Disk Clamp Uniform Clamping Load via Coined Profile
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Solution Overview
Problem
Conventional disk drives face issues with non-uniform clamping forces due to the radial positioning of screws in disk clamps, leading to disk distortion and potential data transfer errors, and the use of a single screw can result in over-stressing spindle shaft bearings.
Innovation Solution
A disk clamp design featuring a circular coined profile at the innermost section and balance weight holes with formed or coined profiles around them, which reduces clamp force variation by operating in the plastic region of the stress-strain curve, providing a uniform clamping load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If radial positioning of screws is used in disk clamp, then disk clamp can secure disks to spindle motor hub, but non-uniform clamping force causes disk distortion
Solution Approach 1:
The patent applies local quality by positioning screws at specific angular intervals (e.g., 90 degrees apart) around the disk clamp rather than radially. This creates a uniform distribution of clamping force around the circumference of the disk, preventing localized distortion while maintaining secure attachment to the spindle motor hub.
2Device complexity
If single screw is used to secure disk clamp, then device complexity is reduced, but spindle shaft bearing is over-stressed
Solution Approach 1:
The patent segments the single screw connection into multiple screws distributed around the disk clamp. This divides the total clamping load into multiple smaller forces applied at different locations, reducing the stress on any single spindle shaft bearing while achieving the same overall clamping effect.
3Quantity of substance
If transducer flying height is reduced to read densely stored information, then storage capacity increases, but transducer contacts disk surface causing damage
Solution Approach 1:
The patent implements beforehand cushioning by ensuring uniform disk flatness through proper clamping, which creates a consistent air bearing gap between the transducer and disk surface. This prevents intermittent contact that would occur with disk distortion, thereby protecting the transducer from damage while enabling reduced flying height for higher storage 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 design minimizes clamp force variation and disk distortion, enhancing data transfer reliability while reducing the risk of spindle motor failure by ensuring a uniform and stable clamping force across the disk surface.
Implementation Method 1
A disk clamp design featuring a circular coined profile at the innermost section and balance weight holes with formed or coined profiles around them, which reduces clamp force variation by operating in the plastic region of the stress-strain curve
Data Source
AI summary
A disk clamp for clamping a number of magnetic hard disks within a disk drive has a plurality of balance weight holes and a coined index mark for use as a reference in balancing the hard disks after assembly. The disk clamp also has a coined profile located adjacent or around the balance weight holes in order to provide uniform circumferential clamp force by the disk clamp. The disk clamp has a profile that places the inner region of the disk clamp in the plastic deformation region at a certain specified clamping force at the center of the disk clamp.