Dynamo-Electric Machine Stator with Radial Insulation Gradient
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Solution Overview
Problem
Dynamo-electric machines face challenges in reducing size and improving cooling performance, particularly in narrow vehicle spaces, where coil end height needs to be low and liquid refrigerants struggle to uniformly cool the coil due to its shape.
Innovation Solution
A stator design with segment coils surrounded by a stator core, featuring an insulating coating that increases in volume radially outward, ensuring effective cooling by allowing liquid refrigerants to flow and contact the coil surface uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If coil end height is reduced to fit narrow vehicle spaces, then the dynamo-electric machine size is reduced, but cooling performance deteriorates because liquid refrigerant cannot uniformly flow along the coil end
Solution Approach 1:
The insulating coating is designed with non-uniform thickness, being thicker at the radially outer side and thinner at the radially inner side. This local variation in coating thickness creates corresponding variations in coil end height, allowing the refrigerant to uniformly contact and cool the coil surface while maintaining compact overall dimensions.
2Reliability
If insulating coating thickness is increased to improve insulation performance, then electrical insulation is improved, but cooling performance deteriorates due to reduced heat dissipation efficiency
Solution Approach 1:
The insulating coating thickness is varied locally across different radial positions. The thicker coating at the radially outer side provides enhanced insulation where needed, while the thinner coating at the radially inner side maintains better thermal contact for heat dissipation, thus balancing both insulation and cooling requirements.
Solution Approach 2:
Instead of uniformly increasing coating thickness in one dimension, the solution transitions to a three-dimensional gradient structure where coating thickness varies radially. This dimensional approach allows simultaneous optimization of insulation (outer region) and cooling (inner region) functions.
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 achieves a reduction in size and enhances cooling performance by ensuring uniform cooling of the dynamo-electric machine, effectively managing heat and maintaining high output while being compact.
Implementation Method 1
a liquid refrigerant (RF) such as oil dropped from the upper side must uniformly and effectively cool the whole circumference of a coil
Implementation Method 2
the refrigerant (RF) falls and is less likely to flow along the coil end
Data Source
AI summary
A reduction in size and an improvement in cooling performance of a dynamo-electric machine are achieved. A stator of a dynamo-electric machine according to the present invention includes a plurality of segment coils surrounding a rotation axis, a stator core partially accommodating each of the segment coils, and an insulating coating covering at least certain portions of the segment coils protruding from the accommodating space of the stator core, in which the segment coils are arranged in a direction from the rotation axis to a radially outer side, and the volume of the insulating coating is larger on a radially outer side than on a side close to the rotation axis.