Pneumatic Tire Outside-In Carcass Winding for Durability
Solution Overview
Problem
Existing pneumatic tire designs face issues with durability and adhesiveness between the inner liner and rubber chafer, leading to potential air leakage and reduced durability due to direct contact and rubbing between the carcass ply and bead cores, as well as inadequate adhesiveness between the inner liner and rubber chafer.
Innovation Solution
A pneumatic tire design where the carcass ply is wound from the outside to the inside in the tire width direction, with the inner liner extending between the beads and carcass ply as a buffer, and adhesion-reinforcing rubber layers with specific modulus values are used to enhance adhesiveness between the inner liner and rubber chafer, preventing direct contact and improving durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the carcass ply is wound from the inside to the outside in the tire width direction, then the tire structure is conventional and easy to manufacture, but the carcass ply directly contacts the bead cores causing rubbing and reduced durability
Solution Approach 1:
The patent inverts the conventional winding direction of the carcass ply from inside-to-outside to outside-to-inside in the tire width direction. This inversion changes the layer arrangement so that the inner liner is positioned between the bead cores and the carcass ply, preventing direct contact and rubbing between the carcass ply and bead cores, thereby improving durability while maintaining manufacturing feasibility
Solution Approach 2:
The patent introduces the inner liner as an intermediary layer positioned between the bead cores and the carcass ply. This intermediary structure prevents direct contact between the carcass ply and bead cores, eliminating the rubbing issue and improving durability without complicating the manufacturing process
2Reliability
If low permeability rubber is used for the inner liner to prevent air permeation, then air leakage is prevented, but the adhesiveness between the inner liner and rubber chafer is reduced due to modulus value difference
Solution Approach 1:
The patent changes the physical parameters of the inner liner by using rubber compositions with specifically controlled modulus values (e.g., 300% modulus between 2.0-4.0 MPa) and hardness (50-65 degrees). This parameter optimization allows the inner liner to maintain low permeability while achieving sufficient adhesiveness to the rubber chafer, resolving the contradiction between air leakage prevention and bonding strength
3Reliability
If the carcass ply is wound from the outside to the inside in the tire width direction, then steering stability is enhanced through improved tension distribution, but the structure becomes more complex
Solution Approach 1:
The patent inverts the conventional winding direction to achieve improved tension distribution in the carcass ply. By winding from outside-to-inside instead of inside-to-outside, the carcass ply creates optimal tension patterns that enhance steering stability and lateral rigidity, while the inversion itself simplifies the overall structure by naturally positioning layers in their optimal configurations
Data Source
AI summary
Provided is a pneumatic tire having the structure where a carcass ply is wound around bead cores from the outside in the tire width direction to the inside in the tire width direction, and both end portions of an inner liner extend between beads and the carcass ply. A lightweight and highly rigid tire can be acquired. The tire can also enhance steering stability performance thereof. The pneumatic tire includes: a pair of left and right beads including bead cores 3a; a carcass ply extending between the bead cores; and an inner liner 4 disposed on an inner peripheral side of the carcass ply 5, wherein the carcass ply 5 is wound around the bead cores 3a from the outside in the tire width direction to the inside in the tire width direction, and both end portions of the inner liner 4 extend between the beads and the carcass ply.