Molding ring radially expandable beads for one tire mold.

摘要

Mold (200) for a green tire (110) comprising a tread (116), two beads (112a, 112b) each with a bead base directed radially inward (124a, 124b) extending from a heel axially outer (120a, 120b) to an axially inner toe (122a, 122b), and two sidewalls (114a, 114b) extending between the beads and the tread, the mold comprising: first and second sidewall plates ( 202a; 202b) for molding, respectively, an outer surface of each sidewall and an axially outer portion of each of the beads approximately in the heel; first and second bead molding rings (252, 230) for molding at least the bead bases of the two beads; and inflatable vulcanizing membrane (210) for molding the inside surfaces of the tire; wherein at least the first ring bead molding (252) comprising: a plurality of segments (254, 256), half of the segments being first segments (254) that are complementary to the second segments (256) and that they are staggered circumferentially thereof; the first segments having wedge-shaped with circumferentially lateral faces (255) converging towards a surface bead molding directed radially outward from the first ring bead molding, the side faces of the first segments being planar and oriented in the axial direction ; wherein the second segments have lateral faces (257) that are complementary to the first segment lateral faces; and wherein means for the radial expansion of the first ring bead molding are provided from a first outside diameter (Dr) to a second outside diameter (De), thereby forming a circumferentially continuous surface directed radially outward (259) for molding one of the beads in cooperation with a first plate adjacent edge (202b) and the vulcanizing membrane, characterized by a guide bars (260) to restrict first and second segments (254, 256) only a radial movement (310 ); each guide rod being mounted in a mounting hole radially aligned (272) drilled in one of the first and second segments, and each mounting hole being aligned with a guide hole (273) drilled in the first plate adjacent flank ( 202b) so that the guide rod slides within the radially-aligned guide hole; springs preloaded to force a movement directed radially inward of the first and second segments (254, 256); and each spring residing in a retaining hole spring radially aligned (275) drilled in the first plate adjacent edge (202b) and aligned with a bag spring (274) cut into a contiguous segment of the first and second segments, so that a spring can be positioned with one end in the spring holding hole and the other end in an adjacent spring bag.