Disk Drive Pivot Post Structure to Prevent Dropout and Gas Leakage
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Solution Overview
Problem
The existing disk driving devices suffer from poor fluidity during casting of the pivot post, leading to shrinkage cavities and gas leakage, and the pivot post is prone to dropping due to upward forces when screwed to the cover.
Innovation Solution
The pivot post is designed as a separate member from the base plate, with an annular portion protruding radially and a tubular portion overlapping to cancel out upward and downward forces, and optionally reinforced with adhesives and grooves for secure fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pivot post is formed as a separate member to avoid shrinkage cavities and gas leakage, then gas tightness is improved, but the pivot post may drop from the base plate due to upward forces when the screw is tightened
Solution Approach 1:
The pivot post is divided into functionally distinct segments: an annular portion for secure attachment to the base plate and a main body portion for structural support. This segmentation allows the annular portion to provide attachment stability while the main body maintains gas tightness, resolving the contradiction between these two requirements.
Solution Approach 2:
The annular portion acts as an intermediary element between the pivot post and the base plate. It provides a dedicated attachment interface that mediates the connection, ensuring both gas tightness and attachment stability without requiring the entire pivot post structure to be optimized for both functions simultaneously.
2Stability of the object's composition
If the pivot post is formed integrally with the base plate, then attachment stability is improved, but shrinkage cavities form during casting causing gas leakage
Solution Approach 1:
The pivot post is separated from the base plate as a distinct component rather than being cast integrally. This segmentation eliminates the shrinkage cavity problem that occurs during integral casting while maintaining attachment stability through the specialized annular portion designed for secure mounting.
Solution Approach 2:
The pivot post is extracted from the base plate structure as a separate component. This extraction eliminates the casting defects (shrinkage cavities) inherent in integral formation while the annular portion provides the necessary attachment functionality, thereby resolving the contradiction between attachment stability and gas tightness.
3Length of stationary object
If the tubular portion is shortened to reduce device height, then compactness is improved, but the force balance between upward and downward forces is compromised
Solution Approach 1:
The solution moves the attachment mechanism from relying on vertical force balance through the tubular portion to relying on radial engagement through the annular portion. This dimensional shift allows for shorter tubular portion length while maintaining attachment stability through the ring-shaped structure that engages with the base plate.
Solution Approach 2:
The pivot post is segmented into the annular portion for attachment and the tubular portion for structural support. This segmentation allows the tubular portion to be optimized for minimum necessary length (improving compactness) while the annular portion independently provides attachment stability, resolving the contradiction between device height and attachment stability.
Data Source
AI summary
A disk driving device includes a disk, a motor, an arm, a head, and a housing. The disk rotates about a rotation shaft. The motor causing the disk to rotate. The arm swings about a swinging shaft. The head is disposed at a tip of the arm for reading or writing information. The housing accommodates the disk, the motor, the arm, and the head, and includes a cast base plate with a bottom wall and an open top, and a cover. A separate pivot post protrudes from the bottom wall, and a tubular portion accommodates the pivot post, with the arm attached via a bearing. A screw inserted through the cover attaches to the pivot post's top end. The pivot post includes an annular portion. The tubular portion's top end contacts the cover, and its bottom end rests on the annular portion.