Disk Drive Base Plate Composite Design for Stiffness
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Solution Overview
Problem
Conventional disk drive apparatuses face challenges in reducing axial thickness to make them thinner, which leads to weakened stiffness, increased vibration and noise, and instability in disk position, affecting data reading and writing accuracy.
Innovation Solution
A base plate design featuring a motor base made of a high Young's modulus metallic material, such as stainless steel, integrated with a base body portion made of a lower Young's modulus material, like aluminum, using insert casting to reduce axial thickness while maintaining stiffness, with protruding portions to prevent motor base extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the axial thickness of the base plate is reduced to make the disk drive apparatus thinner, then the axial thickness is reduced, but the stiffness of the base plate is weakened
Solution Approach 1:
The base plate employs different materials with different Young's moduli in different regions: a first material with high Young's modulus (e.g., stainless steel) in the motor base region requiring high stiffness, and a second material with lower Young's modulus (e.g., aluminum alloy) in the base body portion. This local differentiation allows the axial thickness to be reduced overall while maintaining sufficient stiffness in the critical motor support region.
Solution Approach 2:
The base plate is constructed as a composite structure combining two different metallic materials. The motor base is made of a first metallic material with high Young's modulus, while the base body portion is made of a second metallic material with lower Young's modulus. This composite approach enables the structure to achieve both reduced thickness and adequate stiffness by placing the stiffer material only where structurally necessary.
2Length of moving object
If the axial thickness of the base plate is reduced, then the axial thickness is reduced, but vibration and noise due to motor driving are increased
Solution Approach 1:
The high-stiffness first material is specifically positioned in the motor base region where motor components are mounted, providing local vibration resistance exactly where needed to suppress motor-induced vibration and noise, while allowing the rest of the base plate to be thinner.
Solution Approach 2:
The composite structure with high Young's modulus material in the motor base region provides sufficient rigidity to dampen vibrations generated by the motor, thereby reducing both vibration and noise while still enabling overall thinning of the base plate.
3Length of moving object
If the axial thickness of the base plate is reduced, then the axial thickness is reduced, but the position of the disk becomes unstable
Solution Approach 1:
The motor base made of high Young's modulus material provides a stable, rigid foundation for the motor and disk assembly, ensuring disk position stability in the critical mounting region even when the overall base plate thickness is reduced.
Solution Approach 2:
The composite construction ensures that the disk mounting region benefits from the high stiffness of the first material, maintaining disk position stability while allowing the base plate to be thinner in non-critical areas.
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 allows for a significant reduction in axial thickness without compromising stiffness, reducing vibrations and noise, stabilizing the disk position, and minimizing errors in data reading and writing.
Implementation Method 1
A Young's modulus of the metallic material of the first type is larger than a Young's modulus of the metallic material of the second type
Implementation Method 2
The base body portion is preferably a casting product in which the motor base is provided as an insert component
Data Source
AI summary
A base plate of a disk drive apparatus includes a motor base disposed around a central axis and a base body portion extending radially outward of the motor base. The motor base is made of a metallic material of a first type. The base body portion is made of a metallic material of a second type. The base body portion is a casting product in which the motor base is an insert component. An upper protruding portion and a lower protruding portion are defined in one of an outer end portion of a bottom plate portion of the motor base and an inner end portion of the base body portion.