Rotary Electric Machine Stator Coil Cooling Guide
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Solution Overview
Problem
Rotary electric machines face challenges in maintaining effective cooling due to the design of stator coils with multiple conductor segments, which creates wide spaces between turn portions, leading to reduced coolant guidance and deteriorated cooling capability.
Innovation Solution
The implementation of a coolant guide with holes that directs coolant along the stator coil's circumferential direction, utilizing interfacial tension to ensure sufficient contact with the coil ends, and a coolant recovery member to efficiently cool the stator coil by recovering and redistributing the coolant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a stator coil is constructed with multiple conductor segments to facilitate manufacturing, then the ease of manufacture is improved, but the cooling capability deteriorates due to wide spaces between turn portions allowing coolant to drop
Solution Approach 1:
A coolant guide member is introduced as an intermediary component between the coolant supply system and the stator coil. This member has a coolant guide portion that directs coolant along the outer circumferential surface and holes that allow coolant to reach the coil, preventing coolant drop through the spaces between conductor segments while maintaining the multi-segment construction for ease of manufacture
Solution Approach 2:
The coolant guide member extends in the axial direction beyond the coil end, creating a new spatial dimension for coolant distribution. By positioning the guide member to protrude axially and forming holes at specific locations, the system guides coolant in multiple directions (along the outer surface and through holes to the coil) rather than allowing uncontrolled vertical drop, thus improving cooling effectiveness without changing the conductor segment structure
2Reliability
If grooves are formed in the outer circumferential surface of coil ends to guide coolant, then the cooling capability is improved, but the manufacturing complexity increases
Solution Approach 1:
The coolant guide member is divided into functionally distinct portions: a coolant guide portion with grooves for directing coolant along the outer circumferential surface, and holes for delivering coolant to the coil. This segmentation of cooling functions into separate structural elements allows each portion to be optimized independently while maintaining overall simplicity compared to integrating all cooling features directly into the coil structure
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 enhances the cooling capability of rotary electric machines by ensuring consistent coolant contact with the stator coil, even with multiple conductor segments, thereby maintaining high cooling efficiency across the coil's circumference.
Implementation Method 1
guiding, through the plurality of holes, a part of the coolant as a first coolant to the end portion of the stator coil
Data Source
AI summary
In a rotary electric machine, a stator coil includes in-slot portions each contained in a corresponding one of slots of a stator core. The stator coil includes turn portions each connecting one end of a corresponding one of the in-slot portions projecting from one axial end of the stator core with one end of a corresponding alternative one of the in-slot portions projecting the one axial end of the stator core. The turn portions provide an end portion of the stator coil. A coolant guide is placed to cover a circumferential outer part of the end portion of the stator coil from radially outside thereof and provided with holes therethrough. The coolant guide guides a coolant therealong in a circumferential direction of the end portion of the stator coil while guiding, through the holes, a part of the coolant to the end portion of the stator coil.