Tire Tread Sipes and Rubber Stiffness for Snow Braking Trade-off
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Solution Overview
Problem
All-season tires face a trade-off between improved traction on snow-covered surfaces and maintaining braking performance on dry and wet grounds due to the reduction in tread block stiffness caused by sipes, which impair dry braking performance.
Innovation Solution
A vehicle tire design with a specific tread pattern and rubber composition, featuring a set of consecutive blocks, first grooves between blocks, and sipes that define an edge ingredient ratio, combined with a rubber composition having an elastic modulus (E') of at least 25 MPa to 45 MPa at -20°C, balances the stiffness loss from sipes to maintain dry braking performance while enhancing snow traction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sipes are added to the tread pattern to improve snow traction, then snow performance is improved, but block stiffness is reduced which impairs dry braking performance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the edge ingredient (EI) within the range of 2-20 and the void volume ratio within 20-40%. These parameter optimizations balance the conflicting requirements: sufficient sipes for snow traction while maintaining adequate block stiffness for dry braking performance.
Solution Approach 2:
The patent implements local quality by creating different functional zones within the tread blocks. Sipes are strategically positioned to provide snow grip where needed, while the overall block structure maintains stiffness for braking. The differentiated properties within the tread pattern allow simultaneous optimization of both snow performance and dry braking.
2Reliability
If the edge ingredient is increased to improve snow performance, then snow traction is enhanced, but block stiffness is reduced too far which impairs dry ground braking performance
Solution Approach 1:
The patent resolves this contradiction by establishing the edge ingredient within the specific range of 2-20. This parameter optimization ensures sufficient sipes for snow performance while preventing excessive stiffness reduction that would compromise dry braking performance.
Solution Approach 2:
The patent applies partial action by providing sipes to only certain portions of the tread blocks rather than throughout the entire block structure. This selective placement provides enough snow performance enhancement while preserving the overall structural integrity and stiffness needed for dry braking.
3Reliability
If the void volume ratio is increased to improve snow performance, then snow traction is improved, but the structural integrity and stiffness of the tread are reduced
Solution Approach 1:
The patent resolves this contradiction by optimizing the void volume ratio within the range of 20-40%. This parameter control ensures sufficient void space for snow performance while maintaining adequate structural integrity for overall tread stability and durability.
Data Source
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AI summary
According to aspects of the invention, a tire for a vehicle comprising a tread is provided. The tread comprises a set of consecutive blocks arranged along a circumference of the tire, a plurality of first grooves arranged over the circumference of the tire, wherein each of the plurality of first grooves is arranged between two blocks of the set of consecutive blocks, and a plurality of sipes defining an edge ingredient, El, corresponding to the ratio between a sum of projected lengths of the plurality of sipes in an axial direction, SAP, and the circumference of the tread, C, such that EI=∑SAPC. The El is at least 2 and at most 20. The tread is made of a rubber composition having an E' @ -20°C of at least 25 MPa and at most 45 MPa.