Pneumatic Tire Reinforcing Layer for Tread Block Stability
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Solution Overview
Problem
Current tire designs with circumferentially oriented grooves face issues with tread block tilting and excessive pressure leading to overheating and reduced grip performance, especially on wet surfaces, due to the use of soft rubber mixtures which promote shearing and limited reinforcing effects from existing solutions.
Innovation Solution
A tire design featuring a belt reinforcement with a reinforcing layer of elastomeric material having constant circumferential elasticity, positioned radially outside the carcass layer, which opposes meridian bending and tilting of tread elements, using a material with a dynamic shear modulus less than 1.25 MPa and a high MA10 modulus to maintain contact and reduce pressure on leading edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a soft rubber compound is used for the tread to improve grip, then the tire can better conform to the road surface and increase contact area, but the tread blocks shear and tilt under circumferential grooves, generating high overpressures and overheating
Solution Approach 1:
The tread is segmented into multiple independent tread blocks separated by circumferential grooves. This segmentation allows each block to independently conform to road irregularities while the grooves provide water evacuation paths, preventing water buildup and reducing the risk of hydroplaning that would otherwise cause excessive heat generation.
Solution Approach 2:
The tread compound exhibits locally optimized properties where the base compound provides softness for conformability and grip, while specific regions incorporate reinforcing elements (steel belts, fabric plies) that provide structural support. This local reinforcement prevents excessive deformation and shearing of tread blocks under load, reducing internal friction and heat generation in critical areas.
2Reliability
If circumferential grooves are added to evacuate water and maintain contact on wet surfaces, then water evacuation is improved, but the tread blocks are prone to shearing and tilting which generates high overpressures
Solution Approach 1:
Reinforcing elements (steel belts and fabric plies) are pre-installed beneath the tread compound before the tire enters service. These elements create a rigid foundation that prevents tread block deformation and tilting under operational loads, eliminating the source of high overpressures on leading edges while maintaining the groove configuration for water evacuation.
Solution Approach 2:
The tire structure employs a composite construction combining soft rubber compound for the tread surface with rigid reinforcing elements (steel cable belts, polyester or nylon fabric plies) underneath. This composite structure allows the tread to remain soft for water evacuation and grip while the rigid layers provide structural support to prevent tread block shearing and the resulting high overpressures.
3Strength
If a reinforcement ply with cable-type elements is placed under the carcass ply to improve transverse adhesion, then reinforcement is provided, but the industrial production cost increases significantly and the reinforcing effect remains limited
Solution Approach 1:
The steel belt layers serve multiple functions simultaneously: they provide radial strength and structural support, prevent tread separation, maintain tread block alignment to reduce shearing, and contribute to overall tire rigidity. This multi-functionality eliminates the need for separate reinforcement plies, maintaining cost-effectiveness while achieving superior transverse adhesion through proper belt construction and orientation.
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
This design enhances transverse grip and handling by maintaining a large contact surface, reducing tread block tilting and overheating, while maintaining rolling resistance and extending the tire's lifespan without increasing volume.
Implementation Method 1
the reinforcement layer extending axially over a width WR equal to at least 50% of the axial width W of the belt reinforcement and extending radially over a thickness T between the radially upper end of the belt reinforcement and an upper radial limit located radially towards the inside of the groove bottom, the circumferentially constant elasticity material constituting the reinforcement layer having a modulus MA10 greater than 10 MPa
Implementation Method 2
the constituent material of the tread having a dynamic shear modulus G* less than 1.25 MPa
Data Source
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AI summary
Disclosed is a pneumatic tire (1) comprising two beads (2), two sidewalls (3), a crown (5) having a belt carcass (6), a tread (5) having a plurality of tread bars (50), and grooves (7) that are delimited radially towards the interior by a groove base (70); the material of which the tread (5) is made has a dynamic shear modulus G* of less than 1.25 MPa; the crown includes a reinforcement layer (8) made of reinforcing material that has an MA10 modulus of more than 10 MPa.