Turntable

A turntable for storage disk drive apparatuses, comprising:

• a plate member made of a ferromagnetic material;
• and
• a central resin member arranged at the center of the plate member and formed by injection-molding a resin,
• wherein the central resin member includes a disk guide portion provided on an upper surface of the central resin member to guide a central hole of a disk and a plurality of gate cut portions formed on a lower surface of the central resin member, and the plate member includes hole portions or cutout portions formed at the positions overlapping with the gate cut portions in the direction parallel or substantially parallel to the center axis.

A method for manufacturing a turntable for storage disk drive apparatuses, which comprises the steps of:

• a) attaching a plate member made a ferromagnetic material to a movable mold or a fixed mold in a posture perpendicular or substantially perpendicular to the moving direction of the movable mold;
• b) defining a cavity between the movable mold and the fixed mold by clamping the movable mold and the fixed mold together;
• and
• c) forming a central resin member at the center of the plate member by injecting a resin into the cavity from a gate provided in one of the movable mold and the fixed mold,
• wherein the position of the mold in which the gate is provided corresponds to the lower side of the central resin member while the position of the other mold corresponds to the upper side of the central resin member;
• the central resin member includes a disk guide portion formed on an upper surface thereof to guide a central hole of a disk;
• the mold in which the gate is provided includes a protrusion portion protruding toward the other mold in the direction parallel or substantially parallel to the moving direction of the movable mold, the gate being provided at the tip end of the protrusion portion, the tip end of the protrusion portion passing through a center hole of the plate member in step b).