Rotating Electric Machine Coil End Design
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Solution Overview
Problem
Existing rotating electric machines face limitations in flexibility when adjusting design specifications, such as reducing the outer diameter, increasing the number of slots, or modifying the thickness of coil segments, due to constraints in reducing the circumferential dimension of the coil head portion crossing region.
Innovation Solution
The configuration of the armature coil with paired electrical conductor groups having different circumferential pitches and axially overlapping connecting portions allows for greater design flexibility by providing clearance between connecting portions, reducing the coil end size, and preventing interference while maintaining insulation and electromagnetic balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the circumferential dimension of the coil head portion crossing region is reduced to compactly overlap head portions, then the size of the coil end is reduced, but the flexibility in adjusting design specifications (such as outer diameter, number of slots, coil segment thickness) is limited
Solution Approach 1:
The armature coil is segmented into multiple electrical conductor groups (first and second groups) with different circumferential pitches. This segmentation allows independent optimization of each group's positioning, enabling the connecting portions to be arranged axially overlapping while maintaining different circumferential spacings. This resolves the contradiction by allowing compact coil end arrangement without constraining design parameter adjustments.
Solution Approach 2:
The patent transitions from a single-plane circumferential arrangement to a three-dimensional arrangement where connecting portions overlap in the axial dimension while maintaining different circumferential pitches. By utilizing the axial dimension for overlapping placement, the coil end size is reduced without being constrained by circumferential spacing requirements, thereby enabling greater design flexibility.
2Adaptability or versatility
If electrical conductor groups are arranged with different circumferential pitches and axially overlapping connecting portions, then design flexibility is improved and coil end size is reduced, but the complexity of arrangement and insulation requirements increase
Solution Approach 1:
The patent employs asymmetric arrangement where the first electrical conductor group has a different circumferential pitch than the second electrical conductor group. This asymmetric positioning allows the connecting portions to overlap axially while maintaining proper insulation distances. The asymmetry resolves the contradiction by enabling flexible design adjustment without requiring symmetric, overly complex arrangements.
Solution Approach 2:
Different regions of the armature coil are assigned different circumferential pitches according to their specific functional requirements. The first electrical conductor group operates with one circumferential pitch optimized for its position, while the second group uses a different pitch suitable for its location. This local optimization reduces overall arrangement complexity while maintaining design flexibility.
Data Source
AI summary
A rotating electric machine includes a multi-phase armature coil wound on an armature core. The armature coil is formed of electrical conductor groups each being a bundle of electrical conductor segments and having a pair of leg portions and a connecting portion that connects the leg portions. The connecting portion is bent radially with respect to a circumferential direction. The electrical conductor groups are paired such that each pair of the electrical conductor groups consists of a first electrical conductor group and a second electrical conductor group both belonging to a same phase of the armature coil. The circumferential pitch between the leg portions of the first electrical conductor group is greater than that between the leg portions of the second electrical conductor group. In each pair of the electrical conductor groups, the connecting portions of the first and second electrical conductor groups are arranged to axially overlap each other.