Heavy-Duty Tire Reinforcing Layer for Shoulder Shape Stability
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Solution Overview
Problem
Heavy duty pneumatic tires experience shape changes during running, leading to uneven wear resistance and a risk of band cord breaks and belt edge loose due to tension fluctuations in the spirally wound band cord, which can result in reduced holding force and peeling of the belt edge.
Innovation Solution
A heavy duty pneumatic tire design with a reinforcing layer that includes a full band and edge bands, where the edge bands are located radially outward of the full band, and a buffer layer formed from crosslinked rubber, with specific dimensions and stress ratios to stabilize the tread shape and reduce tension fluctuations, thereby minimizing the risk of band cord breaks and belt edge loose.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a full band with spirally wound band cord is used to suppress shape change, then shape change suppression is improved, but the risk of band cord break increases due to repeated tension fluctuation
Solution Approach 1:
The band is divided into a full band and edge bands as separate functional segments. The full band (with spirally wound band cord) provides shape change suppression in the central region, while the edge bands provide structural support and tension stabilization at the edges. This segmentation allows each part to optimize its function without compromising the other.
Solution Approach 2:
The edge bands act as intermediary elements between the full band and the tread/belt structure. They mediate the tension forces by providing a transition zone that reduces the magnitude of tension fluctuation acting on the full band's band cord, thereby preventing break while maintaining shape stability.
2Reliability
If edge band is added to suppress tension fluctuation, then band cord break risk is reduced, but belt edge loose may occur due to strain on edge band
Solution Approach 1:
The invention specifies precise geometric parameters for the edge band configuration: width (20-40mm), radial thickness (3-8mm), and axial position relative to the full band end (5-20mm overlap). These parameter optimizations ensure the edge band is thick and wide enough to resist strain-induced peeling while maintaining its tension-stabilizing function.
Solution Approach 2:
The edge band is constructed as a composite structure combining rubber matrix with reinforcing cords (steel cords or organic fiber cords). This composite construction provides both the flexibility needed to accommodate tension fluctuations and the strength required to prevent belt edge loose and peeling.
3Productivity
If aspect ratio is reduced to 65% or less for low-flatness tire, then vehicle performance is improved, but shape change around shoulder circumferential groove increases
Solution Approach 1:
The reinforcing layer configuration varies locally across the tire structure. The full band extends axially outward of the shoulder circumferential groove to provide enhanced reinforcement specifically in the shoulder region where shape change is most critical, while the center region maintains standard reinforcement. This local quality optimization addresses the specific problem area without over-reinforcing the entire tire.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The tire effectively suppresses shape changes during running, reducing the risk of band cord breaks and belt edge loose, while maintaining stable ground-contact shape and improving wear resistance and steering stability.
Implementation Method 1
a buffer layer formed from crosslinked rubber
Implementation Method 2
a band including a spirally wound band cord... The band cord of the tire in a running state undergoes repeated fluctuation of the tension
Data Source
AI summary
A tire 2 includes a reinforcing layer 20 located between a tread 4 and a carcass 12. The reinforcing layer 20 includes a band 38 and a belt 40. The band 38 includes a full band 42 and a pair of edge bands 44. The full band 42 has an end 42e located axially outward of a shoulder circumferential groove 28s. The belt 40 includes a third belt ply 46C located radially inward of the pair of edge bands 44. A distance Y between each edge band 44 and the full band 42 or the third belt ply 46C is not less than 2.2 mm and not greater than 4.0 mm. A ratio of a tire thickness E at an end PE of a tread surface 22 to a tire thickness D at an equator plane is not less than 1.2 and not greater than 2.0.