Stator Coil End Portion Single-Bend Welding Design
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Solution Overview
Problem
Conventional stator coil manufacturing for electric rotating machines faces issues with poor weld quality due to gaps between electric wire end portions, leading to increased manufacturing costs and heat-related damage to insulating coats, especially in high-voltage applications.
Innovation Solution
The stator coil design features electric wires with end portions that have a bent part bent only once, allowing for gap-free parallel arrangement and reliable welding, while maintaining a constant cross-sectional area to prevent heat damage to the insulating coats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating coat is stripped from the end portions of electric wires to enable welding, then the welding can be performed, but a gap forms between the end portions resulting in poor weld quality
Solution Approach 1:
The insulating coat is stripped from the end portions of electric wires in advance before the wires are assembled into the coil. This preliminary preparation ensures that when the end portions are positioned for welding, the conductors are already exposed and ready for immediate welding without requiring additional positioning adjustments, thereby eliminating gaps and ensuring good weld quality while maintaining manufacturing simplicity
Solution Approach 2:
The patent introduces an intermediary step of pre-stripping the insulating coat and preparing the end portions with proper spacing considerations. This intermediary preparation acts as a mediator between the insulating requirement (for electrical isolation) and the welding requirement (for electrical connection), allowing both functions to be satisfied by preparing the wires in advance with appropriate exposed conductor lengths
2Manufacturing precision
If step portions are formed by bending electric wires twice to eliminate gaps between end portions, then parallel arrangement without gap is achieved, but the shape becomes complicated and manufacturing cost increases considerably
Solution Approach 1:
The patent extracts the complexity of multiple bends from the wire shape by instead using a straight wire configuration with pre-stripped insulating coats at the ends. The solution takes out the unnecessary bending operations and keeps only the essential stripping operation, thereby achieving gap-free welding arrangement while maintaining simple wire geometry and low manufacturing cost
Solution Approach 2:
Instead of bending the wires to achieve proper positioning for welding, the patent inverts the approach by positioning the wires in a simple straight configuration and achieving proper alignment through the pre-prepared exposed conductor ends. The solution reverses the conventional wisdom of shaping wires to fit, instead fitting the simple wire shapes through proper preparation of the connection ends
3Object-affected harmful factors
If the end portions are plastically deformed to reduce cross-sectional area, then heat transmission to electric wires is reduced preventing insulating coat damage, but electrical resistance increases causing large heat generation during operation
Solution Approach 1:
The patent applies local quality by maintaining the full cross-sectional area of the electric wire throughout its length, including at the end portions where welding occurs. This ensures uniform electrical properties and minimizes resistance-induced heat generation. The solution protects the insulating coat from heat damage during welding through proper welding technique and heat management, rather than compromising the wire's electrical conductivity by reducing its cross-sectional area
4Loss of energy
If constant cross-sectional area is maintained at end portions, then electrical resistance is minimized reducing heat generation, but the insulating coats may be damaged by heat during welding
Solution Approach 1:
The insulating coat is stripped from the end portions in advance before welding, removing the vulnerable insulating material from the heat-affected zone. This preliminary action protects the insulating coats from heat damage during welding while maintaining the full cross-sectional area of the conductors, thereby minimizing electrical resistance and heat generation during operation
Solution Approach 2:
The patent extracts the insulating coat from the end portions where heat concentration occurs during welding. By removing the insulating material only at the specific locations where welding is performed, the solution protects the insulating coats from heat damage while preserving the full cross-sectional area and low electrical resistance of the conductors in the operational portions
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 design simplifies the manufacturing process, reduces costs, and enhances the electrical reliability of the stator coil by ensuring strong welds and minimizing heat-induced damage to the insulating coats, even in high-voltage applications.
Implementation Method 1
each of the electric wires is comprised of an electric conductor and an insulating coat that covers the outer surface of the electric conductor
Implementation Method 2
welding together the exposed electric conductors of the end portions of the electric wires
Implementation Method 3
it is possible to reduce the amount of heat transmitted to the electric wires during the welding of the end portions, thereby preventing the insulating coats of the main portions of the electric wires from being damaged by the heat
Data Source
AI summary
A stator includes a stator coil that is formed of a plurality of electric wires each being comprised of an electric conductor having a substantially rectangular cross section and an insulating coat covering the electric conductor. The electric wires include a pair of first and second electric wires each having an end portion where the electric conductor is not covered by the insulating coat. Each of the end portions of the two electric wires includes a joined part at a distal end thereof; the joined parts of the end portions are joined together. At least one of the first and second electric wires has a bent part that is bent only once and adjoins the joined part of the end portion of the electric wire. The end portion of the at least one of the first and second electric wires includes at least part of the bent part.