Fluid Dynamic Bearing Fixation via Segmented Press-Fit and Adhesive
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Solution Overview
Problem
Fluid dynamic bearing devices face challenges in achieving stable fixation strength between the bearing sleeve and housing, particularly with increased weight from multiple disks, leading to potential adhesive flow issues and compromised bearing performance.
Innovation Solution
Incorporating a press-fitting part and an adhesive-filled part between the housing and bearing sleeve, with the adhesive-filled part formed on the opening side of the press-fitting part, allowing for controlled adhesive interposition and enhanced fixation strength without compromising bearing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If press-fit bonding is used to increase fixation strength between bearing sleeve and housing, then fixation strength is improved, but adhesive flows around during press-fitting causing deterioration in bearing performance
Solution Approach 1:
The bonding area is segmented into two distinct parts: a press-fitting part for mechanical fixation and an adhesive-filled part for chemical bonding. This segmentation prevents adhesive from flowing into the press-fitting area during assembly while ensuring both fixation methods work effectively in their designated zones.
Solution Approach 2:
Different bonding mechanisms are applied to different locations: press-fitting is applied in the press-fitting part for mechanical interlocking, while adhesive is applied in the adhesive-filled part for chemical bonding. This local differentiation optimizes the function of each area and prevents adverse interactions between the two bonding methods.
2Quantity of substance
If multiple disks are layered to increase capacity, then storage capacity is improved, but weight increases requiring higher fixation strength
Solution Approach 1:
Two bonding mechanisms (press-fitting and adhesive bonding) are merged to work together in the same assembly. The press-fitting provides immediate mechanical fixation while the adhesive provides additional chemical bonding strength, creating a combined fixation system capable of withstanding the increased loads from multiple layered disks.
Solution Approach 2:
The fixation system uses a composite approach combining mechanical (press-fit) and chemical (adhesive) bonding methods. This composite fixation strategy provides superior strength compared to either method alone, enabling the bearing sleeve to securely hold the housing even when supporting the increased weight from multiple layered disks.
3Ease of manufacture
If adhesive is applied before press-fitting to achieve bonding, then bonding is simplified, but adhesive flows forward during press-fitting reducing the amount available for bonding
Solution Approach 1:
The bonding area is divided into a press-fitting part where no adhesive is applied and an adhesive-filled part where adhesive is applied. This segmentation prevents adhesive from flowing forward during press-fitting while ensuring sufficient adhesive remains in the designated area for effective bonding.
Solution Approach 2:
The adhesive-filled part is prepared in advance with the appropriate amount of adhesive before the press-fitting operation. This preliminary preparation ensures that the adhesive is already in position and will not be displaced during the subsequent press-fitting process, maintaining both the simplicity and effectiveness of the bonding operation.
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 configuration increases the fixation strength between the bearing sleeve and housing, ensuring stable bearing performance while preventing adhesive flow and maintaining smooth lubricant circulation, thus addressing the limitations of traditional press-fit bonding.
Implementation Method 1
a press-fitting part at which the housing and the bearing sleeve are fixed by press-fitting
Implementation Method 2
the bearing sleeve is press-fitted to the inner periphery of the housing
Implementation Method 3
an adhesive-filled part formed on an opening side with respect to the press-fitting part
Implementation Method 4
a fluid film of a lubricating fluid which is formed in radial bearing gaps between an outer peripheral surface of the shaft member and an inner peripheral surface of the bearing sleeve
Data Source
AI summary
Fixation strength of a bearing sleeve with respect to a housing is increased so that stable bearing performance can be achieved. A fluid dynamic bearing device (1) includes a housing (7) and a bearing sleeve (8) fixed to an inner periphery of the housing (7). The housing (7) and the bearing sleeve (8) have therebetween a press-fitting part (10) at which the housing (7) and the bearing sleeve (8) are fixed by press-fitting, and an adhesive-filled part (11) formed on an opening side with respect to the press-fitting part (10).