Copper-Free Brake Pad Friction Material for Noise and Seizure Control
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Solution Overview
Problem
Friction materials for disc brake pads without copper components face challenges in reducing creeping groan noise and preventing corrosion-induced seizure on mating surfaces while maintaining braking effectiveness and wear resistance.
Innovation Solution
A friction material composition for disc brake pads that includes 2-10 weight % calcium silicate particles, 15-30 weight % non-whisker-like titanates, and 1-9 weight % metal sulfides, along with 3-10 weight % graphite, which absorb substances forming films on the disc rotor surface, inhibit excessive film formation, and enhance porosity and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper component is added to NAO friction material to secure required performance, then braking effectiveness is improved, but environmental pollution increases due to copper discharge
Solution Approach 1:
The invention removes the copper component from the friction material composition entirely, extracting the harmful element while maintaining performance through alternative materials. The patent specifies a composition without copper that uses other inorganic friction modifiers and lubricants to achieve the required braking performance.
Solution Approach 2:
The invention uses a composite material composition combining multiple inorganic friction modifiers (such as calcium silicate, alumina, zirconia) and lubricants (such as graphite, metal sulfides) to replace the functional role of copper while eliminating its harmful environmental effects. This composite approach allows the material to maintain braking effectiveness without copper pollution.
2Object-generated harmful factors
If friction material composition is modified to reduce copper content, then environmental pollution is reduced, but creeping groan noise increases
Solution Approach 1:
The invention changes the compositional parameters of the friction material by introducing specific inorganic friction modifiers (calcium silicate at 2-10 wt%, alumina at 5-20 wt%, zirconia at 3-15 wt%) and lubricants (graphite at 3-10 wt%, metal sulfides at 1-9 wt%) to replace copper's noise-reducing function while maintaining the low-copper or copper-free formulation.
3Object-generated harmful factors
If friction material without copper is used, then environmental pollution is reduced, but wear resistance decreases
Solution Approach 1:
The invention employs a composite material system incorporating multiple inorganic friction modifiers with different properties (calcium silicate for film formation, alumina for hardness, zirconia for thermal stability) combined with solid lubricants (graphite and metal sulfides) to achieve wear resistance comparable to or exceeding copper-containing formulations while maintaining environmental benefits.
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 effectively reduces creeping groan noise and prevents corrosion-induced seizure, ensuring sufficient braking effectiveness and wear resistance without copper contamination.
Implementation Method 1
containing 2-10 weight %, relative to the entire amount of the friction material composition, of a calcium silicate particle as one of inorganic friction modifiers, 15-30 weight %, relative to the entire amount of the friction material composition, of a non-whisker-like titanate as one of inorganic friction modifiers, and 1-9 weight %, relative to the entire amount of the friction material composition, of a metal sulfide as one of lubricants
Implementation Method 2
3-10 weight %, relative to the entire amount of the friction material composition, of a graphite as one of lubricants
Data Source
AI summary
To provide the friction material for the disc brake pad manufactured by forming the NAO friction material composition that does not contain the copper component and does not generate the creeping groan and the seizure to mating surface due to corrosion but possessing sufficient braking effectiveness and wear resistance. The friction material composition relative to the entire amount of the friction material composition, has 2-10 weight % of the calcium silicate as one of the inorganic friction modifiers, 15-30 weight % of the non-whisker-like titanate as one of the inorganic friction modifiers, 1-9 weight % of the metal sulfide as one of the lubricants and 3-10 weight % of the graphite as one of the lubricants.