Gear Tooth Flank Optical Measurement for Surface Waviness Analysis

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Solution Overview

Problem

Existing methods for measuring gear teeth are time-consuming and inefficient in industrial production, failing to reliably analyze surface waviness and noise behavior, which is critical for transmission noise reduction in hybrid or fully electric vehicles.

Innovation Solution

An optical measurement method that extrapolates measured segments of tooth flanks to determine complete topography, using a confocal chromatic distance sensor and tactile verification, enabling rapid analysis of surface waviness and deviations from target geometry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complete measurement data of individual tooth flanks is collected, then measurement precision of surface waviness is improved, but measurement time increases

Engineering Contradiction:
Improvesurface waviness measurement precisionVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the tooth flank measurement into multiple segments (first segment, second segment, third segment) along the tooth flank trace. By measuring only critical segments and extrapolating to the complete topography, the method achieves accurate surface waviness measurement without requiring measurement of the entire tooth flank, thus reducing measurement time while maintaining precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent measures only the necessary partial segments of the tooth flank (first segment near the pitch point, second segment for extrapolation, third segment for verification) rather than the complete tooth flank topography. This partial measurement approach, combined with extrapolation, provides sufficient data for accurate surface waviness analysis while significantly reducing measurement time.

Inventive Principle:
Principle #16Partial or excessive action

2Productivity

If measurement is performed rapidly with segment extrapolation, then productivity is improved, but measurement precision may deteriorate

Engineering Contradiction:
Improvemeasurement efficiencyVSAvoidsurface waviness measurement precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent employs a feedback mechanism where a third segment of the tooth flank is measured to verify the extrapolation results. The measured third segment is compared with the extrapolated values, and if deviations exceed a threshold, the extrapolation is adjusted. This feedback loop ensures measurement precision is maintained even when using rapid segment-based measurement and extrapolation methods.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary measurement of critical segments (first segment near the pitch point and second segment for extrapolation) before conducting the full evaluation. This preliminary action captures the essential surface waviness characteristics that dominate noise behavior, enabling rapid yet accurate assessment without requiring complete topography measurement.

Inventive Principle:
Principle #10Preliminary action

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

Enables rapid and reliable analysis of gear tooth surface waviness, improving noise prediction and manufacturing efficiency by reducing measurement time and enhancing compliance with noise behavior requirements.

Implementation Method 1

optical measurement method that extrapolates measured segments of tooth flanks

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 2

using a confocal chromatic distance sensor

Methodology Applied
Scientific EffectConfocal chromatic detection:

Data Source

PatentEP4113094B1Method and testing system
Publication Date: 2025.06.25 KLINGELNBERG GMBH
  • EP4113094B1 patent drawingFigure 1
  • EP4113094B1 patent drawingFigure 2~3
  • EP4113094B1 patent drawingFigure 4~6

AI summary

Method comprising the following steps: providing a gear (14) having a plurality of teeth (16) with tooth flanks (18); measuring two or more teeth (16) of the gear (14), wherein for each of the two or more teeth (16) the following steps are performed: measuring a segment (20) of at least one tooth flank (18) of the tooth (16), wherein the measurement is carried out optically by means of an optical measuring device (8), extrapolating the measured segment (20) to an extrapolated segment (24); evaluating deviations of the extrapolated segments (24) of the two or more teeth (16).