HDD Base Insert Structure for Rigidity and Hermetic Sealing
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Solution Overview
Problem
The challenge lies in increasing the number of disks in a hard disk drive (HDD) while maintaining a standard form factor, operational shock and vibration tolerance, and ensuring a robust hermetically-sealed enclosure, particularly when using thinner enclosure base plates that are difficult to cast with high stiffness materials like steel.
Innovation Solution
Incorporating base inserts made of higher Young's modulus materials, such as steel, into the HDD enclosure base plate, coupled via friction stir welding and sealed with a thin film material, to enhance rigidity and reduce windage loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thinner enclosure base plates are used to fit more disks in standard form factor, then storage capacity increases, but rigidity and structural strength deteriorate
Solution Approach 1:
The patent employs a composite structure consisting of a thinner base plate made of a first material (e.g., aluminum alloy) combined with base inserts made of a second material (e.g., steel) having higher Young's modulus. This composite construction allows the overall base assembly to achieve the required rigidity and strength while maintaining the thinner profile necessary for increased disk capacity in standard form factor drives.
2Strength
If high stiffness materials like steel are used for the base plate, then rigidity improves, but manufacturing difficulty increases due to casting challenges
Solution Approach 1:
The base structure is segmented into two distinct components: a base plate made of easily cast material (such as aluminum alloy) and separate base inserts made of high-stiffness material (such as steel). This segmentation allows each component to be manufactured using appropriate processes - the base plate can be easily cast, while the inserts can be precision-formed or machined - and then joined together through friction stir welding, thereby resolving the manufacturing difficulty associated with casting high-stiffness materials.
3Strength
If base inserts are added to enhance rigidity, then structural strength improves, but device complexity increases
Solution Approach 1:
The base inserts are integrated with the base plate through friction stir welding, creating a unified and reinforced base structure. This merging process combines the advantages of both materials - the ease of manufacture and light weight of the base plate material with the high rigidity and strength of the insert material - while forming a structurally cohesive assembly that reduces overall complexity compared to alternative reinforcement approaches.
4Strength
If friction stir welding is used to couple base inserts, then joint strength improves, but manufacturing process complexity increases
Solution Approach 1:
The patent replaces traditional mechanical joining methods (such as riveting, bolting, or adhesive bonding) with friction stir welding, which is a solid-state welding process that creates metallurgical bonds. This substitution provides superior joint strength and integrity while, despite the advanced process requirement, offers a streamlined manufacturing approach by eliminating the need for multiple fasteners, holes, or adhesive curing steps, thereby reducing overall assembly complexity.
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 approach allows for more disks in a standard form factor HDD by enhancing rigidity and maintaining a hermetic seal, reducing operational shock and vibration effects, and minimizing power consumption due to reduced windage.
Implementation Method 1
coupled via friction stir welding
Implementation Method 2
sealed with a thin film material
Data Source
AI summary
A hard disk drive enclosure base includes a main base composed of a first material and having at least one bottom opening therethrough, a base insert composed of a second material having a higher Young's modulus than the first material and inserted into a corresponding opening of the main base, and a friction stir weld (FSW) coupling the base insert to the main base. The base may further include a thin film sealing material between a base insert flange and the main base, which is heated by way of the FSW process and further hermetically seals the interface between the base insert and the main base. Such a base insert may be used to support with additional stiffness the spindle motor assembly and/or the actuator assembly, and provides for increasing the number of disks while maintaining sufficient rigidity in a standard form factor drive while maintaining a hermetically-sealed enclosure.