Segmented Rotor Yokes for Axial Flux Motor Eddy Current Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing axial magnetic flux motors face efficiency losses due to eddy currents and high production costs associated with laminating silicon steel sheets for the yoke, which is not feasible for common radial motors.
Innovation Solution
A rotor design featuring a nonmagnetic rotary frame with radially extending ribs and annular ribs supporting yokes with magnets arranged to minimize magnetic flux loops, reducing eddy current losses and production costs by using a nonmagnetic material and optimizing magnetic permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a disk-shaped yoke made of low-carbon steel is used to guide magnetic flux circuits, then the motor structure is simple, but eddy current losses increase reducing motor efficiency
Solution Approach 1:
The patent divides the disk-shaped yoke into multiple separate yoke pieces arranged radially around the rotating shaft. Each yoke piece is independently positioned and contributes to the magnetic flux circuit. This segmentation breaks the continuous conductive path that causes eddy currents in a solid disk yoke, thereby reducing eddy current losses while maintaining the structural simplicity and magnetic flux guiding function.
2Loss of energy
If laminated silicon steel sheets are used to define the yoke to reduce eddy current losses, then motor efficiency improves, but production complexity and cost increase
Solution Approach 1:
The patent uses separate yoke pieces made of low-carbon steel that can be individually manufactured and assembled, replacing the need for complex lamination processes. These discrete pieces are simpler to produce and assemble than laminated structures, achieving comparable or sufficient performance for the application while significantly reducing manufacturing complexity and cost.
3Loss of energy
If multiple separate yokes are arranged in the nonmagnetic rotary frame, then eddy current losses are reduced, but the device structure becomes more complex
Solution Approach 1:
The nonmagnetic rotary frame serves multiple functions: it provides the structural framework for mounting the separate yoke pieces, acts as a nonmagnetic support that does not interfere with magnetic flux paths, and provides mechanical connection to the rotating shaft. This multi-functionality consolidates several roles into a single component, offsetting the added complexity of having multiple yoke pieces.
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 enhances motor efficiency by reducing magnetic flux leakage and eddy current losses, while simplifying production and reducing material costs through effective use of magnetic materials.
Implementation Method 1
a disk-shaped yoke made of one low-carbon steel, and having a plurality of magnets attached to the disk-shaped yoke. The disk-shaped yoke is arranged to guide magnetic flux circuits as a magnetic permeable assembly
Implementation Method 2
A known technique of defining a yoke of an axial magnetic flux motor by laminated silicon steel sheets has been proposed to solve such a problem
Data Source
AI summary
A motor includes a rotor including a rotating shaft, a nonmagnetic rotary frame, yokes arranged separately in the nonmagnetic rotary frame, and magnets arranged on surfaces of the yokes at least on one side of the yokes. To hold the yokes and the magnets, the nonmagnetic rotary frame includes a first annular rib that extends along a circumferential direction on a radially outer side of the rotating shaft, radially extending ribs that extend from a radially outer side of the first annular rib along radial directions, and a second annular rib joined to the radially extending ribs and concentric with the first annular rib.