Internal Gear Tooth Gap Measurement Using Angled Grinding Wheel

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Solution Overview

Problem

Measuring the tooth gap of internal gears is challenging due to their unique geometry, which makes it difficult for the grinding wheel to contact the tooth flanks accurately, often resulting in incorrect measurements.

Innovation Solution

The grinding wheel is positioned at an angle α relative to the root circle diameter of the tooth gap, allowing it to contact one of the tooth flanks between the root and tip circle diameters, enabling precise measurement using structure-borne noise sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the grinding wheel contacts the tooth flank of an internal gear, then measurement data can be obtained, but the unique geometry of internal gears makes it difficult to contact the actual flanks, leading to incorrect measurements

Engineering Contradiction:
Improvetooth gap measurement accuracyVSAvoiddifficulty to contact tooth flanks
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces a new dimensional approach by positioning the grinding wheel at an angle α relative to the radial direction, rather than approaching the tooth flank purely radially. This angular dimension allows the grinding wheel to access the tooth flanks of internal gears that are otherwise difficult to reach, enabling accurate contact in the area between root and tip circle diameters.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the positional parameter of the grinding wheel by defining a specific angular position α. This parameter change transforms the grinding wheel's orientation from a standard radial approach to an inclined approach, allowing it to properly contact the tooth flanks of internal gears and obtain accurate measurement data.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the grinding wheel is positioned radially to contact the tooth gap, then the measurement process is simple, but the contact point may be at the tip of the tooth rather than the actual flank, resulting in incorrect measurements

Engineering Contradiction:
Improvesimplicity of measurement processVSAvoidcontact point accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent modifies the positional parameter α of the grinding wheel from zero (radial position) to a non-zero angle. This parameter change ensures that the grinding wheel contacts the tooth flank at the correct location between root and tip circle diameters, preventing contact at the tooth tip while maintaining measurement process simplicity.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the grinding wheel approaches the tooth gap without angular positioning, then setup is straightforward, but the tip circle diameter or existing burrs may prevent proper contact with the tooth flanks

Engineering Contradiction:
Improveease of grinding wheel positioningVSAvoidreliability of tooth flank contact
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces an angular positioning parameter α to modify the grinding wheel's approach angle. This change in operational parameter allows the grinding wheel to bypass obstructions such as inaccurate tip circle diameters or burrs that would otherwise prevent reliable contact with the tooth flanks, thereby improving measurement reliability.

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 method ensures accurate measurement of internal gear tooth gaps, improving the reliability of data for subsequent grinding operations and enhancing the quality of the manufactured gears.

Implementation Method 1

a structure-borne noise that can be easily detected with suitable sensors being generated

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP2246658B1Method for measuring gaps between teeth
Publication Date: 2012.01.04 BHS HOFLER MASCHBAUU
  • EP2246658B1 patent drawingFigure 1
  • EP2246658B1 patent drawingFigure 2
  • EP2246658B1 patent drawingFigure 3

AI summary

The method involves aligning a grinding wheel (S) and a tooth gap (L) relative to each other in a positioning movement. A gap part end foot circle diameter (D-F) of the processed tooth gap intersects a rotation plane (E-S) of the grinding wheel at a certain angle. The grinding wheel and the tooth gap move relative to one another in a contact motion.