HDD Sidewall Protrusion for Airtight Seal and Castability
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Solution Overview
Problem
Hard disk drives (HDDs) with thin sidewalls face challenges in forming airtight seals due to dimensional restrictions, which affect the thickness and surface contact area with sealing members, leading to compromised airtightness and castability.
Innovation Solution
The HDD design incorporates protruding portions on the sidewalls and notches on the top cover to increase the contact area with the gasket, enhancing airtightness by compressing the gasket between the sidewall and top cover, and includes a damper to reinforce the top cover and improve mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the sidewall is made thinner to reduce overall dimensions, then the HDD size is reduced, but the airtightness deteriorates due to insufficient gasket contact area
Solution Approach 1:
The invention adds a protruding portion that extends in the radial direction from the sidewall, transforming a one-dimensional thin wall into a three-dimensional structure with increased surface area. This protruding portion creates additional contact area with the gasket without increasing the overall height of the HDD, effectively solving the contradiction between compact size and airtight sealing.
Solution Approach 2:
The gasket is pre-compressed between the protruding portion of the sidewall and the top cover during assembly. This preliminary compression action ensures that the gasket is already under sufficient pressure to maintain airtightness before the HDD is fully assembled and operated, compensating for the thin sidewall design.
2Quantity of substance
If the sidewall is made thinner to reduce material usage, then manufacturing cost is reduced, but castability deteriorates due to difficulty in forming thin high sidewalls
Solution Approach 1:
The sidewall is segmented into two functional parts: the main thin sidewall structure that minimizes material usage, and the protruding portion that provides adequate gasket contact area. This segmentation allows the thin wall to be cast efficiently while the added protruding portion is formed through a separate, more controllable process that ensures proper geometry for sealing.
Solution Approach 2:
The sidewall employs local quality by having different thicknesses in different regions: the main body remains thin to reduce material usage, while the protruding portion has increased thickness to provide sufficient contact area with the gasket. This localized thickening is applied only where needed for sealing, not throughout the entire sidewall structure.
3Reliability
If the gasket contact area is increased to improve airtightness, then sealing reliability is improved, but the top cover deformation increases under compression
Solution Approach 1:
The protruding portion acts as an intermediary structure between the thin sidewall and the top cover. It distributes the compression force from the top cover over a larger area and provides a more gradual transition zone, reducing stress concentration that would otherwise cause top cover deformation while still ensuring adequate gasket compression for sealing reliability.
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 configuration increases the thickness of the sidewall, improves castability, and enhances the airtightness of the casing by increasing the gasket contact area and mechanical strength, ensuring a robust seal and reduced deformation during compression.
Implementation Method 1
enhancing airtightness by compressing the gasket between the sidewall and top cover
Data Source
AI summary
A disk apparatus includes a base including a bottom wall and a sidewall disposed along a peripheral portion of the bottom wall, a cover including a ceiling plate and a side plate disposed along a periphery of the ceiling plate, the ceiling plate being fixed to the sidewall and the side plate facing an outer surface of the sidewall, and a rotatable recording medium disposed between the cover and the bottom wall. The sidewall of the base includes a first portion adjacent to the recording medium and a protruding portion that protrudes from the first portion outward and away from the recording medium, and at least a portion of a sidewall of the protruding portion faces an opening formed in the side plate.