Rotating Electric Machine Weld Insulation Adhesion
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Solution Overview
Problem
Rotating electric machines face adhesion issues with weld-insulating members due to thermal expansion and contraction, leading to peeling off, as the material coefficients of thermal expansion differ between welds and insulating members, and random uneven portions concentrate stress.
Innovation Solution
The formation of annular recesses and protrusions on the weld surface, which are alternately and continuously arranged, reduces stress concentration during thermal expansion and contraction, and the molten insulating material is impregnated into these recesses to enhance adhesion, eliminating the need for blow holes that could weaken the welds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random blow holes are created to form uneven portions on the weld surface, then the adhesion area of the resin member to the joint is increased, but stress concentrates on peripheral portions of the resin member causing peeling
Solution Approach 1:
The invention applies local quality by creating uneven portions with specific annular recesses and protrusions at predetermined locations on the weld surface, rather than random blow holes. This localized, controlled structure increases adhesion area while distributing stress evenly across the weld-insulating member, preventing peripheral stress concentration and peeling.
Solution Approach 2:
The invention changes the parameters of the uneven portions from random blow holes to controlled annular recesses and protrusions with specific dimensions and arrangements. By controlling the shape, size, and distribution of these features, the invention optimizes both adhesion area and stress distribution, resolving the contradiction between increased adhesion and stress concentration.
2Reliability
If the weld-insulating member covers the weld surface, then electrical insulation is provided, but the different thermal expansion coefficients cause adhesion force reduction and peeling during temperature changes
Solution Approach 1:
The invention applies local quality by creating uneven portions with annular recesses and protrusions at specific locations on the weld surface. This controlled structure increases the adhesion area and distributes thermal stress more evenly during temperature changes, preventing the peeling that occurs with random blow holes while maintaining electrical insulation.
Solution Approach 2:
The invention uses annular (curved) recesses and protrusions instead of random irregular shapes. The curved, symmetrical geometry of the annular features distributes stress more uniformly during thermal expansion and contraction, improving adhesion stability while maintaining the electrical insulation function.
3Reliability
If blow holes are created during welding to form uneven portions, then adhesion area is increased, but the weld structure is weakened
Solution Approach 1:
The invention applies preliminary action by forming the uneven portions with annular recesses and protrusions after welding, rather than creating blow holes during the welding process itself. This approach allows the weld structure to maintain its full strength while still providing the adhesion area enhancement needed for the weld-insulating member.
Solution Approach 2:
The invention changes the method of creating uneven portions from in-process blow holes (which weaken the weld) to post-welding controlled features. By separating the weld formation process from the uneven portion creation, the invention maintains weld strength while achieving the desired adhesion area through controlled annular recesses and protrusions.
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 significantly enhances the adhesion force of weld-insulating members to the welds, preventing peeling and maintaining mechanical strength, while improving cooling performance and efficiency.
Implementation Method 1
weld-insulating members that cover, at least, the surfaces of the welds
Implementation Method 2
The uneven portion is constituted of a plurality of annular recesses and a plurality of annular protrusions. The annular recesses are formed alternately and continuously with the annular protrusions
Implementation Method 3
with the temperature change in the rotating electric machines, the welds and the weld-insulating members repeatedly undergo expansion and contraction
Data Source
AI summary
A rotating electric machine includes a weld formed by welding end portions of a pair of electric conductors for forming a coil and a weld-insulating member that covers, at least, a surface of the weld. The weld has an uneven portion formed on at least part of the surface thereof. The uneven portion is constituted of a plurality of annular recesses and a plurality of annular protrusions. The annular recesses are formed alternately and continuously with the annular protrusions.