Railway Disc Brake Pad Layout for Low-Noise Braking
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Solution Overview
Problem
Existing disc brakes for low- and medium-speed trains face challenges in achieving low noise during braking without compromising braking efficiency and reducing fine powder production.
Innovation Solution
A disc brake pad design featuring a combination of friction elements made from materials with different compressibility moduli, specifically a higher number of friction elements with a lower compressibility modulus, such as organic material, and a smaller number with a higher compressibility modulus, such as sintered material, to ensure effective braking performance while minimizing noise and fine powder generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple friction elements of smaller size are used instead of a single large friction element, then braking noise is reduced and pressure distribution on the disk is improved, but braking force transmission efficiency decreases
Solution Approach 1:
The patent applies local quality by using friction elements with different compressibility moduli in specific locations. The first friction elements have higher compressibility modulus while the second friction elements have lower compressibility modulus, creating localized variations in mechanical properties to optimize both noise reduction and braking force transmission in different areas of the pad.
Solution Approach 2:
The patent uses composite materials by combining friction elements made from materials with different compressibility moduli. This composite approach allows the pad to exhibit both noise-reducing characteristics from the lower compressibility elements and efficient force transmission from the higher compressibility elements, resolving the contradiction between noise reduction and braking efficiency.
2Object-affected harmful factors
If friction elements with lower compressibility modulus are used to reduce noise, then braking noise decreases, but fine powder production increases
Solution Approach 1:
The patent applies local quality by strategically positioning friction elements with different compressibility moduli. The lower compressibility elements (second friction elements) are distributed among higher compressibility elements (first friction elements) to locally reduce noise while the higher compressibility elements maintain overall braking efficiency and reduce fine powder generation through better force distribution.
Solution Approach 2:
The patent combines materials with different compressibility moduli in a composite friction element structure. This composite approach balances the noise-reducing effect of lower compressibility materials with the fine powder-reducing effect of higher compressibility materials, achieving both goals simultaneously.
3Object-affected harmful factors
If a higher number of friction elements are used to improve pressure distribution, then noise is reduced, but the complexity of the pad structure increases
Solution Approach 1:
The patent applies segmentation by dividing the friction pad into multiple smaller friction elements instead of using a single large element. This segmentation improves pressure distribution and reduces noise while keeping each individual element simple in structure. The patent further segments these elements into two types based on compressibility modulus to optimize performance.
Solution Approach 2:
The patent uses local quality by assigning different compressibility moduli to different friction elements based on their position and function. This allows the structure to remain relatively simple while achieving complex performance characteristics through localized material property variations.
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 design effectively reduces braking noise and fine powder production while maintaining braking efficiency, as demonstrated by noise and friction tests, without sacrificing performance.
Implementation Method 1
said second material has a compressibility modulus (pressure needed to compress the material by 1 mm) smaller than the one of said first material by a value equal or greater to 5 Mpa, preferably 10 MPa
Implementation Method 2
disc brakes are subject to great stress and, in order to obtain optimal braking action, it is necessary to have a good transmission of braking force from pad to disk
Data Source
AI summary
A disc brake for railway vehicles comprising a pad and a disk on which the pad acts is provided. The pad comprises a base plate and a plurality of friction elements fixed to the base plate. The friction elements comprise first friction elements made of a first material and second friction elements made of a second material. The second material has a compressibility modulus (e.g., the pressure needed to compress the material by 1 mm) that is at least 5 MPa less smaller than the compressibility modulus of the first material. There may be more of the first friction elements than the second friction elements.