A venting valve and method of mounting a valve stem of a venting valve. The venting valve (3) comprises a valve body (4) inside which is a venting channel (5) which is provided with a movable valve stem (6) comprising a valve member (7) and a collar (8) at an opposite end of the valve stem. A spring element (9) is arranged around the valve stem. Movement of the valve stem is limited by means of an external retaining ring (11) mounted to an external retaining groove (12) of the valve body. Bottom of the retaining groove comprise openings extending to the venting channel and the retaining ring partly protrudes inside the venting channel through the openings, whereby the protruding parts of the retaining ring are configured to form retaining surfaces (15) preventing the collar to pass them.

A pneumatic tire includes: a lateral groove that includes a groove bottom surface extending in a direction crossing a tire circumferential direction; and a protrusion provided on the groove bottom surface and extending in an extension direction of the groove bottom surface. The protrusion includes: a main body; and a raised portion provided at least at one end portion on one side in a longitudinal direction of the main body, and shaped such that a height of the raised portion from the groove bottom surface increases from an outside to an inside in the longitudinal direction of the main body. The raised portion has at least one vent mark that is a mark of a vent of a tire vulcanization mold.

A tire 22 includes a pair of bead portions 66 to be fitted to a rim R. Each bead portion 66 includes a bead 30 having a core 52 and an apex 54. An outer surface 68 of the bead portion 66 includes a seat face 70 and a flange face 72 disposed radially inward and axially outward, respectively, of the bead 30, a heel face 74 disposed between the seat face 70 and the flange face 72, and a plurality of vent lines 78 projecting from the heel face 74 and extending in the circumferential direction. A contour of the heel face 74 is represented by an arc on a cross-section, of the tire 22, taken along a plane including a rotation axis of the tire 22, and a radius Rh of the arc is not less than 8 mm and not greater than 15 mm.

A pneumatic tire includes a tread portion and a pair of sidewall portions extending inward in a tire radial direction from both edges of the tread portion. At least one of the sidewall portions is provided with a vent line and a recessed portion adjacent to each other in the tire radial direction. The vent line protrudes from a sidewall outer surface and extends in a tire circumferential direction. The recessed portion is recessed from the sidewall outer surface at a first depth. A serration pattern, in which a plurality of ridges extending in the tire radial direction are arranged in the tire circumferential direction, is formed in the recessed portion. Each of heights of the ridges is smaller than the first depth.

Method for curing a tyre during which a green tyre is pressed against the lining of a curing mould provided with a venting device, the moulding surface of said lining forming protrusions that define cavities, the venting device comprising vents that pass through the lining, one cavity being divided into chambers by a protrusion in the form of a blade (26), each cavity closing on one or more vents, at least one of said chambers not closing on a vent, at least one duct (42) passing through the blade (26) so that the chamber(s) that does/do not close on a vent communicate(s) through the duct with a chamber that does close on a vent.

According to the invention, the cross-section of the duct (42) has an area of between 0.0001 mm.sup.2 and 0.25 mm.sup.2 and, more preferably, 0.01 mm.sup.2 and 0.1 mm.sup.2.

Provided are a method for producing a tire vulcanization mold and a maintenance method. A positioning member protrudes at a position corresponding to a position on a master mold surface. A positioning hole is formed by a tip end of the positioning member in a rubber mold to which the surface of the master mold is transferred. The tip end is embedded in the positioning hole so that a rear end protrudes from the surface of the rubber mold. The rear end is embedded in a plaster mold to which the surface of the rubber mold is transferred. A case is detachably fixed to the tip end protruding from the surface of the plaster mold. The case is cast into a mold to which the surface of the plaster mold is transferred and fixed. A valve body is inserted into the case from which the positioning member is removed.

The subject invention relates to a mold segment comprising a tread molding element for manufacturing a tire wherein the tread molding element comprises a shell and an infill, wherein the shell has a first wall with a negative tread pattern extending from its external surface for molding the tread, a second wall opposed to the first wall, and lateral walls; wherein the infill is a fluid-permeable structure defining a fluid-permeable infill; and wherein at least one of a lateral wall and the second wall comprises at least one fluid passage passing through the lateral wall or the second wall.

A system for venting a tire mold includes a tire mold having an interior region and an exterior region. The interior region is defined by a surface having a non-smooth portion that defines a pattern. The interior and exterior regions of the tire mold are in fluid connection with each other via at least one conduit extending from the exterior region to the non-smooth portion of the surface defining the interior region. The system further includes a vent insert at least partially disposed inside the at least one conduit. The vent insert has a non-smooth face that corresponds to the pattern defined by the non-smooth surface of the surface of the interior region.

A system for venting a tire mold including at least one conduit that creates a fluid connection between an interior and an exterior of a tire mold, with at least one sipe blade extending across the conduit such that the air to either side of the sipe blade will exit the tire mold interior when a tire is formed.

A spring vent for a tire vulcanizing mold comprises: a sleeve having a flow path vertically passing therethrough; a head opening/closing an inlet at an upper end of the flow path; a rod comprising a bar-type body formed below the head and disposed along the flow path and a stopper formed below the body to be hung to an outside of an outlet at a lower end of the flow path; and a spring inserted into the body. The stopper of the rod is formed to have a spherical shape. An elastic hole having an open bottom is formed in the stopper.