Segmented Sidewall Tire Protrusion for Even Wear
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Solution Overview
Problem
Conventional tires for trucks and buses with protrusion portions on the sidewalls to prevent damage from curbstones suffer from uneven wear, leading to increased maintenance costs, environmental impact, and potential stress-induced cracks, as the protrusion portions are not worn evenly and may remain partially intact during replacement.
Innovation Solution
A tire design featuring a protrusion portion on the sidewall with multiple protrusion parts arranged in a circular pattern, each with a specific rubber composition and geometry, including narrow grooves and chamfered edges, to distribute stress and facilitate even wear, allowing for targeted replacement of worn parts and reducing the risk of cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protrusion portion is formed on the side wall to prevent damage from curbstones, then durability of the tire side portion is improved, but the protrusion portion is not worn evenly leading to increased maintenance costs and environmental impact
Solution Approach 1:
The protrusion portion is divided into multiple protrusion parts (first, second, third, and fourth protrusion parts) arranged circumferentially around the tire. This segmentation allows each protrusion part to wear independently and evenly during operation, preventing the uneven wear pattern that occurs with a single large protrusion portion. The segmented structure enables more uniform stress distribution and wear patterns across the entire protrusion portion.
2Reliability
If a protrusion portion is formed on the side wall to prevent damage from curbstones, then durability of the tire side portion is improved, but rolling resistance and weight increase reducing environmental performance
Solution Approach 1:
The protrusion portion is segmented into multiple smaller protrusion parts with gaps between them. This segmentation reduces the total volume of rubber material required compared to a single solid protrusion portion, thereby reducing the overall weight of the tire and minimizing the increase in rolling resistance while still providing the necessary protective function.
Solution Approach 2:
The protective function is localized to specific protrusion parts positioned at critical areas of the side wall that are most likely to contact curbstones. This localized approach provides adequate protection where needed while minimizing the total material used, thus reducing weight and rolling resistance compared to a full circumferential protrusion.
3Reliability
If a protrusion portion is formed on the side wall to prevent damage from curbstones, then durability of the tire side portion is improved, but stress concentration causes cracks in or around the protrusion portion
Solution Approach 1:
The protrusion portion is divided into multiple separate protrusion parts arranged circumferentially. This segmentation distributes the stress from curbstone impacts across multiple discrete contact points rather than concentrating it in a single large protrusion. The gaps between protrusion parts act as stress relief zones, preventing crack propagation through the entire protrusion structure.
Solution Approach 2:
The protrusion parts are positioned asymmetrically at specific locations around the tire circumference where stress concentration is most likely to occur during normal operation and docking maneuvers. This asymmetric distribution optimizes stress distribution patterns and prevents uniform stress concentration that would lead to cracking.
Data Source
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AI summary
A protrusion portion (110) of a pneumatic tire is formed by a plurality of protrusion parts (111) extended along a tire circumferential direction. The protrusion parts (111) are arranged with predetermined gaps therebetween so as to form a circle along the tire circumferential direction. A length (S1) of the protrusion part (111) in the tire circumferential direction is larger than a maximum width (W1) of the protrusion part (111) in a tire radial direction. In a tire side view, a narrow groove (200) extended along the tire circumferential direction is formed on a surface (111s) of the protrusion part (111).