Motorcycle Tire Carcass Ply Angles for Smoother Cornering
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Solution Overview
Problem
Existing tires for two-wheeled automotive vehicles face challenges in achieving stable and smooth transitions between straight running and cornering, with a need for improved handling performance.
Innovation Solution
A tire design featuring a carcass with a first ply inclined at 90° to the equator plane and a second ply inclined between 65° to 85°, combined with specific cord angles and orientations to enhance handling and cornering performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tire uses a conventional carcass structure with uniform cord angles, then the manufacturing is simpler, but the handling performance and cornering stability are insufficient
Solution Approach 1:
The carcass is segmented into multiple plies (first ply, second ply, and optionally third ply) with different cord angle configurations. Each ply is assigned a specific function: the first ply with 90° cords provides vertical support, the second ply with 65°-85° cords enhances cornering stability, and the third ply with 45°-60° cords improves straight running stability. This segmentation allows each layer to contribute differently to overall tire performance.
Solution Approach 2:
Different regions of the carcass are given different cord angles to optimize local performance characteristics. The first ply uses 90° cords for maximum vertical stiffness, the second ply uses 65°-85° cords for cornering stability, and the third ply uses 45°-60° cords for straight running stability. This local differentiation of cord angles creates zones of optimized mechanical properties throughout the carcass structure.
2Stability of the object's composition
If the tire increases vertical stiffness for straight running stability, then the straight running stability improves, but the handling performance and cornering responsiveness deteriorate
Solution Approach 1:
The tire structure is designed to dynamically adapt its stiffness characteristics based on operating conditions. During straight running, the 90° first ply dominates providing vertical stability. During cornering, the 65°-85° second ply becomes more active providing lateral stability and camber thrust. The multi-ply construction with different cord angles creates a dynamic stiffness profile that responds to the specific demands of each maneuver.
Solution Approach 2:
The carcass uses a composite construction of multiple plies with different cord angle orientations and potentially different material properties. This composite structure combines the advantages of each ply: the 90° first ply for vertical support, the 65°-85° second ply for cornering, and the 45°-60° third ply for straight running. The composite nature allows the tire to exhibit different effective stiffness characteristics depending on the direction and type of load applied.
3Ease of operation
If the tire uses a single ply configuration for simplicity, then the manufacturing is easier, but the ability to achieve smooth transition between straight running and cornering is insufficient
Solution Approach 1:
The solution moves from a single-dimension (single ply) approach to a multi-dimensional (multi-ply with different angles) approach. By adding the dimensional aspect of cord angle variation across multiple plies, the tire gains the capability to independently optimize for both straight running and cornering performance. The third dimension of ply stacking allows complex stress distribution patterns that enable smooth transitions between different riding modes.
Data Source
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AI summary
A tire 2 for a two-wheeled automotive vehicle includes: a pair of beads 10; and a carcass 12 extended on and between the beads 10. The carcass 12 includes: a first ply 12a including a plurality of first cords 36 arranged in parallel; and a second ply 12b layered outward of the first ply 12a and including a plurality of second cords 40 arranged in parallel. The first cords 36 are inclined relative to an equator plane CL, and each of the first cords 36 forms an angle θ1 relative to the equator plane CL, the angle θ1 being substantially 90°. The second cords 40 are inclined relative to the equator plane CL, and each of the second cords 40 forms an angle θ2 relative to the equator plane CL, the angle θ2 being greater than or equal to 65° and less than or equal to 85°.