Abstract: Plural ejector pins are made to project before a molten resin containing reinforcing fibers is injected into an inside of a cavity through pin point gates in a web forming portion in the inside of the cavity and at positions outside the pin point gates in a radial direction. The ejector pins are retracted from the inside of the cavity after a flow of the molten resin containing reinforcing fibers injected into the inside of the cavity through the pin point gates impinges on the ejector pins and is divided and before a tooth portion forming portion in the inside of the cavity is filled with the molten resin containing reinforcing fibers. Accordingly, weld lines which extend along the radial direction are formed at positions outside the ejector pins in the radial direction, and the molten resin is filled in portions formed after the ejector pins are retracted.

Abstract: A movable mold includes a movable mold main body and a gear piece attached to the movable mold main body so as to relatively movable, and having a cavity formation space for forming a cavity. In the gear piece, a piece-side coolant flow path includes an annular flow path surrounding the cavity formation space, a piece-side supply flow path introducing coolant into the annular flow path, and a piece-side discharge flow path introducing the coolant from the annular flow path. The piece-side coolant flow path is connected to a movable mold main body-side supply flow path of the movable mold main body and a movable mold main body-side discharge flow path of the movable mold main body and the coolant flows therein under negative pressure generated by a coolant circulation device, so the inside of the cavity can be cooled effectively.

Abstract: Plural ejector pins are made to project before a molten resin containing reinforcing fibers is injected into an inside of a cavity through pin point gates in a web forming portion in the inside of the cavity and at positions outside the pin point gates in a radial direction. The ejector pins are retracted from the inside of the cavity after a flow of the molten resin containing reinforcing fibers injected into the inside of the cavity through the pin point gates impinges on the ejector pins and is divided and before a tooth portion forming portion in the inside of the cavity is filled with the molten resin containing reinforcing fibers. Accordingly, weld lines which extend along the radial direction are formed at positions outside the ejector pins in the radial direction, and the molten resin is filled in portions formed after the ejector pins are retracted.

Abstract: Plural ejector pins are made to project before a molten resin containing reinforcing fibers is injected into an inside of a cavity through pin point gates in a web forming portion in the inside of the cavity and at positions outside the pin point gates in a radial direction. The ejector pins are retracted from the inside of the cavity after a flow of the molten resin containing reinforcing fibers injected into the inside of the cavity through the pin point gates impinges on the ejector pins and is divided and before a tooth portion forming portion in the inside of the cavity is filled with the molten resin containing reinforcing fibers. Accordingly, weld lines which extend along the radial direction are formed at positions outside the ejector pins in the radial direction, and the molten resin is filled in portions formed after the ejector pins are retracted.

Abstract: A movable mold includes a movable mold main body and a gear piece attached to the movable mold main body so as to relatively movable, and having a cavity formation space for forming a cavity. In the gear piece, a piece-side coolant flow path includes an annular flow path surrounding the cavity formation space, a piece-side supply flow path introducing coolant into the annular flow path, and a piece-side discharge flow path introducing the coolant from the annular flow path. The piece-side coolant flow path is connected to a movable mold main body-side supply flow path of the movable mold main body and a movable mold main body-side discharge flow path of the movable mold main body and the coolant flows therein under negative pressure generated by a coolant circulation device, so the inside of the cavity can be cooled effectively.

Abstract: A plurality of ejector pins are made to project before a molten resin containing reinforcing fibers is injected into the inside of a cavity through pin point gates in a web forming portion in the inside of the cavity and at positions outside the pin point gates in the radial direction. The plurality of ejector pins are retracted from the inside of the cavity after the flow of the molten resin containing reinforcing fibers injected into the inside of the cavity through the pin point gates impinges on the plurality of ejector pins and is divided and before a tooth portion forming portion in the inside of the cavity is filled with the molten resin containing reinforcing fibers. Accordingly, weld lines which extend along the radial direction are formed at positions outside the ejector pins in the radial direction, and the molten resin is filled in portions formed after the ejector pins are retracted.

Abstract: A method of producing a plastic molded object, including preparing a mold assembly including a cavity that forms a surface of the plastic molded object with a transfer surface of the cavity, a slide cavity piece including a sliding surface and a molding surface forming at least a part of one surface of the plastic molded object, and a metallic mold that slidably holds the slide cavity piece, heating the mold assembly to a temperature lower than a softening temperature of a molten resin, filling the cavity with the molten resin, cooling the molten resin to a temperature lower than the softening temperature of the molten resin, wherein the cooling includes contracting a volume of the molten resin, and sliding the slide cavity piece toward the molten resin by a contact-force of the molding surface with the molten resin, thereby compensating for contraction of the volume of the molten resin.