Pneumatic Tire Tread Block Raised Web Stiffness
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Solution Overview
Problem
Pneumatic vehicle tires with radially raised profile bands experience reduced circumferential stiffness due to transverse grooves, leading to impaired power transmission, handling, and braking properties, especially on dry roads, as the profile block elements can bend and twist excessively.
Innovation Solution
The design includes raised webs in the two axially outer edge regions of each transverse groove, connecting tread block elements and enhancing circumferential rigidity, which stabilizes the profile block elements against bending and twisting, ensuring uniform ground contact and improved grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transverse grooves are introduced to drain water, then wet grip is improved, but circumferential stiffness of tread block rows is reduced
Solution Approach 1:
The transverse groove is segmented into multiple sections by dividing it axially into a first extension section and a second extension section with different directions. This segmentation allows the groove to maintain water drainage functionality while reducing its overall axial extent, thereby preserving circumferential stiffness of the tread block rows.
Solution Approach 2:
The transverse groove is designed with local quality changes by altering its extension direction in different sections. The first extension section extends in a first axial direction while the second extension section extends in a second axial direction that differs from the first. This local variation optimizes water drainage in specific areas while minimizing the groove's impact on overall structural stiffness.
2Ease of operation
If tread block elements are made flexible to absorb deformation, then comfort is improved, but power transmission is impaired
Solution Approach 1:
The tread block elements are segmented through the introduction of transverse grooves that divide them into multiple sections. This segmentation allows each section to deform independently for comfort while the overall structure maintains sufficient rigidity for power transmission through the circumferential grooves and tread pattern design.
Solution Approach 2:
Different regions of the tread block elements have different flexibility characteristics. The areas between circumferential grooves maintain higher stiffness for power transmission, while the regions with transverse grooves allow localized deformation for comfort. This spatial variation in mechanical properties resolves the contradiction between flexibility and rigidity.
3Reliability
If web is placed at center of transverse groove to increase rigidity, then wet grip is improved, but dry handling is impaired due to torsional movement
Solution Approach 1:
The web structure is extracted from the center position of the transverse groove and repositioned to extend between the first and second extension sections of the groove. This extraction from the traditional central position eliminates the lever arm effect that caused torsional movement, while still providing the necessary structural support for wet grip performance.
Solution Approach 2:
Instead of placing the web at the center of the transverse groove as conventionally done, the invention inverts this arrangement by positioning the web to span between the separated extension sections. This inverted configuration changes the mechanical behavior from one that allows torsion to one that provides stable corner support for dry handling.
Data Source
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AI summary
The invention relates to a pneumatic tire for an automobile having tread lug rows, each being interspaced in an axial direction by a peripheral groove, and wherein at least one tread lug row (2, 3) is configured to include a transverse groove (13, 14) of interspaced tread lug elements (9, 10). In each transverse groove (13, 14) of the tread lug row (2, 3), in the respective two axial outer border areas of the transverse groove (13, 14) within the footprint width TA, a connecting piece (16, 17) elevated from the groove bottom of the transverse groove (13, 14) is formed extending in a peripheral direction U, and interconnecting the two tread lug elements (9, 10) interspaced by the transverse groove.