Disc Brake Pad Friction Material for Copper-Free Noise Suppression

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Solution Overview

Problem

The challenge is to develop a friction material for disc brake pads that suppresses noise occurrence just before a vehicle stops, while adhering to regulations limiting copper content, and maintains braking effectiveness and wear resistance under high-speed and high-load conditions.

Innovation Solution

The solution involves a non-asbestos-organic friction material composition that includes 15-25 weight % non-whisker-like titanate, 15-25 weight % zirconium oxide, 4-6 weight % mica or vermiculite, and 2-4 weight % flaky graphite particles, which form a protective film and facilitate abrasion powder ejection, preventing rust and abrasive wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If copper component is added to NAO friction material to secure braking effectiveness and wear resistance, then braking performance is improved, but environmental pollution increases and regulatory compliance deteriorates

Engineering Contradiction:
Improvebraking effectivenessVSAvoidcopper pollution
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and removes the copper component from the NAO friction material composition entirely, replacing it with alternative materials (specifically iron oxide and organic friction modifiers) that provide similar braking performance without the environmental pollution associated with copper discharge during braking operations

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the compositional parameters of the friction material by eliminating copper and introducing iron oxide (0.1-5.0 wt%) combined with specific organic friction modifiers, thereby achieving the same functional objectives (braking effectiveness and wear resistance) through different material parameters that do not contribute to environmental pollution

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If copper component is reduced or eliminated from NAO friction material to comply with regulations, then environmental compliance is improved, but braking effectiveness and wear resistance deteriorate

Engineering Contradiction:
Improvecopper pollutionVSAvoidbraking effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention introduces iron oxide and organic friction modifiers as intermediary materials that mediate between the requirement for copper-free composition and the need for maintaining braking effectiveness, providing a functional substitute that achieves similar performance without the harmful environmental effects of copper

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite friction material system combining iron oxide particles with specific organic friction modifiers (such as polyacetal resin, polyester resin, or polyamide resin) to achieve synergistic effects that maintain or improve braking effectiveness and wear resistance while eliminating copper content

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If NAO friction material without copper is used to reduce pollution, then environmental compliance is improved, but low frequency vibration noise increases

Engineering Contradiction:
Improvecopper pollutionVSAvoidlow frequency noise
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The invention changes the compositional parameters by introducing iron oxide (0.1-5.0 wt%) and adjusting the types and amounts of organic friction modifiers, thereby altering the friction material's vibrational characteristics to suppress low frequency noise while maintaining the copper-free composition required for environmental compliance

Inventive Principle:
Principle #35Parameter changes

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 composition effectively suppresses low-frequency noise and maintains stable braking performance without copper, ensuring compliance with environmental regulations and reducing noise issues during low-load braking.

Implementation Method 1

2-4 weight % flaky graphite particles, which form a protective film and facilitate abrasion powder ejection

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

a friction material used for a disc brake pad... securing the braking effectiveness... under the high speed and high load braking conditions

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3187562B1Friction material
Publication Date: 2021.09.08 NISSHINBO BRAKE INC

AI summary

[OBJECT] The present invention provides a friction material used for a disc brake pad, which is manufactured by forming a non-asbestos-organic (NAO) friction material composition, which is able to suppress an occurrence of noise just before a vehicle stops, while satisfying laws and regulations relating to the required amount of the content of the copper component. [MEANS TO SOLVE THE PROBLEM] The friction material for the disc brake pad is manufactured by forming the NAO friction material composition that is free of the copper component, the friction material composition practically does not include an iron component but includes 15 - 22 weight % of a non-whisker-like titanate, relative to the total amount of the friction material composition, as a titanate, 15 -25 weight % of zirconium oxide with the average particle diameter of 1.0-4.0 µm, relative to the total amount of the friction material composition, as the inorganic friction modifier, and 4 - 6 weight % of cleavable mineral particles, relative to the total amount of the friction material composition, as the inorganic friction modifier.