Gear wheel and method for manufacturing gear wheel

摘要

Provided is a method for manufacturing a gear wheel, the method including: preparing an insertion unit formed of a steel material having a hollow pipe shape; injection-molding an outer side unit including teeth on an outer circumference; and molding a connection unit having a wheel shape by injecting resin into at least three points between the insertion unit and the outer side unit so as to connect the insertion unit and the outer side unit after arranging the insertion unit on the inner center of the outer side unit. According to the method, removing of an unnecessarily injected portion may be omitted since the resin is injected between the insertion unit and the outer side unit while injection-molding the connection unit. Also, productivity is increased by decreasing a number of defective products generated due to cracks.

主权项

1. A method of manufacturing a gear wheel for an automobile steering wheel, the method comprising:
preparing an insertion unit formed of a steel material having a hollow pipe shape, wherein the insertion unit comprises a pair of coupling grooves sunken inward in a circumferential direction along two ends of an outer circumference of the insertion unit, and a plurality of coupling protrusions protruding from the outer circumference of the insertion unit and connecting the pair of coupling grooves in a vertical direction, the plurality of coupling protrusions having an arc shape sunken inward along the vertical direction, wherein a connection between the pair of coupling groves and the plurality of coupling protrusions does not form an angled corner; injection-molding an outer side unit having teeth on an outer circumference of the outer side unit; and molding a connection unit having a wheel shape by injecting resin into at least three different points between the insertion unit and the outer side unit so as to connect the insertion unit and the outer side unit and arrange the insertion unit at an inner center of the outer side unit, wherein said at least three different points are apart from each other at same interval of distance.