Tire Tread Depth Tracking Across Non-Use Rolling Radius Drift

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Solution Overview

Problem

Existing methods for determining tire tread depth using the rolling radius-based approach are inaccurate when tires are not used for extended periods due to changes in tire dimensions caused by creep or aging effects, leading to distorted measurements during subsequent use.

Innovation Solution

A method that incorporates an additional sensor, such as an acceleration sensor or tire pressure monitoring system (TPMS), to detect non-use phases and record a new starting value for the dynamic rolling radius upon resumption of use, accounting for dimensional changes during storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If optical measurement methods are used for tire tread depth, then measurement speed and automation are improved, but measurement precision deteriorates due to contamination and environmental factors

Engineering Contradiction:
Improvemeasurement speedVSAvoidtread depth accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces optical measurement systems with a mechanical probe-based measurement system. The probe physically contacts the tire tread to measure depth, eliminating the problems of optical contamination and environmental sensitivity while maintaining automated operation through motorized probe actuation and digital data processing.

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

Solution Approach 2:

The patent introduces a mechanical probe as an intermediary between the measurement system and the tire tread. This probe serves as a reliable mediator that physically transfers measurement information from the tread surface to the sensor, providing consistent and accurate measurements regardless of optical conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If manual measurement methods are used, then measurement precision is maintained, but productivity and automation are reduced

Engineering Contradiction:
Improvetread depth accuracyVSAvoidmeasurement speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The measurement system is designed to be self-servicing through automated probe actuation, automatic data capture, and integrated data processing. The system performs measurements, processes data, and generates reports without continuous manual intervention, combining automated efficiency with precise mechanical measurement capabilities.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual measurement operations with an automated mechanical system that uses a motorized probe, electronic sensors, and computer-controlled measurement sequences to achieve both high speed and precision in tread depth measurement.

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

3Measurement precision

If complex calibration procedures are implemented, then measurement precision is improved, but device complexity and ease of operation worsen

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidcalibration procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-calibration using built-in reference features and automated calibration routines. The probe system includes integrated reference targets and automatic calibration algorithms that adjust measurement parameters without requiring external calibration equipment or complex manual procedures, maintaining precision while simplifying operation.

Inventive Principle:
Principle #25Self-service

4Reliability

If frequent manual inspections are performed, then measurement reliability is improved, but loss of time and productivity increase

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidinspection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system enables continuous automated measurement operations without requiring periodic manual intervention or inspection pauses. The automated probe system continuously measures tread depth across multiple locations and tires, maintaining reliable data collection while eliminating time losses associated with manual inspection cycles.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP4522429B1Method, control unit and system for determining the tread depth of a tire
Publication Date: 2026.05.06 CONTINENTAL REIFEN DEUTSCHLAND GMBH
  • EP4522429B1 patent drawingFigure 1~2

AI summary

The invention relates to a method for determining the tread depth (tp) of a tread of a tire (2) mounted on a rim (1) on a vehicle, in which method the current dynamic rolling radius (Rd) of the tire is continually determined in usage phases (A1, A2) of the tire (2) by ascertaining a current angular velocity (ω) of the tire (2) from data determined by a first sensor and ascertaining a current velocity (V) of the vehicle from data determined by a second sensor (21) and determining the current dynamic rolling radius (Rd) on the basis of the determined current angular velocity (ω) and the current velocity (V) of the vehicle, wherein a starting value (S1) of the dynamic rolling radius (Rd) is recorded at the beginning of a first usage phase (A1) and a current tread depth (tp) of the tire (2) is determined from deviations of the current dynamic rolling radius (Rd) from the starting value, and wherein a current movement status of the tire (2) is ascertained from data determined by a third sensor (20), by determining a usage phase (A1, A2) as the movement status if data determined above a predefined limit value exist and determining a non-usage phase (N) as the movement status if data determined below a predefined limit value over a predefined time period exist, and, in the event of a change in the movement status from a non-usage phase (N) to a subsequent usage phase (A2), a new starting value (S2) of the dynamic rolling radius (Rd) is recorded and the subsequently determined current dynamic rolling radii (Rd) are compared with said new starting value instead of with the previous starting value in order to continually determine the current tread depth (tp). The invention also relates to a control unit and to a system for determining the tread depth (tp).