Tire Bead Contact Geometry for Lower Rolling Resistance
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Solution Overview
Problem
Pneumatic tires experience increased rolling resistance due to deformation of the bead portions when a load is applied, generating heat and increasing energy loss.
Innovation Solution
The pneumatic tire design includes a specific contact region length and pressure distribution in the bead portions, supported by the rim flange to reduce bending deformation and heat generation, with optimized dimensions and contact pressures to enhance fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the bead portion structure is conventional, then the tire can be manufactured with standard design, but the bead portions deform with the rim flanges as a fulcrum when load is applied, generating heat and causing increased rolling resistance
Solution Approach 1:
The patent applies parameter changes by optimizing the contact region length between the bead portion and rim flange. Specifically, the contact region length L is set to 37-45mm, which changes the geometric parameters of the bead portion to reduce deformation and heat generation, thereby suppressing rolling resistance and energy loss.
2Loss of energy
If the contact region length is increased to suppress deformation, then rolling resistance is reduced, but the bead portion structure becomes more constrained
Solution Approach 1:
The patent resolves this contradiction by changing the parameter of contact region length to a specific range (37-45mm). This parameter optimization achieves the goal of reducing rolling resistance while maintaining a relatively simple and conventional bead portion structure, avoiding unnecessary complexity.
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 design effectively suppresses rolling resistance and improves fuel efficiency by reducing heat generation and air resistance, while maintaining tire support and reducing energy loss.
Implementation Method 1
When a load is applied to a pneumatic tire, the bead portions deform with the rim flanges as a fulcrum, generating heat and causing an increase in rolling resistance.
Data Source
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AI summary
A pneumatic tire includes a pair of sidewall portions, and a pair of bead portions each connected to a respective one of the pair of sidewall portions. Each bead portion includes a bead outer surface extending from a bead toe toward outward in the tire axial direction through a bead heel to the sidewall portion. In a state where the tire is mounted on a standard rim, inflated to a standard internal pressure, and loaded with a standard load, each bead portion has a contact region in contact with the standard rim. In at least one of the bead portions, a length of the contact region along the bead outer surface from the origin located 16.5 mm inward in the tire axial direction from a reference line defining the rim width in a tire meridian cross-section is in a range from 37 mm to 45 mm.