Rotary Machine Coil Groove Geometry for Low-Resistance Cooling
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Solution Overview
Problem
Existing rotary electric machine coils face challenges in maintaining surface strength while minimizing cooling liquid flow resistance, as forming cooling liquid flow grooves can degrade the surface and increase resistance.
Innovation Solution
The rotary electric machine coil is designed with a rectangular wire cross-section and cooling liquid flow grooves having a recess shape with specific dimensions (b/a ≤ T1 and ((b−a)R+ax)/2 ≥ T2) to prevent surface degradation and reduce flow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cooling liquid flow groove having a recess shape is formed on the side surface of the coil insertion portion, then the cooling liquid flow path is reliably ensured, but the surface strength of the coil may be degraded and the flow resistance of the cooling liquid may be increased
Solution Approach 1:
The invention applies parameter changes by precisely controlling the geometric parameters of the cooling liquid flow groove (depth, width, shape) to optimize both cooling performance and surface strength. By adjusting the groove dimensions within specific ranges, the design achieves reliable cooling flow paths while minimizing surface degradation and maintaining structural integrity.
2Reliability
If a cooling liquid flow groove having a recess shape is formed on the side surface of the coil insertion portion, then the cooling liquid flow path is reliably ensured, but the flow resistance of the cooling liquid may be increased
Solution Approach 1:
The invention optimizes the groove parameters (depth, width, cross-sectional shape) to reduce flow resistance while ensuring reliable cooling. By carefully selecting the groove dimensions and adopting an arc-shaped cross-section, the design minimizes turbulence and pressure loss, thereby reducing energy consumption for cooling liquid circulation.
Solution Approach 2:
The invention applies curvature by using an arc-shaped cross-section for the cooling liquid flow groove instead of sharp corners. This curved geometry reduces flow separation and turbulence, thereby lowering flow resistance and energy loss while maintaining effective cooling liquid flow paths.
3Ease of operation
If the groove having a recess shape is processed on the side surface of the coil insertion portion, then cooling liquid flow is enabled, but the surface strength of the coil may be degraded
Solution Approach 1:
The invention controls the groove parameters (depth, width, shape) within optimized ranges to enable cooling liquid flow while minimizing surface strength degradation. The arc-shaped cross-section and controlled dimensions ensure that the groove provides adequate flow capability without excessive material removal that would compromise structural integrity.
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 maintains surface strength and reduces cooling liquid flow resistance, ensuring efficient cooling with minimal power loss.
Implementation Method 1
the cooling liquid that is introduced from a first end side in the axis direction of the stator core flows into the cooling liquid flow groove of the insertion portion of the coil, and the cooling liquid flows out to a second end side in the axis direction. At this time, the coil is efficiently cooled by the cooling liquid that flows through the cooling liquid flow groove.
Data Source
AI summary
In a rotary electric machine coil, a cooling liquid flow groove is formed on one side surface. In a recess shape cross section of the cooling liquid flow groove, values a, b, x, R are set such that the following conditions (1), (2) are satisfied.b/a≤T1 (1)((b−a)R+ax)/2≥T2 (2)a: a length of a virtual string that connects opening ends of a recess shape having the recess shape cross section to each other by a straight lineb: a length of an arc along an inner surface of the recess shapex: a depth from the virtual string of the recess shape to the deepest portion of the arcR: a radius of the arcT1: a first predetermined valueT2: a second predetermined value