Counterbalance gear with shot damper

A balance gear for a vehicle shaft comprising:

• a disc having first and second opposite sides extending radially outwardly to an edge defining a series of teeth, the disc having a first sector defining at least one aperture therethrough and a second sector defining a recess intersecting the first side;
• a plurality of particles positioned in the recess;
• and
• a cover plate connected to the first side of the disc to enclose the recess, wherein the cover plate, the recess, and the plurality of particles cooperate to form a damper for the balance clear;
• wherein the at least one aperture intersects the first and second opposite sides of the disc and remains empty such that the balance clear is eccentrically weighted by the damper and the at least one aperture.

A method of forming a balance gear for a vehicle balance shaft comprising:

• forming a disc having first and second opposite sides extending radially outwardly to a circumferential edge;
• forming a series of teeth on the circumferential edge;
• forming a single recess into the disc, the recess intersecting the first side of the disc and extending to a blind depth therein, the recess extending adjacent to the circumferential edge;
• forming at least one aperture in the disc, the at least one aperture intersecting the first and second sides of the disc such that the at least one aperture extends through the disc, and the at least one aperture being radially opposed to the recess;
• providing a plurality of shot particles into the recess to a specified fill fraction;
• and
• attaching a cover plate to the first side of the disc to enclose the recess, retain the plurality of shot particles therein, and form an internal damper in the balance gear;
• wherein a volume of the internal damper, the specified fill fraction, and a diameter of shot particles are sized to damp whine caused by at least second orders of distortion of the balance gear;
• and
• wherein the at least one aperture is empty such that the balance gear is eccentrically weighted by the internal damper and the at least one aperture.