Heavy truck tire tread having a longitudinal direction, a transverse direction and a thickness direction, said tread having a ground engaging surface and comprising a series of similar tread features repeated along its longitudinal direction, each tread feature comprising: two ducts extending from the ground-engaging surface in the thickness direction, said ducts being apart one from the other and having a duct section area of at least 10 mm.sup.2 and a length comprised between 50% and 100% of a thickness of said tread; one void being in fluidic connection with said two ducts, said void extending substantially parallel to the ground-engaging surface of the tread and at a distance therefrom and having a void section area of at least 10 mm; and one sipe joining said two ducts and said void; wherein said feature is otherwise blind and said series comprises 50 of said similar tread features.

A tire having a carcass reinforcement surmounted radially by a crown reinforcement having at least two working plies, the width Lt of which is equal to the width of the axially narrowest working ply, and surmounted radially by a tread (or cap) and interposed radially between the cap and the crown reinforcement by a sublayer (or base), this base extending axially and radially under all of the cap and radially on the outside of the crown reinforcement over a total width at least equal to the width Lt of the crown reinforcement, an equatorial plane dividing the cap axially into an outer half cap (TE) and an inner half cap (TI) of the same axial width, the outer half cap (TE) positioned axially towards the outside of a vehicle and the inner half cap (TI) positioned axially towards the inside of the vehicle, the base comprising an additional volume radially under the inner half cap (TI), such that the volume occupied by the base radially under the inner half cap (TI) is greater than the volume occupied by the base radially under the outer half cap (TE), and the material of the base is a rubber-based composition having hysteresis lower than the hysteresis of the rubber-based material of the cap.

The present invention provides a pneumatic tire including a tread block 10 having a sipe 100 formed therein. A three-dimensional inclined surface groove 110 is formed at an upper portion of the sipe 100 formed in the tread block 10, such that three-dimensional inclined surface protrusions 16 and inclined surface grooves 17 respectively formed on both sipe side wall surfaces 15 forming the sipe 100 so as to correspond to each other may minimize a movement of the tread blocks 10 due to a stress generated from the tire contacting with a ground during driving, so as to increase a traction force. In addition, a lower through groove is formed at a lower portion of the sipe 100 formed in the tread block 10, such that it is possible to reduce a resonance noise of the tire occurring when driving, more easily and automatically discharge the foreign matters caught in the sipes 100 of the tire during driving, and improve a traction performance of the tire in the latter half of the tire lifespan by dividing the remaining tread block 10 after the upper portion of the tread block 10 is worn.

The tread has a total width W and two main grooves. The main grooves divide the tread into a middle region and edge regions. The middle region has an axial width Lm that is 45% to 70% of the total width W. The volume void ratio of the tread when new is less than 17%. An internal surface extends parallel to the tread surface when new and is in contact radially with the innermost points of the deepest main grooves. The middle part has a plurality of transverse sipes, each of which has a depth at least equal to the depth of the main grooves. The transverse sipes open into the main grooves. The middle region has a volume void ratio when new that is less than half the total volume void ratio of the tread, and at least one circumferential channel appears when the tread becomes part worn.

Tyre comprising a tread, this tread including a rolling surface (12) intended to come into contact with the ground, at least one circumferential row of upstanding elements (11), these upstanding elements (11) being separated from one another in the circumferential direction by incisions (20) of transverse or substantially transverse orientation, each incision (20) of transverse or substantially transverse orientation leading onto the rolling surface (12) and having a depth P, each incision (20) forming, on the rolling surface of the tyre when new, two facing edges (21, 22), these edges (21, 22) delimiting at least one narrow portion (30) of the incision, i.e. a portion having a mean width LE less than or equal to 2 mm, and at least one wide portion (40) of the incision, i.e. a portion having a mean width LL greater than 2 mm, these wide and narrow portions being disposed alternately, each narrow portion (30) and each wide portion (40) extending the full depth P of the incision (20), each narrow portion (30) having a volume uniformly distributed over the full depth P of the incision, each wide portion (40) having a volume for the most part between half the depth P of the cut-out and the depth P, this tread being characterized in that the following condition is satisfied:
0.90E/R<(sum LE)/Pr<1.10E/R, in which: (sum LE) is the sum of the mean widths LE of the narrow portions of all the incisions separating the upstanding elements of the same row on a circle centred on the rotation axis of the tyre, R is the mean radius of the circle centred on the rotation axis on the rolling surface of the row concerned when new and Pr is the mean perimeter of the circle centred on the rotation axis and passing through a circumferential series of incisions in accordance with the invention, E is the mean thickness of the tread at the level of the row concerned.

A heavy truck tire tread is provided that has a rolling direction that is in a longitudinal direction of the tread. A circumferential sipe (20) is present and extends in the longitudinal direction completely around the tread. The circumferential sipe does not bound a sacrificial rib. A plurality of micro sipes (22) engage the circumferential sipe and are located on opposite sides of the circumferential sipe in the lateral direction. The micro sipes extend from the circumferential sipe so as to terminate within rubber of the tread at a terminal end.

The tread has circumferential grooves delimiting intermediate and edge parts and formed so as to be present at least until a tread wear limit is reached. The tread also having a tread surface with at least one tread wear indicator formed in a circumferential groove. The tread comprising on its edge regions a plurality of transverse cuts that have depths suited to be present down to the tread wear limit. Each transverse cut is formed of a first part opening onto the tread surface when new and extending towards the inside of the tread by a void part forming a channel of mean width greater than a mean width of the groove. The channel forms a new transverse groove after a predetermined amount of part wear. A cross section of each channel increases when progressing along the cut axially from the inside towards the outside of the tread.

A layer of cellular material forms a running layer (14A) of a tread (14) in which tread pattern elements (20, 22, 26) are made. In order to form the cellular material, an uncured blank is provided with a mass of material comprising p,p-oxybis(benzenesulphonyl hydrazide) that forms a pore-forming agent. The uncured blank is placed in a vulcanization mold (28) comprising molding elements (30, 32, 34). At least 95% of the molding elements (30, 32, 34) each satisfy the following two conditions: a) the molding element (30, 32, 34) is separated from at least one other molding element (30, 32, 34) by a distance, expressed in millimeters, of less than or equal to
DM=6.85+0.0065T3, T, greater than or equal to 3 phr, being the amount of p,p-oxybis(benzenesulphonyl hydrazide) in the mass of material intended to form the cellular material, b) the molding element (30, 32, 34) is intended to form a tread pattern element (20, 22, 26) having a depth at least equal to 80% of the thickness of the running layer (14A).

A tread (2), said tread having a tread surface (20) and a plurality of grooves (21), at least one groove having, in cross section, an undulating overall shape with entirely open groove parts (210) at the tread surface (20) and completely or partially closed groove parts (211) at said tread surface (20). The tire is characterized in that the open groove parts (210) comprise a contrasting texture (3) in the tread, the texture (3) having a plurality of elements that protrude from or are recessed into the surface of the groove. The texture (3) is absent from the closed groove parts (211).

A tread for a heavy goods vehicle tire, the tread having a surface when new suitable for coming into contact with a road surface, this tread having a plurality of optimized incisions opening onto its tread surface when new, each incision made of at least two narrow portions and wide portions, each narrow portion surrounded by wide portions, the sum of the areas of narrow portions representing at least 40% of the total surface of the incision (and the width being less than 0.4 mm, each portion having a width at least equal to 0.4 mm, this tread being such that for each optimized incision each of the wide portions extending between two narrow portions includes at least one section inclined in a plane parallel to the mid-plane of the optimized incision, and forming an angle at least 15 degrees with the direction of the tread thickness.