Disc Drive Spindle Cup Capillary Seal Lubricant Retention
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Solution Overview
Problem
Disc drive memory systems using fluid dynamic bearings face lubricant fluid loss issues due to evaporation and space constraints of effective labyrinth seals, which limit operational lifetime and mechanical stability.
Innovation Solution
A disc drive assembly design incorporating a spindle with journal and thrust bearing patterns, a cup-shaped structure forming capillary seals, and a lubricant recirculation channel to maintain lubricant fluid pressure and reduce evaporation, combined with a thrust washer for enhanced sealing and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If labyrinth seals are used to reduce lubricant evaporation, then lubricant retention is improved, but device complexity and space consumption increase
Solution Approach 1:
The seal is divided into multiple functional segments: capillary seal channels for primary sealing, labyrinth seal pathways for vapor trapping, and reservoir regions for lubricant storage. This segmentation allows each segment to perform its specific function efficiently while collectively providing comprehensive lubricant retention without requiring a single complex seal structure.
Solution Approach 2:
The capillary seal channels are nested within the spindle structure, and the labyrinth seal pathways are integrated within the same space. The reservoir regions are positioned to contain both the capillary seals and labyrinth seals in a nested arrangement, maximizing space utilization and reducing overall device complexity while maintaining effective sealing.
2Quantity of substance
If capillary seals are used as lubricant reservoirs, then lubricant storage capacity is improved, but lubricant loss through evaporation increases
Solution Approach 1:
The labyrinth seal pathways act as an intermediary between the capillary seal reservoir and the external environment. These pathways create a tortuous route that traps lubricant vapor, preventing direct evaporation from the reservoir while allowing the reservoir to maintain its lubricant storage function. The intermediary labyrinth structure effectively decouples the storage capacity from evaporation loss.
3Reliability
If different seal designs are used at each end of the spindle, then sealing effectiveness is improved, but manufacturing complexity increases
Solution Approach 1:
A single integrated seal structure is designed to perform multiple sealing functions at both ends of the spindle. The capillary seal channels and labyrinth seal pathways are configured to provide both primary sealing and vapor trapping functions simultaneously at each end, eliminating the need for different seal designs while maintaining sealing effectiveness. This universal design simplifies manufacturing while preserving reliability.
4Loss of substance
If lubricant recirculation channels are added, then lubricant retention is improved, but device complexity increases
Solution Approach 1:
The lubricant recirculation channels are merged with the existing capillary seal channels and reservoir structures. The same channels that provide sealing functions also serve as recirculation pathways, allowing lubricant to flow from areas of high concentration to low concentration and back. This merging eliminates the need for separate recirculation channels, reducing device complexity while improving lubricant retention.
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
The design effectively reduces lubricant fluid loss and maintains mechanical stability by utilizing capillary seals and labyrinth seals, while allowing for compact and efficient lubricant recirculation, thereby extending the operational lifetime of disc drive systems.
Implementation Method 1
Capillary seals are flared channels that rely on the surface tension of the lubricant fluid to form a meniscus as the walls of a channel flare apart.
Implementation Method 2
Capillary seals are flared channels that rely on the surface tension of the lubricant fluid to form a meniscus
Implementation Method 3
Journal bearings fix the radial position of a hub as it rotates around a spindle. Such bearings are of the journal and thrust types. Journal bearings fix the radial position of a hub as it rotates around a spindle.
Implementation Method 4
Thrust bearings constrain the axial position of the hub as it rotates.
Implementation Method 5
Such pumps can maintain lubricant fluid pressure gradients while the hub is rotating
Data Source
AI summary
Multifunctional components enable the construction of economical motor assemblies. A first embodiment of the present invention provides a hub, cup, spindle, and base assembly for a motor assembly having at least one journal bearing, at least one thrust bearing, and at least one fluid seal. A second embodiment of the present invention provides a hub, spindle, and base with integrated cup assembly for a disc drive bearing having at least one journal bearing, at least one thrust bearing, and at least one fluid seal. In a third embodiment, a hub is rotatably assembled with a spindle coupled to a thrust bearing, prior to assembly with a base. In further embodiments, motor assemblies comprise the above embodiments combined with stator and rotor assemblies.