Spindle Motor Magnet Shielding for Low-Oxygen HAMR Disk Drives
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Solution Overview
Problem
The use of oxygen-enriched helium in magnetic disk devices leads to increased gas density, deteriorating head positioning accuracy and power consumption, while coating components with resin fails to fully cover surfaces, allowing oxygen consumption through pinholes.
Innovation Solution
A shielding film made of high-density materials like Ni plating is applied to the magnet, reducing oxygen permeation, and a desiccant maintains low humidity to minimize oxygen consumption, ensuring a stable oxygen content of 5% in the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxygen content is increased to 10% or more to ensure reliability, then reliability is improved, but gas density increases leading to deterioration in head positioning accuracy and increased power consumption
Solution Approach 1:
The patent changes the oxygen concentration parameter from the conventional 10% or more to a reduced level of 1% to 5%, thereby maintaining reliability while improving head positioning accuracy and reducing power consumption. This parameter optimization resolves the contradiction by finding a new optimal point that satisfies reliability requirements without the adverse effects of high oxygen content.
2Object-affected harmful factors
If components are coated with resin to prevent oxidation, then oxidation resistance is improved, but pinholes remain exposing surfaces to oxygen consumption
Solution Approach 1:
The patent changes the oxygen concentration parameter in the housing from conventional levels (10% or more) to a reduced level of 1% to 5%. This parameter optimization reduces the driving force for oxidation reactions, thereby suppressing oxygen consumption through pinholes and other exposed areas while maintaining system reliability.
Solution Approach 2:
The patent converts the previously harmful high oxygen environment into a beneficial low oxygen environment (1% to 5%). By reducing oxygen concentration, the patent transforms the oxidation risk into an advantage, suppressing oxygen consumption and chemical reactions while maintaining reliability, thus turning a potential harm into a benefit.
3Manufacturing precision
If 100% helium is used in the housing, then gas density is reduced improving performance, but oxygen content is insufficient compromising HAMR reliability
Solution Approach 1:
The patent optimizes the oxygen concentration parameter to 1% to 5%, finding the optimal balance between maintaining HAMR reliability and preserving the low-density benefits of helium. This parameter optimization ensures sufficient oxygen for reliability while maintaining the performance advantages of low gas density.
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 approach maintains disk device performance by suppressing oxygen consumption, enhancing reliability and reducing chemical reactions, thus improving the HAMR-type disk device's operational stability.
Implementation Method 1
a magnet whose surface is covered with a shielding film blocking oxygen permeation
Implementation Method 2
a desiccant maintains low humidity to minimize oxygen consumption
Data Source
AI summary
According to one embodiment, a disk device includes a housing filled with a low density gas containing oxygen and having a density lower than a density of air, a disk-shaped recording medium provided in the housing to be rotatable, a spindle motor provided in the housing and supporting and rotating the recording medium, and a magnetic head including a heat assist element which heats the recording medium. A surface of magnet of the spindle motor is covered with a shielding film blocking oxygen permeation.