Magnetizing Device Magnetic Shield Geometry
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Solution Overview
Problem
Existing magnetizing devices for magnetic encoders face challenges in achieving a balance between magnetization strength and precision, as smaller magnetic resistance leads to increased flux flowability but reduced magnetization strength, while greater resistance causes magnetic saturation and reduced shielding effectiveness.
Innovation Solution
A magnetizing device with a magnetic shield geometry that progressively decreases in thickness towards the magnetization heads, maintaining appropriate magnetic resistance and preventing magnetic saturation, allowing for precise magnetization of adjacent tracks without reducing magnetization strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the magnetic resistance between the magnetization head and magnetic shield is reduced to increase magnetic flux flowability, then the flux can flow more easily through the shield, but the magnetization strength introduced into the target magnetic encoder track is reduced
Solution Approach 1:
The magnetic shield employs a non-uniform thickness design where the thickness varies along the direction of magnetic flux flow. The shield is thinner at regions where flux introduction to the target track is prioritized and thicker at regions where shielding of adjacent tracks is prioritized. This local variation in geometry allows different sections of the shield to perform different functions optimally, resolving the contradiction between flux flowability and magnetization strength.
2Measurement precision
If the magnetic resistance between the magnetization head and magnetic shield is increased to improve shielding effect, then adjacent magnetic encoder tracks are better protected from leakage flux, but magnetic saturation occurs at the magnetic shield reducing shielding effectiveness
Solution Approach 1:
The invention changes the geometric parameters of the magnetic shield, specifically the thickness dimension, to optimize its performance. By carefully selecting and varying the thickness parameter along different sections of the shield, the magnetic resistance is adjusted to prevent saturation while maintaining effective shielding. This parameter optimization ensures that the shield operates within its linear magnetic regime, preserving shielding effectiveness.
3Ease of manufacture
If a uniform thickness magnetic shield is used, then the structure is simple and easy to manufacture, but it cannot simultaneously achieve both high magnetization strength and high magnetization precision for adjacent tracks
Solution Approach 1:
The magnetic shield transitions from a uniform thickness design to a non-uniform thickness design where different sections have different thicknesses optimized for their specific functions. This local differentiation allows the shield to simultaneously achieve high magnetization strength for the target track and high magnetization precision for adjacent tracks, overcoming the limitations of uniform thickness designs.
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 stabilizes magnetic flux flow, enabling precise magnetization of multiple tracks without influencing adjacent tracks, optimizing both magnetization strength and precision.
Implementation Method 1
a magnetic shield 11 is provided on a magnetic yoke 6 in such a way that magnetic flux is diverted from a left magnetization head 6a into the magnetic shield 11
Implementation Method 2
magnetic flux is diverted from a left magnetization head 6a into the magnetic shield 11 and is directed through a magnetic path generating member 10 towards a right magnetization head 6a
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A magnetizing device includes a magnetization yoke including a pair of magnetization heads confronting each other through a magnetic gap, an excitation coil wound around the magnetization yoke, and a magnetization power supply that supplies a magnetizing current to the excitation coil to generate magnetic flux between the magnetization heads. A magnetic shield is provided on the magnetization yoke. The magnetic shield is spaced apart from one of the magnetization heads with a gap being formed therebetween along a direction in which the plurality of magnetic encoder tracks are arranged. The magnetic shield blocks a flow of magnetic flux that is present outside a defined extension of a flow of the magnetic flux between the pair of magnetization heads. The magnetic shield is of such a geometry that a thickness thereof progressively decreases towards the one of the magnetization heads.