Drum Brake Friction Lining Composition for Crescent-Shape Molding
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Solution Overview
Problem
Existing drum brake linings face challenges in achieving optimal friction properties and flowability to conform to the crescent shape of the brake drum while avoiding production difficulties and ensuring a stable, adhesive-free connection to the lining carrier plate.
Innovation Solution
A friction lining mixture comprising at least 15% steel fibers, 7-10% glass fiber bundles, 4-9% resin, and 2-10% friction particles, with minimal phyllosilicates and flake graphite, allowing direct pressing onto the carrier plate without adhesives, and using carrier plates with protrusions or recesses for stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If glass fibre bundles and resin are used to improve flowability, then the friction lining can conform to the brake drum shape, but production difficulties and long pressing times occur
Solution Approach 1:
The patent modifies the chemical composition parameters of the friction lining mixture by incorporating specific amounts of phyllosilicates (5-15 wt%) and flake graphite (2-10 wt%) alongside glass fibre bundles. This parameter change alters the rheological properties of the mixture, enabling it to achieve the required flowability and crescent shape conformity without requiring extended pressing times, thus resolving the contradiction between shape accuracy and production efficiency.
2Shape
If phyllosilicates and flake graphite are added to improve flowability, then the friction lining conforms better to the brake drum, but production difficulties arise
Solution Approach 1:
The patent creates a composite friction lining material that combines glass fibre bundles with specific proportions of phyllosilicates (5-15 wt%) and flake graphite (2-10 wt%). This composite approach leverages the complementary properties of each component: glass fibres provide structural reinforcement while phyllosilicates and flake graphite enhance flowability and reduce hot wear. The synergistic effect of this composite material enables successful manufacturing without the production difficulties associated with using individual components alone.
3Reliability
If steel wool is used to improve friction properties, then the friction coefficient increases, but the lining requires increased resin and flake graphite which complicates production
Solution Approach 1:
The patent applies the local quality principle by strategically distributing different components within the friction lining structure. Steel wool (10-30 wt%) is incorporated to provide high friction coefficients at the contact surface, while phyllosilicates (5-15 wt%) and flake graphite (2-10 wt%) are distributed throughout the matrix to ensure flowability and reduce hot wear. This localized optimization of material properties throughout the lining structure achieves reliable friction performance without requiring excessive resin content, thereby simplifying the overall composition and manufacturing process.
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 achieves friction coefficients of 0.3 to 0.5 and ensures a stable, crack-free fit against the brake drum, simplifying production by eliminating the need for adhesives and underlayers.
Implementation Method 1
Friction linings or friction materials for drum brakes therefore have the necessary flowability to take on the required crescent shape in the moulding process
Implementation Method 2
The solution achieves friction coefficients of 0.3 to 0.5
Data Source
AI summary
The invention relates to a friction lining mixture for the production of a brake pad for drum brakes comprisingat least 15% by weight of metal fibres, preferably steel fibres, in particular steel wool,at least 7% by weight of glass fibres, in the form of glass fibre bundles,at least 4% by weight resin andat least 2% by weight of friction particles, preferably with a Mohs hardness equal to or greater than 9, and a friction lining and drum brake lining produced therefrom, and a process for producing a drum brake lining