Stator Winding Insulating Film Evaporatable Component Control
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Solution Overview
Problem
Rotary electric machines, such as vehicle alternators, face issues with foreign particles entering the stator windings due to thermal stress causing insulating film deterioration, leading to defective insulation and reduced environmental resistance.
Innovation Solution
The stator windings are designed with conductor segments joined by TIG welding, and an insulating film with a controlled amount of evaporatable components (≤20000 ppm) is used, preventing film deterioration and foreign particle ingress by reducing gas bubble generation and enhancing resin adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conductor segments are joined by welding to provide high density windings, then power output is improved, but thermal stress causes insulating film deterioration and foreign particle ingress
Solution Approach 1:
The insulating film is applied to the conductor segments before the welding process. This preliminary application ensures that the insulating film is in place to protect against foreign particle ingress during welding, while still allowing the welding to proceed for high density winding formation. The film is applied in advance to prevent the harmful effect rather than attempting to repair it afterward.
Solution Approach 2:
The insulating film is selectively applied to specific portions of the conductor segments - particularly to the surfaces that will be exposed during welding and assembly, while maintaining conductor connectivity where needed. This local application provides targeted protection against foreign particle ingress at critical locations without compromising the electrical connectivity required for high power output.
2Reliability
If insulating film is coated at joint portions to improve electrical isolation, then insulation is improved, but thermal stress causes film peeling and cracking
Solution Approach 1:
The insulating film is applied to the conductor segments before welding and assembly operations. This timing allows the film to be in place during subsequent thermal and mechanical processes, preventing foreign particle ingress while the conductor joints are being formed. The film is positioned in advance to avoid the thermal stress and mechanical deformation that would occur if applied afterward.
3Reliability
If resin material is used to coat joint portions for improved adherence, then environment resistance is improved, but cost and manufacturing complexity increase
Solution Approach 1:
The patent extracts and eliminates the need for additional resin coating materials and processes by using the insulating film alone to provide both electrical isolation and environmental protection. The insulating film is applied directly to the conductor segments and provides sufficient protection against foreign particles and environmental factors, removing the need for separate resin coating operations and reducing manufacturing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively prevents foreign particles from entering the stator windings, improving insulation and environmental resistance while reducing material costs and enhancing cooling capacity.
Implementation Method 1
an insulating film with a controlled amount of evaporatable components (≤20000 ppm) is used, preventing film deterioration and foreign particle ingress by reducing gas bubble generation
Implementation Method 2
an insulating film coated at a portion of a conductor of one of the multiphase windings, which is close to the corresponding one of the joint portions, may deteriorate by thermal stress applied while the corresponding one of the joint portions is formed by welding
Implementation Method 3
one end of each of the conductor segments projecting one of the slots is sequentially welded to the other end of a corresponding one of the conductor segments projecting a corresponding another one of the slots
Implementation Method 4
the joint portions of each of the multiphase windings are only exposed and the remaining portions thereof are coated with an insulating film
Data Source
AI summary
In a rotary electric machine, at least one of first and second ends of each conductor segment is at least partially joined to at least one of the first and second ends of a corresponding another one of the conductor segments to provide the stator winding including a plurality of joint portions of the plurality of conductor segments. An insulating film covers each of the conductor segments except for at least the joint portions of the stator winding. At least part of the insulating film of each of the conductor segments located close to a corresponding one of the joint portions contains an evaporatable component. An amount in ppm of the evaporatable component contained in the at least part of the insulating film is adjusted to be equal to or lower than 20000 ppm.