Hardened Layer Depth Measuring Apparatus With Shielded Detection Coil
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Solution Overview
Problem
Conventional hardened layer depth measuring apparatuses suffer from inadequate measurement accuracy due to the detection coil's proximity to the excitation coil, which leads to interference from magnetic flux inside the yoke, making it difficult to accurately measure the depth of the hardened layer on a workpiece.
Innovation Solution
The apparatus features a detecting coil with a detection core positioned between the magnetic poles of the excitation core, allowing it to detect leakage magnetic flux along the surface of the workpiece, while the holding member securely positions the coils to prevent interference and ensure accurate measurements. The detecting coil is arranged such that it is separated from the exciting coil, reducing the impact of internal magnetic flux and improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detecting coil is provided on the leg portion of the yoke to detect magnetic flux, then the apparatus can detect magnetic flux, but the measurement accuracy deteriorates because both spatial magnetic flux and internal yoke magnetic flux are detected
Solution Approach 1:
The invention extracts only the spatial magnetic flux component from the total magnetic flux detected by the detecting coil. This is achieved by providing a shielding member that blocks the internal magnetic flux of the yoke from reaching the detecting coil, allowing the coil to detect only the spatial magnetic flux generated by the workpiece. This resolves the contradiction by removing the harmful internal flux component while preserving the useful spatial flux detection capability.
Solution Approach 2:
The shielding member acts as an intermediary element between the yoke and the detecting coil. It selectively blocks the internal magnetic flux path while allowing the spatial magnetic flux to pass through to the detecting coil. This mediator structure enables the detecting coil to distinguish between useful spatial flux and harmful internal flux, thereby improving measurement accuracy without sacrificing detection capability.
2Device complexity
If the detecting coil is positioned close to the excitation coil for compact design, then the device complexity is reduced, but the measurement precision deteriorates due to magnetic flux interference
Solution Approach 1:
The shielding member serves as a mediator that enables close positioning of the detecting coil to the excitation coil without suffering from internal magnetic flux interference. By blocking the harmful flux paths while allowing spatial flux detection, the shielding member allows compact arrangement of components while maintaining high measurement precision, thus resolving the contradiction between device simplicity and measurement accuracy.
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 configuration enhances measurement accuracy by isolating the detecting coil from the internal magnetic flux, allowing for precise determination of the hardened layer depth based on the detected voltage, which correlates linearly with the layer's depth, thereby improving the reliability of the measurement process.
Implementation Method 1
an excitation coil portion (12) wound on the excitation core portion (11)
Implementation Method 2
a detection coil portion (22) wound on the detection core portion (21)... the detection coil (2) detects leakage magnetic flux flowing in this space
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
An apparatus to measure a depth of a hardened layer formed at a surface layer of a quenched workpiece. The apparatus includes an exciting coil configured to generate a magnetic flux to magnetize the workpiece and a detecting coil configured to detect the magnetic flux generated by the exciting coil. The exciting coil has a U-shaped excitation core portion and an excitation coil portion wound on the excitation core portion. The excitation core portion is arranged such that distal ends of magnetic poles of the excitation core portion face the workpiece. The detecting coil has a detection core portion and a detection coil wound on the detection core portion. The detection core portion is arranged between the magnetic poles of the excitation core portion and along a surface of the workpiece.