Mixed-Conductor Stator Coil for Electric Motor Weight Reduction
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Solution Overview
Problem
Existing electric motors using aluminum conductors for stator coils face reduced conductivity and output performance compared to copper conductors, necessitating thicker conductors and larger motor sizes to achieve equivalent performance, which increases weight and size.
Innovation Solution
The electric motor design incorporates a stator coil with both a first conductor made of aluminum and a second conductor made of copper, with the copper conductor placed in slots and the aluminum conductor outside, allowing for equivalent performance without increasing slot size, thereby reducing weight and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If aluminum material is used for the conductor to reduce weight, then the weight of the stator coil is reduced, but the conductivity decreases and the resistance value increases
Solution Approach 1:
The stator coil uses a composite conductor structure with both aluminum conductors (for weight reduction) and copper conductors (for high conductivity). The copper conductors are positioned in the slots where magnetic flux density is highest, while aluminum conductors are positioned elsewhere, creating a composite material system that balances both weight and conductivity requirements
2Power
If the conductor is thickened to compensate for lower aluminum conductivity, then the output performance is maintained, but the slot size must be enlarged and the motor size increases
Solution Approach 1:
The conductor configuration applies local quality by placing copper conductors specifically in slots with high magnetic flux density (where they contribute most to output performance) and aluminum conductors in other slots. This localized material distribution maintains output performance without requiring uniform thickening of all conductors, thus avoiding motor size increase
3Reliability
If copper material is used for the conductor to maintain high conductivity, then the output performance is maintained, but the weight of the stator coil increases
Solution Approach 1:
Copper conductors are selectively positioned only in slots where high conductivity is most critical (high magnetic flux density regions), while aluminum conductors are used in other slots. This local quality approach maintains necessary conductivity levels while minimizing copper usage and overall weight compared to using copper throughout
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 configuration maintains output performance equivalent to copper-only conductors while reducing the motor's weight and size, and minimizes the use of copper, thus lowering costs.
Implementation Method 1
a stator coil inserted into each slot and wound around the stator core... the second conductor is disposed in the slots
Data Source
AI summary
An electric motor includes: a rotary shaft member rotating about an axis; a rotor including a rotor core and a magnet, the rotor core being provided on the rotary shaft member, the magnet being provided on the rotor core; and a stator including a stator core and a stator coil, the stator core having a plurality of slots formed in a circumferential direction, the stator core being disposed at an interval in a radial direction that is a direction orthogonal to an axial direction of the rotary shaft member with respect to the rotor core, the stator coil being inserted into the plurality of slots and wound around the stator core. Further, the stator coil includes a first conductor and a second conductor having a conductivity greater than a conductivity of the first conductor, and the second conductor is disposed in the slots.