Heavy-Duty Tire Buffer Layer Structure for Stable Ground Contact
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Solution Overview
Problem
Heavy duty pneumatic tires with low-flatness designs face challenges in stabilizing the ground-contact shape and reducing the load on the tread portion, while also achieving mass reduction.
Innovation Solution
A heavy duty pneumatic tire design featuring a nominal aspect ratio not greater than 65%, incorporating a tread with circumferential grooves, a reinforcing layer with a belt and band structure, and a buffer layer formed from crosslinked rubber, which includes a sheet portion and hump portions to alleviate strain and maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If cushion layers having conventional specifications are used in a low-flatness tire, then the tire structure is simpler, but each end of a belt may be raised when the tire expands, leading to unstable ground-contact shape and decreased uneven wear resistance
Solution Approach 1:
The buffer layer is designed with non-uniform thickness, featuring a sheet portion and thicker hump portions positioned at specific locations. The hump portions have maximum thickness at the end of the first belt ply, creating local reinforcement exactly where strain concentration occurs at belt ends during tire expansion, preventing belt end raising while maintaining overall structural simplicity
Solution Approach 2:
The buffer layer's thickness parameter is strategically varied across different regions. The sheet portion has a controlled apparent thickness of 2.2-2.8mm, while hump portions extend to 2.5-6.5mm maximum thickness. This parameter change optimizes the distribution of internal pressure and strain, stabilizing the ground-contact shape without requiring complex multi-layer cushion structures
2Weight of moving object
If the belt is composed of three belt plies, then mass reduction is achieved, but the load acting on the tread portion increases due to reduced bending allowance
Solution Approach 1:
The buffer layer acts as an intermediary component between the three-ply belt and the carcass. It absorbs and distributes the strain that would otherwise be transmitted to the belt ends, enabling the three-ply configuration to reduce tire mass while the buffer layer compensates for the reduced bending allowance by providing additional cushioning and load distribution
Solution Approach 2:
The buffer layer is formed from crosslinked rubber, creating a composite structure with the belt plies. This composite material approach allows the three-ply belt to maintain structural integrity while the crosslinked rubber buffer layer provides enhanced elasticity and load distribution, reducing the load concentration on the tread portion
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 achieves stabilization of the ground-contact shape, reduction of the load on the tread portion, and mass reduction, resulting in improved durability, uneven wear resistance, and productivity.
Implementation Method 1
a buffer layer located radially inward of the reinforcing layer and formed from a crosslinked rubber
Data Source
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AI summary
A heavy duty pneumatic tire 2 includes a tread 4, a carcass 12, a reinforcing layer 18, and a buffer layer 20. The reinforcing layer 18 includes a belt 38 and a band 40. The buffer layer 20 is stacked on the carcass 12. Each end 20e of the buffer layer 20 is located axially outward of an end 38e of the belt 38. The belt 38 includes a first belt ply 42A, a second belt ply 42B, and a third belt ply 42C. The buffer layer 20 includes a sheet portion 60 and a pair of hump portions 62 located axially outward of the sheet portion 60 and thicker than the sheet portion 60. Each of the pair of hump portions 62 has a maximum thickness Tb at an end 42Ae of the first belt ply 42A.