Composite Magnetic Bearing With Nested Auxiliary Bearing
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Solution Overview
Problem
The existing magnetic bearing systems require additional auxiliary bearings to support the rotor during stationary conditions and potential faults, which increase the length and volume of the rotor, limiting the operation speed due to increased bending occurrence and reduced critical speed.
Innovation Solution
A composite magnetic bearing system is designed with an auxiliary bearing integrated within the magnetic bearing, utilizing a homopolar type magnetic bearing and a rolling type auxiliary bearing, such as a ball bearing, to minimize rotor length and system volume by positioning the auxiliary bearing inside the stator cores and using a magnetic bearing housing to surround the magnetic bearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auxiliary bearings are provided separately from magnetic bearings to support the rotor during stationary conditions and faults, then the rotor support reliability is improved, but the rotor length and system volume increase
Solution Approach 1:
The patent combines the magnetic bearing and auxiliary bearing into a single integrated structure. The auxiliary bearing is positioned inside the magnetic bearing assembly, allowing both bearing types to coexist in one compact unit rather than requiring separate mounting spaces, thus maintaining reliability while reducing rotor length
Solution Approach 2:
The auxiliary bearing is nested within the magnetic bearing structure. Specifically, the auxiliary bearing is installed in the magnetic bearing housing, utilizing the existing space within the magnetic bearing assembly. This nesting approach allows the auxiliary bearing to be housed without increasing the overall rotor length or system volume
2Reliability
If auxiliary bearings are provided separately from magnetic bearings, then the rotor support reliability is improved, but the system volume increases
Solution Approach 1:
The magnetic bearing and auxiliary bearing are merged into a single integrated assembly. The auxiliary bearing is housed within the magnetic bearing housing, eliminating the need for separate mounting spaces and reducing overall system volume while maintaining dual bearing functionality for improved reliability
Solution Approach 2:
The magnetic bearing housing serves multiple functions: it houses the magnetic bearing components and simultaneously accommodates the auxiliary bearing. This multi-functional design allows the same structural space to support both bearing types, reducing the total system volume required
3Reliability
If the rotor length is increased to accommodate separate auxiliary bearings, then the rotor support reliability is improved, but the critical speed decreases due to increased bending occurrence
Solution Approach 1:
By merging the auxiliary bearing into the magnetic bearing assembly, the rotor length is kept short. This compact configuration reduces rotor bending and maintains higher critical speed while still providing the reliability benefits of dual bearing support during stationary conditions and faults
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 reduces the rotor length, minimizing system volume and enhancing the critical speed, allowing for a broader operation speed range while ensuring stable rotor support during system stops or malfunctions.
Implementation Method 1
a plurality of permanent magnets respectively provided to outermost sides of the stator cores, and a plurality of coils provided to the stator cores to surround the permanent magnets
Implementation Method 2
make the shaft to be buoyant by magnetic levitation
Implementation Method 3
an auxiliary bearing which has direct contact with the shaft is provided in addition to the magnetic bearing
Data Source
AI summary
The present invention relates to a composite magnetic bearing having an auxiliary bearing coupled thereto, which has an improved structure for minimizing a length of a rotor and a system volume. The composite magnetic bearing of a radial type provided around a rotor having an auxiliary bearing coupled thereto for reducing friction, includes a magnetic bearing, and an auxiliary bearing fixed in the empty space in an inside of the stator cores on an inner side of a position the coils and the permanent magnets are provided thereto.