Terminal Fitting Resilient Contact Preventing Fretting Wear
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Solution Overview
Problem
Existing terminal fittings with resilient contact pieces are prone to fretting wear due to relative displacements in the width direction between the tab and the resilient contact piece, leading to potential dislocation and increased insertion resistance.
Innovation Solution
A terminal fitting design featuring a rectangular tubular body with a resilient contact piece and integral holding portions that sandwich the tab in the plate thickness direction, restricting displacement and reducing insertion resistance through frictional contact, while allowing the holding portions to be resiliently deformed during insertion, and incorporating deflection suppressing and excessive deflection restricting features to prevent plastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the resilient contact piece is made displaceable in the width direction, then the tab can be inserted more easily, but relative displacement between the tab and resilient contact piece occurs causing fretting wear
Solution Approach 1:
The resilient contact piece is segmented into a contact portion and a holding portion. The contact portion allows width-direction displacement for easy insertion, while the holding portion restricts such displacement to prevent fretting wear, thus resolving the contradiction between insertion ease and contact stability.
Solution Approach 2:
Different portions of the resilient contact piece have different functional qualities: the contact portion is designed to be displaceable for easy insertion, while the holding portion is designed to restrict displacement for preventing fretting wear. This local differentiation resolves the contradiction between ease of operation and reliability.
2Reliability
If the holding portion restricts tab displacement completely, then fretting wear is prevented, but insertion resistance increases due to friction
Solution Approach 1:
The holding portion is separated from the contact portion, allowing the contact portion to provide easy insertion while the holding portion provides displacement restriction. This segmentation reduces insertion resistance while maintaining contact stability.
Solution Approach 2:
The holding portion is designed to be resiliently displaceable during insertion, dynamically adapting to the insertion process. This dynamic behavior reduces friction and insertion resistance while still preventing fretting wear after insertion is complete.
3Reliability
If the holding portion is bent at the curved surface portion, then contact with the tab is improved, but manufacturing complexity increases
Solution Approach 1:
The holding portion is bent at the flat surface portion rather than the curved surface portion, creating a specific local geometric quality that is more favorable for manufacturing. This local modification maintains contact effectiveness while improving ease of manufacture.
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
Effectively prevents fretting wear and relative displacement between the tab and resilient contact piece, reduces insertion resistance, and prevents excessive deformation, ensuring reliable contact and prolonged service life.
Implementation Method 1
the holding portion may be resiliently displaceable in the width direction with respect to the resilient contact piece. According to this configuration, the holding portion slides in contact with the side edge of the tab while being resiliently deformed in the process of inserting the tab into the body.
Implementation Method 2
A holding portion is formed integrally with the resilient contact piece and can contact a side edge of the tab to restrict displacement of the tab in a width direction with respect to the resilient contact piece. Thus, fretting wear due to relative displacements in the width direction does not occur between the resilient contact piece and the tab.
Data Source
AI summary
A terminal fitting (10) includes a body (11) in the form of a rectangular tube, a tab (41) of a mating terminal (40) being inserted into the body (11) from the front. A resilient contact piece (22) is accommodated in the body (11). The tab (41) is sandwiched resiliently in a plate thickness direction thereof between the resilient contact piece (22) and a receiving plate (15) of the body (11). Holding portions (30) are formed integrally to the resilient contact piece (22) and capable of holding the tab (41) with a relative displacement of the tab (41) in a width direction with respect to the resilient contact piece (22) restricted by coming into contact with side edges (41S) of the tab (41).