Compagnie Generale Des Etablissements Michelin

Michelin Recherche Et Technique S.a.

Guillaume Demaziere

Olivier Ropars

Hichem Rehab

François Barbarin

Christophe Gayton

Tire () for a heavy-duty vehicle of civil engineering type, and more particularly to the tread () thereof, and seeks to improve the grip thereof, while at the same time ensuring a satisfactory compromise with wearing and thermal endurance. The tread () comprises cuts () distributed, in a circumferential direction (XX') of the tire, among circumferential grooves () and, in an axial direction (YY&#x2032;) of the tire, transverse sipes () and transverse grooves (), the cuts () delimiting elements in relief (), each cut () being delimited by two faces facing one another and each face intersecting the tread surface () along an edge corner (). The tread () having a longitudinal edge corners ratio TAequal to the ratio L/S between the sum Lof the projections, on to the circumferential direction (XX&#x2032;), of the effective edge corner lengths, contained in an elementary tread surface portion of surface area S, and the surface area S, and a transverse edge corners ratio TAequal to the ratio L/S between the sum Lof the projections, onto the axial direction (YY&#x2032;), of the effective edge corner lengths, contained in an elementary tread surface portion of surface area S, and the surface area S, the longitudinal edge corners ratio TAis at least equal to 4 mand the transverse edge corners ratio TAis at least equal to 6 m.

Tread for a tire of a heavy civil engineering vehicle

Tread () for a tire of an off-road vehicle. Total width Wt of the tread is greater than 600 mm and has at least three circumferential main grooves () at least 60 mm deep that divide the tread into intermediate ribs () and edge ribs (). The edge ribs have a width&#x2264;0.25 Wt. At least one of the intermediate ribs () has fine grooves () of depth Hdelimiting blades of material () of mean width BH. Grooves () are oriented in the axial direction of the tire. Each intermediate rib () has a mean width&#x2264;0.25 Wt and &#x2265;0.75 Ht (thickness of material to be worn away). Grooves, () have, over a height Hat least equal to 65% of H, a width&#x2264; to the value obtained from 0.04&#x221a;{square root over (B&#xb7;H)}.

Siped tread for off-road tire

Tread of a tire () for a heavy-duty vehicle of civil engineering type. The tread (), having an axial width Wand having a radial thickness Hat least equal to 70 mm, comprises at least two circumferential grooves () positioned axially on each side of an equatorial plane (XZ). Each circumferential groove () has an axial width W and a radial depth H, such that the ratio W/H is at least equal to 0.06, the axial distance C between two consecutive circumferential grooves () is at least equal to 12% and at most equal to 21% of the axial width Wof the tread and each of the axially outermost circumferential grooves () is positioned axially, with respect to the equatorial plane XZ, at an axial distance Lat least equal to 35% of the axial width Wof the tread.

Tire tread for a heavy civil-engineering vehicle

The tread has a total width W and is provided with circumferential cuts that have a mean depth at least equal to 70 mm and at most equal to the thickness of wearable material. The circumferential cuts divide the tread into a middle region with an axial width Wm of 50% to 80% of the total width W. The middle region has transverse or oblique sipes opening into the circumferential cuts and closing at least in part when they enter the contact patch. The sipes have a depth at least equal to 75% of the depth of the circumferential cuts and delimit elements of material of height equal to the mean depth H of the said sipes and of circumferential length B equal to the mean distance between two sipes. For all the elements of material, the ratio H/B is greater than 0.5 and at most equal to 2.5.

Growing community of inventors

Clermont-Ferrand, France

Guillaume Demaziere