Rotary Electric Machine Connection Terminal Groove Brazing Flow Control
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Solution Overview
Problem
The existing terminal treatment structure in rotary electric machines, particularly in vehicle AC generators, faces issues with the 'liquid-metal embrittlement phenomenon and electrochemical corrosion due to the flow of copper phosphorus brazing material, leading to potential cracks and reliability concerns.
Innovation Solution
Incorporating groove portions on the inner and outer circumference of the connection terminal's hole portion to contain the brazing material, preventing it from flowing beyond the predetermined range and adhering on weak mechanical portions, thus avoiding hardening and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If copper phosphorus brazing material is applied to join butting portions of the connection terminal, then the connection terminal can be formed by rolling and joining, but the brazing material flows out and adheres on the inner or outer circumference of the hole portion and on the torsional portion, causing hardening and deformation
Solution Approach 1:
The groove portion is provided only at specific locations (inner or outer circumference of the hole portion) where brazing material flow needs to be controlled, rather than modifying the entire connection terminal structure. This localized structural feature allows the brazing material to be contained where needed while maintaining the overall manufacturing process integrity.
Solution Approach 2:
The groove portion acts as an intermediary structure that intercepts and contains the flowing brazing material, preventing it from reaching the torsional portion and causing damage. The groove serves as a barrier that mediates between the brazing process and the vulnerable areas of the connection terminal.
2Ease of manufacture
If the copper phosphorus brazing material adheres on the torsional portion, then the joining process is complete, but the torsional portion becomes hardened and difficult to deform, leading to cracks during fusing
Solution Approach 1:
The groove portion is provided in advance before the brazing material can flow to the torsional portion. This preliminary structural feature prevents the harmful action of brazing material adhesion on the torsional portion before it can occur, thereby preventing the hardening and subsequent cracking that would result from such adhesion.
3Ease of manufacture
If the copper phosphorus brazing material flows out in thick amount over wide range on the outer circumference, then the brazing is complete, but the clearance between the hole portion and cooling fan blade becomes small, allowing salt water invasion and electrochemical corrosion
Solution Approach 1:
The groove portion is strategically positioned on the outer circumference of the hole portion to locally contain the brazing material flow. This localized containment prevents the brazing material from spreading excessively in the radial direction, thereby maintaining adequate clearance between the connection terminal and the cooling fan blade, and preventing salt water invasion and electrochemical corrosion.
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 enhances the mechanical strength and reliability of the connection terminal by preventing cracks and electrochemical corrosion, ensuring a stable and durable joint.
Implementation Method 1
joining butting portions via brazing material through brazing work
Implementation Method 2
from the outside, pressure and current are applied to the connection terminal by an electrode, whereby fusing (pressure resistance welding) is performed
Data Source
AI summary
An object of the present invention is to provide a rotary electric machine that can improve the reliability of a connection terminal by preventing brazing material applied to butting portions of the connection terminal from flowing out. The rotary electric machine according to the present invention has, on at least one of the inner and outer circumferences of a hole portion 22 of a connection terminal 20, a groove portion 22a, 22b, 22c, 22d, or 22e that can prevent brazing material 24 from flowing out from between butting portions 23, thereby solving a problem that a crack occurs on the connection terminal upon fusing of the connection terminal and a lead conductive wire.