Terminal Fitting With Variable Slit Sizes For Uniform Contact Load

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Solution Overview

Problem

The existing terminal fittings experience variation in resilient piece displacement, leading to inconsistent contact load when the inserter is inserted, due to unequal deformation of resilient pieces closest and farthest from the joining portion.

Innovation Solution

A terminal fitting design with cylindrical electrical contacts featuring slits of varying sizes along the length, where the slits farthest from the joining portion are larger, allowing uniform displacement and consistent contact load through elastic deformation of resilient pieces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If all slits are made with the same size, then the manufacturing process is simple, but the resilient pieces exhibit non-uniform displacement causing inconsistent contact load

Engineering Contradiction:
Improveuniformity of resilient piece displacementVSAvoidvariation in slit sizes
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by making the slits have different sizes at different locations along the electrical contact. Specifically, slits farther from the joining portion are made larger than those closer to the joining portion. This local variation in slit size compensates for the non-uniform stress distribution in the resilient pieces, ensuring that all resilient pieces achieve uniform displacement and consistent contact load during insertion.

Inventive Principle:
Principle #3Local quality

2Reliability

If resilient pieces are uniformly deformed, then the contact load is consistent, but this requires complex slit size variations

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by varying the size parameter of the slits along the length of the electrical contact. The slit size is specifically increased for those farther from the joining portion to compensate for the greater displacement they experience. This parameter variation ensures uniform deformation of all resilient pieces, achieving consistent contact load and improved connection reliability.

Inventive Principle:
Principle #35Parameter changes

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

Ensures a constant contact load by making the displacement of resilient pieces uniform, enhancing the reliability of the connection between the terminal fitting and the mating terminal.

Implementation Method 1

the resilient pieces constituting the electrical contact, the one resilient piece most proximate to the one slit farthest away from the joining portion of the is allowed to be readily elastically deformed in the electrical contact's diameter-expansion direction and diameter-contraction direction

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2700128B1Terminal fitting
Publication Date: 2015.03.04 YAZAKI CORP
  • EP2700128B1 patent drawingFigure 1~2
  • EP2700128B1 patent drawingFigure 3~5
  • EP2700128B1 patent drawingFigure 6~8

AI summary

The present invention provides a terminal fitting that ensures constant contact load of an inserter that is inserted into an electrical contact by making uniform the amounts of displacement among a plurality of resilient pieces constituting the electrical contact. A terminal fitting 1, 1' includes a cylindrical electrical contact portion 2 obtained by making the both ends of the conductive metal plate close to each other and joined to each other. The electrical contact portion 2 includes a plurality of slits 20, 21, 22, 23, and 26 extending in a cylinder-length direction N and provided at intervals in the circumferential direction of the electrical contact portion 2. Out of the slits 20, 21, 22, 23, 26, the slits 23, 26 provided farthest away from the joining portion at the both ends of the metal plate have a size in the cylinder-length direction N larger than those of the other slits 20, 21, and 22.