Preformed Stator Coil Assembly With Equal-Gap Tooth Centering
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Solution Overview
Problem
Accurate positioning of preformed coil assemblies on stator teeth is difficult, leading to asymmetrical gaps that compromise dielectric insulation and motor lifetime, and existing winding carriers are costly and fragile, limiting manufacturing efficiency and winding speed.
Innovation Solution
A preformed coil assembly with insulation films and winding carriers designed to center the coil assembly on the stator tooth, featuring equal gaps on both sides to enhance dielectric insulation and robustness, using a method that includes folding insulation films around winding carriers to ensure precise alignment and robust construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a winding carrier with thin lateral walls is used to center the coil assembly, then dielectric insulation is improved, but the winding carrier becomes fragile and limits winding speed
Solution Approach 1:
The patent uses glass-reinforced polymer material for the winding carrier, creating a composite structure that combines the insulating properties of polymer with the strength of glass fibers. This allows the lateral walls to be thin enough for proper centering (0.5-2mm) while remaining robust enough to withstand winding tensions and speeds without breaking.
2Manufacturing precision
If injection technology is used to produce thin lateral walls, then centering precision is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent specifies precise thickness parameters for the lateral walls (0.5-2mm) and for the insulation films (1-5mm), transforming the qualitative requirement of 'thin walls' into quantifiable design parameters. This allows standard manufacturing processes to produce the required precision without requiring complex injection molding techniques, thereby reducing manufacturing complexity while maintaining centering accuracy.
3Ease of operation
If manual positioning is used to position coil assemblies, then flexibility is maintained, but positioning accuracy deteriorates
Solution Approach 1:
The insulation films are designed with self-centering functionality through their geometric configuration and material properties. The films automatically position the coil assembly centrally on the tooth through their folded structure and elastic deformation during installation, eliminating the need for manual positioning adjustments while maintaining both flexibility and precision.
4Reliability
If the gap between coil assembly and tooth is increased, then dielectric insulation is improved, but copper filling factor and heat dissipation deteriorate
Solution Approach 1:
The patent applies different gap dimensions at different locations: the lateral gaps (between coil sides and tooth sides) are minimized to 0.5-2mm to maximize copper filling, while the radial gap (between coil assembly and tooth tip) is maintained at 1-5mm through insulation film thickness to ensure dielectric insulation. This localized differentiation of gap sizes optimizes both competing requirements.
Data Source
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AI summary
The invention relates to a preformed coil assembly (20) for a stator (10) of an electric motor, comprising a first and a second winding carrier (30a, 30b) located on respective opposite ends of the preformed coil assembly (20) and a winding part (22) wound around the first and second winding carriers (30a, 30b) such as to form a first and a second elongated winding portion (24a, 24b) with an elongated opening (26) therebetween to be fitted around a tooth (12) of a stator (10). The preformed coil assembly (20) further comprises a first and a second insulation film (27a, 27b) disposed around respectively the first and second winding portions (24a, 24b). Each insulation film (27a, 27b) comprises an upper and a lower folded portion (28a, 28b) resting against respective first and second opposite walls (38a, 38b) of respective winding carriers (30a, 30b) to ensure a first and a second distance (d1, d2) between respective opposite lateral sides (14a, 14b) of the tooth (12) and a corresponding non-folded portion (29) of respective first and second insulation films (27a, 27b). The first and second distances (d1, d2) are equal so that the preformed coil assembly (20) is centered with respect to said tooth when mounted therearound.