TIRE TREAD FOR MOVEMENT ON SNOW CONTAINING GROOVES AND CAVITIES Russian patent published in 2016 - IPC B60C11/12 B60C11/03 

FIELD: manufacturing technology.

SUBSTANCE: tread comprises multiple blocks (2) divided by grooves (3). Blocks (2) are made with fissures (5), which are slit-like drain grooves split into several parts from a certain depth and further referred to as complex slitted drain grooves. Each complex slitted drain groove (5) has, if observed in the cross section, straight first part (9) passing in the radial direction from the tread surface and second part (11), which is a continuation of the first part and has at least two branches (13), each of which has end (15). Tread comprises extra cavities (17), and each cavity extends between branches (13) of a complex slitted drain groove. Each cavity comprises bottom (19) located at the same level that ends (15) of the branches. Cavities (17) and grooves (3) of the tread are made with such a configuration that the said tread has a share of the voids surface in the end of the wear exceeding or equal to 35 %. Besides, distance (D) between two branches (13) of two adjacent complex slitted drain grooves (5) is equal to at least 2 mm.

EFFECT: better grip on snow including the one at the end of the tires service life while maintaining or even increasing their total mechanical strength.

7 cl, 10 dwg