Wiper Rubber Coating Thickness for Friction and Noise Control

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Solution Overview

Problem

Existing wiper rubbers for windshield wipers face challenges in achieving optimal initial wiping quality and minimizing noise such as squeaking, smacking, and humming, with existing coatings' effectiveness being largely dependent on average layer thickness rather than composition.

Innovation Solution

A wiper rubber coating with an average layer thickness between 2 µm to 10 µm, specifically comprising a structured coating of plastic particles and a graphite coating, optimizes the functional properties by reducing friction and noise during the wiping process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coating layer thickness is increased to reduce friction and improve wiping quality, then the initial wiping quality improves, but the wiping noise (squeaking, smacking, humming) increases

Engineering Contradiction:
Improveinitial wiping qualityVSAvoidwiping noise
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the coating layer thickness within the range of >2 μm to <10 μm. This specific parameter range optimizes both friction reduction and noise minimization, resolving the contradiction between improving wiping quality and reducing harmful noise during the wiping process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining friction-reducing particles (such as graphite and/or plastic particles) with a binder to create a coating layer. This composite structure enables the coating to simultaneously reduce friction for better wiping quality and control noise through the optimized thickness range.

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If the coating layer thickness is decreased to reduce wiping noise, then the wiping noise decreases, but the initial wiping quality deteriorates

Engineering Contradiction:
Improvewiping noiseVSAvoidinitial wiping quality
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent resolves this contradiction by establishing the optimal parameter range for coating thickness (>2 μm to <10 μm). This parameter optimization ensures that the coating is thin enough to minimize noise while maintaining sufficient thickness to provide friction reduction and improve initial wiping quality.

Inventive Principle:
Principle #35Parameter changes

3Force

If a thick coating is applied to ensure adequate friction reduction, then friction is reduced effectively, but the coating material consumption increases

Engineering Contradiction:
Improvefriction reductionVSAvoidcoating material consumption
Core Design Contradiction:
ForceVSLoss of substance

Solution Approach 1:

The patent optimizes material consumption by precisely controlling the coating thickness parameter within >2 μm to <10 μm. This optimized parameter range ensures adequate friction reduction effectiveness while minimizing unnecessary material usage, achieving cost-effective performance.

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 specified coating thickness range significantly improves initial wiping quality and reduces noise, with optimal performance observed between 3 µm to 9 µm, enhancing the overall functionality of the wiper rubber.

Implementation Method 1

the coating includes particles, in particular to reduce friction

Methodology Applied
Scientific EffectFriction reduction: Friction

Implementation Method 2

the structured coating, in particular made of plastic particles, for example made of polyethylene, for example made of high density polyethylene (HD-PE) and/or ultra-high molecular weight polyethylene (UHMW-PE), and/or made of Polytetrafluoroethylene, for example micro-PTFE

Methodology Applied
Scientific EffectLow friction property of plastic particles: Polytetrafluoroethylene (PTFE)

Data Source

PatentEP3645348B1Wiper rubber with optimized coating layer thickness
Publication Date: 2023.01.04 ROBERT BOSCH GMBH
  • EP3645348B1 patent drawingFigure 1~3

AI summary

The present invention relates to a wiper rubber (10) for a wiper blade of a wiper, which comprises a main wiper rubber body (11). The main wiper rubber body (11) is coated here with a coating (12) which comprises particles (12a, 12a'), in particular for reducing friction. In order to improve the functional properties of the wiper rubber, in particular in respect of a good initial wiping quality in combination with as little wiping noise, such as squeaking, smacking and/or humming, as possible during the wiping operation, the coating (12) has an average layer thickness (d) within a range of &gt; 2 μm to &lt; 10 μm. The invention also relates to a corresponding wiper blade.