Magnetic Bearing Circuit Ring Grooves for Uniform End-Field Flux
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Solution Overview
Problem
The magnetic field near the axial end surface of a permanent magnet ring in magnetic bearing devices is not uniform along the circumferential direction, leading to decreased rotation efficiency and heat generation due to magnetic friction.
Innovation Solution
A magnetic circuit device with a permanent magnet ring formed by arraying anisotropic permanent magnets in a circumferential direction, accompanied by first and second soft magnetic material rings that contact the outer and inner surfaces of the permanent magnet ring respectively, and featuring grooves in the axial direction on at least one of the soft magnetic material rings to enhance magnetic field uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a permanent magnet ring is used in a magnetic bearing device, then magnetic suspension force is generated, but the magnetic field near the axial end surface is not uniform along the circumferential direction, leading to decreased rotation efficiency
Solution Approach 1:
The invention introduces grooves at specific locations (axial end surfaces) of the permanent magnet ring to create local magnetic pole portions. This local modification addresses the non-uniform magnetic field problem at the axial end surfaces without changing the overall magnet structure, thereby improving rotation efficiency while maintaining the magnetic suspension force.
Solution Approach 2:
The permanent magnet ring is segmented by introducing grooves that divide the magnet structure into distinct regions. These grooves create separate magnetic pole portions at the axial end surfaces, which helps to uniformize the magnetic field distribution along the circumferential direction and reduce magnetic friction.
2Reliability
If a permanent magnet ring is used in a magnetic bearing device, then magnetic suspension force is generated, but magnetic friction increases due to non-uniform magnetic field, leading to heat generation
Solution Approach 1:
By adding grooves at the axial end surfaces, the invention creates local magnetic pole portions that uniformize the magnetic field in the problematic regions. This reduces magnetic friction and heat generation at the axial ends while preserving the overall magnetic suspension force generated by the permanent magnet ring.
3Manufacturing precision
If grooves are formed on soft magnetic material rings, then circumferential uniformity of magnetic field is enhanced, but device complexity increases
Solution Approach 1:
Instead of modifying the entire soft magnetic material rings, the invention introduces grooves only at specific locations (axial end surfaces) where magnetic field non-uniformity occurs. This localized approach enhances magnetic field uniformity while minimizing the increase in device complexity.
Solution Approach 2:
The grooves segment the soft magnetic material rings at critical locations, creating distinct magnetic pole portions. This segmentation approach achieves magnetic field uniformity with minimal structural modification, avoiding the need for complex overall redesign.
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 the circumferential uniformity of the magnetic field near the axial end surface of the permanent magnet ring, reducing magnetic friction and maintaining high rotation efficiency while allowing for both increased magnetic field strength and uniformity.
Implementation Method 1
Each of the plurality of anisotropic permanent magnets is magnetized parallel to a straight line that passes through a center of the anisotropic permanent magnet and that extends in a radial direction. The entirety of the outer circumferential surface of the permanent magnet ring has homopolarity, and the entirety of the inner circumferential surface of the permanent magnet ring has homopolarity and has reverse polarity of the outer circumferential surface of the permanent magnet ring.
Implementation Method 2
a first soft magnetic material ring that contacts an outer circumferential surface of the permanent magnet ring; and a second soft magnetic material ring that contacts an inner circumferential surface of the permanent magnet ring. Grooves in an axial direction are formed on at least one of the first soft magnetic material ring and the second soft magnetic material ring.
Implementation Method 3
The solution enhances the circumferential uniformity of the magnetic field near the axial end surface of the permanent magnet ring, reducing magnetic friction and maintaining high rotation efficiency while allowing for both increased magnetic field strength and uniformity.
Data Source
AI summary
In a magnetic circuit device for a magnetic bearing that includes a permanent magnet ring constituted by a plurality of permanent magnets and a soft magnetic material ring, the circumferential uniformity of the magnetic field near an axial end surface of the permanent magnet ring is enhanced. A magnetic circuit device for a magnetic bearing includes: a permanent magnet ring that is formed by disposing a plurality of anisotropic permanent magnets in a circumferential direction; a first soft magnetic material ring that contacts an outer circumferential surface of the permanent magnet ring; and a second soft magnetic material ring that contacts an inner circumferential surface of the permanent magnet ring. Each of the plurality of anisotropic permanent magnets is magnetized parallel to a straight line that passes through a center of the anisotropic permanent magnet and that extends in a radial direction. The entirety of the outer circumferential surface of the permanent magnet ring has homopolarity, and the entirety of the inner circumferential surface of the permanent magnet ring has homopolarity and has a reverse polarity of the outer circumferential surface of the permanent magnet ring. Grooves in an axial direction are formed on at least one of the first soft magnetic material ring and the second soft magnetic material ring.