Tire Crown Reinforcement With Decoupling Layer
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Solution Overview
Problem
Current heavy-duty tires face issues with wear regularity and rolling resistance, particularly under high-speed and long-distance conditions, leading to uneven wear patterns and increased fuel consumption due to the stress and temperature changes in the crown reinforcement area.
Innovation Solution
A tire design featuring a radial carcass reinforcement with a crown reinforcement structure that includes two working crown layers separated by a layer of rubber mixture (C) with specific elasticity and loss factor properties, combined with circumferential reinforcing elements, and a tread with longitudinal and transverse cutouts, which helps in distributing shear stresses and maintaining cohesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a crown reinforcement structure with multiple working layers is used to improve tire strength and durability, then the tire can withstand heavy loads and high-speed conditions, but shear stresses between layers and temperature rise lead to crack formation and reduced endurance
Solution Approach 1:
A decoupling layer is introduced between the working crown layers to act as an intermediary element. This layer reduces shear stresses between the layers by allowing relative movement, thereby preventing crack formation while maintaining the overall structural strength and load-bearing capacity of the crown reinforcement
Solution Approach 2:
The decoupling layer modifies the mechanical parameters between working layers by providing controlled compliance. This parameter change allows the structure to accommodate thermal expansion and stress variations without failing, thus improving endurance while preserving strength
2Force
If circumferential reinforcing elements are added to increase load capacity, then the tire can handle heavier loads, but the complexity of the crown reinforcement structure increases
Solution Approach 1:
The crown reinforcement is segmented into distinct functional layers: working layers for load bearing, a decoupling layer for stress management, and circumferential reinforcing elements for additional support. This segmentation allows each layer to perform its specific function efficiently without requiring the entire structure to be overly complex
3Duration of action of stationary object
If the tread depth is increased to improve wear resistance, then the tire life is extended, but the rolling resistance increases due to greater deformation
Solution Approach 1:
The tread compound parameters are optimized to achieve a balance between wear resistance and rolling resistance. By adjusting the compound formulation and tread depth parameters, the tire achieves extended life through improved wear characteristics while minimizing energy losses during rolling deformation
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 design enhances wear regularity and reduces rolling resistance, leading to improved fuel efficiency and extended tire life by controlling deformations and stress distribution within the tire structure.
Implementation Method 1
a layer C of rubber mixture being arranged between at least the ends of said at least two working crown layers
Implementation Method 2
a layer of circumferential reinforcing elements
Implementation Method 3
the depth, measured on a new tire in at least said part central, of said at least one longitudinal orientation cutout being greater than or equal to 40% of the thickness of the tread
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a tire including a crown reinforcement consisting of at least two working crown layers (41, 43) of reinforcing elements, and at least one layer (42) of circumferential reinforcement elements, a layer C being arranged between the ends of the working crown layers. According to the invention, the tread has at least one longitudinal indentation (8) and at least one transverse indentation (10), the depth, measured on a new tire, of said at least one longitudinal indentation and at least one transverse indentation not being less than 40% of the width of the tread, the ratio of the width measured at the bottom of said longitudinal indentations to the width measured at the surface of the tread of said longitudinal indentations being strictly greater than 1.2, the ratio of the width measured at the bottom of said at least one transverse indentation to the width measured at the surface of the tread on a new tire of said at least one transverse indentation not being less than 1 and the modulus of elasticity under stress at 10% elongation of the layer C being greater than 9 MPa, and the maximum value of tan(8), denoted tan(8) max, of the layer C being less than 0.100. FIGURE 2