Patent ID: 8828300

Claim:
A die for molding, the die being used in order to manufacture boot for constant-velocity universal joint (hereinafter being abbreviated to as“CVJ boot”) by injection molding, the CVJ boot comprising: a minor-diameter cylindrical portion having a given diameter; a major-diameter cylindrical portion having a diameter that is larger than the diameter of the minor-diameter cylindrical portion, and being disposed to separate away from the minor-diameter cylindrical portion as well as to be coaxially with the minor-diameter cylindrical portion; and a bellows portion having a configuration of circular truncated cone substantially, and connecting the minor-diameter cylindrical portion with the major-diameter cylindrical portion integrally, and the die comprising: an outer mold having a mold face for molding an outer peripheral surface of the CVJ boot; and a core mold having a mold face for molding an inner peripheral surface of the CVJ boot; the core mold comprising: a central core having a configuration whose diameter tapers from wide to narrow in the direction away from a trailing end to a leading end; and a plurality of divisional molds being disposed radially about the central core, and having a mold face for molding an inner peripheral surface of the CVJ boot on an outer peripheral surface thereof, respectively; the divisional molds comprising: a pair of first divisional molds being disposed to face one another about the central core; a pair of second divisional molds being disposed to face one another about the central core in an orthogonal direction with respect a disposition direction of the paired first divisional molds; and a plurality of third divisional molds being disposed between one of the paired first divisional molds and one of the paired second divisional molds, respectively; and the die further comprising: a first driver for retracting the central core in order to move the paired first divisional molds diametrically toward a center of the die in such a direction that the paired first divisional molds approach one another, thereby releasing a molded body from the paired first divisional molds; a second driver for not only moving the paired first divisional molds axially in such a direction that the paired first divisional molds get away from the paired second divisional molds but also moving the paired second divisional molds diametrically toward the center of the die in such a direction that the paired second divisional molds approach one another, after actuating the first driver, thereby releasing the molded body from the paired second divisional molds; and a third driver for not only moving the paired second divisional molds axially in such a direction that the paired second divisional molds get away from the third divisional molds but also moving the third divisional molds diametrically toward the center of the die in such a direction that the third divisional molds approach one another, after actuating the second driver, thereby releasing the molded body from the third divisional molds.