Curved Wedge-Pole Shoe Rotor for Higher Winding Space
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Solution Overview
Problem
The challenge lies in designing a rotor for a salient-pole motor that accommodates more windings while maintaining sufficient strength and effective winding space, as higher power density requirements necessitate smaller yet stronger wedges and pole shoes.
Innovation Solution
The rotor design incorporates wedges and pole shoes that fit through curved portions, relieving stress concentration and increasing the effective winding space, thereby enhancing the strength and power density of the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the wedge and pole shoe are made smaller to increase effective winding space, then the power density increases, but the strength and structural integrity deteriorate
Solution Approach 1:
The patent applies curvature to the inner circumferential surface of the wedge and the outer circumferential surface of the pole shoe, creating curved portions that fit together. This curved interface distributes stress more evenly compared to a straight interface, relieving stress concentration at the joint portions while maintaining smaller overall dimensions for the wedge and pole shoe, thus increasing effective winding space while preserving structural strength
Solution Approach 2:
The curved portions are specifically located at the joint portions between the wedge and pole shoe where stress concentration occurs. By modifying only this local region with curved surfaces rather than changing the entire structure, the patent achieves stress relief and strength enhancement precisely where needed, allowing the rest of the wedge and pole shoe to remain compact for maximizing winding space
2Power
If more windings are accommodated in the rotor, then the torque density and power density increase, but the space for windings becomes more constrained
Solution Approach 1:
The curved portions at the wedge-pole shoe interface create more efficient use of the slot space. The curved geometry allows for better packing arrangement of windings within the slot compared to straight interfaces, effectively increasing the usable winding space without expanding the overall rotor dimensions, thereby enabling higher torque density
3Area of stationary object
If the wedge and pole shoe are made smaller, then the effective winding space increases, but the stress concentration at joint portions increases
Solution Approach 1:
By introducing curved portions at the interface between the wedge and pole shoe, the patent eliminates sharp corners and straight edges that would cause stress concentration. The curved geometry distributes mechanical stresses more uniformly across the joint area, relieving stress concentration even when the overall size of the wedge and pole shoe is reduced to maximize winding space
Data Source
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AI summary
Embodiments of this application provide a rotor, a motor, a powertrain, and a vehicle. The rotor includes wedges and pole shoes. The wedges fit the pole shoes through curved portions. The curved portions can effectively relieve stress concentration of joint portions, increase strength of the wedges and the pole shoes, and effectively increase effective winding space of slots in the rotor. In this way, power density of a motor in which the rotor is used is increased.