Non-Contact Optical Sensor for Hollow Cylindrical Specimen Measurement
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Solution Overview
Problem
Existing measuring apparatuses for hollow cylindrical test specimens, such as rotors and stators, face challenges in achieving accurate and rapid measurements, particularly in large-scale production, due to issues like deformation during fixation and high cycle times caused by the need for precise alignment and contact-based measurement methods.
Innovation Solution
A non-contact measuring apparatus using a combination of first and second sensors for measuring inner and outer peripheral surfaces, with the first sensor introduced into the inner opening and the second sensor positioned around the outer surface, allowing for accurate distance measurements without deforming the specimen, and a control circuit to process signals for determining cylindricity, straightness, and diameter dimensions in short cycle times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tactile measuring apparatuses with measuring ball are used to measure hollow cylindrical specimens, then measurement points can be contacted to determine dimensions, but the measurement is time consuming and requires fixation of the stack which may deform the specimen
Solution Approach 1:
The patent replaces the mechanical tactile measuring ball system with an optical measuring system using a laser distance sensor. This substitution eliminates the need for physical contact and fixation mechanisms, thereby reducing measurement time while maintaining or improving accuracy. The laser sensor can rapidly scan the specimen surface without requiring the specimen to be fixed, thus resolving the contradiction between measurement precision and cycle time.
2Measurement precision
If fixation of lamination stack with mandrel is performed to enable measurement, then the stack position can be determined, but this may lead to slight deformation of the stack resulting in non-repeatable measurements
Solution Approach 1:
The patent eliminates the mechanical mandrel fixation system by using a non-contact optical measuring approach. The laser distance sensor can measure the specimen in its natural, unfixed state, thereby avoiding any deformation caused by mandrel insertion. This resolves the contradiction by removing the harmful mechanical intervention while maintaining measurement precision through optical detection.
Solution Approach 2:
The patent creates an optical copy or representation of the specimen surface using laser reflection and distance measurement. Instead of physically fixing the specimen with a mandrel, the system captures geometric information through light interaction, allowing accurate measurement without physical interference. This copying approach avoids deformation while preserving measurement repeatability.
3Measurement precision
If precise determination and setting of measuring planes is performed to avoid gaps between laminations, then measurement accuracy can be maintained, but cycle times become too high for large-scale production
Solution Approach 1:
The patent enables continuous measurement by allowing the laser sensor to scan across the entire specimen surface without interruption or need to precisely position between laminations. The optical system can detect and ignore gaps between laminations, maintaining measurement accuracy while enabling continuous scanning motion. This continuity eliminates the time-consuming precise positioning steps, thereby increasing productivity for large-scale production.
4Object-affected harmful factors
If non-contact distance measurements are used with sensors, then the specimen is not deformed during measurement, but the sensors must be precisely positioned to ignore gaps and grooves between laminations
Solution Approach 1:
The patent uses the laser distance sensor to create an optical map or copy of the specimen surface topography, including gaps and grooves between laminations. By capturing the complete geometric information optically, the system can identify and exclude measurement points that fall in gaps, without requiring complex mechanical positioning. This approach maintains the non-contact advantage while simplifying the measurement process through data processing rather than mechanical complexity.
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 apparatus enables precise and reliable measurement of hollow cylindrical specimens with high accuracy and reduced cycle times, suitable for large-scale production by ignoring gaps and grooves, achieving measurement deviations less than 0.01 mm and completing measurements within 30 seconds.
Implementation Method 1
a first sensor (3) configured to measure a shape of the inner peripheral surface (24), wherein the first sensor (3) is a distance sensor designed for non-contact distance measurements
Implementation Method 2
a second sensor (4) configured to measure a shape of the outer peripheral surface (22), wherein the second sensor (4) is a distance sensor designed for non-contact distance measurements
Data Source
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AI summary
A measuring apparatus and method for measuring a shape of a stack of sheets assembled for forming a rotor or a stator of an electric motor, the stack comprising an outer peripheral surface and an inner peripheral surface, the apparatus comprising a first sensor configured to measure a shape of the inner peripheral surface and a second sensor configured to measure a shape of the outer peripheral surface.