Indoor Tire Stress Simulation via Road Force Data

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Solution Overview

Problem

Current indoor endurance bench tests for tires lack the precision to accurately replicate the stresses experienced during outdoor road use, due to variations in speed and conditions, making it difficult to simulate real-world tire wear effectively.

Innovation Solution

A method utilizing a vehicle equipped with a measuring unit comprising a satellite positioning device, camera, and processing device to record and process data on the vehicle's position, speed, and road conditions, allowing for the determination of the stress forces to be applied to a tire during an indoor test, ensuring high accuracy in simulating outdoor conditions by correcting speed data to match maximum permitted speeds and calculating inertial, gravitational, and aerodynamic forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If outdoor tests are carried out on public roads to measure and record forces acting on tyres, then the realism and accuracy of stress data is improved, but the test duration becomes excessively long and repeatability is compromised due to traffic conditions

Engineering Contradiction:
Improveaccuracy of stress dataVSAvoidtest duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by conducting a one-time outdoor characterization test to capture the course over time of forces acting on tyres, then using this pre-acquired data to control subsequent indoor bench tests. This eliminates the need for repeated long-duration outdoor tests while maintaining data accuracy, as the force profiles are measured in advance and reused for simulation purposes.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the vehicle is driven at maximum permitted speed during outdoor tests to reduce test duration, then productivity is improved, but measurement accuracy deteriorates due to inability to maintain consistent maximum speed under real traffic conditions

Engineering Contradiction:
Improvetest efficiencyVSAvoidspeed consistency
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies self-service by using the vehicle's own motion and the measuring unit to automatically capture the actual course over time of forces acting on tyres during normal driving conditions. The system records real speed variations and traffic conditions without requiring the driver to maintain artificial maximum speeds, thereby obtaining authentic stress data that naturally reflects real-world driving while maintaining test efficiency.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If indoor bench testing is used to simulate tyre stresses, then test cost is reduced and repeatability is improved, but the realism of stress simulation deteriorates without precise knowledge of actual road stresses

Engineering Contradiction:
Improvetest costVSAvoidrealism of stress simulation
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies copying by using a measuring unit that records the actual course over time of forces acting on tyres during outdoor tests, then providing this recorded data to bench actuators to create an accurate copy of real-world stress conditions in the indoor environment. This allows faithful reproduction of road stresses on the test bench without requiring continuous outdoor testing, thereby maintaining realism while achieving the cost and repeatability benefits of indoor testing.

Inventive Principle:
Principle #26Copying

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 method provides a simple, inexpensive, and precise way to simulate outdoor tire wear in indoor tests, eliminating noise and time drift issues, ensuring that the stresses applied to tires closely match real-world conditions, thereby accurately replicating outdoor tests.

Implementation Method 1

a satellite positioning device (4) for measuring the position P and the longitudinal speed Vx of forward travel of the vehicle (1)

Methodology Applied
Scientific EffectSatellite positioning:

Implementation Method 2

calculating inertial, gravitational, and aerodynamic forces

Methodology Applied
Scientific EffectInertial force calculation: Inertia

Implementation Method 3

calculating inertial, gravitational, and aerodynamic forces

Methodology Applied
Scientific EffectGravitational force: Gravitation

Implementation Method 4

calculating inertial, gravitational, and aerodynamic forces

Methodology Applied
Scientific EffectAerodynamic force: Drag

Data Source

PatentEP2689228B1Method of determining the stress that should be applied to a tyre during an indoor endurance bench test
Publication Date: 2016.06.29 BRIDGESTONE CORP
  • EP2689228B1 patent drawingFigure 1
  • EP2689228B1 patent drawingFigure 2
  • EP2689228B1 patent drawingFigure 3

AI summary

A method of determining the stress that should be applied to a tyre during an indoor endurance bench test, the method comprising the steps of: driving a vehicle (1) along a sample road route; measuring variations in the longitudinal speed (Vx) and position (P) of the vehicle (1) during its journey along the sample road route; and calculating the inertial forces (FIx, FIy) acting on the vehicle (1) during its journey along the sample road route, on the basis of variations in the longitudinal speed (Vx) and position (P) of the vehicle (1).