Air Foil Journal Bearing Structure for Bump Foil Alignment
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Solution Overview
Problem
Air foil journal bearings face issues with the deviation of bump foils due to vibrations when rotors are rotated at high speeds, leading to potential deformation and damage.
Innovation Solution
The design incorporates a structure with a free end bump foil that includes through holes and fixed tabs on the outer and inner top foils, which are rolled and inserted through holes in the middle top foil, preventing deviation by overlapping positions and providing elastic support to maintain alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the rotor is rotated at high speed, then the bearing supports the radial load effectively, but the bump foil deviates from the bearing housing due to vibration
Solution Approach 1:
The bump foil is designed as a thin, flexible component that can elastically deform to accommodate vibrations while maintaining its functional shape. The free end of the bump foil is formed to have elasticity, allowing it to absorb vibrational energy without permanent deformation or deviation from the bearing housing.
Solution Approach 2:
The invention adds a dimensional constraint by forming the free end of the bump foil with specific geometric features (such as folded structures or restricted movement paths) that prevent deviation in the central axis direction while allowing elastic deformation in other directions to absorb vibrations.
2Device complexity
If the free end of the bump foil is left unconstrained, then the structure remains simple and flexible, but the free end deviates from the bearing housing under vibration
Solution Approach 1:
The bump foil utilizes its inherent flexibility as a thin film structure to provide both the simplicity of an unconstrained design and the stability needed to prevent deviation. The elastic properties of the thin film allow it to respond to vibrations without requiring complex constraint mechanisms.
Solution Approach 2:
The free end of the bump foil is designed to self-regulate its position through elastic deformation. When subjected to vibrational forces, the elastic structure naturally returns to its original position, providing self-correcting stability without external constraints or complex control mechanisms.
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 effectively prevents the free end of the bump foil from deviating from the bearing housing, enhancing the stability and reducing vibration and friction, thus preventing deformation and improving dynamic stability.
Implementation Method 1
An air foil bearing is a bearing supporting a load by forming a pressure by introducing a viscous fluid or air between a rotor or a bearing disk and a foil in contact therewith
Implementation Method 2
a bump foil disposed inside the bearing housing and formed in a circumferential direction thereof, having an uneven-shaped elastic bump
Data Source
AI summary
Provided is an air foil journal bearing including a bearing housing; a bump foil disposed inside the bearing housing, having an uneven-shaped elastic bump, having one end coupled and fixed to the bearing housing in the circumferential direction, and having the other end formed as a free end; an outer top foil disposed inside the bump foil; an inner top foil disposed inside the outer top foil; and a middle top foil interposed between the outer top foil and the inner top foil, and coupled and fixed to the bearing housing, thereby preventing deviation of the free end of the bump foil in the width direction due to vibration occurring when a rotor is rotated at a high speed.