Arcuate Tread Tire for Three-Wheeled Vehicle Cornering Stability
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Solution Overview
Problem
Three-wheeled vehicles with two front wheels and a single rear wheel face instability during cornering due to insufficient cornering force and sensitivity to road undulations when equipped with two-wheeled motorcycle tires, especially at small camber angles.
Innovation Solution
A tire with an arcuate tread profile featuring a crown region with a land ratio of not less than 98% and shoulder regions with a land ratio of 85% to 93%, along with a tread rubber loss tangent of 0.27 or higher, and crown slots for wear indication, designed for the rear wheel of a three-wheeled vehicle, enhancing cornering force and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a two-wheeled motorcycle tire with arcuate tread profile is mounted on the rear wheel of a three-wheeled vehicle, then the tire can be easily obtained and installed, but the cornering force becomes insufficient and the vehicle behavior becomes unstable during cornering at small camber angles
Solution Approach 1:
The tread portion is divided into crown region and shoulder region with different land ratio characteristics. The crown region has a land ratio of not less than 98% to provide high rigidity and sufficient cornering force at small camber angles, while the shoulder regions have a land ratio of from 85% to 93% to provide appropriate cornering force at large camber angles. This local differentiation resolves the contradiction by optimizing each region's properties for its specific function.
2Adaptability or versatility
If the tread portion has low rigidity to provide slide controllability, then the tire can adapt to road surfaces, but the cornering force becomes insufficient to generate required large lateral force
Solution Approach 1:
Different regions of the tread portion are assigned different rigidity levels through controlled land ratios. The crown region with land ratio ≥98% provides high rigidity for generating sufficient cornering force, while the shoulder regions with land ratio 85-93% provide appropriate flexibility for slide controllability. This resolves the contradiction by spatially separating the functions of force generation and adaptability.
Solution Approach 2:
The tread portion is segmented into functionally distinct crown and shoulder regions with different land ratio characteristics. This segmentation allows each region to independently optimize its performance - the crown region for cornering force generation and the shoulder regions for slide controllability - thereby resolving the contradiction between these two opposing requirements.
3Force
If the crown region has high land ratio to increase cornering force, then the rigidity of tread portion increases, but the slide controllability may be reduced
Solution Approach 1:
The crown region is assigned a land ratio of not less than 98% to maximize rigidity and cornering force, while the shoulder regions are assigned a land ratio of from 85% to 93% to maintain slide controllability. This local quality differentiation resolves the contradiction by concentrating high rigidity requirements in the crown region while preserving flexibility in the shoulder regions.
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
The tire design stabilizes the rear wheel and vehicle behavior during cornering by generating a large cornering force and maintaining balance between cornering force and slide controllability, reducing the impact of road undulations and improving lane change and wet performance.
Implementation Method 1
the tread portion is provided with a tread profile which is arcuate in the tire meridian section... the crown region has a land ratio of not less than 98%, and the shoulder regions have a land ratio of from 85% to 93%... A tread rubber disposed in the tread portion to define the ground contacting surface thereof preferably has a loss tangent not less than 0.27 at a temperature of 0 deg. C.
Implementation Method 2
A tread rubber disposed in the tread portion to define the ground contacting surface thereof preferably has a loss tangent not less than 0.27 at a temperature of 0 deg. C.
Data Source
AI summary
A tire includes a tread portion provided with a tread profile which is curved in an arcuate shape in a tire meridian section so that the tread portion includes a crown region contacting with the ground during straight running, and a pair of shoulder regions contacting with the ground during cornering by leaning the tire at a certain camber angle. The crown region has a land ratio of not less than 98%, and the shoulder regions have a land ratio of from 85% to 93%. A three-wheeled vehicle has a pair of front wheels and a single rear wheel on which the tire is mounted.