Vehicle Tyre Bead Core with Differentiated Filament Twist Counts

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Solution Overview

Problem

Existing cable cores used as bead cores in vehicle tires are heavy and costly due to high twist counts, which increase material and weight, and suffer from fretting issues due to high layer contact, making them inefficient in balancing price and processability.

Innovation Solution

A cable core design with a core filament covered by three layers of filaments, where the first and second layers have 9 twists and the third layer has 8 twists, reducing material usage and weight while maintaining durability by minimizing layer contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the number of twists in filament layers is increased to improve structural stability, then the cable core becomes heavier and more expensive, but weight and cost increase

Engineering Contradiction:
Improvestructural stabilityVSAvoidcable core weight
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The patent applies local quality by differentiating the twist counts across different layers: the first layer has 9 twists, the second layer has 9 twists, and the third layer has 8 twists. This localized variation optimizes structural stability where needed while reducing material usage and weight in outer layers, resolving the contradiction between stability and weight.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the twist count parameter from uniform high values to a differentiated sequence (9, 9, 8). This parameter optimization maintains the necessary structural stability for heavy-duty tire applications while reducing the overall material volume and weight compared to conventional uniform high-twist designs.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the number of twists in filament layers is increased to improve structural stability, then the cable core becomes more expensive, but production cost increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidproduction cost
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

By applying local quality with differentiated twist counts (9, 9, 8) across layers, the patent achieves structural stability in critical inner layers while using fewer twists in outer layers, thereby reducing total material consumption and production cost without compromising overall stability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The optimization of the twist count parameter from uniform high values to a differentiated sequence reduces material requirements and manufacturing complexity, making the cable core more cost-effective for heavy-duty tire production while maintaining necessary structural integrity.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the number of twists in filament layers is increased to improve structural stability, then fretting effects increase, but durability decreases

Engineering Contradiction:
Improvestructural stabilityVSAvoiddurability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies local quality by using lower twist counts (8 twists) in the outer third layer compared to inner layers (9 twists). This reduces the contact pressure and fretting effects between layers where outer layers interact with the tire structure, thereby improving durability and reducing fretting while maintaining structural stability through the inner layers.

Inventive Principle:
Principle #3Local quality

4Weight of moving object

If thinner diameter filaments are used to reduce weight, then processing difficulty increases

Engineering Contradiction:
Improvecable core weightVSAvoidprocessability
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent optimizes the filament diameter parameter to 2.0 mm, which provides a balance between weight reduction and processability. This diameter is thin enough to reduce overall cable core weight but thick enough to remain easy to process and handle during manufacturing, resolving the contradiction between weight and ease of manufacture.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3446895B1Cable core, suitable as bead core of a vehicle tyre
Publication Date: 2020.03.04 CONTINENTAL REIFEN DEUTSCHLAND GMBH
  • EP3446895B1 patent drawingFigure 1~2

AI summary

The invention relates to a cable core (1) suitable as a bead core of a vehicle tire, wherein the cable core (1) comprises a core filament (2) which is encased by at least three layers (31, 32, 33) of filaments (4), wherein the filaments (4) of each of these at least three layers (31, 32, 33) have a specific number of twists around the layer or core filament (2) below it. The filaments (4) of the first and second layers (31, 32) have the same number of twists, and the filaments (4) of the third and subsequent layers (33) have the same or a lower number of twists, wherein the layer (31) directly on the core filament (2) is designated as the first layer, and the subsequent layers are numbered consecutively.