Narrowed Width Tire-Rim Assembly Reducing Rolling Resistance

Solution Overview

Problem

The challenge is to reduce both the rolling resistance value and weight of a tire in a compatible manner, as wider tires increase air resistance and weight, affecting fuel consumption and vehicle comfort, while also requiring sufficient space for electric vehicle components.

Innovation Solution

The solution involves a tire-rim assembly with a narrowed width and increased outer diameter, utilizing high internal pressure to minimize tread deformation and maintain load-bearing capacity, thereby reducing rolling resistance and weight effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If tire width is increased to reduce rolling resistance, then rolling resistance value decreases, but tire weight increases and air resistance increases

Engineering Contradiction:

Improverolling resistance valueVSAvoidtire weight

Core Design Contradiction:

Loss of energyVSWeight of moving object

Solution Approach 1:

The patent changes the geometric parameters of the tire by narrowing the tire width (cross-sectional width) to reduce tire weight and air resistance. This parameter change is designed to maintain or improve fuel consumption rates while reducing the rolling resistance value through optimized tire dimensions rather than relying on wider tires.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent shifts the optimization focus from increasing tire width (one-dimensional solution) to optimizing the ratio between cross-sectional width and outer diameter (multi-dimensional approach). By controlling the width-to-diameter ratio within a specific range, the patent achieves reduced rolling resistance without proportionally increasing tire weight, effectively moving to a different dimensional optimization space.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of energy

If tire width is increased to reduce rolling resistance, then rolling resistance value decreases, but air resistance increases

Engineering Contradiction:

Improverolling resistance valueVSAvoidair resistance

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent changes the geometric parameters of the tire by narrowing the tire width (cross-sectional width) to reduce tire weight and air resistance. This parameter change is designed to maintain or improve fuel consumption rates while reducing the rolling resistance value through optimized tire dimensions rather than relying on wider tires.

Inventive Principle:

Principle #35Parameter changes

3Object-generated harmful factors

If tire width is narrowed to reduce air resistance, then air resistance decreases, but rolling resistance increases

Engineering Contradiction:

Improveair resistanceVSAvoidrolling resistance value

Core Design Contradiction:

Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The patent shifts the optimization focus from increasing tire width (one-dimensional solution) to optimizing the ratio between cross-sectional width and outer diameter (multi-dimensional approach). By controlling the width-to-diameter ratio within a specific range, the patent achieves reduced rolling resistance without proportionally increasing tire weight, effectively moving to a different dimensional optimization space.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Use of energy by moving object

If tire width is narrowed to improve fuel consumption, then fuel consumption rate improves, but vehicle space decreases

Engineering Contradiction:

Improvefuel consumption rateVSAvoidvehicle space

Core Design Contradiction:

Use of energy by moving objectVSVolume of moving object

Solution Approach 1:

The patent optimizes the tire's geometric parameters, specifically controlling the cross-sectional width and outer diameter ratio, to achieve a balance between fuel consumption and vehicle space. By narrowing the tire width while maintaining an appropriate outer diameter, the patent reduces air resistance and improves fuel consumption without excessively compromising vehicle space.

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 results in improved fuel efficiency, reduced air resistance, and increased vehicle space, allowing for better accommodation of electric vehicle components without excessive weight or resistance.

Implementation Method 1

utilizing high internal pressure to minimize tread deformation and maintain load-bearing capacity

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 2

paying attention to deformation of a tread as a main factor of energy loss affecting a rolling resistance value of a tire

Methodology Applied

Scientific EffectDeformation: Deformation

Data Source

PatentEP2724871B1Passenger vehicle

Publication Date: 2020.04.01 BRIDGESTONE CORP

Figure 1A~1B
Figure 2
Figure 3A~3B

AI summary

The present invention provides: a pneumatic radial tire for a passenger car, the tire having cross sectional width SW and outer diameter OD satisfying a predetermined relationship formula when the tire is assembled with a rim and inflated at internal pressure of at least 250 kPa; a tire-rim assembly formed by assembling bead portions of said tire with the rim; and a method for using a tire, including preparing a pneumatic radial tire for a passenger car in which cross sectional width SW and outer diameter OD of the tire satisfy a predetermined relationship formula, and using the tire at internal pressure of at least 250 kPa.