Optical Shaft Hole Thickness Measurement Without Probe Insertion

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Solution Overview

Problem

Existing methods for measuring the thickness of shafts with holes, such as hollow or blind holes, are inaccurate due to limitations in measuring instruments that cannot enter the shaft and require additional processing for ultrasonic wave measurements, resulting in errors of up to 0.1 mm and additional machining steps.

Innovation Solution

A system comprising measuring heads for the outer and inner peripheries that use optical fibers and laser light to non-contactly measure distances through OCT, FMCW, TOF, or phase shift methods, allowing for simultaneous measurement of inner and outer diameters and thickness, with a control device processing data for accurate machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If ultrasonic waves are used to measure thickness from the outer periphery, then measurement can be performed without entering the shaft, but measurement accuracy deteriorates with errors of up to 0.1 mm

Engineering Contradiction:

Improvemeasurement accessibilityVSAvoidthickness measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The measurement system divides the thickness measurement into two separate measurements: one from the outer periphery and one from the inner periphery. By measuring each surface independently with high-precision optical sensors and calculating the difference, the system achieves accurate thickness measurement without the limitations of single-sided ultrasonic measurement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces optical fibers as intermediaries to transmit laser light to the measurement surfaces. This allows non-contact, high-precision optical measurement to be performed inside the shaft where measuring instruments cannot physically enter, while maintaining measurement accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If ultrasonic waves are applied to measure thickness, then additional machining process is avoided, but surface smoothness requirement increases manufacturing complexity

Engineering Contradiction:

Improveprocess simplicityVSAvoidsurface smoothness requirement

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces contact-based ultrasonic measurement with non-contact optical measurement using laser and optical fibers. This eliminates the requirement for smooth surfaces needed for ultrasonic coupling, allowing measurement of rough or as-machined surfaces without additional machining processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If measuring instruments are inserted into the shaft, then accurate thickness measurement is achieved, but measuring instrument accessibility becomes limited

Engineering Contradiction:

Improvethickness measurement accuracyVSAvoidmeasuring instrument accessibility

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

Optical fibers serve as flexible intermediaries that can be inserted into the shaft to deliver laser light to internal surfaces for measurement. This enables high-precision optical measurement inside the shaft without requiring rigid measuring instruments to physically access and contact the measurement points.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical contact measurement instruments with non-contact optical measurement using laser. This allows measurement of internal surfaces through the shaft opening without requiring physical insertion of bulky measuring devices, improving accessibility while maintaining precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 system achieves precise measurement of shaft thickness and diameters, reducing measurement errors and eliminating the need for additional machining processes, thereby improving accuracy and efficiency in manufacturing shafts with holes.