Fiber reinforced resin gear, method of forming fiber reinforced resin gear by injection molding, fiber reinforced resin rotary body, method of forming fiber reinforced resin rotary body by injection molding

A method of injection molding of a fiber reinforced resin rotary body by injecting a molten resin containing reinforcing fibers into the inside of a cavity through a plurality of pin point gates to form a cylindrical portion on an outer peripheral side of a disk-shaped portion, wherein

• a plurality of ejector pins are made to project in a disk-shaped portion forming portion in the inside of the cavity and at positions outside the pin point gates in the radial direction before the molten resin containing reinforcing fibers is injected into the inside of the cavity through the pin point gates, and
• 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 cylindrical portion forming portion in the inside of the cavity is filled with the molten resin containing reinforcing fibers, so that weld lines which extend along the radial direction are formed at positions outside the plurality of ejector pins in the radial direction and the molten resin containing reinforcing fibers is filled in portions formed after the plurality of ejector pins are retracted.