Pneumatic Tire Bead Geometry for Rim Engagement Stability
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Solution Overview
Problem
Conventional pneumatic tires face challenges in maintaining steering stability and engagement property between bead portions and the rim due to lateral forces during cornering, which is exacerbated by difficulties in mounting and deteriorating engagement properties.
Innovation Solution
The pneumatic tire design features bead portions with specific geometric configurations, including varying distances and widths to optimize engagement and stability, where the distance between the bead core inner end and toe is between 0.5 to 2.5 times the maximum width, and the bead core width increases radially outward, enhancing rubber volume and contact with the rim.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the tightening force onto the rim is increased to suppress bead portion displacement, then steering stability is improved, but mounting difficulty increases and engagement property deteriorates
Solution Approach 1:
The bead portion is designed with non-uniform cross-sectional geometry, where the distance H from the bead core inner end to the bead toe is specifically controlled to be 0.5 to 2.5 times the maximum width Y of the bead core. This local geometric optimization creates a gradient in rubber volume distribution, providing enhanced engagement with the rim at critical locations while maintaining overall structural integrity and steering stability.
Solution Approach 2:
The invention optimizes the geometric parameters of the bead portion, specifically controlling the ratio between distance H and maximum width Y of the bead core within the range of 0.5 to 2.5 times. This parameter optimization balances the rubber volume to achieve both easy mounting and stable engagement, resolving the contradiction between mounting ease and steering stability.
2Stability of the object's composition
If the contact between rim and bead portions is increased by increasing tightening force, then bead portion displacement is suppressed, but engagement property deteriorates
Solution Approach 1:
The bead portion features a specifically controlled local geometry where distance H is 0.5 to 2.5 times the maximum width Y of the bead core. This creates an optimized rubber volume distribution that enhances engagement reliability at the bead-toe contact region with the rim, while maintaining overall bead portion stability during cornering operations.
Solution Approach 2:
Rather than uniformly increasing tightening force throughout the entire bead portion, the invention applies geometric optimization specifically at the critical engagement zone by controlling the H/Y ratio. This partial optimization of the bead toe region provides sufficient engagement reliability without requiring excessive tightening force that would cause mounting difficulties.
Data Source
AI summary
A pneumatic tire comprises bead portions each having a bead core therein. Each of the bead portions has an outer side surface which is to be in contact with a standard rim on an outer side in a tire axial direction of the bead core. In a tire meridian section of the pneumatic tire in a pre-mounted state, a distance in a tire radial direction between an inner end in a tire radial direction of the bead core and a bead toe is larger than 0.5 times and smaller 2.5 times a maximum width in the tire axial direction of the bead core.