BEAD APEX RUBBER-FORMING METHOD, AND BEAD APEX RUBBER-FORMING DEVICE

摘要

The present invention forms bead apex rubber with good precision on the outer circumferential surface of the bead core. A molding process, in which unvulcanized rubber is made to flow into a bead apex molding chamber that is surrounded by surfaces that include the outer circumferential surface of a circular bead core and the bead apex rubber is formed directly on the outer circumferential surface of the bead core that is rotating around the core axis, is provided. The molding process comprises: a tip forming step that forms the leading end of the bead apex rubber; a middle section forming step that sequentially forms the bead apex rubber to be continuous with the leading end; and a joining step to join the back end and the leading end of the bead apex rubber by inflowing the unvulcanized rubber therebetween.

主权项

1. A bead apex rubber forming method to form the bead apex rubber continuously in a full circle on an outer circumferential surface of the annular bead core having a core axis, wherein
the method comprises a molding process to form the bead apex rubber integrally on the outer circumferential surface of the bead core rotating around the core axis by flowing unvulcanized rubber from a rubber inflow port positioned in a first inner wall surface of a molding head into a bead apex molding chamber, the bead apex molding chamber is surrounded by the outer circumferential surface of the bead core, a first inner wall surface of the molding head on one side of the core axis direction, and a second inner wall surface of the molding head on the other side of the core axis direction, and the bead apex molding chamber extends in the circumferential direction, and of which circumferential both ends are opened, wherein the molding process comprises
a tip forming step to form a tip portion of the bead apex rubber between front and rear shutters by flowing the unvulcanized rubber into the bead apex molding chamber, in a closed state that the bead apex molding chamber is closed by the front and rear shutters on the front and rear sides in the bead core rotating direction in relation to the rubber inflow port, and in a rotating stopped state of the bead core,a middle section forming step to form serially the bead apex rubber to be continuous with the tip portion by taking off the front shutter to open the front side in the bead core rotational direction and flowing the unvulcanized rubber while rotating the bead core, anda joining step to joint integrally the back-end portion and the tip portion by a rubber connecting portion, and wherein, in the joining step,
the bead core is stopped when the tip portion returns again to the bead apex molding chamber,the rear shutter is taken off to open the rear side in the bead core rotational direction and to form a connecting space between the back-end portion and the tip portion of the bead apex rubber, andthe unvulcanized rubber is flowed into the connecting space to form the rubber connecting portion.