Retread Tire Groove Depth via Casing Pre-Buffing

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Solution Overview

Problem

Retreading processes require significant tire tread volume to achieve sufficient tread groove depth, leading to high material costs and inefficient wear volume in retreaded tires.

Innovation Solution

A method and system for retreading tires using a pre-cured tread band with a smooth back face and aligned tread grooves, which conform to the casing grooves during curing, increasing the final tread groove depth and wear volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a pre-cured tread band with grooves is applied to a buffed casing, then the tread can be bonded to the casing, but the tread groove depth is insufficient and wear volume is reduced

Engineering Contradiction:

Improvetread groove depthVSAvoidtread material volume

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The casing is pre-buffed with grooves formed at predetermined locations and depths before the tread band is applied. This preliminary action creates a recessed profile in the casing that, when combined with the tread band grooves, produces the desired final tread groove depth after curing, eliminating the need for additional deep grooves in the tread band itself.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The tread band grooves are nested within or aligned with the pre-formed casing grooves. The tread band is positioned such that its grooves coincide with the recessed profiles of the buffed casing, creating a synergistic effect where the combination of tread and casing grooves achieves the required final groove depth without requiring the tread alone to provide the full depth.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If significant tread volume is used to achieve sufficient groove depth, then compliant skid base gauges can be met, but material costs increase and wear volume efficiency decreases

Engineering Contradiction:

Improveskid base gauge complianceVSAvoidtread material consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the approach from providing groove depth entirely through the tread band to a combined approach where the casing contributes a portion of the groove depth through pre-buffing. This parameter change in the depth contribution distribution allows using a thinner tread band while achieving the same final groove depth and skid base gauge compliance.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If the tread back face has discontinuities or features, then it may facilitate bonding, but it prevents conforming to the casing profile and forming synergistic grooves

Engineering Contradiction:

Improvebonding facilitationVSAvoidprofile conformance

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The tread band is designed with a smooth back face in the regions that will contact and conform to the casing grooves, while other portions of the tread may have different characteristics. This local quality differentiation allows the critical groove-forming areas to conform precisely to the casing profile while maintaining bonding capabilities through the smooth conforming contact.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

An adhesive layer is applied to the smooth back face of the tread band before mounting it to the casing. This preliminary action of applying adhesive to a smooth surface ensures proper bonding while allowing the smooth surface to subsequently conform to the recessed profile of the buffed casing during curing, forming the desired synergistic grooves.

Inventive Principle:

Principle #10Preliminary action

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 method results in retreaded tires with compliant skid base gauges and increased tread wear volume, reducing material usage and extending tire life while conserving casing material during the retreading process.

Implementation Method 1

The assembly, including the casing and the tread, may then be cured or vulcanized in a curing chamber such as an autoclave

Methodology Applied

Scientific EffectVulcanization (curing):

Implementation Method 2

curing the tire assembly under pressure such that the back side of the tire tread conforms to at least a portion of the casing profile

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3086934B1System and method for forming retread tires using flat backed tread and retreaded tire

Publication Date: 2021.01.20 BRIDGESTONE BANDAG LLC

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AI summary

Retreaded tires and methods for manufacturing the same. A tire is retreaded with a pre-cured tread band having a smooth back face and one or more tread grooves with compliant skid base gauge on a front face. The grooves in the pre-cured tread band align with grooves in a tire casing and upon curing conform to the shape of the casing grooves. The tire tread depths are greater than the original tire tread depth of the pre-cured tread band, thereby increasing the wear volume of the tire tread.