Low-Copper Friction Material Without Titanate for Brake Noise

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Solution Overview

Problem

Existing friction materials either fail to provide sufficient friction coefficient or lead to brake noise due to the presence of titanate, which forms a transfer film and decreases friction coefficient, or they do not adequately prevent brake noise while maintaining strength.

Innovation Solution

A friction material composed of steel fibers as the fiber base material, natural graphite as the lubricant, with a copper content of 0.5% by mass or less, and without titanate, along with optional coke and magnesium oxide, to enhance strength and friction coefficient while preventing brake noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If titanate is added to improve strength, then the strength of the friction material is improved, but a transfer film is formed on the counterpart material surface and the friction coefficient decreases

Engineering Contradiction:
Improvestrength of friction materialVSAvoidfriction coefficient
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent removes titanate from the friction material composition entirely. Instead of using titanate for strength enhancement, the invention employs steel fibers as the primary reinforcement component, achieving both strength and friction coefficient requirements without the harmful transfer film effect that titanate causes on the counterpart material surface.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent specifies precise compositional parameters: steel fiber content of 10-50% by mass, natural graphite content of 1.0-5.0% by mass, and copper content of 0.5% by mass or less. These parameter controls optimize both the mechanical strength and friction characteristics while preventing brake noise, eliminating the need for titanate addition.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If natural graphite is added as lubricant to prevent brake noise, then the brake noise is prevented, but the friction coefficient may decrease

Engineering Contradiction:
Improvebrake noiseVSAvoidfriction coefficient
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent optimizes the natural graphite content to 1.0-5.0% by mass, which provides sufficient lubrication to prevent brake noise while maintaining an adequate friction coefficient. This controlled addition of graphite as PWD (particulate wear debris) achieves noise prevention without excessive friction loss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite friction material system combining steel fibers for strength, natural graphite for lubrication and noise prevention, and copper-free formulation for optimal friction characteristics. This multi-component composite approach balances strength, friction, and noise prevention requirements simultaneously.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If copper content is reduced to 0.5% by mass or less, then the aggressiveness against counterpart material is reduced, but the friction coefficient may be affected

Engineering Contradiction:
Improveaggressiveness against counterpart materialVSAvoidfriction coefficient
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent严格控制 copper content to 0.5% by mass or less, which significantly reduces the aggressiveness and wear on the counterpart material (disc). This low copper formulation, combined with steel fiber reinforcement and natural graphite lubrication, maintains sufficient friction coefficient while being gentler on the braking system components.

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

The solution provides a high-strength friction material with a sufficient friction coefficient, preventing brake noise and aggressiveness against counterpart materials, while avoiding the drawbacks of titanate presence.

Implementation Method 1

natural graphite is contained as a lubricant

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

magnesium oxide is contained as an abrasive

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 3

a steel fiber is contained as the fiber base material

Methodology Applied
Scientific EffectReinforcement:

Data Source

PatentUS20220373053A1Friction material
Publication Date: 2022.11.24 AKEBONO BRAKE IND CO LTD

AI summary

A friction material including a friction modifier, a binder, and a fiber base material. A steel fiber is contained as the fiber base material. A natural graphite is contained as a lubricant. A content of copper is 0.5% by mass or less in terms of copper element. A titanate is not contained.