Rotary Electric Machine Insulating Sheet Bend Line Design
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Solution Overview
Problem
Conventional rotary electric machines experience tears in the insulating sheet members at the axial ends, leading to insufficient insulation due to the formation of bend lines that protrude outside the stator core slots, causing detachment and insulation failure.
Innovation Solution
The insulating sheet member is bent in a rectangular cylindrical shape with shorter axial bend lines that do not reach the ends, preventing tears and ensuring reliable insulation by configuring the bend lines to be shorter than the axial length of the sheet member, and optionally incorporating folded portions or spaced bend lines for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If bend lines are formed extending to the axial ends of the insulating sheet member, then the insulating sheet member can be properly fitted into the slot, but tears occur easily at the axial ends causing insulation failure
Solution Approach 1:
The insulating sheet member is divided into multiple axial sections by forming multiple bend lines at different axial positions. This segmentation allows the sheet to be fitted into the slot while preventing tears from propagating across the entire axial length, as the bend lines create discrete folding zones that contain potential tear propagation.
Solution Approach 2:
Bend lines are formed in advance during manufacturing at specific axial positions that do not extend to the axial ends of the insulating sheet member. This preliminary formation of bend lines prepares the sheet for slot insertion while pre-defining safe folding zones that prevent tear occurrence at the critical axial end regions during subsequent assembly and operation.
2Ease of operation
If the insulating sheet member protrudes from the end surface of the stator core, then it can be easily installed, but the folded portions at the axial ends are pulled by electrical conductors causing tears
Solution Approach 1:
The insulating sheet member has non-uniform structural properties along its axial direction: the central region contains bend lines for folding, while the axial end regions are designed without bend lines to maintain structural integrity. This local quality differentiation allows the central portion to be flexible for installation while the axial ends remain strong and tear-resistant during operation.
Solution Approach 2:
Instead of forming bend lines across the entire axial length of the insulating sheet member, bend lines are formed only in the central portion, extending partially along the axial direction but stopping before reaching the axial ends. This partial action provides sufficient flexibility for installation while avoiding the creation of weak points at the axial ends where tears would occur.
Data Source
AI summary
A rotating electric machine includes a rotor, and a stator that has a stator core and a stator winding. The stator core has a plurality of slots. The stator winding is wound around the stator core as a plurality of electrical conductors is aligned in the radial direction in the slots. The stator has an insulating sheet member that is bent in a rectangular cylindrical shape, and is intervened between the electrical conductor and an inner wall surface of the slot. A length of a bend line formed extending in the axial direction on the insulating sheet member from a reference position in a central section of the insulating sheet member in the axial direction to a tip in the axial direction is configured shorter than a length from the reference position to an end in the axial direction of the sheet member.