Rotary Electric Machine Coil Phase Dispersion Heat Management
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Solution Overview
Problem
In electric motors used in automotive electric power steering systems, localized heat generation is increased due to adjacent coil portions having identical phases, leading to reduced performance and torque output.
Innovation Solution
A rotary electric machine design where the number of turns or wire diameter of conducting wires in coil portions is varied to create electrical angular phase differences, ensuring that adjacent coil portions have different phases and reduced heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the number of turns or wire diameter of conducting wires in coil portions is varied to create electrical angular phase differences, then localized heat generation is suppressed and torque output is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by varying the number of turns or wire diameter of conducting wires in specific coil portions to create different electrical angular phase differences. This local differentiation ensures that adjacent coil portions have different phases, preventing heat concentration at specific locations while maintaining overall system performance.
Solution Approach 2:
The patent introduces asymmetry by deliberately creating non-uniform coil portions with different turn counts or wire diameters around the stator circumference. This asymmetric configuration breaks the symmetry that would otherwise cause identical phases in adjacent coil portions, thereby dispersing heat generation across all coil portions rather than concentrating it locally.
2Ease of manufacture
If coil portions with identical phase are adjacent in the circumferential direction, then manufacturing is simplified, but localized heat generation increases
Solution Approach 1:
The patent changes the parameters of coil portions by varying either the number of turns or the wire diameter of conducting wires in different coil portions. This parameter variation creates different electrical angular phase differences between adjacent coil portions, effectively preventing the formation of adjacent identical-phase coil portions while still allowing for systematic manufacturing approaches.
3Power
If the number of turns of conducting wire is increased to improve output, then electric current can be reduced, but localized heat generation increases due to overwound coil portions
Solution Approach 1:
The patent applies local quality by strategically varying the number of turns in different coil portions rather than uniformly increasing turns throughout. This localized differentiation allows the motor to achieve the required power output while distributing the thermal load across all coil portions, preventing any single location from becoming an overwound heat-generating hotspot.
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 effectively suppresses localized heat generation and improves torque output by dispersing heat and maintaining uniform magnetic field strength, enhancing the performance and efficiency of the electric motor.
Implementation Method 1
an armature winding that includes a plurality of coil portions that are mounted to the teeth of the stator core
Implementation Method 2
a rotor that is disposed inside the stator so as to have a magnetic air gap portion interposed, and that rotates around a rotating shaft
Implementation Method 3
coil portions that are adjacent to coil portions that have a large number of turns of conducting wire, i.e., overwound coil portions, have identical phase, and heat generation is concentrated locally
Data Source
AI summary
In the armature winding of a rotary electric machine, in a series coil portion group, the numbers of turns of conducting wire in the coil portions that have an electrical angular phase difference of θk that satisfies θ1<θkθm are different than the numbers of turns of conducting wire in the θ1 and θm coil portions, and are also different than the numbers of turns of conducting wire in the coil portions that are adjacent to the θk coil portions on two sides in a circumferential direction of the stator core, and phases of the θk coil portions are also different than phases of each of the coil portions that are adjacent to the θk coil portions on the two sides in the circumferential direction.