Tire Wear Estimation Using Deflection for Center Wear Accuracy

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Solution Overview

Problem

Existing methods for estimating tire wear, particularly when the wear shape is center wear, tend to underestimate the actual wear amount by shifting the residual groove amount towards the new tire side, leading to inaccurate wear assessments.

Innovation Solution

A method that estimates tire wear by using the index of deformation velocity, contact time ratio, and deflection amount, which is the difference between the tire radius under non-loaded and loaded states, allowing for accurate wear assessment regardless of the wear shape, and optionally correcting estimates using regression formulas or master curves specific to even and center wear shapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the residual groove amount is estimated using only the index of deformation velocity and contact time ratio, then the estimation process is simple, but the accuracy deteriorates when the wear shape is center wear (estimated wear amount becomes smaller than actual wear amount)

Engineering Contradiction:
Improveaccuracy of wear estimationVSAvoidcomplexity of estimation parameters
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a new parameter (deflection amount) to change the parameter set used for wear estimation. By adding this parameter that specifically captures tire deformation characteristics, the estimation accuracy for center wear is improved without fundamentally changing the existing estimation framework.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent moves from a two-parameter estimation (deformation velocity index and contact time ratio) to a three-parameter estimation by adding deflection amount. This dimensional expansion in parameter space allows the system to distinguish between different wear shapes more effectively, particularly center wear scenarios.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the tire wear estimation method is applied to center wear tires, then the method can be used universally, but the measurement precision deteriorates (shift toward new tire side)

Engineering Contradiction:
Improveapplicability to different wear shapesVSAvoidaccuracy of residual groove amount detection
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by making the estimation process adaptive to different wear shapes. By detecting whether the tire exhibits center wear characteristics and then applying appropriate correction based on the deflection amount, the system tailors the estimation approach to the specific local condition of the tire wear pattern.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements a feedback mechanism where the deflection amount is used to detect and correct estimation errors. The system continuously monitors the relationship between deformation velocity index, contact time ratio, and deflection amount, and adjusts the wear estimation accordingly to compensate for center wear effects.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4124842B1Method for estimating tire wear and method for determining tire wear shape
Publication Date: 2024.11.20 BRIDGESTONE CORP
  • EP4124842B1 patent drawingFigure 1~2B
  • EP4124842B1 patent drawingFigure 3A~3C
  • EP4124842B1 patent drawingFigure 4~5

AI summary

In order to provide a method for accurately estimating a degree of wear of a tire during travelling regardless of a tire wear shape, there is provided a tire wear estimation method for estimating a degree of wear of a tire, in which the degree of wear is estimated by using: an index of deformation velocity at a tire contact edge or in the vicinity of the tire contact edge, the index of deformation velocity having been calculated from magnitude of one of or both of positive and negative peaks appearing in a radial acceleration waveform obtained by differentiating a time-series waveform of tire radial acceleration detected by an acceleration sensor mounted on the tire; a contact time ratio of contact time to tire rotation time, the contact time being a time interval between the positive peak and the negative peak, the tire rotation time being a time interval between either of positive peaks or negative peaks; and a deformation amount which is a difference between a tire radius and an effective radius, the tire radius being a radius of the tire under a non-loaded state and the effective radius being a radius of the tire during travelling.