| 主权项 |
1. An injection mold having a cavity for forming a molded resin article, a runner for introducing a molten resin injected from an injection machine into the cavity, and a gate for communication between the runner and the cavity, wherein
the runner has: a first communication hole which extends toward the cavity and one of opposite ends of which communicates with the gate; and a second communication hole which communicates with the other end of the first communication hole remote from the gate, and which extends in a direction perpendicular to the direction of extension of the first communication hole, and a pin member is disposed within the first communication hole so as to be spaced apart from an inner circumferential surface of the first communication hole and to extend coaxially with the first communication hole, and such that a distal end portion of the pin member extends through the gate, whereby a ring runner portion is defined by a cylindrical space between the inner circumferential surface of the first communication hole and an outer circumferential surface of the pin member, which surfaces are opposed to each other, and the gate takes the form of an annular ring gate, the injection mold being characterized in that: at least one protrusion is provided in a first region of the ring runner portion, which first region is a half of a circumference of the ring runner portion and is opposite to a circumferential position of the ring runner portion, at which the first communication hole and the second communication hole communicate with each other, with respect to the pin member, the at least one protrusion projecting from either one of the inner circumferential surface of the first communication hole and the outer circumferential surface of the pin member, such that an end face of the at least one protrusion is held in contact with the other of the inner circumferential surface of the first communication hole and the outer circumferential surface of the pin member. |
