Motorcycle Tire Carcass Reinforcement Angulation for Stability
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Solution Overview
Problem
Radial tires for motorcycles struggle to maintain stability both in straight-line high-speed trajectories and curved trajectories with high camber angles, as existing designs either prioritize one over the other due to limitations in torsional rigidity and reinforcement architecture.
Innovation Solution
A radial tire design featuring a carcass reinforcement with an inverted carcass layer and a circumferential crown layer, where the inverted carcass layer has a top portion with a substantially constant angle of at least 65° and a lateral portion with an increasing angle, providing low drift rigidity for straight-line stability and high drift rigidity for curved stability through a unique angulation and layer configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the carcass reinforcement uses a traditional inverted carcass layer with constant angle, then the tire structure is simple and easy to manufacture, but the tire cannot maintain stability in both straight-line high-speed trajectories and curved trajectories with high camber angles
Solution Approach 1:
The inverted carcass layer is segmented into three distinct portions: a first portion with angle increasing from bead to equatorial plane, a second portion with substantially constant angle, and a third portion with angle increasing from equatorial plane to bead. This segmentation allows each portion to contribute differently to tire performance, achieving both straight-line stability and curved trajectory stability through coordinated structural zones.
Solution Approach 2:
Different portions of the inverted carcass layer are assigned different angular characteristics tailored to local functional requirements. The first and third portions provide drift rigidity for curved trajectory stability, while the second portion maintains stability for straight-line high-speed trajectories. This local differentiation of structural properties optimizes overall tire performance.
2Ease of manufacture
If the inverted carcass layer has reinforcements forming a constant angle with the circumferential direction, then the manufacturing process is simplified, but the drift rigidity cannot be optimized for both straight-line and curved trajectory stability
Solution Approach 1:
The angular configuration of reinforcements in the inverted carcass layer transitions from dynamic (increasing angle) in the first and third portions to static (constant angle) in the second portion. This dynamic angular variation allows the structure to adapt to different operational conditions, optimizing drift rigidity for both straight-line and curved trajectory stability while remaining manufacturable.
Data Source
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AI summary
The objective is satisfactory motorbike stability both in a straight line at high speed and in curves at high camber angles. Tyre (1) for a motorized two-wheeled vehicle of the motorcycle type, comprising: a tread (2) connected by two sidewalls (3) to two beads (4); a crown ply (5) comprising at least one crown layer (51); and a carcass ply (6) comprising at least one turned-up carcass layer (61), said turned-up carcass layer (61) comprising mutually parallel reinforcements and being wound around a bead wire (7), within each bead, from the inside toward the outside of the tyre, in order to form a turn-up (8) having a free end (E). The turned-up carcass layer (61) comprises a crown-region portion (611) and a lateral portion (612), the crown-region portion (611) extending axially between a first and a second end (E1, E'1), which are symmetric with respect to the equatorial plane (P), the lateral portion (612) extending radially inwards, from a first end (E2) as far as a second end (E3). The reinforcements in the crown-region portion (611) make, with the circumferential direction (X), a substantially constant angle equal at least to 65?. The reinforcements in the lateral portion (612) make, with the circumferential direction (X), an angle that increases, from the first end (E2) to the second end (E3), from an angle smaller than at least 5? to the substantially constant angle, formed by the reinforcements of the crown-region portion (611). The reinforcements in the turn-up (8) make, with the circumferential direction (X), an angle equal in terms of absolute value but with opposite sign, to the angle formed by the reinforcements in the lateral portion (612).