Carbon Fiber Driveshaft Insert for Delamination-Free Torque Transfer

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Solution Overview

Problem

Existing driveshafts made of carbon fiber tubes face challenges in achieving precise shapes and connections that maintain mechanical strength, prevent delamination, and ensure efficient torque transfer without drive loss, especially when using traditional steel processing methods are not applicable.

Innovation Solution

A carbon fiber reinforced driveshaft design featuring a mounting element with a cylindrical insert having centering rings of a regular polygon cross-section, allowing for tight fit and adhesive bonding, which creates a chamber for adhesive application, ensuring secure attachment and preventing delamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional steel processing methods (cutting, bending, turning, milling, extrusion) are used on carbon fiber tubes, then precise shapes and dimensions can be achieved, but the mechanical strength and structural integrity of the carbon fiber tube deteriorate due to exposure and layer damage

Engineering Contradiction:
Improveshape precisionVSAvoidmechanical strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The polygonal cross-section shape is integrated into the carbon fiber tube during the winding manufacturing process itself, rather than attempting to machine the shape afterward. This preliminary formation of the desired geometry eliminates the need for subsequent machining operations that would damage the carbon fiber structure, thereby maintaining mechanical strength while achieving precise dimensional control.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If carbon fiber tubes are machined to obtain desired shapes, then precise dimensions can be achieved, but the structure of the fiber tube is weakened and damaged

Engineering Contradiction:
Improvedimensional precisionVSAvoidstructural integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The polygonal cross-section is formed during the carbon fiber winding process before the tube is completed, eliminating the need for post-manufacturing machining. This ensures both precise dimensional control and preservation of structural integrity by avoiding any interference that would break the fiber structure.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If a circular insert connection is used in carbon fiber tube, then assembly is simplified, but torque transfer is inefficient and delamination occurs between layers

Engineering Contradiction:
Improveassembly easeVSAvoiddrive loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent introduces an asymmetric polygonal cross-section (non-circular) for the insert connection instead of using a symmetric circular shape. This asymmetric geometry creates interlocking features between the insert and the tube that prevent relative rotation and slippage, enabling efficient torque transfer while eliminating delamination. The polygonal shape provides mechanical engagement surfaces that maintain the connection under torsional loading.

Inventive Principle:
Principle #4Asymmetry

4Loss of energy

If polygonal connection is used to eliminate delamination, then torque transfer is improved, but the complexity of the connection design increases

Engineering Contradiction:
Improvedrive loss reductionVSAvoidconnection complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The polygonal cross-section integrates the torque transfer function directly into the basic geometric shape of the insert, rather than adding separate complex mechanical features. The asymmetric polygonal form itself creates the necessary interlocking engagement with the tube, providing both structural integrity and torque transmission in a single integrated design element, thereby limiting the increase in overall complexity.

Inventive Principle:
Principle #4Asymmetry

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 enhances mechanical strength, prevents delamination, ensures efficient torque transfer, reduces noise, and increases the driveshaft's lifespan under dynamic loading, while allowing for various designs and connections without welding.

Implementation Method 1

The insert is equipped with at least one centering ring with a cross-section in the shape of a substantially regular polygon with 10 to 20 angles, wherein the shape of the insert corresponds to the shape of the seating sleeve inside the tube and is configured to mount the mounting element to the seating sleeve of the driveshaft tube by means of a tight fit and/or adhesive bonding

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP4571134B1Carbon fiber reinforced driveshaft
Publication Date: 2026.04.15 KRAWCZYK MACIEJ
  • EP4571134B1 patent drawingFigure 1
  • EP4571134B1 patent drawingFigure 2~3
  • EP4571134B1 patent drawingFigure 4~5

AI summary

A carbon fiber reinforced driveshaft, especially for vehicles, comprising a mounting element (1) including a body (11) and an insert (12), and a carbon fiber tube (2), wherein the insert has a cylindric-like shape and is equipped with at least one centering ring (13a, 13b) with a cross-sectional shape of a substantially regular polygon having from 8 to 20 angles, wherein the shape of the insert corresponds to the shape of a seating sleeve (21) inside the tube and is configured so that the mounting element is attached to the seating sleeve of the tube of the drive shaft by tight fitting and/or adhesive.