Carbon Fiber Driveshaft Mounting Insert for Delamination-Free Bonding

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Solution Overview

Problem

Existing drive shafts made from carbon fiber tubes face issues with delamination between layers, which leads to torque loss and reduced mechanical strength, especially under high engine power and torque conditions, and traditional manufacturing methods cannot achieve precise shapes or connections without compromising the structural integrity.

Innovation Solution

A mounting element with a cylindrical insert featuring two centering rings and a recessed section forms an adhesive chamber, allowing for both press-fit and adhesive bonding, ensuring precise alignment and preventing delamination, while enabling torque transmission through the entire cross-section of the carbon tube.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If carbon fiber tubes are used to reduce weight, then weight is reduced, but delamination between layers occurs leading to torque loss and reduced mechanical strength

Engineering Contradiction:
ImproveweightVSAvoidmechanical strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The insert is designed with centering rings that preliminarily align and center the mounting element within the carbon fiber tube before adhesive bonding occurs. This preliminary mechanical alignment prevents misalignment stresses that could cause delamination during operation, allowing the carbon fiber tube to maintain its weight advantage while preventing strength loss from delamination

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

An adhesive is introduced as an intermediary substance between the insert and the carbon fiber tube, filling the chamber formed by the recessed section. This adhesive layer bonds the mounting element to the tube while distributing stresses uniformly, preventing direct stress concentrations that would cause layer delamination and torque loss

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If traditional manufacturing methods are used, then production is simpler, but precise shapes and connections cannot be achieved without compromising structural integrity

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidshape precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The mounting element is segmented into distinct functional parts: centering rings for alignment, a recessed section for adhesive containment, and the main body for structural support. This segmentation allows each feature to be manufactured and assembled separately, maintaining manufacturing simplicity while achieving precise geometric relationships that prevent delamination and ensure proper torque transmission

Inventive Principle:
Principle #1Segmentation

3Productivity

If press-fit assembly is used to connect mounting elements, then assembly is faster, but delamination occurs causing torque loss

Engineering Contradiction:
Improveassembly speedVSAvoidtorque transmission reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The solution merges two assembly methods: the rapid press-fit assembly provides immediate mechanical alignment and initial torque transmission capability, while the subsequently introduced adhesive provides permanent bonding that prevents delamination. This combination maintains the productivity benefit of fast assembly while eliminating the reliability problem of torque loss from delamination

Inventive Principle:
Principle #5Merging (Combining)

4Ease of manufacture

If the insert is made cylindrical for ease of manufacture, then manufacturing is easier, but the insert cannot prevent rotation within the tube

Engineering Contradiction:
Improvemanufacturing easeVSAvoidrotational stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

While the overall insert remains cylindrical for ease of manufacture, asymmetric features are introduced: the centering rings have a specific cross-sectional shape that matches the tube's internal geometry, and the recessed section is positioned at a specific location. This asymmetric design within the cylindrical form prevents rotation while maintaining manufacturing simplicity

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 solution enhances mechanical strength, prevents delamination, ensures efficient torque transmission, and increases the service life of the drive shaft under dynamic loads, while maintaining an aerodynamic shape and reducing noise.

Implementation Method 1

The use of a specifically shaped internal profile within the tube enhances strength and physically prevents the insert from rotating

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP4579096A1Mounting element and tube of automotive driveshaft
Publication Date: 2025.07.02 KRAWCZYK MACIEJ
  • EP4579096A1 patent drawingFigure 1
  • EP4579096A1 patent drawingFigure 2~3
  • EP4579096A1 patent drawingFigure 4~5

AI summary

Mounting element (1) of an automotive drive shaft for use with the drive shaft tube (2), wherein the mounting element (1) comprises a body (11) and an insert (12), characterized in that the insert (12) is approximately cylindrical in shape and is equipped with at least two centering rings (13a, 13b), wherein the shape of the centering rings (13a, 13b) of the insert (12) corresponds to the shape of the seating sleeve (21) of the tube (2), and between the centering rings (13a, 13b), there is a section of the insert with a reduced profile (15), which, when the insert (12) is inserted into the tube (2), forms a chamber for placing adhesive. The invention also includes the tube (2) of the drive shaft, the drive shaft, and the method of bonding the actuating element (1) to the aforementioned tube (2).