Rotary Spindle Disk Clamp Bottom Land Shaft Top Land Contact
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Solution Overview
Problem
Existing disk drive spindle designs face issues with press-fit interfaces and bonds between the disk mounting hub and rotating shaft, which are prone to plastic deformation, mechanical shock-induced slippage, and oil leakage, especially under extreme temperatures, and are costly to manufacture.
Innovation Solution
A disk drive spindle design featuring a rotatable shaft with an annular shaft top land and a disk mounting hub with a radially stepped cylindrical hub-to-shaft interface, where the disk clamp is fastened to the shaft rather than the hub, and includes circumferential grooves with adhesive sealing material to enhance bond strength and reduce plastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a press-fit interface is used to attach the disk mounting hub to the rotating shaft, then the assembly can be manufactured efficiently, but the interface is prone to plastic deformation and mechanical shock-induced slippage
Solution Approach 1:
The patent combines the press-fit mechanical attachment with adhesive bonding by integrating adhesive sealing material into the hub structure. The adhesive is positioned in grooves or recesses at the interface between the hub and shaft, creating a composite attachment system that leverages both mechanical interference and chemical bonding to achieve superior reliability under mechanical shock while maintaining manufacturing efficiency.
Solution Approach 2:
The invention uses composite attachment mechanisms where metallic press-fit surfaces are combined with adhesive sealing material. This composite approach creates a multi-mode attachment system that exploits both the mechanical strength of the press-fit interface and the bonding strength of the adhesive, resulting in enhanced overall bond strength that resists both static loads and dynamic mechanical shocks.
2Strength
If the disk clamp is fastened to the disk mounting hub, then the clamping force is distributed across the hub, but mechanical shocks can overcome the press-fit and bond causing slippage and oil leakage
Solution Approach 1:
The adhesive sealing material acts as a beforehand cushioning element that is pre-positioned at the hub-shaft interface. This adhesive layer provides continuous bonding that compensates for the limitations of press-fit alone, creating a more resilient connection that absorbs mechanical shock energy and prevents slippage before it can occur, thereby eliminating oil leakage pathways.
Solution Approach 2:
The adhesive sealing material serves as an intermediary substance between the hub and shaft surfaces. This intermediate layer enhances the interaction between the two components by providing additional bonding surface and flexibility, allowing the connection to accommodate mechanical shocks without failing, thus preventing both slippage and oil leakage.
3Reliability
If adhesive sealing material is added to enhance bond strength, then the connection resists mechanical shocks better, but the manufacturing complexity increases
Solution Approach 1:
The adhesive sealing material is applied locally at specific positions within grooves or recesses at the hub-shaft interface, rather than requiring complete surface coating. This localized approach provides sufficient bonding strength at critical stress points while minimizing the overall complexity of the manufacturing process and allowing for straightforward assembly operations.
Solution Approach 2:
The adhesive sealing material is pre-positioned in the hub structure before final assembly, or is designed to be automatically distributed during the press-fit assembly process. This preliminary preparation ensures proper adhesive placement without requiring complex additional manufacturing steps, thereby enhancing bond strength while maintaining manufacturing simplicity.
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 design improves robustness against mechanical shocks, reduces the risk of oil leakage, and maintains bond strength across the operating and non-operating temperature range while minimizing plastic deformation and manufacturing costs.
Implementation Method 1
The disk mounting hub may have an inner cylindrical bore that faces and is in radial compression with an outer cylindrical surface of the rotatable shaft at a cylindrical hub-to-shaft interface. The disk clamp may have a clamp bottom land that faces and is in contact with a shaft top land.
Data Source
AI summary
A rotary spindle has a rotatable shaft that defines a shaft axis of rotation, and has a shaft top land that is normal to the shaft axis of rotation. A disk mounting hub has an outer disk mounting surface, and has an inner cylindrical bore with an inner cylindrical surface that faces and is in radial compression with an outer cylindrical surface of the shaft at a cylindrical hub-to-shaft interface. The cylindrical hub-to-shaft interface is substantially concentric about the shaft axis of rotation. A disk clamp is fastened to the rotatable shaft, and the disk clamp has a clamp bottom land that faces and is in contact with the shaft top land.