Stator Coil Segmentation for Weld Strength and Cooling
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Solution Overview
Problem
Dynamo-electric machines used in automobiles face challenges in reducing size while maintaining weld strength and cooling efficiency, particularly due to stress from temperature changes at welded coil ends, which affects the gap between coil ends and transmission components.
Innovation Solution
A stator design with a stator core and insulating film-covered coils, where segment coils are arranged in a specific radial direction with controlled displacement for enhanced weld strength and cooling, utilizing a distributed winding method and rectangular wire with insulating film to reduce stress and improve cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the coil end height is reduced to ensure a gap between coil ends and transmission portion, then the machine size is reduced, but the weld strength at welded portions deteriorates due to increased stress from temperature changes
Solution Approach 1:
The stator coil is divided into multiple layers (first-layer segment through fourth-layer segment) arranged radially. This segmentation allows each layer to be independently positioned and welded, distributing the thermal stress across multiple smaller welded portions rather than concentrating it in a single large welded area, thereby maintaining weld strength while reducing overall coil end height
Solution Approach 2:
The patent transitions from a conventional single-plane coil arrangement to a multi-layer radial arrangement where coils are stacked from inner radius to outer radius. This dimensional change in coil configuration reduces the axial height requirement while creating multiple welded portions at different radial positions, distributing thermal stress and maintaining weld strength
2Strength
If the welded portion area is increased to enhance weld strength, then the weld strength is improved, but the coil end height increases, reducing the gap with transmission portion
Solution Approach 1:
The coil structure is segmented into multiple layers with multiple welded portions distributed radially. Each welded portion can be optimized for strength while the overall coil end height is controlled by the radial stacking arrangement, preventing excessive height increase
Solution Approach 2:
By arranging welded portions across multiple radial layers instead of concentrating them in a single axial plane, the patent achieves enhanced total weld strength while maintaining compact axial height through radial distribution
3Temperature
If segment coils are arranged in multiple radial layers, then the cooling efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The stator coil is segmented into multiple radial layers that can be manufactured and positioned independently. This segmentation creates natural cooling channels between layers, improving heat dissipation while allowing modular manufacturing that reduces overall complexity
Solution Approach 2:
Different radial layers can be designed with locally optimized characteristics for their specific thermal and electrical requirements. The insulating films and welded portions are positioned at specific local locations to optimize cooling pathways and thermal management
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
The design achieves a compact, high-output dynamo-electric machine with improved weld strength and cooling efficiency, reducing stress on welded portions and enhancing insulation quality while allowing for efficient heat dissipation.
Implementation Method 1
a stator coil covered with an insulating film inserted into the slots in the stator core
Implementation Method 2
alternating-current power can be outputted from a coil by converting mechanical energy applied to a rotor into electric energy
Implementation Method 3
a rotating magnetic field is produced by supplying alternating-current power to a stator winding and a rotor is rotated by this rotating magnetic field
Data Source
AI summary
The heat dissipation of a coil of a stator is enhanced. A stator of a dynamo-electric machine or a dynamo-electric machine according to the present invention includes: a stator core in which a plurality of slots arranged in the circumferential direction are formed; and a stator coil with an insulating film inserted in the slots in the stator core. The stator coil is composed of a first-layer segment to a fourth-layer segment each of which is formed by arranging a plurality of segment coils in the circumferential direction and which are arranged from the inner radius side to the outer radius side in the radial direction. The first-layer segment and the second-layer segment are displaced from each other by a first amount of displacement in the circumferential direction and connected to each other. The third-layer segment and the fourth-layer segment are displaced from each other by a second amount of displacement different from the first amount of displacement in the circumferential direction and connected to each other.