Starter Gear Antifriction Coating for Noise Reduction

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Solution Overview

Problem

Existing starter motor systems for internal combustion engines face issues with volatile friction-reducing agents, such as greases, which can lead to wear, noise, and failure due to consumption or pastiness from dust and dirt, especially in start-stop systems where low noise and high temperature performance are critical.

Innovation Solution

The use of non-volatile anti-friction coatings, such as Teflon, MoS2, WS2, or graphite, applied as bonded coatings on the drive and driven parts of the planetary gear system, providing a durable and temperature-resistant lubrication solution that prevents pastiness and blockages, ensuring consistent performance and longer service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If volatile friction-reducing agents (greases) are used in the planetary gear system, then initial lubrication is provided, but they are consumed during operation or become pasty due to dust and dirt, leading to wear, noise, and failure

Engineering Contradiction:
Improvestarter operation reliabilityVSAvoidlubricant service life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent changes the physical and chemical parameters of the lubricating material from volatile grease to non-volatile solid friction-reducing agents (Teflon, MoS2, WS2, graphite). This fundamental parameter change eliminates consumption and pastiness issues while maintaining friction reduction capabilities throughout the starter's operational life

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite material structures where solid friction-reducing agents are incorporated into coating matrices or applied as layered composites on gear surfaces. This combines the low friction properties of solid lubricants with the adhesion and protective properties of coating materials, creating a durable lubrication system that resists dust and dirt contamination

Inventive Principle:
Principle #40Composite materials

2Reliability

If solid lubricating layers are applied through carburizing and chemical conversion, then friction is reduced, but the process requires bonder or chemical conversion steps and additional molybdenum application

Engineering Contradiction:
Improvefriction reduction effectivenessVSAvoidcoating process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex chemical conversion and bonder application steps from the coating process. By using direct physical vapor deposition or simple bonding methods for solid friction-reducing agents, the invention maintains effective friction reduction while significantly simplifying the manufacturing process

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces complex chemical processes (carburizing, chemical conversion, multiple coating steps) with simpler physical deposition methods or direct bonding techniques. This substitution maintains the friction-reducing functionality while reducing process complexity and eliminating the need for multiple sequential steps

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If grease is used as lubricant, then friction is reduced initially, but it becomes pasty and blocks the gear system during prolonged operation or high temperature

Engineering Contradiction:
Improveinitial lubrication performanceVSAvoidoperation continuity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the physical state parameter of the lubricating material from liquid/grease phase to solid phase. Solid friction-reducing agents maintain their structural integrity and friction-reducing properties across a wide temperature range and prolonged operation, eliminating the pastiness and blockage problems associated with grease

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the consumable, short-lived grease lubricant with durable, long-lasting solid friction-reducing coatings. These coatings are applied once and provide continuous friction reduction throughout the starter's service life, eliminating the need for periodic replacement or replenishment

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

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 non-volatile anti-friction coatings maintain optimal friction properties across a broad temperature range, reducing noise and ensuring reliable operation even at high temperatures, thereby extending the service life and maintaining performance in smaller installation spaces with increased loads.

Implementation Method 1

non-volatile friction-reducing agents are used as friction-reducing agents. The non-volatile friction reducing agents eliminate this failure mechanism.

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP2331847B1Starter gear with antifriction lacquer coating
Publication Date: 2014.05.07 ROBERT BOSCH GMBH
  • EP2331847B1 patent drawingFigure 1
  • EP2331847B1 patent drawingFigure 2
  • EP2331847B1 patent drawingFigure 3

AI summary

The object of the present invention relates to a reduction gear (83) of a starter motor (13) for internal combustion engines, comprising a drive part (44, 80) and a driven part (22, 132) in functional tribological connection with the drive part, wherein a friction-reducing means is provided between the drive part and the driven part for operation, wherein the friction reducing means is designed as a non-volatile friction-reducing means.