Method of manufacturing boot for constant-velocity universal joint and manufacturing apparatus for use in the method, and boot for constant velocity universal joint

摘要

There is disclosed a boot for a constant-velocity universal joint, in which a secondary molded portion including a thick portion is formed in a large-diameter side end portion of a primary molded member, and the boot is easily pulled out of a core mold. The boot is downsized and lightened to reduce costs. A manufacturing method includes: a step of forming a secondary molding space 43 between an inner peripheral surface of a large-diameter side end portion 3 of the primary molded member and an outer peripheral surface of a core mold 69; a step of injecting a molten material into the secondary molding space to mold the secondary molded portion; and a step of integrally molding a secondary molded member on the inner peripheral surface of the large-diameter side end portion of the primary molded member to form a boot 1, moving a removable portion 83 of a second mold section 79 of the core mold 69 which abuts on at least the end portion of the thick portion in the vicinity of the bellows portion in a central axial direction of the core mold to remove the removable portion from an undercut portion 17a of a thick portion 17 just before separating the boot from the core mold, and separating the core mold 69 from the boot 1 in this state.