts: an annular flange made of light alloy and a drum made of steel or cast iron. This segmentation allows each component to be optimized independently - the flange for minimal weight and the drum for braking functionality - thereby reducing the overall weight of the bell while maintaining the auxiliary braking function.
Solution Approach 2:
The bell combines two different materials with distinct properties: light alloy (aluminum or aluminum alloy) for the annular flange to reduce weight, and steel or cast iron for the drum to ensure structural strength and braking performance. This composite approach resolves the contradiction between weight reduction and functional requirements.
2Force
If the bell size is increased to accommodate the auxiliary brake, then the auxiliary brake can exert sufficient braking force, but the unsprung mass inertia increases
Solution Approach 1:
By separating the bell into a light alloy flange and a steel/cast iron drum, the design concentrates the mass necessary for braking force in the drum component while minimizing the mass of the flange. This segmentation allows the braking force requirement to be met through the drum's material properties rather than increasing the overall bell mass.
Solution Approach 2:
Different regions of the bell are assigned different material qualities based on their functional requirements: the annular flange uses light alloy for minimal mass, while the drum uses dense steel or cast iron to provide the necessary braking force through friction contact with the brake shoes.
3Strength
If the bell is made entirely of steel or cast iron to ensure strength, then structural integrity is maintained, but the weight increases
Solution Approach 1:
The bell structure applies different material qualities to different regions: the annular flange is made of light alloy where minimal strength is needed for structural integrity, while the drum is made of steel or cast iron where high strength and wear resistance are critical for braking contact. This local differentiation maintains overall bell strength while minimizing total weight.
Solution Approach 2:
The bell employs a composite construction combining light alloy and steel/cast iron materials, each selected for their specific properties. The light alloy flange reduces weight while the steel/cast iron drum provides the necessary strength and durability for the braking function, achieving an optimal balance between strength and weight.
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 solution reduces the weight and inertia of the brake disc while maintaining braking performance, providing a lighter alternative that is interchangeable with standard 'drum-in-hat' brake discs, thus addressing the weight and size issues of traditional designs.
Implementation Method 1
the brake shoes are placed within the bell and, when the auxiliary brake is actuated, they act against an inner surface of the bell in order to exert a braking force by friction
Data Source
AI summary
A bell for brake disc with integrated “drum-in-hat” auxiliary brake. The bell (2) includes an annular flange (5) configured to be coupled to a braking band (4) of a brake disc (1), and a drum (6) coupled coaxially to the annular flange (5), wherein the drum (6) accommodates or is configured to accommodate an auxiliary brake (7). The annular flange (5) and the drum (6) are separate elements joined together. The annular flange (6) has at least one recess (13). The drum (6) comprises a cylindrical body (14) and an auxiliary annular flange (15) positioned on a peripheral edge of the cylindrical body (14). The recess (13) has an annular shape coaxial with a common symmetry axis (X-X) and houses the auxiliary annular flange (15).