Wire Harness Terminal Crimp Structure to Prevent Aluminum Wire Cracking
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Solution Overview
Problem
Aluminum conductor wires in wire harnesses are prone to cracking due to stress concentration at the boundaries between straight and tapered portions of crimping dies, leading to potential crimping failures and reliability issues.
Innovation Solution
A terminal design with a crimping portion featuring main depressions across the periphery and sub-depressions on both sides, positioned to avoid stress concentration areas, ensuring even deformation and preventing cracking during crimping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If serrations are provided to the crimping portion to prevent conductor wire from coming out and destroy oxide film on aluminum, then connection reliability is improved, but stress concentration occurs at the boundaries between straight and tapered portions of crimping dies leading to cracking
Solution Approach 1:
The invention applies local quality by providing serrations (depressions) only in specific regions of the crimping portion where they are most effective for locking the conductor wire, while avoiding stress concentration areas. The crimping portion is designed with different local characteristics: serrated regions for secure locking and non-serrated regions for stress distribution, optimizing both connection reliability and structural strength.
Solution Approach 2:
The crimping portion is segmented into multiple functional regions: a first crimping portion with serrations for locking the conductor wire, and a second crimping portion without serrations for distributing stress during crimping. This segmentation allows each region to perform its specific function optimally without interfering with the other.
2Weight of moving object
If aluminum conductor wires are used to reduce wire harness weight, then weight reduction is achieved, but the wires are prone to cracking due to stress concentration during crimping
Solution Approach 1:
The terminal design applies local quality by creating specific non-serrated regions in the crimping portion that avoid stress concentration areas. These protected regions prevent cracking in aluminum conductor wires during crimping, while other regions maintain the necessary locking function through serrations.
3Strength
If multiple locking portions are formed in the crimping portion to securely retain the conductor wire, then connection strength is improved, but the complexity of the crimping structure increases
Solution Approach 1:
Instead of uniformly distributing locking features throughout the crimping portion, the invention applies serrations only in specific local regions where they provide maximum locking effect. This localized approach achieves strong connection while maintaining simpler overall structure 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
The terminal design effectively suppresses cracking and enhances the reliability of wire harness connections by distributing stress evenly and securely retaining the conductor wire, while also preventing oxide film destruction on aluminum wires.
Implementation Method 1
The crimping portion is formed by rolling a body to thereby obtain a cylindrical body and joining the side edge portions of body together at a joining portion
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A conductor wire crimping portion (7) has depressions (13a, 13b, 13c) that are disposed at prescribed intervals in the axial direction and that are linear locking portions. The depressions (13a, 13b, 13c) are continuously depressed grooves on the inner surface of a crimping portion (5). On an upper die (30a), at a portion corresponding to the conductor wire crimping portion (7), a straight portion is formed, and in the front-back direction thereof, tapered portions are formed. More specifically, the upper die (30a) is formed to have an inverted trapezoid shape, a middle portion of which protrudes in the crimping direction. Consequently, at each boundary between the straight portion and the tapered portion, a die angled portion (32) is formed. At an area corresponding to the straight portion of the upper die (30a), the depression (13a) is provided, and at an area corresponding to the die angled section (32), the depression (13b) is provided.