Hard Disk Drive Spindle Motor Hub Flange with Multiple Contact Protrusions
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Solution Overview
Problem
Increasing the number of disks in a hard disk drive while maintaining a standard form factor and operational shock tolerance poses challenges due to increased disk stack clamping load, leading to substantial coning deformation that affects read and write processes.
Innovation Solution
A multiple contact disk clamp with radially offset and axially optimized inner and outer protrusions is used to distribute clamping force evenly across multiple contact points, reducing coning deformation by maintaining the top and middle disks relatively flat, and a similar design for the spindle motor hub flange to inhibit coning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of disks in a hard disk drive is increased to enhance storage capacity, then storage capacity is improved, but the disk stack clamping load increases causing substantial coning deformation
Solution Approach 1:
The clamping system is segmented into multiple contact points (inner and outer protrusions) instead of a single contact point. This segmentation distributes the clamping load across multiple locations on the disk stack, preventing excessive force concentration that causes coning deformation while maintaining the ability to clamp increased numbers of disks
Solution Approach 2:
Different regions of the disk stack are addressed with locally optimized contact points. The inner protrusion contacts the disk stack at an inner radius while the outer protrusion contacts at an outer radius, with each contact point having specific axial offset values optimized for its location. This local quality approach ensures uniform pressure distribution across the entire disk stack width, maintaining flatness even as disk count increases
2Reliability
If the disk stack clamping load is increased to meet operational shock requirements, then operational shock tolerance is improved, but coning deformation increases affecting read and write processes
Solution Approach 1:
The clamping force is segmented into multiple contact points (inner and outer protrusions) that distribute the operational shock load across different locations. This prevents any single point from bearing excessive force that would cause coning deformation, while the cumulative effect of all contact points maintains the required operational shock tolerance
Solution Approach 2:
The multiple contact points act as counterbalancing elements that distribute and counteract the shock loads. By having contact points at different radial positions with optimized axial offsets, the system creates a balanced force distribution that resists coning deformation while maintaining overall structural integrity under shock conditions
Data Source
AI summary
A disk spindle assembly for a hard disk drive includes a hub and a hub flange extending radially from the hub and configured to apply a clamping force to secure disk media to the hub. The hub flange includes multiple protrusions extending from a surface of a top side and configured to contact a disk medium at multiple contact positions in response to application of a clamping load. The protrusions may be annular protrusions circumscribing the hub, where the height of an inner protrusion may be less than the height of an outer protrusion to inhibit coning of the bottom disk medium, and the protrusions may be positioned so that an equivalent contact radius corresponding to contact radii of the inner and outer annular protrusions is at a position halfway between the inner and outer diameters of the disk spacers to inhibit coning of the middle disk media.