Tyre Sidewall Defect Detection Using Controlled Lateral Force

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Solution Overview

Problem

Existing methods for controlling tire quality, particularly in identifying 'weak sidewall' defects, are subjective and prone to variability due to operator experience and inconsistent measurement processes, leading to unreliable and repeatable results.

Innovation Solution

A method and apparatus that arrange a tire on a support plane with the axial middle line parallel to the support plane, applying different forces to a free lateral portion while maintaining constant input data during rotation, allowing for objective and repeatable measurements by calculating the difference in reactions to ensure consistent control outcomes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual visual control is used to identify weak sidewall defects, then operator experience can detect quality issues, but the control accuracy is highly subjective and varies significantly with operator experience

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidcontrol repeatability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces manual visual inspection with an automated measurement system that applies mechanical forces to the tyre and uses sensors to objectively measure the responses. This substitution eliminates subjectivity while maintaining detection capability, directly resolving the contradiction between measurement precision and reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables the tyre to 'self-test' by applying forces to its own structure and measuring its natural response characteristics. This self-service approach provides objective, repeatable measurements without requiring operator expertise, improving both precision and reliability simultaneously.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If more accurate manual control is inserted to improve product quality, then defect detection improves, but tyre production times are excessively increased

Engineering Contradiction:
Improvequality control accuracyVSAvoidproduction speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The automated system performs measurements continuously as the tyre rotates on the turntable, eliminating the time-consuming sequential nature of manual inspection. This continuous measurement approach maintains high precision while dramatically improving production speed.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system performs all necessary measurements during a single rotation cycle, preparing and executing the complete inspection process in advance rather than requiring multiple sequential checks. This preliminary action approach ensures accurate quality control without extending production time.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If automatic controls are used to improve objectivity, then measurement consistency improves, but precision and repeatability cannot be ensured due to high number of factors at play

Engineering Contradiction:
Improvemeasurement objectivityVSAvoidcontrol precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the measurement process into distinct phases: applying specific forces in controlled directions, measuring responses at defined positions, and analyzing data separately. This segmentation isolates variables and eliminates the precision problems caused by uncontrolled factors in comprehensive automatic control systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes physical parameters systematically - applying forces in different directions (vertical, horizontal, diagonal) and measuring responses at different angular positions. This controlled parameter variation approach ensures both objectivity and precision by isolating the effects of each factor.

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

This approach provides reliable and repeatable tire quality control by minimizing factors affecting the measurement process, enabling objective identification of defects and non-uniformities, and automating the selection of defective tires.

Implementation Method 1

applying, to a measurement surface of the free lateral portion, a force directed towards the support plane

Methodology Applied
Scientific EffectForce: Force

Data Source

PatentEP3074746B1Method and apparatus for controlling tyres
Publication Date: 2017.08.30 PIRELLI TYRE SPA
  • EP3074746B1 patent drawingFigure 1
  • EP3074746B1 patent drawingFigure 2
  • EP3074746B1 patent drawingFigure 3

AI summary

An apparatus (1 ) for controlling tyres comprises a support plane (2) configured for receiving a tyre (3) with axial middle line plane (4) parallel to the support plane, defining an abutted lateral portion (10a) and a free lateral portion (10b) arranged at a specific height with respect to the support plane. A thrust element (23) is configured for applying, to a measurement surface of the free lateral portion (10b), a force (F) directed towards the support plane. A positioning actuator (19) is operatively associated with the thrust element (23) and configured for moving the thrust element (23) with at least one motion component perpendicular to a rotation axis (X) of the tyre. The apparatus also comprises devices for modifying the angular position of the measurement surface. A control unit is programmed for detecting a first value (U1 ) of output data at each position of the measurement surface as a function of a first value (11 ) of input data maintained substantially constant along at least one complete rotation of the measurement surface around the rotation axis (X) and for detecting a second value (U2) of the output data at each position of the measurement surface. The second value (U2) of the output data corresponds with a second value (I2) of the input data maintained substantially constant along at least one complete rotation of the measurement surface. The control unit comprises a module programmed for calculating, at each position of the measurement surface, a difference (D) between the second value (U2) of the output data and the first value (U1 ) of the output data.