Disk Device Ramp Positioning via Tapered Screw Contact
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Solution Overview
Problem
In disk devices like hard disk drives, the ramp load mechanism can be displaced from its predetermined position due to gaps between the screw shaft and the inner surface of the through hole in the ramp, leading to potential collisions with magnetic disks and instability in the unload positions of the magnetic head and suspension.
Innovation Solution
The use of a screw with a tapered lower surface that contacts the attachment tab of the ramp load mechanism, holding it between the support surface and the tapered contact surface, restricts movement in multiple directions and prevents displacement, ensuring the ramp load mechanism remains accurately positioned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a screw is used to attach the ramp to the housing, then the ramp can be securely fixed, but gaps between the screw shaft and the through hole may cause displacement of the ramp
Solution Approach 1:
A positioning protrusion is introduced as an intermediary element between the ramp and housing. This protrusion fits into a corresponding positioning groove to prevent lateral displacement of the ramp, while the screw provides the primary attachment strength. The intermediary positioning structure resolves the contradiction by addressing positioning precision separately from attachment strength.
Solution Approach 2:
The attachment function is segmented into two independent components: a positioning protrusion that handles lateral positioning precision, and a screw that provides attachment strength. This segmentation allows each component to optimize its specific function without compromising the other, resolving the contradiction between strength and positioning precision.
2Device complexity
If the ramp is held by the screw alone, then the structure is simple, but the ramp may collide with magnetic disks due to displacement
Solution Approach 1:
The positioning protrusion is designed to preliminarily establish the correct position of the ramp relative to the housing before the screw is fully tightened. This preliminary positioning action prevents potential collisions with magnetic disks by ensuring the ramp is correctly aligned, while adding minimal complexity to the overall structure.
Solution Approach 2:
The positioning protrusion acts as an intermediary safety mechanism that prevents harmful collisions between the ramp and magnetic disks. This simple geometric feature provides reliable operational safety without requiring complex control systems or additional active components.
3Ease of manufacture
If the through hole has a larger diameter than the screw shaft, then assembly is easier, but the ramp becomes unstable in the unload position
Solution Approach 1:
The through hole functionality is segmented into two parts: a larger diameter portion that facilitates easy screw assembly, and a smaller diameter positioning portion that provides lateral constraint. This segmentation allows the hole to serve both assembly ease and stability functions simultaneously, resolving the contradiction between these two requirements.
Solution Approach 2:
The positioning protrusion introduces local quality variation to the otherwise simple through-hole structure. The protrusion creates a localized constraint region that provides lateral positioning precision without affecting the overall ease of assembly, as the protrusion can be easily formed during manufacturing.
Data Source
AI summary
In general, according to one embodiment, a disk device includes a magnetic disk, a magnetic head, a suspension, a ramp, a housing, and a screw. The suspension holds the magnetic head and moves to an unload position. The ramp includes an attachment tab with a through hole. The ramp holds the suspension at the unload position. The housing has a support surface with a screw hole to support the attachment tab. The screw includes a screw head, a screw shaft, and a first contact surface. The screw shaft extends from the screw head in a first direction and is fitted into the screw hole through the through hole. The first contact surface is located on the screw head, tapers in the first direction, and contacts the attachment tab. The screw holds the attachment tab in-between the support surface and the first contact surface.