Active Magnetic Bearing Thermal Stress Buffering
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Solution Overview
Problem
Existing magnetic bearings lack a structure to buffer stress caused by differences in thermal expansion coefficients and temperatures between the bearing housing and the jacket, leading to potential damage or leakage.
Innovation Solution
An active magnetic bearing design that includes a stress buffering member, such as a bellows, connected to the jacket and bearing housing to mitigate thermal stress, along with a jacket that serves as a seal and may have a lubricant flow path for additional support, and an electronic control unit for position detection and electromagnet control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a jacket is used to seal the space between the bearing stator and bearing housing, then sealing performance is improved, but the jacket is subjected to strong stress due to thermal expansion differences between the bearing housing and jacket
Solution Approach 1:
The patent introduces a bellows structure as a flexible component connected to the jacket. The bellows can expand and contract axially to accommodate thermal expansion differences between the bearing housing and jacket, thereby reducing stress on the jacket while maintaining sealing performance. This directly applies the principle of using flexible structures to handle thermal stress.
Solution Approach 2:
The bellows acts as an intermediary component between the rigid bearing housing and the jacket. It mediates the thermal expansion mismatch by providing a flexible connection that can absorb dimensional changes, protecting the jacket from excessive stress while preserving the sealing function.
2Reliability
If the jacket is made rigid to maintain sealing integrity, then sealing reliability is improved, but the jacket cannot buffer thermal stress and may crack or leak
Solution Approach 1:
The bellows introduces flexibility into the sealing system. While the jacket itself remains relatively rigid for sealing, the bellows connection allows the system to accommodate thermal stress through elastic deformation, preventing cracks and leaks that would occur in a completely rigid structure.
Solution Approach 2:
The bellows structure provides beforehand cushioning by being pre-designed to accommodate expected thermal expansion ranges. This preventive measure ensures that thermal stress is absorbed within design limits, preventing damage before it occurs.
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 stress buffering member effectively reduces stress on the jacket, enhancing its sealing integrity and preventing damage from thermal expansion differences, while the jacket's additional functions provide supplementary support for rotor rotation.
Implementation Method 1
a magnetic bearing includes an electromagnet for generating a magnetic force
Implementation Method 2
a stress buffering member connected to opposite ends of the jacket and the bearing housing, to buffer a stress generated due to differences between thermal exposition coefficients and temperatures of the bearing housing and the jacket
Data Source
AI summary
An active magnetic bearing includes a bearing housing, a bearing stator, a bearing armature, a position detector, a jacket, and a stress buffering member. The bearing stator is accommodated in the bearing housing to support rotation of a rotor by using a magnetic force. The bearing armature is disposed to be spaced apart from the bearing stator by an interval and fixed to the rotor. The position detector is installed in the bearing housing to detect a position of the rotor. The jacket is interposed between the bearing stator and the bearing armature to seal a space between the bearing stator and the bearing housing. The stress buffering member connected to opposite ends of the jacket and the bearing housing, to buffer a stress generated due to differences between thermal exposition coefficients and temperatures of the bearing housing and the jacket.