Stator Coil Oblique Segments Reduce Axial Height
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Solution Overview
Problem
Conventional stator coils in rotating electric machines face challenges in minimizing axial height and cooling air resistance, leading to larger sizes and reduced performance due to axially-extending sections and high radial projection areas in the joining regions of the coil ends.
Innovation Solution
The stator coil is designed with electric conductor segments having oblique portions that protrude along the circumferential direction, featuring a thick section and a thin section with reduced thickness, eliminating axially-extending sections and minimizing the radial projection area of the joining region, allowing for reduced axial height and improved cooling air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If axially-extending sections are used in the protruding parts of electric conductor segments, then the joining of corresponding pairs is simplified, but the axial height of the coil ends increases
Solution Approach 1:
The invention changes the geometric parameters of the protruding parts by eliminating the axially-extending section and replacing it with an oblique section that extends obliquely with respect to the axial end face. This parameter change reduces the axial projection length while maintaining the joining functionality through the oblique configuration that allows corresponding pairs to be welded together.
2Strength
If the radial projection area of the joining region is increased, then the joining strength is improved, but the resistance to cooling air flow increases
Solution Approach 1:
The invention applies local quality by creating a thin section with reduced thickness at the distal end of the oblique section. This local reduction in thickness decreases the radial projection area of the joining region, thereby reducing resistance to cooling air flow, while the joining strength is maintained through the oblique configuration and welding process applied to the thin sections.
3Area of stationary object
If the thickness of the electric conductor segment is reduced in the thin section, then the radial projection area is minimized, but the mechanical strength is reduced
Solution Approach 1:
The invention uses parameter changes by transitioning from a constant thickness to a variable thickness profile along the oblique section. The thickness is reduced at the distal end to minimize radial projection area for cooling, while the proximal end maintains sufficient thickness for mechanical strength. The oblique angle and thickness distribution are optimized to balance both requirements.
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 reduces the axial height of the coil ends, lowers cooling air resistance, minimizes the size of the rotating electric machine, enhances performance, and decreases wind noise, while also reducing weld heat input and ensuring sufficient electrical insulation.
Implementation Method 1
The oblique portion includes a thick section and a thin section. The thick section has one end connected to the in-slot portion and the other end connected to the thin section; the thick section has substantially the same thickness as the in-slot portion. The thin section has one end connected to the thick section and the other end defining a distal end of the oblique portion; the thin section has a thickness less than the thickness of the thick section.
Implementation Method 2
Each corresponding pair of the oblique portions of the electric conductor segments are connected by joining the thin sections of the oblique portions.
Data Source
AI summary
A stator includes an annular stator core and a stator coil. The stator coil is formed of electric conductor segments each of which is bent in its thickness direction to include, at least, an in-slot portion and an oblique portion. The in-slot portion is received in a corresponding slot of the stator core with its width direction coinciding with a radial direction of the stator core. The oblique portion protrudes from the in-slot portion outside the corresponding slot and extends, over its entire length, along the circumferential direction of the stator core obliquely with respect to an axial end face of the stator core. The oblique portion includes a thick section on the proximal side and a thin section on the distal side. Each corresponding pair of the oblique portions of the electric conductor segments are connected by joining the thin sections of the oblique portions.