Rotating Electrical Machine Stator Cooling via Bridge Portion Gaps
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Solution Overview
Problem
Conventional rotating electrical machines with concentrated windings face heat dissipation issues due to the lack of gaps in coil winding, limiting output increase despite efforts to improve space factor.
Innovation Solution
A rotating electrical machine design featuring a stator with insulated and coated coils placed between tooth portions, where bridge portions form coil ends coaxially and are located outward of the stator's inner peripheral surface, creating a gap for improved cooling efficiency, along with a production method that includes winding, shaping, temporary mounting, and inserting coils to ensure efficient cooling paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the coil is wound without gaps to improve space factor, then the coil space factor increases, but the heat dissipation deteriorates
Solution Approach 1:
The stator core is divided into an inner core and an outer core that are separated by a gap. The coil is positioned in this gap region, with bridge portions extending outward from the inner core. This segmentation allows the coil to be spatially separated from the main body of the stator core, creating channels for coolant flow while maintaining high coil density in the active regions.
Solution Approach 2:
The coil bridge portions are arranged in the radial direction (outward from the inner core) rather than only in the axial direction. This radial arrangement creates three-dimensional cooling channels that allow coolant to flow through the gap between the inner and outer cores, providing effective heat dissipation without compromising the coil space factor in the active regions.
2Quantity of substance
If the coil is wound without gaps to improve space factor, then the coil space factor increases, but the output cannot be increased
Solution Approach 1:
The stator core is divided into an inner core and an outer core that are separated by a gap. The coil is positioned in this gap region, with bridge portions extending outward from the inner core. This segmentation allows the coil to be spatially separated from the main body of the stator core, creating channels for coolant flow while maintaining high coil density in the active regions.
Solution Approach 2:
The gap between the inner and outer cores, which could be considered wasted space, is converted into a beneficial cooling channel. Coolant flows through this gap region, efficiently removing heat from the coil bridge portions and enabling sustained high-power operation without compromising the compact design.
3Temperature
If bridge portions are located outward of the stator to create cooling gaps, then cooling efficiency improves, but coil interference may increase
Solution Approach 1:
The coil bridge portions are asymmetrically arranged, extending outward from the inner core into the gap region rather than being symmetrically positioned. This asymmetric arrangement, combined with the specific positioning of bridge portions at different radial distances, allows coolant flow paths to be optimized while minimizing magnetic interference between adjacent coils.
Solution Approach 2:
The bridge portions are pre-positioned in the gap region during the winding process, with their radial and axial positions carefully determined in advance. This preliminary positioning ensures that the cooling gaps are established before assembly, preventing coil interference while maintaining optimal cooling efficiency.
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
Enhances coil cooling efficiency by creating a flow path for refrigerants while minimizing coil interference, enabling a small-sized, high-output, and high-efficiency rotating electrical machine.
Implementation Method 1
a gap is present between an end surface of the stator core in the axial direction and each bridge portion
Implementation Method 2
it is possible to ensure a flow path for passing refrigerant such as air or cooling oil to improve coil cooling efficiency
Data Source
AI summary
Bridge portions forming coil end portions, at both ends in an axial direction, of a stator of the rotating electrical machine according to the present invention are configured coaxially about an axis of the stator; at least one bridge portion of the bridge portions of each coil at both ends in the axial direction is located outward of an inner peripheral surface of the stator; and a gap is present between an end surface of a stator core in the axial direction and each bridge portion.