Magnetic Disk Device Spacer Optimization
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Solution Overview
Problem
Hard disk drives face a dilemma in increasing capacity while maintaining impact resistance and fluttering resistance, as thinning magnetic disks to accommodate more disks compromises their rigidity and resistance.
Innovation Solution
A 3.5-inch hard disk drive design with magnetic disks of specific thickness and number, and spacers of defined outer diameter and thickness, optimized for aluminum or glass substrates, to balance capacity, impact resistance, and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of each magnetic disk is thinned to increase the number of magnetic disks, then the data space per hard disk drive is increased, but the rigidity of the magnetic disk decreases and the impact resistance and fluttering resistance deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness of magnetic disks to specific ranges (0.3-0.6mm for aluminum alloy, 0.3-0.49mm for glass) and defining precise relationships between spacer outer diameter, magnetic disk thickness, and number of magnetic disks through mathematical formulas. This resolves the contradiction by finding optimal parameter values that simultaneously achieve high capacity and maintain sufficient rigidity.
Solution Approach 2:
The patent employs composite material strategies by specifying different substrate materials (aluminum alloy or glass) with their respective optimal thickness ranges and pairing them with spacers made of materials like aluminum, stainless steel, or glass. The composite structure of magnetic disks combined with spacers creates a system where the spacer provides additional structural support, allowing thinner disks while maintaining overall rigidity.
2Quantity of substance
If the thickness of each magnetic disk is thinned to increase the number of magnetic disks, then the data space per hard disk drive is increased, but the impact resistance and fluttering resistance deteriorate
Solution Approach 1:
The patent resolves the impact resistance issue through parameter changes by establishing specific thickness ranges and mathematical relationships between key dimensions. The formulas define precise boundaries that ensure impact resistance is maintained while maximizing capacity, transforming the reliability concern into a controlled parameter optimization problem.
Solution Approach 2:
The spacer acts as an intermediary element that mediates between the thin magnetic disks. By positioning spacers at specific locations and dimensions according to the defined formulas, the spacer provides structural support and protection against impact, allowing the use of thinner disks without compromising reliability.
3Quantity of substance
If the thickness of each magnetic disk is thinned to increase the number of magnetic disks, then the data space per hard disk drive is increased, but the fluttering resistance deteriorates
Solution Approach 1:
The patent addresses fluttering resistance through parameter changes by defining specific thickness ranges and mathematical relationships that control the mechanical properties of the magnetic disk stack. The optimized parameters ensure that even with thinner individual disks, the overall structure maintains sufficient fluttering resistance for reliable operation.
Solution Approach 2:
The composite structure of multiple thin magnetic disks separated by spacers creates a system where the combined structure achieves adequate fluttering resistance. The spacers act as structural elements that prevent excessive flexing of individual thin disks during rotation, maintaining reliability despite reduced individual disk thickness.
4Strength
If spacers with larger outer diameter are used to maintain rigidity, then the impact resistance and fluttering resistance are improved, but the data space in the hard disk drive is reduced
Solution Approach 1:
The patent resolves this contradiction through parameter changes by defining precise mathematical relationships between spacer outer diameter, magnetic disk thickness, and number of magnetic disks. The formulas optimize the spacer dimensions to provide sufficient rigidity while minimizing the impact on data space, finding the optimal balance point.
Solution Approach 2:
The patent applies local quality by positioning spacers at specific radial locations and defining their dimensions locally according to the mathematical relationships. The spacer outer diameter is optimized locally to provide rigidity exactly where needed, rather than uniformly increasing all dimensions, thus preserving maximum data space.
Data Source
AI summary
This magnetic disk device is a 3.5-inch magnetic disk device equipped with magnetic disks formed from an aluminum alloy substrate. The magnetic disks arranged in a stacked manner have a thickness Td of 0.3 mm to 0.6 mm, the number N of magnetic disks involved is 10 to 16, and spacers disposed between the magnetic disks have an outside diameter 2 Rso of 35 mm to 65 mm. The outside diameter 2 Rso (mm) of the spacers satisfies 2 Rso≥−60 Td+70 and 2 Rso≤−0.5 N2−+16.5 N−73.