Disk Drive Base Unit Helium Sealing via Adhesive Gap Control
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Solution Overview
Problem
In disk drive apparatuses, the use of low-density gases like helium to reduce disk rotation resistance and power consumption is hindered by inadequate sealing due to thermal expansion differences between the feedthrough flange and base, leading to potential solder joint cracks and gas leaks.
Innovation Solution
A base unit design that uses an adhesive with a filler, such as an anaerobic adhesive, to secure the connector to the base member, featuring a recessed loop-shaped surface and collar portions to create a gap structure that enhances sealing by minimizing helium leakage through capillary action and surface roughness to prevent adhesive escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder is used to join the feedthrough flange to the base, then electrical connection is achieved, but thermal expansion differences cause solder joint cracks and sealing failure
Solution Approach 1:
The patent introduces an adhesive as an intermediary material between the feedthrough flange and the base. This adhesive layer accommodates thermal expansion differences between the flange and base, preventing stress concentration and crack formation in solder joints while maintaining both electrical connection and sealing reliability.
Solution Approach 2:
The patent employs a composite joining approach combining solder and adhesive materials. The solder provides electrical conductivity and mechanical bonding, while the adhesive compensates for thermal expansion mismatches and enhances sealing. This composite material strategy resolves the contradiction between joint strength and sealing reliability under thermal cycling conditions.
2Reliability
If adhesive is used to join the connector to the base member, then sealing against helium leakage is improved, but the connector positioning precision may be affected
Solution Approach 1:
The patent implements preliminary mechanical positioning features (protrusions fitting into recesses, flange engagement with the base member) before applying the adhesive. This preliminary action establishes precise connector positioning, and the adhesive subsequently seals the gaps without compromising the pre-established positional accuracy.
Solution Approach 2:
The patent applies adhesive selectively in specific locations and gaps where sealing is critical, rather than uniformly across the entire connector-base interface. This localized adhesive application maintains positioning precision in critical areas while providing sealing where needed, resolving the contradiction between sealing effectiveness and positioning accuracy.
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
The adhesive-based sealing effectively reduces helium leakage below tolerance thresholds, maintaining a secure seal and preventing adhesive escape, thus ensuring reliable operation and reduced motor power consumption.
Implementation Method 1
A minimum value of a gap distance in a radial direction between an outer end of the connector and an inner end of the recessed portion in which the outer end of the connector and the inner end of the recessed portion are opposed to each other with the adhesive therebetween is greater than a minimum value of a gap in a vertical direction distance between an upper surface of the connector and the recessed portion loop-shaped surface, in which the upper surface of the connector and the recessed portion loop-shaped surface are opposed to each other with the adhesive therebetween
Data Source
AI summary
A base member includes a recessed portion extending in radial directions and recessed upward from a lower surface of the base member, and a hole extending through the recessed portion in the vertical direction. The recessed portion includes a recessed portion loop-shaped surface defining a loop-shaped surface in the radial direction. A connector is located on a lower side of the recessed portion to cover the hole portion. An adhesive is located between the connector and the recessed portion. A minimum value of a gap distance in the radial direction between an outer end of the connector and an inner end of the recessed portion in which the outer end of the connector and the inner end of the recessed portion are opposed to each other with the adhesive therebetween is greater than a minimum value of a gap in the vertical direction distance between an upper surface of the connector and the recessed portion loop-shaped surface, in which the upper surface of the connector and the recessed portion loop-shaped surface are opposed to each other with the adhesive therebetween. The adhesive includes a filler.