RIGID CORE MOLD AND METHOD FOR MANUFACTURING PNEUMATIC TIRE USING THE SAME

摘要

A technique for easily taking out a main body of a core mold is proposed. An annular core-mold main portion 11 having a molding surface 18 for shaping an inner surface of a pneumatic tire is included, and the core-mold main portion 11 is composed of a plurality of segments each of which is taken out toward the inside in a radial direction. In the molding surface 18 of the core-mold main portion 11, a ratio Bd/W of a maximum width W lying in regions for shaping sidewall portions and a width Bd in the tire axial direction measured at toe-end shaping positions 18e for shaping toe ends of bead portions is not less than 0.80. In an inside zone 30 from the toe-end shaping position 18e of the molding surface 18 to the position of the maximum width W, the angle α of a tangent T drawn to the molding surface 18 is not more than 15 degrees. The inside zone 30 includes an oblique part 32 in which the angle α of the tangent T is 30 to 45 degrees, and a ratio h/H of a length h in a radial direction of the oblique part 32 and a length H from the toe-end shaping position 18e to an intersecting point P of a line drawn in the tire radial direction from the toe-end shaping position 18e outwardly in the radial direction with the molding surface 18 is less than 0.25.

主权项

1. A rigid core mold which is a rigid core mold for manufacturing a pneumatic tire including
an annular core-mold main portion having a molding surface for shaping the inner surface of a toroidal pneumatic tire having a tread portion, sidewall portions and bead portions, the core-mold main portion composed of a plurality of core segments arranged in the tire circumferential direction and each taken out from the pneumatic tire by moving inwardly in the tire radial direction,and characterized in that
in a meridian section of the core-mold main portion including a tire revolution axis, the ratio Bd/W of a maximum width W in the tire axial direction lying in regions for shaping the sidewall portions, and a width Bd in the tire axial direction measured at toe-end shaping positions for shaping the toe ends of the bead portions is not less than 0.80, an inside zone of the molding surface from the toe-end shaping positions to the position of the maximum width W has a width in the tire axial direction gradually decreasing toward the inside in the tire radial direction, the angle α of the tangent to the molding surface in the inside zone is not more than 45 degrees with respect to a line in the tire radial direction, the inside zone includes an oblique part where the angle α of the tangent is 30 to 45 degrees, and the ratio h/H of the length h in the tire radial direction of the oblique part and the length H in the tire radial direction measured to an intersecting point at which a line in the tire radial direction drawn outwardly in the tire radial direction from the toe-end shaping position intersects with the molding surface is less than 0.25.