Magnetic Disk Device Startup Filtration via High-Speed Spindle Rotation
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Solution Overview
Problem
Magnetic disk devices face challenges in balancing areal density capability and component cleanliness due to particle-related failures, where the recirculation filter's effectiveness is limited by the initial low gas cleanliness at startup, leading to a high risk of particle catching during head loading.
Innovation Solution
The magnetic disk device employs a spindle motor that rotates at a higher speed than normal during startup to accelerate airflow through a recirculation filter, allowing it to gather particles efficiently within a controlled high-speed steady rotation time before reducing speed and loading the magnetic head, thus improving cleanliness without extending startup time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the recirculation filter is used to reduce particles, then particle reduction effectiveness is improved, but startup time is extended because the filter requires airflow generation and waiting time to improve gas cleanliness
Solution Approach 1:
The spindle motor rotates the magnetic disk at high speed before the magnetic head is loaded onto the disk. This preliminary high-speed rotation generates airflow that activates the recirculation filter to collect particles in advance, ensuring clean environment before head loading occurs
Solution Approach 2:
The spindle motor operates at variable speeds during startup: initially rotating at high speed to generate airflow for particle collection, then reducing to normal operating speed. This dynamic speed adjustment allows the system to balance particle reduction effectiveness with startup time requirements
2Productivity
If the magnetic head is loaded early to reduce startup time, then productivity is improved, but the risk of particle catching increases due to low gas cleanliness
Solution Approach 1:
The system performs preliminary high-speed rotation to activate particle collection before head loading. This ensures that the recirculation filter has sufficient time to reduce particle density in the gas, lowering the risk of particle catching when the head is loaded
Solution Approach 2:
The control section monitors the startup process and determines when particle reduction has reached an acceptable level before permitting head loading. This feedback mechanism ensures that productivity is maintained while reliability is protected through timing control
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 reduces particle-related failures by shortening the time required to reduce particle density, ensuring the magnetic head is loaded when the environment is cleaner, thereby enhancing the reliability of the magnetic disk device.
Implementation Method 1
a recirculation filter which an airflow generated by rotation of the magnetic disk passes when the magnetic disk is rotated by the spindle motor
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a magnetic disk, a spindle motor, a magnetic head, a ramp load mechanism, a filter, and a control section. The control section rotates the spindle motor at a second rotating speed for a given period of time at startup of the device, and then loads the magnetic head from the ramp load mechanism to a prescribed position on the magnetic disk. The second rotating speed is higher than a first rotating speed at which the spindle motor is rotated at the magnetic head reads/writes data from/to the magnetic disk.