Electrical Connector Recessed Lock Piece Shear Length

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Solution Overview

Problem

In connectors where a terminal is mounted to a resin housing, the proximity of the core wire caulked portion to the flexible lock piece can lead to interference, resulting in a shallow engagement margin and reduced terminal holding force due to limitations in shear length, making it difficult to maintain a strong locking mechanism.

Innovation Solution

The connector design incorporates a recessed clearance portion on the flexible lock piece, which creates a clearance between the core wire caulked portion and the inclined surface, along with protruding line portions and a lock protrusion, to increase the shear length and engagement margin, thereby enhancing the terminal holding force and locking strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the core wire caulked portion is positioned close to the flexible lock piece to reduce connector size, then the connector becomes more compact, but the engagement margin becomes shallow and terminal holding force decreases

Engineering Contradiction:
Improveconnector sizeVSAvoidterminal holding force
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent introduces a recessed clearance portion that creates additional spatial dimension between the core wire caulked portion and the flexible lock piece. This recessed structure allows the components to be positioned closer in the overall connector volume while maintaining adequate clearance through the vertical dimension created by the recess, thus resolving the contradiction between compact size and sufficient engagement margin.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The recessed clearance portion is nested within the flexible lock piece structure, creating a layered configuration where the clearance space is integrated into the lock piece itself. This nesting approach allows the core wire caulked portion to be positioned closer to the lock piece while the recessed portion provides the necessary clearance, maintaining both compactness and holding force.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If the core wire caulked portion is positioned close to the flexible lock piece, then manufacturing is simpler, but interference occurs and locking strength is compromised

Engineering Contradiction:
Improveassembly simplicityVSAvoidlocking mechanism reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The recessed clearance portion is pre-formed in the flexible lock piece during manufacturing, establishing the clearance space before assembly. This preliminary action ensures that when the core wire caulked portion is inserted, the clearance is already in place to prevent interference, maintaining both manufacturing simplicity and locking reliability without requiring complex adjustment procedures.

Inventive Principle:
Principle #10Preliminary action

3Strength

If the shear length is increased to improve terminal holding force, then the locking strength is enhanced, but the connector size increases

Engineering Contradiction:
Improvelocking strengthVSAvoidshear length
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The recessed clearance portion utilizes the vertical dimension to provide clearance space, allowing the shear length to be extended in the horizontal direction without increasing the overall connector height. This dimensional separation enables increased locking strength through longer shear length while maintaining compact connector dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 design effectively prevents interference between the core wire caulked portion and the flexible lock piece, ensuring a larger shear length and improved terminal holding force, thus enhancing the locking strength and stability of the connector.

Implementation Method 1

a front end of the box portion 527 abuts against a chamfer 533 of the lance 521 and pushes up the lance 521. That is, the terminal 525 elastically deforms the band 511

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3588689B1Electrical connector
Publication Date: 2021.06.30 YAZAKI CORP
  • EP3588689B1 patent drawingFigure 1
  • EP3588689B1 patent drawingFigure 2
  • EP3588689B1 patent drawingFigure 3

AI summary

A connector includes a terminal including an electric contact portion having a lock end edge at a rear end thereof in an insertion direction and a wire connection portion having a core wire caulked portion; a housing having an insertion opening on a rear end surface thereof and a terminal accommodation chamber to accommodate the terminal inserted from the insertion opening; a flexible lock piece integrally formed with the housing and having a lock surface locking the lock end edge of the terminal inserted into the terminal accommodation chamber; an inclined surface formed on the flexible lock piece, pressed by the terminal during insertion, and moving the lock surface in an unlocking direction; and a recessed clearance portion formed on the inclined surface and having a bottom surface located farther from the core wire caulked portion of the insertion-completed terminal and the vicinity thereof than the inclined surface.