Multi-Layer Casting Coil Structure for Higher Motor Slot Fill
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Solution Overview
Problem
Conventional motor technologies face limitations in increasing the slot filling factor, which restricts the efficiency and output of motors due to space constraints in vehicles, with existing coil designs resulting in low slot filling factors and increased interference between windings.
Innovation Solution
A casting coil with a multi-layer structure made of aluminum, featuring coils bent at 90 degrees and wider than thick, is press-fitted into slots to maximize the slot filling factor, eliminating the need for winding and reducing production costs and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional circular or quadrangular coils are used in motor slots, then the motor structure is simple and easy to manufacture, but the slot filling factor is limited to 25-50% which restricts motor output and efficiency
Solution Approach 1:
The casting coil is segmented into multiple layers with each layer containing multiple coils arranged in specific patterns. Each coil within a layer has substantially the same width, and adjacent coils are spaced apart by a predetermined distance. This segmentation allows efficient space utilization in the motor slot while maintaining manufacturability through standardized coil dimensions and arrangements.
Solution Approach 2:
Multiple coils are nested within layers, and multiple layers are stacked within the motor slot to achieve high slot filling factors. The nested arrangement of coils in layers enables the casting coil structure to maximize space utilization while maintaining ease of manufacture through repetitive modular patterns.
2Power
If more coils are wound in the same space to increase slot filling factor, then motor output and efficiency increase, but interference between windings increases and manufacturing becomes more difficult
Solution Approach 1:
The traditional mechanical winding process is replaced with a casting process. The casting coil is formed by casting conductive material into a pre-designed mold that defines the multi-layer coil structure, eliminating the need for manual or automated winding operations. This substitution dramatically simplifies manufacturing while enabling high slot filling factors through precise control of coil geometry and arrangement during the casting process.
3Temperature
If copper coils are used to maintain thermal performance, then efficiency is maintained, but weight and production cost increase
Solution Approach 1:
The material parameter is changed from copper to aluminum for the casting coil. Aluminum has lower density than copper, significantly reducing coil weight. The casting process enables optimized coil geometry and arrangement that compensates for aluminum's lower conductivity, maintaining acceptable thermal performance while achieving weight reduction and cost savings.
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 solution achieves a slot filling factor of 70% or more, significantly improving motor efficiency and reducing production costs and weight, while maintaining equivalent thermal performance and efficiency compared to copper coils.
Implementation Method 1
a great deal of current flows through the package in the same space and thus an electromagnetic force is increased, a torque can be increased
Data Source
AI summary
A casting coil for a motor assembly, which is formed in a multi-layer structure, includes: a first coil formed to extend in one direction; a second coil bent to extend from an end of the first coil; a third coil bent to extend from an end of the second coil in a direction parallel to the first coil; and a fourth coil bent to extend from an end of the third coil in a direction parallel to the second coil. The first coil, the second coil, the third coil, and the fourth coil form one layer so that a hollow multi-layer structure is formed. A larger magnetic field can be formed by securing a slot filling factor of 50% or more of a stator in the same motor package.