Hydrodynamic Bearing Adhesive Inflow Space Design
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Solution Overview
Problem
Hydrodynamic bearing devices in spindle motors face issues with air bubbles and fluid leakage due to uneven pressure and adhesive flow, leading to reduced bearing performance and instability during rotation.
Innovation Solution
A hydrodynamic bearing device with a circular communication path and adhesive inflow allowing space, where the adhesive is set between the cover and sleeve to prevent leakage and blockage, allowing the working fluid to circulate and exhaust air bubbles, while the adhesive inflow space ensures reliable bonding without obstructing the communication path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If communication paths are formed in the sleeve to equalize pressure, then pressure difference is resolved and bearing function is stabilized, but air bubbles enter the working fluid and attach to dynamic pressure generating grooves, reducing bearing performance
Solution Approach 1:
The invention extracts and removes air bubbles from the working fluid through dedicated air bubble discharge paths. These paths are formed separately from the communication paths that equalize pressure, allowing air bubbles to be discharged to the outside without interfering with the bearing function. The air bubble discharge paths communicate with the dynamic pressure generating grooves, enabling direct removal of air bubbles that would otherwise attach to these grooves and reduce bearing performance.
Solution Approach 2:
The invention segments the fluid pathways into distinct functional channels: communication paths for pressure equalization and air bubble discharge paths for air removal. This segmentation allows each path to perform its specific function independently, preventing air bubbles from entering through the communication paths while maintaining pressure balance. The dynamic pressure generating grooves are also segmented to include both fluid intake and air bubble discharge functions.
2Reliability
If adhesive is applied to bond the cover and sleeve, then sealing is improved and working fluid leakage is prevented, but adhesive may flow into the circular communication path and block it, reducing productivity
Solution Approach 1:
The invention applies adhesive only in specific localized areas (adhesive application grooves) rather than across the entire bonding surface. These grooves are positioned at locations that do not interfere with the circular communication path, ensuring that adhesive remains confined to designated areas. This local quality approach maintains effective sealing at the cover-sleeve interface while preventing adhesive from blocking the communication path, thus avoiding assembly rework and maintaining productivity.
Solution Approach 2:
The adhesive application grooves serve as intermediaries that contain and guide the adhesive material. These grooves act as barriers that prevent adhesive from spreading into the circular communication path while still allowing adequate adhesive to be applied for reliable bonding. The grooves mediate between the need for strong sealing and the need to keep the communication path clear, resolving the contradiction between these two requirements.
3Manufacturing precision
If the gap between shaft and sleeve is reduced to improve rotating precision, then bearing performance is enhanced, but air bubbles more easily enter and attach to dynamic pressure generating grooves, causing instability
Solution Approach 1:
The invention extracts air bubbles from the narrow gap between the shaft and sleeve through air bubble discharge paths that are integrated into the dynamic pressure generating grooves. Even though the gap is small and would normally prevent easy air bubble removal, the dedicated discharge paths provide a direct route for air bubbles to escape to the outside. This extraction mechanism allows the gap to be reduced for improved rotating precision without the penalty of air bubble accumulation.
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 solution enhances bearing performance by preventing air bubbles from affecting the dynamic pressure generating grooves, maintaining fluid circulation, and ensuring long-term reliability by preventing adhesive leakage and blockage, thus stabilizing rotation and extending the operating life of the bearing.
Implementation Method 1
the shaft and the sleeve are supported in a freely rotating manner through a predetermined gap in a radial direction by the pressure of the working fluid collected by the dynamic pressure generating groove
Implementation Method 2
the shaft and the sleeve are supported in a freely rotating manner through a predetermined gap in a thrust direction by the pressure of the working fluid collected by the dynamic pressure generating grooves
Implementation Method 3
a step of bonding the cover and the sleeve with an adhesive, and a step of filling the working fluid into the bearing
Implementation Method 4
a hydrodynamic bearing device that exhausts air bubbles mixed into or produced in the bearing with a circulating function of the working fluid
Data Source
AI summary
The invention provides a hydrodynamic bearing device with a function of circulating the operating fluid by supplying the operating fluid to between the cover and the sleeve by way of a circular communication path, the hydrodynamic bearing device allowing the cover for covering the sleeve to be satisfactorily bonded, preventing the operating fluid from leaking outward, and preventing the adhesive from blocking the opening of the circular communication path; and a spindle motor. An adhesive inflow allowing space for allowing the adhesive from the adhesive setting and bonding part to flow in is formed between the adhesive setting and bonding part for setting the adhesive and bonding the cover and the sleeve, and a space region on the open end side between the cover and the sleeve for circulating and introducing the operating fluid so as to create a space in the cover.