Rotary-Electric-Machine Stator Coil Brazing with Low-Melting-Point Alloy
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Solution Overview
Problem
Conductor bonding in rotary-electric-machine stator coils often results in increased heat input, damaging insulation coatings and insufficient bonding strength due to high melting point requirements, which existing methods attempt to mitigate by using low-melting-point spacers but still fall short in reliability.
Innovation Solution
A method employing a bonding member with a lower melting point than the coil conductor, forming an alloy layer through brazing to minimize heat input and enhance bonding strength while reducing insulation coating damage, using a gas arc welder to bond the conductors with a T-shaped or comb-tooth alloy layer configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If TIG welding is used to bond conductor surfaces, then bonding strength is achieved, but heat input increases and insulation coating is damaged
Solution Approach 1:
A bonding member with lower melting point than the conductor is introduced as an intermediary substance between the conductor surfaces. This bonding member melts first during welding, creating a eutectic alloy layer that facilitates bonding while limiting heat transmission to the conductor and its insulation coating, thereby resolving the contradiction between achieving bonding strength and preventing heat damage.
Solution Approach 2:
The invention changes the material parameter of the bonding interface by using a bonding member with a lower melting point than the conductor. This parameter change allows the bonding process to occur at a lower temperature threshold, reducing heat input to the conductor and insulation coating while still achieving adequate bonding strength through the eutectic alloy layer formation.
2Object-affected harmful factors
If low melting point spacer is used to reduce heat input, then insulation coating damage is suppressed, but bonding strength becomes insufficient
Solution Approach 1:
The invention creates a composite material structure at the bonding interface consisting of the bonding member and conductor material forming a eutectic alloy layer. This composite structure combines the low melting point advantage of the spacer with the high strength contribution from the conductor-derived alloy phase, achieving both insulation protection and adequate bonding strength simultaneously.
Solution Approach 2:
The invention utilizes phase transition phenomena during welding, where the bonding member melts first and then solidifies to form a eutectic alloy layer with the conductor material. This controlled phase transition allows the bonding process to proceed at lower temperatures while still achieving strong bonding through the crystalline structure of the eutectic alloy.
3Strength
If high heat input is applied for bonding, then bonding strength is achieved, but manufacturing precision of insulation coating deteriorates
Solution Approach 1:
The bonding member serves as a thermal intermediary that absorbs and limits heat transmission to the insulation coating. By positioning this lower melting point material between the heat source and the conductor insulation, the system achieves bonding strength while preserving the manufacturing precision and integrity of the insulation coating.
Solution Approach 2:
The invention changes the thermal parameter of the bonding process by introducing a material with lower melting point and different thermal properties. This parameter change enables the bonding operation to be performed at reduced temperature levels, maintaining insulation coating integrity while achieving sufficient bonding strength through the eutectic alloy layer.
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 approach improves bonding strength and insulation reliability by reducing heat impact on the coil, shortening insulation coating damage, and maintaining dielectric strength, allowing for a more efficient and reliable conductor bonding process.
Implementation Method 1
bonding a base material... a bonding member having a low melting point in advance is inserted between both surfaces for providing a gap between the bonding conductors, and the spacer is melted and bonded through TIG welding
Implementation Method 2
the spacer is melted and bonded through TIG welding... forming an alloy layer through brazing
Implementation Method 3
using a gas arc welder to bond the conductors... TIG welding
Data Source
Figure 1~2
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AI summary
Provided are a rotary-electric-machine stator coil, a rotary-electric-machine stator having the same, and a rotary electric machine having the same, capable of improving a bonding strength and insulation reliability of a conductor bonding portion. A rotary-electric-machine stator coil includes: a conductor 110 having a bonding portion 104 bonded to other conductors; and a bonding member 401 having a melting point lower than a melting point of the conductor, wherein a tip of the bonding portion has an alloy layer 402 formed of an alloy of the conductor and the bonding member, and a root of the bonding portion is electrically connected by the bonding member.