Concave Mold Pressing Surface for Uniform Brake Pad Density
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Solution Overview
Problem
The brake pad friction material often experiences squeal during braking due to uneven hardness and density in the end portions compared to the center portion, which is exacerbated by the compressive forces and heat applied during molding.
Innovation Solution
A mold with a concave pressing surface that gradually recesses from the end portions to the center, ensuring the powder material is compacted uniformly and preventing higher hardness and density in the end portions, and optionally inclines or includes flat portions to match rotor peripheral speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat pressing surface is used to mold the powder material, then the molding process is simple, but the hardness and density in both end portions become higher than in the center portion causing squeal
Solution Approach 1:
The pressing surface is designed with different depths in different regions: the end portions have deeper pressing surfaces while the center portion has a shallower pressing surface. This local variation in pressing depth compensates for the natural tendency of powder material to be more compressed at the ends, resulting in uniform hardness and density across the entire brake pad friction material.
2Productivity
If the powder material is compressed and molded with a flat pressing surface, then the molding operation is straightforward, but the physical properties become non-uniform with higher hardness and density at end portions
Solution Approach 1:
The pressing surface incorporates local quality variations through different pressing depths at different locations. The end portions are pressed deeper into the mold cavity while the center is pressed less, creating a compensated distribution that achieves uniform physical properties throughout the friction material without requiring complex post-processing.
Solution Approach 2:
Instead of applying uniform pressure across the entire pressing surface, the invention inverts the conventional approach by applying greater pressing depth at the end portions where excessive compression naturally occurs, and less pressing depth at the center portion. This inverse compensation strategy achieves uniformity in the final product.
3Device complexity
If uniform pressing is applied across the mold, then the molding process is simple and fast, but the end portions develop higher hardness and density leading to squeal during braking
Solution Approach 1:
The pressing surface is designed with local quality variations where the depth of the pressing surface differs between end portions and the center. This localized differentiation in pressing depth compensates for the non-uniform compression that would otherwise occur, preventing the development of excessive hardness and density at the end portions that cause squeal.
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 ensures appropriate physical properties in the brake pad friction material, preventing squeal by maintaining uniform hardness and density across the end portions and aligning with rotor peripheral speeds, thus enhancing brake performance.
Implementation Method 1
the pressing surface pressing the powder material is formed in a region in the surface of the mold member which abuts the powder material put into the mold frame. The pressing surface forms the concave surface that is formed by being gradually recessed from the both end portion sides to the center portion side.
Implementation Method 2
The powder material before pressed molding can flow in accordance with a shape of the pressing surface of the mold.
Implementation Method 3
The brake pad friction material is molded by being heated and pressurized while being pressed on a pressing surface after a powder material of the friction material is preformed.
Implementation Method 4
The brake pad friction material is molded by being heated and pressurized while being pressed on a pressing surface
Data Source
AI summary
A mold of a brake pad friction material, including a mold member fitted into a mold frame into which a powder material of the brake pad friction material is put, in which the mold member is configured such that a pressing surface in a surface of the mold member, which forms a region abutting the powder material put into a mold frame, has a concave shape that is formed by being gradually recessed from both end portion sides to a center portion side of the pressing surface.