Spindle Motor Medium-Carrying Surface Profile for Disk Stability
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Solution Overview
Problem
Conventional spindle motors for hard disk drives (HDDs) face challenges in reducing deformation and warping of small-size disks due to inadequate precision and stability in the disk-carrying surface, leading to potential collisions and reduced recording density, especially with the increased demand for higher capacity and recording density.
Innovation Solution
The spindle motor design features a medium-carrying surface with profile peaks having narrower widths than profile valleys, and a skewness greater than 0, which allows for elastic deformation of the peaks under clamping force, reducing the likelihood of disk warping and collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large clamping force is applied to secure the disk, then the disk is firmly fixed, but the disk undergoes deformation (cup shape or waviness)
Solution Approach 1:
The disk-carrying surface is designed with localized high spots (protrusions) distributed across the surface. These local protrusions concentrate the clamping force at specific points rather than distributing it uniformly, allowing the disk to be firmly fixed while preventing overall deformation. The protrusions create localized contact areas that secure the disk without applying excessive force across the entire surface.
Solution Approach 2:
The protrusions on the disk-carrying surface are formed in advance during manufacturing before the disk is mounted. This preliminary formation of the surface topology ensures that when the disk is clamped, the force is automatically directed to these pre-positioned high spots, preventing deformation before it occurs. The surface is prepared beforehand to guide the clamping action.
2Manufacturing precision
If the disk-carrying surface is made smoother to reduce deformation, then the surface precision improves, but the profile peaks become less effective at supporting the disk
Solution Approach 1:
The surface is designed with a dual-character topology: overall smoothness combined with localized protrusions. The general surface is smoothed to reduce warping, while specific local areas maintain elevated protrusions that provide the necessary support points. This local quality differentiation allows the surface to be smooth enough to prevent deformation while still having adequate support peaks.
3Stability of the object's composition
If the rotor hub is made stiffer to prevent elastic deformation, then the disk-carrying surface remains flat, but the device complexity increases
Solution Approach 1:
Instead of changing the material or structural parameters of the rotor hub to increase stiffness, the solution changes the surface topology parameter of the disk-carrying surface. By creating protrusions on the surface, the system achieves the same stability effect without modifying the fundamental parameters of the rotor hub itself, thus avoiding increased device complexity.
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 effectively suppresses deformation and warping of the recording medium, enhancing the stability and precision of the disk-carrying surface, thereby reducing the risk of head crashes and enabling higher recording density and yield in HDDs.
Implementation Method 1
the profile peaks in the mean line for the primary profile of the medium-carrying surface in the radial direction have a narrower width than the profile valleys... the profile peaks undergo elastic deformation
Data Source
AI summary
The spindle motor comprises a shaft, a rotor, and a medium-carrying surface. The rotor is disposed on the outer peripheral side of the shaft, and rotates about the shaft. The medium-carrying surface is disposed on the rotor, and carries a circular-disk-form recording medium. The recording medium is pressed and fastened to the medium-carrying surface by a clamping member. The clamping member is a member that presses the recording medium against a medium-carrying surface. The average value of the widths of the profile peaks in the mean line for the primary profile of the medium-carrying surface in the radial direction is smaller than the average value of the widths of the profile valleys.