Charging Terminal Arc-Root Structure for Vibration Fatigue Resistance

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Solution Overview

Problem

Charging terminals in new energy vehicles experience stress concentration and fatigue due to high-frequency vibration during ultrasonic welding, leading to potential fracture, and the finger protective cap is easily detached, posing a risk of electric shock.

Innovation Solution

A connection terminal design featuring an arc-shaped connection part at the root of the installation part to prevent stress concentration, combined with a radial protrusion and blocking surface for secure engagement with the finger protective cap, and a flat welding end offset for reduced mass and improved safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the installation part is designed as a solid body with smaller diameter than the columnar body part, then the finger protective cap can be installed, but stress concentration occurs at the root of the installation part leading to fatigue and fracture

Engineering Contradiction:
Improvestrength of installation partVSAvoidreliability of installation part
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The root of the installation part is designed with an arc-shaped connection part instead of a sharp transition, creating a curved surface that distributes stress evenly. This curvature eliminates stress concentration points and prevents fatigue fracture during high-frequency vibration in ultrasonic welding processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Strength

If the installation part has a smaller diameter than the columnar body part, then the finger protective cap can be installed, but the mass of the installation part becomes relatively large

Engineering Contradiction:
Improvestrength of installation partVSAvoidmass of installation part
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The installation part features a localized arc-shaped connection part at its root, while the rest of the structure maintains its functional dimensions. This localized geometric modification provides the necessary stress distribution without requiring a complete redesign of the entire installation part, thus minimizing mass increase.

Inventive Principle:
Principle #3Local quality

3Productivity

If ultrasonic welding is used for cable conductor and charging terminal, then welding efficiency is improved, but high-frequency vibration causes fatigue and fracture of the installation part

Engineering Contradiction:
Improvewelding efficiencyVSAvoidreliability of installation part
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The arc-shaped connection part is designed in advance to provide stress distribution and fatigue resistance before the ultrasonic welding process begins. This preemptive geometric design cushions the installation part against the high-frequency vibrations inherent in ultrasonic welding, preventing fatigue and fracture while maintaining welding efficiency.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Object-affected harmful factors

If the finger protective cap is installed on the end of the charging terminal, then safety is improved, but the cap is easily detached during mating process

Engineering Contradiction:
Improveprotection from electric shockVSAvoidstability of finger protective cap
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The arc-shaped connection part creates a curved surface that provides better contact area and mechanical interlocking between the installation part and the finger protective cap. This curved geometry prevents the cap from easily detaching during the mating process while maintaining its protective function.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 fracture during high-frequency vibration and enhances the engagement force between the finger protective cap and the connection terminal, ensuring safety by preventing the cap from detaching and reducing the risk of electric shock.

Implementation Method 1

there is stress concentration at the root of the installation part connected to the columnar body part

Methodology Applied
Scientific EffectStress concentration:

Implementation Method 2

the charging terminal will have high-frequency vibration, which will lead to fatigue and fracture of the installation part

Methodology Applied
Scientific EffectFatigue: Fatigue

Implementation Method 3

the radial protrusion on the installation part is interference fit with the inner peripheral surface of the finger protective cap to increase the engagement force

Methodology Applied
Scientific EffectInterference fit:

Data Source

PatentEP4287413A1Connection terminal, connection terminal assembly, cable assembly, and charging seat
Publication Date: 2023.12.06 TYCO ELECTRONICS (SUZHOU) CO LTD
  • EP4287413A1 patent drawingFigure 1
  • EP4287413A1 patent drawingFigure 2
  • EP4287413A1 patent drawingFigure 3

AI summary

The present invention discloses a connection terminal, a connection terminal assembly, a cable assembly, and a charging seat. The connection terminal comprises of: a body part (10) which is adapted to be inserted into a mating terminal for electrical contact with the mating terminal; and an installation part (11) which is adapted to be inserted into a finger protective cap (2) for installing the finger protective cap (2). The installation part (11) is formed on and protrudes from an end face (10a) of one end of the body part (10); the root of the installation part (11) connected to the end face (10a) of the body part (10) is formed into an arc-shaped connection part (11b) to prevent stress concentration at the root of the installation part (11). Therefore, the present invention can effectively prevent the installation part from breaking due to high-frequency vibration.