Bonded Sleeve and Steel Bolt Electrical Joint for High-Torque Stability

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Solution Overview

Problem

Existing electrical connections between conductors using copper or copper alloy bolts face issues with mechanical stability under dynamic loads, leading to thread shear, while steel bolts compromise electrical conductivity.

Innovation Solution

A connection system using a copper alloy sleeve bonded to a conductor, combined with a steel alloy bolt inserted into the sleeve, where the bolt is securely fastened through a recess in the sleeve to prevent rotation and allow higher torque tightening, ensuring mechanical stability without compromising electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a copper or copper alloy bolt is used, then electrical conductivity is maintained, but mechanical stability is reduced and thread shear occurs under dynamic loads

Engineering Contradiction:
Improveelectrical conductivityVSAvoidmechanical stability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The connection system is divided into two separate functional components: a copper alloy sleeve that provides electrical conductivity and is bonded to the conductor, and a steel alloy bolt that provides mechanical strength for tightening. This segmentation allows each component to optimize its material properties for its specific function without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The copper alloy sleeve acts as an intermediary element between the conductor and the steel bolt. The sleeve is bonded to the conductor and receives the bolt, allowing the steel bolt to apply clamping force while the copper sleeve maintains electrical contact with the conductor, thus mediating between mechanical and electrical requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If a steel alloy bolt is used, then mechanical stability is improved, but electrical conductivity is compromised due to increased contact resistance

Engineering Contradiction:
Improvemechanical stabilityVSAvoidelectrical conductivity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The connection system is divided into two separate functional components: a copper alloy sleeve that provides electrical conductivity and is bonded to the conductor, and a steel alloy bolt that provides mechanical strength for tightening. This segmentation allows each component to optimize its material properties for its specific function without compromise.

Inventive Principle:
Principle #1Segmentation

3Force

If high tightening torque is applied to a copper bolt, then mechanical connection is secured, but thread shear occurs

Engineering Contradiction:
Improvetightening torqueVSAvoidthread resistance
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The connection system is divided into two separate functional components: a copper alloy sleeve that provides electrical conductivity and is bonded to the conductor, and a steel alloy bolt that provides mechanical strength for tightening. This segmentation allows each component to optimize its material properties for its specific function without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection system uses a composite structure combining copper alloy and steel alloy materials. The copper alloy sleeve maintains electrical conductivity while the steel alloy bolt provides high strength for withstanding tightening torque and dynamic loads, creating a composite connection that leverages the advantages of both materials.

Inventive Principle:
Principle #40Composite materials

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 solution provides enhanced mechanical stability and maintains electrical conductivity by allowing higher torque tightening, reducing the risk of thread shear and improving the durability of the connection.

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 is securely fastened through a recess in the sleeve to prevent rotation

Methodology Applied
Scientific EffectMechanical fastening: Mechanical Fastener

Implementation Method 3

maintaining electrical conductivity by allowing higher torque tightening

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4304900B1Electric connection
Publication Date: 2025.11.19 ONE MOBILITY AUTOKABEL GMBH
  • EP4304900B1 patent drawingFigure 1a~1b
  • EP4304900B1 patent drawingFigure 1c~1d
  • EP4304900B1 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 through-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 located 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.