Magnetic Head Slider Testing Apparatus with Split Coil Design
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Solution Overview
Problem
Current magnetic head slider testing apparatuses face challenges in size reduction and leakage magnetic field suppression due to the need for separate coils for DC and high-frequency magnetic field generation, which affects test results and apparatus size.
Innovation Solution
The apparatus divides the coil into two coils, with one coil for DC and the other for high-frequency magnetic field generation, allowing for shared current output and reduced inductance, thereby minimizing leakage and enabling size reduction by positioning coils closer to the air gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate coils are used for DC and high-frequency magnetic field generation, then magnetic field generation capability is improved, but apparatus size increases and leakage magnetic field occurs
Solution Approach 1:
A single coil structure is designed to perform multiple functions: generating both DC magnetic fields and high-frequency magnetic fields. The coil can operate in different modes by controlling the input signal frequency, eliminating the need for separate coils and reducing apparatus size while maintaining full magnetic field generation capability.
Solution Approach 2:
The coil structure is divided into multiple independent winding sections that can be selectively activated. By segmenting the coil, the patent enables flexible configuration where the same physical structure can generate different types of magnetic fields by controlling which sections are active, thereby reducing overall apparatus size while maintaining versatility.
2Adaptability or versatility
If separate coils are used for DC and high-frequency magnetic field generation, then magnetic field generation capability is improved, but leakage magnetic field to surroundings increases
Solution Approach 1:
The unified coil structure with shared magnetic path creates more efficient magnetic field confinement. By using a single coil design that can generate both DC and high-frequency fields, the magnetic flux is better contained within the core structure, reducing leakage to surroundings compared to separate coil configurations.
Solution Approach 2:
Different sections of the coil structure are optimized for different field types, with local variations in winding density and core material properties. This localized optimization allows the same coil to efficiently generate both DC and high-frequency fields while minimizing leakage through strategic placement of high-permeability materials in specific regions.
3Volume of stationary object
If coil inductance is reduced for size reduction, then apparatus size decreases, but magnetic field generation efficiency decreases
Solution Approach 1:
The coil inductance is made dynamically adjustable through a switching mechanism that connects different portions of the coil in series or parallel. This allows the inductance to be optimized in real-time: lower inductance for high-frequency operation to reduce size effects, and higher inductance for DC operation to maintain field generation efficiency, thereby resolving the contradiction between size and efficiency.
Solution Approach 2:
The coil is segmented into multiple independent winding sections that can be connected in different configurations. By selectively activating and connecting these segments, the effective inductance can be adjusted to match the operational requirements, enabling efficient magnetic field generation at both DC and high-frequency while maintaining a compact overall structure.
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 magnetic field generation efficiency, reduces the apparatus size, and suppresses leakage magnetic fields, allowing for precise and efficient testing of magnetic head sliders.
Implementation Method 1
for generating a DC magnetic field in the air gap the first coil and the second coil are connected in series and a predetermined drive current is flowed therethrough
Implementation Method 2
for generating a high frequency magnetic field in the air gap an AC drive current of more than 200 Hz is flowed through either the first coil or the second coil
Data Source
AI summary
In the present invention, a coil generating DC magnetic field applied to a magnetic head is divided into two in that a first coil and a second coil, which are provided on a frame shape core. An distance of an air gap is shortened, a slider head is held on a table having a top end portion of thin thickness, while advancing and retreating the table in the direction perpendicular to the core, the head slider is inserted into the air gap from the lateral direction. Thereby, the distance of the air gap is reduced to about half of the conventional one and a reduction of inductance of the first coil and the second coil is realized.