Rotor Pole Layout for Shorter Axial Permanent Magnet Machines
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Solution Overview
Problem
The configuration of rotating electrical machines with increased magnet pole length in the axial direction for torque output results in an increased axial length of the rotor, which is inefficient.
Innovation Solution
A rotating electrical machine design featuring a rotor with alternately disposed magnet and dummy poles in both axial and circumferential directions, non-magnetic holes between adjacent poles, and specific length relationships to reduce the axial length while maintaining torque output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If windings are inserted into slots of a laminated core, then electrical connection is established, but slot openings remain exposed creating entry points for moisture and contaminants
Solution Approach 1:
The slot opening protection element is merged with the winding structure itself, where the insulation layer extends to form a protective barrier that integrates both electrical insulation and environmental protection functions into a single component, eliminating the need for separate protection elements
Solution Approach 2:
The insulation layer of the winding serves multiple functions simultaneously: it provides electrical insulation between conductors, protects against moisture and contaminants entering the slot, and maintains mechanical stability, thereby giving a single component multiple protective roles
2Ease of manufacture
If conventional winding insertion methods are used, then windings can be installed, but manufacturing precision deteriorates due to deformation and misalignment
Solution Approach 1:
The insulation layer is pre-formed with extended portions that protrude beyond the winding ends before insertion occurs. This preliminary preparation ensures that when the winding is inserted into the slot, the protection elements are already in position to guide and support the winding, preventing deformation and misalignment during the insertion process
Solution Approach 2:
The extended insulation layer acts as an intermediary element between the winding and the slot structure. It provides a buffer zone that facilitates smooth insertion while maintaining precise positioning, reducing direct mechanical stress on the conductors and preventing misalignment during the manufacturing process
3Ease of manufacture
If slot openings are left open for winding insertion, then manufacturing is simplified, but electrical insulation and protection are compromised
Solution Approach 1:
The insulation function and protection function are merged into the same extended insulation layer structure. This single component simultaneously provides electrical insulation and protects against environmental factors, eliminating the need for separate insulation and protection elements while maintaining manufacturing simplicity
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 design achieves a reduced axial length of the rotor while enhancing torque output and minimizing torque pulsations, with improved magnetic flux distribution and resistance.
Implementation Method 1
the windings are impregnated with resin in a known manner with the result that no grooves and voids remain in the windings
Implementation Method 2
a rotating electrical machine comprises a stator (110) and a rotor (120)
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
A rotating electrical machine includes a stator and a rotor, the rotor includes a rotor core and a plurality of magnetic poles, the plurality of magnetic poles includes a plurality of magnet poles formed by permanent magnets, and a plurality of dummy poles, the magnet poles and the dummy poles are alternately disposed in both an axial direction and a circumferential direction, non-magnetic holes are provided between the magnet poles and the dummy poles that are adjacent in the axial direction, and when a length of each magnet pole in the axial direction is tm, a length of each dummy pole in the axial direction is tc, a length of each non-magnetic hole in the axial direction is ta, and a length of the rotor core in the axial direction is 1c, the rotating electrical machine satisfies tm > tc and lc < (2 × tm) + ta.