Rotary Electric Machine Radial Coil Ends
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Solution Overview
Problem
Conventional rotary electric machines face challenges in downsizing due to large coil ends and reduced cooling efficiency caused by narrow coolant flow channels, which increase winding resistance and reduce efficiency.
Innovation Solution
The rotary electric machine features an armature with slots formed at a ratio of n per phase per pole, using n types of winding bodies wound in a helical shape with linked rectilinear portions and radially displaced coil ends, creating wider coolant flow channels and increased heat radiating areas to improve cooling performance and reduce dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If hexagonal coils are shaped by bending at vertex portions into crank shapes, then the coils can be inserted into slots, but the coil ends become larger and the length of conductor wires increases
Solution Approach 1:
Instead of bending the coil ends into crank shapes at vertex portions, the patent inverts the approach by forming the coil ends into straight or slightly curved shapes that extend radially outward from the slot openings. This inversion eliminates the need for complex bending while maintaining ease of insertion and reducing coil end dimensions.
Solution Approach 2:
The patent changes the geometric parameters of the coil ends by controlling the bending radius and curvature to be minimal or zero, transforming the traditional crank-shaped coil ends into compact radial extensions. This parameter change reduces the overall coil end dimensions while preserving the winding structure.
2Ease of manufacture
If hexagonal coils are shaped by bending at vertex portions into crank shapes, then the coils can be inserted into slots, but the length of conductor wires increases, increasing winding resistance
Solution Approach 1:
The patent inverts the traditional coil end configuration by eliminating the crank-shaped bending and adopting straight radial extensions. This inversion shortens the conductor wire length required for coil end formation, thereby reducing winding resistance and energy losses while maintaining manufacturing ease.
Solution Approach 2:
The patent converts the previously harmful effect of long conductor wires into a benefit by redesigning the coil end geometry. The straight radial configuration not only reduces wire length but also improves the arrangement of multiple coils in slots, transforming a source of energy loss into an efficient structure.
3Reliability
If columns of vertex portions of coil ends are arranged circumferentially at a pitch of one slot, then coolant flow channels are formed, but the flow channel width is narrow, reducing heat radiating area
Solution Approach 1:
The patent segments the coil end configuration by arranging multiple straight coil ends radially outward from different slots, creating multiple discrete coolant flow channels. This segmentation increases the total heat radiating area while maintaining adequate flow channel widths, as each coil end acts as an independent thermal management element.
Solution Approach 2:
The patent transitions from the traditional circumferential arrangement of coil ends to a radial arrangement that extends outward from the slot openings. This dimensional change creates additional space for coolant flow channels and increases the exposed heat radiating area, improving both cooling performance and thermal management.
Data Source
AI summary
The armature winding is configured by mounting into slot pairs n types of winding bodies that are each configured by winding a conductor wire for m turns into a helical shape, where m is a natural number that is greater than or equal to two, the n types of winding bodies have different spacings between rectilinear portions that are linked by coil ends, are housed in n adjacent pairs of slot pairs, and are configured so as to be concentric, the coil ends include a top portion at an approximately central portion, and the radial displacement at the top portion is approximately a×d, where a is a natural number that is greater than or equal to 1 and less than or equal to (m−1), and d is a radial thickness of the rectilinear portions that are housed inside the slots.