TIRE BUILDING DRUM

To provide a tire building drum capable of sufficiently expanding and contracting thereof in a radial direction.SOLUTION: A tire building drum of the present invention is expandable in a radial direction. A tire building segment comprises a widthwise expansion/contraction member capable of expanding/contracting thereof in a width direction of the tire building drum. The tire building drum comprises: a first drive unit for expanding and contracting the widthwise expansion/contraction member in the width direction; and a second drive unit for expanding and contracting the widthwise expansion/contraction member in the radial direction of the tire building drum. A widthwise outer diameter X1 of an outer end face of a bead set portion formed by the widthwise expansion/contraction member when shrinkage in the width direction of the widthwise expansion/contraction member is caused is smaller than a widthwise inner diameter X2 of the bead set portion formed by the widthwise expansion/contraction member when expansion in the width direction of the widthwise expansion/contraction member is caused. A radial outer diameter Y1 of the tire building segment when shrinkage in the radial direction of the tire building drum is caused is smaller than a radial inner diameter Y2 of the bead set portion when expansion in the radial direction of the tire building drum is caused.SELECTED DRAWING: Figure 6 【課題】本発明は、径方向への十分な拡縮が可能なタイヤ成型ドラムを提供することを目的とする。【解決手段】本発明のタイヤ成型ドラムは、径方向に拡縮可能であり、タイヤ成型セグメントは、前記タイヤ成型ドラムの幅方向に拡縮可能な幅方向拡縮部材を備え、前記タイヤ成型ドラムは、前記幅方向拡縮部材を前記幅方向に拡縮させる第１の駆動部と、前記幅方向拡縮部材を前記タイヤ成型ドラムの径方向に拡縮させる第２の駆動部と、をさらに備え、前記幅方向拡縮部材の幅方向縮小時における、前記幅方向拡縮部材がなすビードセット部の外端面の幅方向外径Ｘ１が、前記幅方向拡縮部材の幅方向拡大時における、前記幅方向拡縮部材がなす前記ビードセット部の幅方向内径Ｘ２よりも小さく、且つ、前記タイヤ成型ドラムの径方向縮小時における、前記タイヤ成型セグメントの径方向外径Ｙ１が、前記タイヤ成型ドラムの径方向拡大時における、前記ビードセット部の径方向内径Ｙ２よりも小さい。【選択図】図６