Disk Drive Bottom-Wall Wiring Layout for Helium Sealing
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Solution Overview
Problem
Existing disk drives face challenges in maintaining airtight sealing of low-density gases like helium while accommodating an increased number of magnetic disks and maintaining a sufficient gap between the hub and the bottom wall to prevent contact during high-speed rotation, which complicates the casting process and limits storage capacity.
Innovation Solution
A disk device design featuring a recess in the bottom wall with a step and through holes for wiring connections, where the wiring board is attached on the outer surface, and an adhesive seals the connections, allowing for a reduced height and increased disk loading without compromising airtightness and casting quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the housing is constructed with high casting quality to maintain airtight sealing, then sealing reliability is improved, but the thickness requirement (at least 1 mm) limits the ability to increase disk loading and expand intervals between disks
Solution Approach 1:
The wiring board is moved from the inner surface to the outer surface of the bottom wall, utilizing the external space dimension. This relocation allows the internal space to be fully utilized for disk stacking, increasing the number of disks that can be loaded without compromising the bottom wall thickness required for casting quality and sealing reliability.
Solution Approach 2:
The housing structure is segmented into distinct functional zones: the bottom wall maintains its thickness for sealing integrity, while the wiring board is separated and positioned on the outer surface. This segmentation allows each component to fulfill its function independently without interfering with the other constraints.
2Reliability
If a predetermined gap is provided between the hub flange and bottom wall to prevent contact during high-speed rotation, then operational reliability is improved, but the available space for disk loading is reduced
Solution Approach 1:
By relocating the wiring board to the outer surface of the bottom wall, the internal vertical space is maximized. This allows the gap between the hub flange and bottom wall to be optimized for operational reliability while still accommodating the maximum number of disks within the available vertical envelope.
3Quantity of substance
If more magnetic disks are loaded in the housing to increase storage capacity, then storage capacity is improved, but the casting quality and airtight sealing may be compromised
Solution Approach 1:
The wiring board is relocated to the outer surface of the bottom wall, freeing up internal space that can be used to increase the number of disks. This dimensional reorganization allows storage capacity to be increased without reducing the bottom wall thickness, thereby maintaining casting quality and airtight sealing.
4Reliability
If the bottom wall thickness is increased to ensure casting quality and sealing, then sealing reliability is improved, but the overall device height increases
Solution Approach 1:
The wiring board is positioned on the outer surface of the bottom wall, utilizing the external dimension rather than increasing the internal height. This allows the bottom wall to maintain sufficient thickness for sealing reliability without increasing the overall device height, as the wiring board occupies external space rather than internal volume.
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
Enables the loading of more magnetic disks while maintaining airtight sealing and adhering to height specifications, enhancing storage capacity and durability.
Implementation Method 1
an adhesive is filled into the recess and the through holes, covering the one end and a solder joint, and sealing the through holes
Data Source
AI summary
According to one embodiment, a disk device includes a housing with a bottom wall, magnetic disks supported on a hub of a motor, a printed circuit board provided on an outer surface of the bottom wall, and a wiring board attached on the outer surface of the bottom wall. The bottom wall includes a recess formed in the outer surface, a step located on border between the outer surface and the recess, and through holes opened to the recess. The wiring board includes one end portion disposed in the recess and connection pads on the one end portion, connected to lead wires of a coil. An adhesive is filled into the recess and the through holes, and covers the one end and a solder joint and seals the through holes.