Random engagement roller chain sprocket with cushion rings and root relief for improved noise characteristics

A unidirectional roller chain drive system including a plurality of sprockets and a roller chain having rollers in engaging contact with the sprockets, wherein at least one of the plurality of sprockets comprises:

• a central body portion having a plurality of sprocket teeth spaced along a circumference of the central body portion, the plurality of sprocket teeth each having an engaging flank and a disengaging flank;
• an engaging flank of a first tooth of the plurality of sprocket teeth cooperating with a disengaging flank of a second tooth of the plurality of sprocket teeth to define a tooth space having a root surface extending between the engaging flank of the first tooth and the disengaging flank of the second tooth, the root surface having a first root surface portion defined by a first radius extending from an arc center of the first root surface portion;
• a cushion ring mounted to a first face of the central body section and having a plurality of compression pads and a plurality of grooves alternately positioned around a circumference of the cushion ring;
• a first groove of the plurality of grooves having a first groove portion defined by a second radius extending from an arc center of the first groove portion, the arc center of the first groove portion being positioned at least proximate a radial line extending between a center of the central body portion and the arc center of the first root surface portion;
• and
• a first compression pad having an inclined outer surface defined by a leading edge that is spaced radially inward relative to a trailing edge, the leading edge being positioned radially inward from the engaging flank of the first tooth, and the trailing edge being positioned radially inward from a disengaging flank of the first tooth.