Fiber Wound Body with Thickness Gradient for Weight Reduction

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Solution Overview

Problem

Current fiber-reinforced resin materials used in load energy absorbing applications, such as vehicle crash boxes, face challenges in weight reduction due to uniform fiber mass distribution, which leads to unnecessary fiber mass in sections requiring varying strength, and complex control of oblique angles to achieve strength variation.

Innovation Solution

A fiber wound body with reinforced fiber yarns that have gradual cross-section changes, achieved through continuous variation in drafting rate during manufacturing, allowing for constant fiber content rate and smooth strength variation along the axis without altering the oblique angle, using non-continuous fibers spun into yarns with varying thickness and fiber content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If fiber mass is uniformly distributed in the fiber-reinforced base, then manufacturing is simplified, but weight reduction is limited due to unnecessary fiber mass in sections requiring varying strength

Engineering Contradiction:
Improveweight of fiber-reinforced resin materialVSAvoidmanufacturing simplicity
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent applies local quality by varying the cross-sectional area of fiber yarns along the longitudinal direction of the fiber-reinforced base. Specifically, the fiber yarn cross-sectional area is made larger in the basal portion and smaller in the distal portion, allowing each section to have the appropriate fiber mass for its strength requirements. This eliminates unnecessary fiber mass in lower-stress areas while maintaining sufficient fiber mass in high-stress areas, thereby achieving weight reduction without compromising structural integrity.

Inventive Principle:
Principle #3Local quality

2Strength

If the cross section of fiber yarn is increased toward the basal portion to vary strength, then strength distribution is improved, but complex control of oblique angles is required

Engineering Contradiction:
Improvestrength distribution along the axisVSAvoidcontrol complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent extracts the strength variation function from the oblique angle control and transfers it to the fiber yarn cross-sectional area variation. By making the fiber yarn cross-sectional area larger in the basal portion and smaller in the distal portion, the strength distribution is achieved directly through the fiber arrangement rather than through complex oblique angle adjustments. This simplifies the manufacturing control by eliminating the need for complex oblique angle control mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If fiber yarn cross section is varied to achieve strength variation, then strength distribution is improved, but fiber mass becomes non-uniform requiring fiber addition or removal

Engineering Contradiction:
Improvestrength variation along the axisVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-varying the cross-sectional area of the fiber yarns before they are wound onto the mandrel. The fiber yarns are prepared with larger cross-sectional areas for the basal portion and smaller cross-sectional areas for the distal portion before the winding process begins. This preliminary preparation eliminates the need for complex fiber addition or removal operations during or after winding, as the desired non-uniform fiber mass distribution is already established in the fiber yarns themselves.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3486075B1Fiber wound body, fiber-reinforced resin material, and method for manufacturing fiber wound body
Publication Date: 2021.03.31 TOYOTA INDUSTRIES CORP
  • EP3486075B1 patent drawingFigure 1~2
  • EP3486075B1 patent drawingFigure 3~4
  • EP3486075B1 patent drawingFigure 5~6

AI summary

This fiber wound body has a plurality of reinforcing fiber yarns wound around a winding axis, each of the reinforcing fiber yarns having a thickness gradient portion in which the fiber content is uniform along the longitudinal direction of the yarn and the thickness gradually changes.