Pitch Cone Angle Measurement for Fast Inline Spline Inspection

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Solution Overview

Problem

Current methods for measuring the pitch cone angle of rotation power transmitting elements, such as face splines, are time-consuming and costly, making them unsuitable for inline measurement in mass production.

Innovation Solution

A pitch cone angle measurement method involving a first and second abutment step with a distance measurement to calculate the pitch cone angle based on the relative height between abutment positions, using abutment portions with predetermined shapes and dimensions, allowing for precise and rapid measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If contact-type probe measurement method is used to scan tooth surfaces, then measurement precision can be maintained, but measurement time increases and device cost increases

Engineering Contradiction:
Improvepitch cone angle measurement precisionVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the essential measurement information (pitch cone angle) by using a simple abutment portion that contacts specific points on the tooth surfaces, rather than scanning the entire tooth surface with a complex contact probe. This extraction of essential information maintains measurement precision while dramatically reducing measurement time and device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses an abutment portion with a predetermined shape that replicates the essential geometric relationship needed for pitch cone angle measurement. Instead of using a complex contact probe that physically scans and measures, the abutment portion creates a simplified geometric copy of the measurement scenario, allowing direct calculation of the pitch cone angle from the measured distance between abutment positions.

Inventive Principle:
Principle #26Copying

2Measurement precision

If contact-type probe measurement method is used to scan tooth surfaces, then measurement precision can be maintained, but device cost increases

Engineering Contradiction:
Improvepitch cone angle measurement precisionVSAvoidmeasurement device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential measurement information (pitch cone angle) by using a simple abutment portion that contacts specific points on the tooth surfaces, rather than scanning the entire tooth surface with a complex contact probe. This extraction of essential information maintains measurement precision while dramatically reducing measurement time and device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses an abutment portion with a predetermined shape that replicates the essential geometric relationship needed for pitch cone angle measurement. Instead of using a complex contact probe that physically scans and measures, the abutment portion creates a simplified geometric copy of the measurement scenario, allowing direct calculation of the pitch cone angle from the measured distance between abutment positions.

Inventive Principle:
Principle #26Copying

3Measurement precision

If conventional measurement methods are used for pitch cone angle, then measurement accuracy can be ensured, but productivity decreases

Engineering Contradiction:
Improvepitch cone angle measurement accuracyVSAvoidmeasurement efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the measurement process into distinct, simple steps: positioning the abutment portion at two different radial distances and measuring the axial distance between abutment positions. This segmentation transforms a complex continuous scanning process into discrete, rapid measurement steps, significantly improving productivity while maintaining accuracy through precise positional control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The abutment portion is designed with a predetermined shape and dimensions before the measurement process begins. This preliminary preparation of the measurement tool allows for direct contact and immediate measurement without requiring complex real-time calculations or adjustments during the measurement process, thereby enhancing both accuracy and productivity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3330662B1Pitch cone angle measurement method and pitch cone angle measurement device
Publication Date: 2021.09.08 NTN CORP
  • EP3330662B1 patent drawingFigure 1
  • EP3330662B1 patent drawingFigure 2~3B
  • EP3330662B1 patent drawingFigure 4

AI summary

A pitch cone angle measurement method according to the present invention includes bringing an abutment portion (51) into abutment against ridges (41), bringing an abutment portion (52) into abutment against the ridges (41) at a position separated in a direction orthogonal to a rotation axis (L) direction of the rotation power transmitting element (40) by a radial distance (d) from a position (Pe1) at which the ridges (41) and the abutment portion (51) are brought into abutment against each other, measuring a distance (S) in the rotation axis (L) direction between the position (Pe1) at which the abutment portion (51) is brought into abutment against the ridges (41) and a position (Pe2) at which the abutment portion (52) is brought into abutment against the ridges (41), and calculating a pitch cone angle (θ) of the rotation power transmitting element (40) based on the distance (S) in the rotation axis direction and the predetermined radial distance (d).