Stator Twisting Jig Assembly for Uneven Coil End Bending

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Solution Overview

Problem

Conventional twisting jigs fail to effectively bend tip portions of varying lengths in stators while protecting coil ends without insulating layers, leading to potential unintended bending and damage.

Innovation Solution

A manufacturing method and device that allows first and second tip portions to be displaced in the circumferential and axial directions, using holding portions to bend the tip portions while protecting the coil ends, and a twisting jig assembly with movable bodies to facilitate this displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the second accommodating recessed portions are configured to be displaceable only in the circumferential direction, then the twisting jig can bend tip portions, but the coil ends without insulating layer may be unintentionally bent when half-inserted

Engineering Contradiction:
Improvebending capabilityVSAvoidcoil end protection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces axial displacement capability to the second holding portions, transforming the single-degree-of-freedom (circumferential only) mechanism into a two-degree-of-freedom system. This dimensional addition allows the holding portions to first move axially to fully accommodate coil ends before bending in the circumferential direction, thereby preventing half-insertion bending while maintaining bending functionality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If the twisting jig uses a conventional design with circumferential displacement only, then the structure is simple, but it is hard to bend tip portions of different lengths while protecting coil ends

Engineering Contradiction:
Improvejig structureVSAvoidtip portion bending precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent makes the second holding portions dynamically displaceable in both axial and circumferential directions, allowing the mechanism to adapt its motion sequence based on the insertion state of different tip portions. This dynamic capability enables precise control over when bending occurs, accommodating varying tip lengths while protecting coil ends, thereby improving manufacturing precision without excessive structural complexity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4716073A1Manufacturing method for stator, twisting machining device, and twisting jig assembly
Publication Date: 2026.03.25 NHK SPRING CO LTD
  • EP4716073A1 patent drawingFigure 1
  • EP4716073A1 patent drawingFigure 2
  • EP4716073A1 patent drawingFigure 3

AI summary

Provided is a manufacturing method for a stator capable of bending tip portions having different lengths and including coil ends of segment coils while protecting the coil ends having no insulating layer. The method relatively displaces and bends first tip portions 7A in a circumferential direction with respect to a stator core 3 while holding at least axial base portions of the coil ends 7a of the first tip portions 7A of segment coils held by the stator core, and allows the first tip portions 7A and second tip portions 7B to be displaced so as to approach each other in the axial direction while holding at least axial base portions of the coil ends 7a of the second tip portions 7B having shorter projecting length than the first tip portions 7A, and relatively displaces the second tip portions 7B with respect to the stator core 3 in the circumferential direction to be bent.