Gear Tooth Flank Microtexturing for Friction Reduction

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Solution Overview

Problem

Existing toothed parts in transmissions experience high friction and wear due to inefficient lubrication, leading to increased energy losses and reduced load-carrying capacity, particularly in areas with significant sliding motion.

Innovation Solution

The toothed parts are microtextured with strategically arranged depressions on the tooth flanks, which facilitate the rapid buildup of a lubricating film, known as the 'aquaplaning effect', by creating a pressure buildup and reducing friction, especially in areas with high sliding components. The depressions are designed to be spaced, angled, and dimensioned to maximize the lubricating film's effectiveness, with a surface proportion between 5% and 50% of the total tooth flank surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If lubricating oil is provided in transmissions with meshing toothed parts, then friction is reduced, but wear and energy losses persist in areas with high sliding components

Engineering Contradiction:
Improveenergy lossesVSAvoidload-carrying capacity
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies local quality by creating indentations specifically in the sliding areas of the tooth flanks where lubrication is most needed. These localized modifications concentrate the lubricating effect precisely where the sliding component is highest, rather than uniformly treating the entire tooth surface. This resolves the contradiction by locally enhancing lubrication effectiveness in critical zones without compromising the overall gear structure or requiring additional lubricant.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The indentations are pre-formed on the tooth flanks before the gear enters operation. This preliminary action ensures that lubricating oil is immediately available in the sliding areas from the start of operation, allowing the lubricating film to build up quickly and reduce friction and wear from the beginning, rather than relying on gradual lubricant accumulation during operation.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If the surface of tooth flanks is modified to reduce friction, then wear is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improveease of producing indentationsVSAvoidcomplexity of tooth flank modification
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The tooth flank surface is segmented into multiple small indentations distributed across the sliding area. This segmentation transforms a complex continuous surface modification into discrete, standardized features that can be produced using automated machining processes. The segmented approach simplifies manufacturing by allowing the use of standard tools and processes while achieving the desired friction reduction effect.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent specifies particular parameter ranges for the indentations (depth, diameter, spacing, and distribution density) to optimize both manufacturing ease and functional performance. By defining specific parameter ranges, the invention makes the complex task of surface modification manageable through standardized specifications that can be implemented using conventional machining equipment with appropriate process parameters.

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 approach significantly reduces friction and wear, enhances the load-carrying capacity, and extends the service life of the toothed parts by ensuring effective lubrication even at low relative speeds, particularly in areas with high sliding friction.

Implementation Method 1

the indentations accelerate the build-up of a lubricating film along the tooth flank during the rotational movement of the toothed part and cause a pressure build-up, in particular the 'aquaplaning effect'

Methodology Applied
Scientific EffectAquaplaning effect: Aquaplaning

Data Source

PatentEP3011204B1Toothed part and gear with toothed part
Publication Date: 2017.11.15 SEW EURODRIVE GMBH & CO KG
  • EP3011204B1 patent drawingFigure 1
  • EP3011204B1 patent drawingFigure 2

AI summary

The invention relates to a toothed part and a gear having a toothed part, said toothed part comprising teeth, wherein a tooth face (2) of one or more of the teeth is provided with an array of recesses (3) and/or a microtextured area (3), and in particular said array and/or microtextured area is introduced into said tooth face.