Serrated Tread Groove Walls for Ice Braking
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Solution Overview
Problem
Studless tires face a significant reduction in traction on icy roads due to the formation of a water film between the tread and the ice, which hinders braking performance, as existing tread patterns are inadequate in effectively sweeping away this film.
Innovation Solution
The tire features a tread pattern with lateral grooves that include serrated portions on their walls, where the first surfaces are inclined outwardly toward the groove bottom and the second surfaces extend parallel to the tread surface, enhancing the wiping effect by maintaining a smaller contact angle and increasing ground pressure, thereby improving braking performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional tread pattern with smooth groove walls is used, then the tyre structure is simple and easy to manufacture, but the wiping effect is insufficient and braking performance on icy roads deteriorates
Solution Approach 1:
The groove wall surface is segmented into multiple inclined surfaces (first inclined surface, second inclined surface, third inclined surface) with different angles, creating a serrated structure that divides the contact area into multiple zones for optimized water film removal at different positions
Solution Approach 2:
Different portions of the groove wall are given different local properties through varying inclination angles - the first inclined surface has a smaller angle for initial water film contact, while subsequent surfaces have progressively larger angles, creating localized optimization for the wiping effect across the groove wall
2Reliability
If the groove wall is inclined outwardly toward the groove bottom, then the wiping effect is improved, but the contact angle increases and ground pressure decreases
Solution Approach 1:
The groove wall structure transitions from a static single-angle inclination to a dynamic multi-angle serrated structure that adapts the contact geometry during braking, with the smaller first inclined surface angle optimizing water film removal while subsequent surfaces maintain structural integrity and ground pressure
3Reliability
If the water film enters under the tread surface, then tyre grip decreases sharply, but conventional tread patterns cannot effectively prevent water film entry
Solution Approach 1:
The serrated groove wall structure with multiple inclined surfaces creates preliminary resistance to water film penetration before it can enter under the tread, with each inclined surface acting as a barrier that redirects and sweeps out the water film in sequence
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 serrated tread pattern effectively suppresses the water film from entering under the tread, ensuring consistent and improved braking performance from new to worn tires by maintaining high ground contact pressure and reducing the likelihood of water film entry, thus enhancing traction and stability on icy surfaces.
Implementation Method 1
it is important to sweep out (hereinafter, may referred to as 'wiping effect') the water film on the icy road so that the water film does not enter under the tread surface
Data Source
AI summary
A tyre includes a tread portion having a tread surface being provided with a plurality of lateral grooves extending in a tyre axial direction. In a cross-sectional view perpendicular to a longitudinal direction of the at least one of the plurality of lateral grooves, the at least one of the plurality of lateral grooves includes a pair of groove walls and a groove bottom. At least one of the pair of groove walls includes a serrated portion including first surfaces and second surfaces that are arranged alternately. Each first surface is inclined outwardly in a groove width direction toward the groove bottom and has a radially inner end thereof, and each second surface extends substantially parallel with the tread surface from the radially inner end of a respective one of the first surfaces toward a groove centerline of the at least one of the plurality of lateral grooves.