Composite Coil Spring Layering for Low Weight and Steel-Like Rigidity

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Composite coil springs face challenges in matching the mechanical properties, durability, and size of steel coil springs while maintaining an acceptable cost, as they tend to be heavier and less cost-effective.

Innovation Solution

A composite coil spring design featuring a carbon fiber core and alternating oblique fiber layers of carbon and glass fibers within a polymer matrix, with silica nanoparticles dispersed in the polymer, which provides enhanced mechanical properties and reduced weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If composite coil springs are used to reduce weight, then weight is reduced, but mechanical properties and durability are compromised

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

Solution Approach 1:

The patent employs a multi-layer composite structure combining carbon fiber layers and glass fiber layers within a polymer matrix. The carbon fiber layers provide high strength and stiffness, while the glass fiber layers contribute to durability and cost-effectiveness. This composite material approach enables the spring to achieve weight reduction while maintaining the necessary mechanical properties and durability comparable to steel coil springs.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If composite coil springs are used to reduce weight, then weight is reduced, but size and mechanical property matching becomes difficult

Engineering Contradiction:
ImproveweightVSAvoidsize
Core Design Contradiction:
Weight of moving objectVSLength of moving object

Solution Approach 1:

The patent applies different fiber materials at different locations within the spring structure. Carbon fiber layers are positioned where high strength and stiffness are most needed, while glass fiber layers are placed in regions where durability and cost-effectiveness are prioritized. This localized material differentiation allows the spring to achieve the required size and mechanical property matching while maintaining weight reduction benefits.

Inventive Principle:
Principle #3Local quality

3Weight of moving object

If composite coil springs are used to reduce weight, then weight is reduced, but cost-effectiveness deteriorates

Engineering Contradiction:
ImproveweightVSAvoidcost
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent optimizes the parameters of the composite structure, including the number of carbon fiber layers (2-5 layers), the number of glass fiber layers (2-5 layers), and the fiber orientation angles (alternating oblique angles). By carefully controlling these parameters, the patent achieves a balance between weight reduction and manufacturing cost, making composite coil springs cost-effective compared to traditional steel springs while maintaining superior mechanical properties.

Inventive Principle:
Principle #35Parameter changes

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 achieves a balance of strength, durability, and cost-effectiveness, offering torsional and bending rigidity, and significantly reducing weight compared to steel coil springs, while demonstrating improved fatigue resistance and comparable performance to steel springs.

Implementation Method 1

a polymer matrix and, disposed in the polymer matrix, a carbon fiber core and a plurality of fiber layers

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the polymer matrix includes a polymer and silica nanoparticles dispersed in the polymer

Methodology Applied
Scientific EffectNanocomposite reinforcement: Nanocomposite

Implementation Method 3

a carbon fiber core and a plurality of fiber layers wrapped around the carbon fiber core in alternating oblique fiber angles to the coiled axis

Methodology Applied
Scientific EffectFiber reinforcement: Composite Materials

Data Source

PatentEP3899313B1Composite coil spring with carbon and glass fiber layers
Publication Date: 2022.08.10 MITSUBISHI STEEL MFG CO LTD
  • EP3899313B1 patent drawingFigure 1
  • EP3899313B1 patent drawingFigure 2~5
  • EP3899313B1 patent drawingFigure 4~6C

AI summary

A composite coil spring includes a coil body that extends along a coiled axis. The coil body includes a polymer matrix and, disposed in the polymer matrix, a carbon fiber core and a plurality of fiber layers wrapped around the carbon fiber core in alternating oblique fiber angles to the coiled axis. The fiber layers include, from inside-out starting from the carbon fiber core, at least two consecutive carbon fiber intermediate fiber layers of alternating oblique fiber angles to the coiled axis, immediately followed by at least two consecutive glass fiber intermediate fiber layers of alternating oblique fiber angles to the coiled axis, and immediately followed by a carbon fiber outermost fiber layer.