Rotary Electric Machine Insulator Recess Wall Structure
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Solution Overview
Problem
In rotary electric machines, the potential difference between the winding start and end portions can lead to a lowered voltage at which discharge is started, potentially causing short circuits due to proximity issues, which existing insulators fail to adequately address.
Innovation Solution
The rotary electric machine incorporates an insulator with a recess portion and wall structure that separates the electric wire wound around the stator core, preventing contact between the start and end portions of the winding, thereby maintaining a reliable isolation and preventing discharge inception voltage reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the winding start portion and end portion are placed in proximity due to product variations, then the manufacturing tolerance is relaxed, but the discharge inception voltage is lowered causing potential short circuits
Solution Approach 1:
The insulator acts as an intermediary component between the winding start portion and end portion. The recess portion receives and isolates the winding start portion, while the protruding portion extends to isolate the winding end portion from the core. This intermediary structure prevents direct contact between high-potential and low-potential regions, maintaining discharge inception voltage even when windings are in proximity due to manufacturing variations.
Solution Approach 2:
The insulator extends in the axial direction (perpendicular to the radial direction where windings are typically arranged). By utilizing this additional dimensional space, the insulator creates isolation paths that do not interfere with the radial winding layout, allowing windings to be placed in proximity radially while maintaining electrical isolation axially.
2Reliability
If additional insulating tubes are added to prevent discharge, then the discharge inception voltage is maintained, but the device complexity and manufacturing cost increase
Solution Approach 1:
The insulator merges multiple functions into a single component: it provides electrical isolation between the core and windings, accommodates the winding start portion in its recess, and extends via the protruding portion to isolate the winding end portion. This consolidation eliminates the need for separate insulating tubes and other auxiliary insulating components, reducing device complexity while maintaining discharge inception voltage.
Solution Approach 2:
The insulator serves multiple purposes simultaneously: structural support for the winding start portion, electrical isolation for both start and end windings, and mechanical anchoring to the core. This multi-functionality reduces the total number of components needed and simplifies the overall insulator system while ensuring reliable electrical isolation.
Data Source
AI summary
A rotary electric machine includes: a rotor rotating about an axis; a stator formed by annularly combining cores having electric wires wound therearound and placed on the outer side of the rotor in a direction orthogonal to the axis; and an insulator including an outer portion placed on the radially outer side of the stator; an inner portion placed on the radially inner side of the stator; a trunk portion coupling the outer portion and the inner portion and having the electric wire wound therearound; a recess portion formed in a portion of the outer portion facing the inner portion to accommodate the electric wire; and a wall placed at the recess portion on the side of the inner portion to partially cover the recess portion. The insulator is attached to one end portion of the cores in a direction parallel with the axis.