Brake Pad Guide Surface Anti-Noise Coating

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Solution Overview

Problem

Vehicle disc brake units experience operating noise due to vibrations and slipping between brake pads and caliper components, with existing solutions like rubber coatings being expensive and prone to jamming, and alternative coatings not effectively addressing the issue in mass production.

Innovation Solution

A brake caliper unit with guide surfaces coated in a crosslinked polymeric resin containing spherical glass particles, applied using methods like spraying or immersion, and cured at low temperatures, providing an anti-noise layer comparable to elastomeric coatings without the drawbacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If rubber or elastomer coatings are applied to sliding springs for noise reduction, then noise is effectively reduced, but the friction between the sliding spring and guide support increases causing jamming

Engineering Contradiction:
ImprovenoiseVSAvoidjamming
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention uses a composite coating material consisting of PTFE (polytetrafluoroethylene) as the base polymer combined with solid lubricant particles (graphite and/or molybdenum disulphide) and filler materials. This composite structure provides both noise reduction through vibration damping and maintains low friction through the lubricating properties of PTFE and solid lubricants, preventing jamming while achieving the desired noise reduction effect.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention modifies the surface properties of the sliding spring by applying a coating with specific friction and damping characteristics. The coating changes the coefficient of friction and vibration absorption parameters of the surface, enabling noise reduction without the excessive friction increase that occurs with pure rubber or elastomer coatings.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If powder coating with phenolic resins, graphite and molybdenum disulphide is applied, then friction is reduced, but the manufacturing process becomes expensive and difficult for mass production

Engineering Contradiction:
Improvefriction reductionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention simplifies the manufacturing process by using a coating composition that can be applied at lower temperatures and with simpler equipment compared to high-temperature powder coating processes. The PTFE-based coating can be applied using conventional coating methods and cured at lower temperatures, making it more suitable for mass production while maintaining friction reduction properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs a coating formulation that uses readily available, cost-effective materials (PTFE, graphite, molybdenum disulphide) that can be processed economically. The coating is designed to be applied in a single layer without requiring complex multi-step processes, reducing manufacturing costs and complexity for mass production.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If PTFE dispersed in organic binder and solvent is sprayed onto surfaces, then application becomes simpler, but noise reduction effectiveness is insufficient

Engineering Contradiction:
Improveapplication simplicityVSAvoidnoise reduction
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention enhances the noise reduction capability of the sprayed PTFE coating by incorporating solid lubricant particles (graphite and/or molybdenum disulphide) and filler materials into the coating composition. This composite formulation provides both the ease of application from sprayable PTFE suspension and improved noise reduction through vibration damping from the particulate fillers, achieving effectiveness comparable to elastomeric coatings.

Inventive Principle:
Principle #40Composite materials

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 anti-noise coating significantly reduces operating noise in vehicle braking units, achieving results comparable to rubber or elastomer coatings without the associated costs or production issues, as demonstrated by NVH test results.

Implementation Method 1

an anti-noise coating or layer consisting of a layer of a crosslinked polymeric resin with glass particles, preferably spherical shaped, with size not larger than 50 micron and preferably not smaller than 10 micron being dispersed therein

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 2

without the friction between the sliding spring and the guide support increases, which in use can produce jamming

Methodology Applied
Scientific EffectFriction reduction: Lubrication

Data Source

PatentEP3431804B1Vehicle braking unit, associated brake pad and associated method for noise reduction
Publication Date: 2020.04.08 ITT ITAL SRL
  • EP3431804B1 patent drawingFigure 1~2
  • EP3431804B1 patent drawingFigure 3
  • EP3431804B1 patent drawingFigure 4~5

AI summary

Vehicle braking unit (3) including a support (5), at least one braking element (6) that is carried in a movable way by the support and first and second guide surfaces (8,9) which are integral, respectively, to the braking element and to the support and cooperating with each other to guide and support the braking element when it is displaced by the activation of actuating elements; the first and/or the second guide surfaces (8,9) are covered by an anti-noise coating (16) consisting of: a layer of a polymeric resin; and glass particles with a rounded shape, preferably spheres, dispersed in the polymeric resin layer.