Actuator Pivot Bearing Coating for Disk Drive Lubricant Control
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Solution Overview
Problem
The migration of lubricant from the actuator pivot bearing in magnetic hard disk drives contaminates other components, reducing the reliability and lifetime of the disk drive and threatening stored data.
Innovation Solution
The use of a coating material with specific surface energy, such as fluorinated acrylates or methacrylates, on the actuator pivot bearing surfaces to prevent lubricant wetting and migration, combined with design enhancements like ball bearings and a rotatable outer sleeve, to control lubricant distribution and reduce contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If lubricant is used in the actuator pivot bearing cartridge, then the bearing operates smoothly with reduced friction, but the lubricant migrates to other components causing contamination
Solution Approach 1:
A coating layer is applied to the bearing cap surface to act as an intermediary barrier between the lubricant and other components. This coating has specific surface energy characteristics that prevent lubricant wetting and migration, allowing the bearing to operate smoothly while containing the lubricant within the cartridge.
Solution Approach 2:
The surface energy parameters of the bearing cap are modified through coating application. By changing the surface energy characteristics, the coating creates a non-wetting surface that repels the lubricant, preventing migration while maintaining the lubrication function within the bearing.
2Reliability
If tight clearance tolerances are specified for the actuator pivot bearing, then precision and reliability are improved, but manufacturing complexity and cost increase
Solution Approach 1:
A thin film coating is applied to the bearing cap, providing a controlled barrier that prevents lubricant migration. This thin film layer allows for relaxed mechanical clearance tolerances while maintaining reliability, as the coating provides the precise control needed for preventing contamination without requiring tight mechanical tolerances.
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
Effectively minimizes lubricant migration, enhancing the reliability and longevity of disk drive components while relaxing manufacturing constraints and reducing costs by allowing for looser clearance tolerances.
Implementation Method 1
The use of a coating material with specific surface energy, such as fluorinated acrylates or methacrylates, on the actuator pivot bearing surfaces to prevent lubricant wetting and migration
Data Source
AI summary
An actuator pivot bearing is disposed at least partially within a bore in the body of a disk drive head actuator. The actuator pivot bearing includes a lubricant wetting a first surface, and a coating on a second surface. The coating has a surface energy such that the lubricant does not wet the second surface.