Low-Profile Tire Bead Core Sizing for Easier Rim Mounting
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Solution Overview
Problem
Pneumatic tires for small-sized shuttle buses face poor rim-mounting workability due to their small rim diameter, low cross-sectional height, and large rim width, which affects space efficiency and durability.
Innovation Solution
The tire design includes a specific configuration with a cross-sectional width of the bead core satisfying the expression Wb ≤ 21 × SH / SW, along with other parameters to enhance rim-mounting workability and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the rim diameter is reduced to 10-18 inches and the cross-sectional height is reduced to ensure large vehicle interior space, then the vehicle interior space is improved, but the rim-mounting workability deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the cross-sectional width of the bead core (Wb) to satisfy the expression Wb ≤ 21 × SH / SW, where SH is cross-sectional height and SW is cross-sectional width. This parameter optimization allows the tire to maintain small overall dimensions for improved vehicle interior space while ensuring adequate bead core width for proper engagement with the rim, thus resolving the contradiction between compact size and rim-mounting workability
2Volume of moving object
If the rim width is increased to accommodate in-wheel motors, then the motor accommodation space is improved, but the rim-mounting workability deteriorates
Solution Approach 1:
The patent addresses this contradiction by optimizing the bead core cross-sectional width parameter Wb to satisfy Wb ≤ 21 × SH / SW. This ensures that even when the rim width is increased to accommodate in-wheel motors (maintaining the ratio RW/SW of 0.78 to 0.99), the bead core maintains sufficient width for proper rim engagement, thereby preserving rim-mounting workability despite the wider rim design
3Volume of moving object
If the cross-sectional height is reduced to ensure large vehicle interior space, then the vehicle interior space is improved, but the durability deteriorates
Solution Approach 1:
The patent resolves this contradiction through parameter optimization of the bead core cross-sectional width Wb, constrained by the expression Wb ≤ 21 × SH / SW. By maintaining an appropriate bead core width relative to the reduced cross-sectional height SH, the tire ensures sufficient structural integrity and bead-to-rim engagement strength, thereby preserving durability despite the reduced cross-sectional height needed for large vehicle interior space
Data Source
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AI summary
Provided is a pneumatic tire having a specific tire size and having an enhanced rim-mounting workability. The present invention is directed to a pneumatic tire to be mounted on a rim R and used. The rim R has a rim diameter RD of 10 to 18 inches. A ratio SH/SW of a cross-sectional height SH of the tire to a cross-sectional width SW of the tire is 0.30 to 0.45. A ratio RW/SW of a rim width RW of the rim R to the cross-sectional width SW of the tire is 0.78 to 0.99. The pneumatic tire includes a pair of bead portions 4 in which respective bead cores 5 are embedded. A cross-sectional width Wb (mm) in a tire axial direction of at least one of the bead cores 5 satisfies expression (1) described below. Wb≤21×SH/SW