Tread Rubber Forming with Electrically-Conductive Layer

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Solution Overview

Problem

Existing methods struggle to form a jointless tread rubber with three rubber layers and an electrically-conductive layer, as they face difficulties in uniformly integrating the conductive layer within the tread structure.

Innovation Solution

A method involving spirally winding and superposing tape-shaped unvulcanized rubber strips on a cylindrical body to form an annular tread rubber, where a base layer, intermediate layers, and cap layers are created with a specifically positioned electrically-conductive layer to ensure jointless formation, utilizing distinct applicators for each rubber strip type.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional methods are used to form tread rubber with multiple layers, then the structure can be formed, but it becomes difficult to achieve jointless formation when integrating an electrically-conductive layer within three rubber layers

Engineering Contradiction:
Improvejointless formation precisionVSAvoidlayer integration complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The tread rubber is divided into three distinct rubber layers (first, second, and third layers) with the electrically-conductive layer integrated within. Each layer is formed by separately winding rubber strips in specific axial direction regions, allowing precise control over layer positioning and avoiding joints while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the tread rubber in the axial direction are assigned different properties: the first layer provides base structure, the second layer (with electrically-conductive material) provides conductivity in specific regions, and the third layer completes the tread structure. This local differentiation enables jointless formation with functional specialization.

Inventive Principle:
Principle #3Local quality

2Reliability

If rubber strips are wound to form multiple layers with an electrically-conductive layer, then wet performance and responsiveness improve, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvewet performanceVSAvoidmanufacturing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The electrically-conductive layer is prepared and positioned in advance within the tread rubber structure during the winding process. By pre-planning the axial direction regions for each layer and winding strips accordingly, the complex multi-layer structure with conductivity functionality is achieved without requiring post-manufacturing assembly or modification.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the electrically-conductive layer is integrated within three rubber layers, then low fuel consumption performance improves, but achieving uniform integration without joints becomes difficult

Engineering Contradiction:
Improvelow fuel consumption performanceVSAvoidlayer uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The winding process dynamically adjusts the positioning of rubber strips in the axial direction to ensure uniform integration of the electrically-conductive layer within the three rubber layers. By controlling the winding trajectory and strip placement in real-time, uniform distribution and seamless integration are achieved, preventing joints while maintaining functional uniformity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3868549B1Tread rubber forming method and tread rubber forming device
Publication Date: 2023.04.05 SUMITOMO RUBBER INDUSTRIES LTD
  • EP3868549B1 patent drawingFigure 1
  • EP3868549B1 patent drawingFigure 2
  • EP3868549B1 patent drawingFigure 3

AI summary

A tread rubber forming method includes: a first step of forming a base layer; a second step of forming a first intermediate layer on a portion of an outer circumferential surface of the base layer; a third step of winding and superposing a third rubber strip on an outer circumferential surface of the first intermediate layer, to form a first cap layer; a fourth step of winding an electrically-conductive fourth rubber strip from a position of contact with the base layer to an outer circumferential surface of the first cap layer, to form an electrically-conductive layer; and a fifth step of forming a second cap layer on an outer side in a radial direction of the base layer such that a portion of the electrically-conductive layer is exposed to an outer side in the radial direction of the tread rubber.