Tapered Pole Piece Stator for Flux Concentration
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Solution Overview
Problem
Existing stator assemblies for electric motors have bulky end turns that increase axial dimensions, limiting packaging space in applications like hybrid vehicles, and struggle to efficiently concentrate magnetic flux for optimal motor efficiency.
Innovation Solution
A stator assembly with a toroidal core of soft magnetic composite material and spirally-wound electrical windings, where the core has a tapered hexagonal shape and pole pieces that taper radially outward and axially inward to concentrate flux, eliminating end turns and enhancing flux distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If bulky end turns are used to create sinusoidal-type flux pattern, then flux distribution is improved, but axial dimensions increase
Solution Approach 1:
The patent extracts and eliminates the end turns from the stator winding configuration. By using a toroidal core with spirally-wound windings that lie substantially entirely within a radial plane, the design removes the axial extensions (end turns) that traditionally extended beyond the stator assembly, thereby reducing axial dimensions while maintaining flux generation capability through the toroidal geometry
Solution Approach 2:
The patent employs a toroidal (doughnut-shaped) core geometry where the windings are spirally wound around the outer surface of the toroidal core. This curved, continuous toroidal path allows magnetic flux to be generated and distributed effectively without requiring axial end turns, as the flux follows the curved toroidal path naturally
2Ease of manufacture
If pole pieces are designed with uniform thickness, then manufacturing is simplified, but flux concentration at rotor interface is reduced
Solution Approach 1:
The patent applies local quality by varying the thickness of the pole pieces along their radial length. The pole pieces are thicker at the outer radius and taper to a thinner section at the inner radius where they interface with the rotor. This non-uniform thickness distribution concentrates magnetic flux at the rotor interface, improving flux density and motor efficiency while remaining manufacturable
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 design reduces the axial dimensions of the stator assembly, improves flux concentration, and enhances motor efficiency by eliminating end turns, making it suitable for compact applications while maintaining effective flux distribution.
Implementation Method 1
The pole pieces are configured to taper both radially outward and axially inward to thereby concentrate flux from the core to an inner surface of the pole pieces facing the rotor
Implementation Method 2
The stator assembly has a plurality of electrical windings, each wound in a respective spiral around the outer surface of the core and arranged for current to flow in the windings
Data Source
AI summary
A stator assembly for an electric motor includes an annular core centered about an axis of rotation of an inner rotor which the stator assembly surrounds. The stator assembly has a plurality of electrical windings, each wound in a respective spiral around the outer surface of the core and arranged for current to flow in the windings. In some embodiments, the respective spirals are spaced from and parallel with one another. The stator assembly may have pole pieces that substantially enclose the core and windings. The pole pieces may be configured to taper both radially outward and axially inward to thereby concentrate flux from the core to an inner surface of the pole pieces facing the rotor.