Vehicle Line Connection Sleeve-Bolt Assembly Against Thread Shear

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing electrical connections using copper conductors are prone to thread shear due to high ductility, especially under dynamic loads, leading to instability and potential failure.

Innovation Solution

A connection design featuring a copper alloy sleeve bonded to a steel alloy bolt, where the bolt is inserted into a through-opening in the sleeve, forming a force-fit and metallurgical bond, allowing higher torque tightening without thread shear, and an electrical path through the sleeve.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If copper conductors are used for electrical connections, then electrical conductivity is improved, but mechanical strength deteriorates due to thread shear under dynamic loads

Engineering Contradiction:
Improveelectrical conductivityVSAvoidthread shear resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs a composite structure combining copper conductor with a steel protective sleeve. The copper provides excellent electrical conductivity while the steel sleeve provides high mechanical strength and thread shear resistance. This composite material approach resolves the contradiction by allowing the system to simultaneously achieve both electrical performance and mechanical durability that neither material could provide alone.

Inventive Principle:
Principle #40Composite materials

2Strength

If high tightening torque is applied to copper bolts, then mechanical connection strength is improved, but thread shear risk increases

Engineering Contradiction:
Improveconnection strengthVSAvoidthread integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The steel protective sleeve acts as an intermediary element between the copper conductor and the external environment. It provides a mechanically robust interface for applying tightening torque while protecting the copper thread from shear forces. The sleeve transfers and distributes the mechanical loads, enabling high connection strength without compromising thread integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If copper is used for both conductor and bolt, then electrical conductivity is maintained, but mechanical durability deteriorates under dynamic loads

Engineering Contradiction:
Improveelectrical conductivityVSAvoidconnection durability
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies local quality by using different materials in different regions of the connection assembly. The copper conductor maintains electrical conductivity where needed, while the steel protective sleeve provides enhanced mechanical durability and thread protection. This localized material differentiation allows the connection to achieve both electrical performance and long-term durability under dynamic loading conditions.

Inventive Principle:
Principle #3Local quality

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

Enhances mechanical stability and durability of electrical connections by preventing thread shear while maintaining electrical conductivity, even under dynamic conditions.

Implementation Method 1

The sleeve is bonded to the terminal part by a material bond

Methodology Applied
Scientific EffectMaterial bond: Welding

Implementation Method 2

the bolt shank is pressed longitudinally into the through-opening of the sleeve. According to the invention, the outer surface of the bolt shank is in direct contact with the inner surface of the through-opening. In this way, a force-fit or form-fit is created when the bolt is inserted into the through-opening

Methodology Applied
Scientific EffectForce-fit: Mechanical Fastener

Implementation Method 3

The bolt plastically deforms the inner surface of the through-opening

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP4208920B1Electric connection for motor vehicle line
Publication Date: 2025.11.12 AUTO KABEL MANAGEMENT GMBH
  • EP4208920B1 patent drawingFigure 1a~1b
  • EP4208920B1 patent drawingFigure 1c~1d
  • EP4208920B1 patent drawingFigure 2a~2b

AI summary

The connection comprises a terminal part, a sleeve which is bonded to the terminal part and which has a passage opening running in the longitudinal direction, and a pin which is connected to the sleeve and has a pin shaft and a pin head, wherein the pin shaft of the pin is compressed in the passage opening of the sleeve in the longitudinal direction, and the pin head of the pin is arranged in a recess arranged on the end-face end of the sleeve. The invention is characterized in that the sleeve end face lying at the end-face end is bonded to the terminal part.