A mold element for molding and vulcanizing a tire tread having a plurality of raised elements, each raised element having a contact face intended to come into contact with a road surface and lateral faces connected thereto. The mold element comprises cutting blades able to cut a cover layer already applied to a green form of the tire. Each cutting blade comprises a body, at least one of the cutting blades comprises a protrusion projecting from this body, able to drive a cut part of the cover layer into the depth of the green tire to cover all or part of a lateral face of a raised element. The cutting blade comprises, at one end of the body, a cutting edge forming an acute angle for cutting the cover layer.

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 tire vulcanization forming mold and a tire manufacturing method using the same. In the forming mold, a plurality of segment blocks divided in a circumferential direction are equal in circumferential length and are formed with tread forming patterns of plural kinds on which blades for forming tread patterns on a tire are arranged in different arrays. The segment blocks formed with the tread forming patterns of the plural kinds are arranged randomly in the circumferential direction to constitute the mold of a ring shape covering a whole circumference of the tire.

The disclosure relates to a molding element of a mold for molding and vulcanizing a tire tread, this tread comprising a tread surface intended to come into contact with the ground when the said tire is running. The molding element includes a rib for molding a groove in the tire tread, the rib being a rounded end.

A method of forming a tire that includes providing a mold configured to mold a tire tread and having a sipe-forming element, spaced apart inwardly from an outermost molding surface, that includes a knife edge oriented towards the outermost molding surface and a submerged void-forming portion extending from the knife edge, arranging an uncured tire tread within the mold, molding the tire tread arranged within the mold, and demolding the tire tread from the mold such that the sipe-forming element forms a sipe by the knife edge (48) lacerating a thickness of the tire tread as the sipe-forming element is pulled in a direction toward the outermost molding surface and forms a submerged void arranged below the sipe within the tire tread. A tire including a sipe (30) and a submerged void (32) as described above is also disclosed.

A vulcanization mold including blades having a distal end side and pullout is performed smoothly without causing any failure and a pneumatic tire. A vulcanization mold in which a blade has a proximal end, a blade distal end side expanded in a thicknesswise direction on the distal end side, and a blade connection portion that connects the proximal end portion and the blade distal end side is a vulcanization mold in which a sweep area is the difference where a cross sectional area of the blade connection is subtracted from an area blade distal end side to a mold surface with a width equal to a maximum width of a thickness of the blade distal end side in a cross sectional shape perpendicular to a tire widthwise direction of the blade is smaller in circumferential end side regions than in a circumferential central side region of the sector mold.

A pneumatic tire includes sipes disposed in a land portion formed in a tread portion, and pin holes for stud pins disposed in the land portion. The sipes are disposed at positions where a distance Ds from the pin hole and a diameter Dp of the pin hole satisfy (Ds/Dp)4.0. A sipe in which the distance Ds from the pin hole and the diameter Dp of the pin hole satisfy (Ds/Dp)5.0 is defined as a pin hole neighboring sipe. A sipe of which the distance Ds from the pin hole is the smallest, among the sipes in which the distance Ds from the pin hole and the diameter Dp of the pin hole satisfy (Ds/Dp)>5.0, is defined as a normal sipe. The pin hole neighboring sipe is formed in a high rigidity shape having higher rigidity than the normal sipe.

In one aspect, a tire is provided, the tire comprising: a tread portion comprising at least one of a tread rib or a tread block, a sipe included in the tread rib or the tread block, the sipe including: a key portion including: a key edge portion angled in a first circumferential direction at an angle KA, and a chamfer portion angled in the first circumferential direction at an angle CA, an upper parallel portion radially inward of and directly connected to the key portion, a central parallel portion radially inward of and directly connected to the upper parallel portion, and a base portion radially inward of and directly connected to the central parallel portion.

A mold segment for forming a tire is provided that has a first sipe element with a protrusion that extends from a first sipe element side surface. The height of the protrusion is less than a height of the first sipe element side surface. A second sipe element is present and has a cavity that extends from a second sipe element side surface. The cavity has a height that is less than a height of the second sipe element side surface. A mold segment base is included that receives the first sipe element and the second sipe element. The cavity receives the protrusion such that the protrusion is located in the cavity and so that the first sipe element side surface directly faces the second sipe element side surface.

A mold for vulcanization molding a tire includes a tread ring. The tread ring includes a ground contacting surface molding portion, a first groove forming convex portion and a second groove forming convex portion raised from the ground contacting surface molding portion, and at least one blade having both ends connected with the first and second groove forming convex portions so as to form a sipe having both ends connected with two grooves. The at least one blade includes a main body portion having a thickness of 0.2 mm or less and a reinforcing portion having a thickness greater than 0.2 mm. The reinforcing portion includes a first reinforcing portion formed locally on a radially inner end edge side of the blade and a first connection portion side. The first connection portion is a connection between the blade and the first groove forming convex portion.