US 5,976,045 A · Random engagement roller chain sprocket having improved noise characteristics

Abstract

A unidirectional roller chain sprocket for use primarily in automotive engine chain drive applications which incorporates an asymmetrical tooth for improved noise reduction. The sprocket includes a first plurality of sprocket teeth each having a first engaging flank with a first contact point at which a roller contacts the first engaging flank, and a second plurality of sprocket teeth each having a second engaging flank with a second contact point at which a roller contacts the second engaging flank. The first engaging flanks include a flank flat which facilitates spacing the first contact point on the first engaging flank relative to the second contact point on the second engaging flank to effect a time delay between an initial roller to first sprocket tooth contact and an initial roller to second sprocket tooth contact. The flank flat is tangent to an engaging flank radius and a first root radius. The asymmetrical tooth profile may also incorporate one or more inclined root surfaces which provide tooth space clearance for maintaining the chain rollers in hard contact with the root surface in the sprocket wrap. The asymmetrical tooth profile may also incorporate added pitch mismatch wherein the sprocket chordal pitch is less than the chain link pitch to facilitate a "staged" roller-tooth contact as a roller moves into full mesh from an initial tangential impact at the flank flat.

Claims25

Dependent claims

A sprocket comprising:

a first plurality of sprocket teeth each having a first engaging side tooth profile including a first engaging flank, a first root radius, and a flank flat, a radially outer end of the flank flat being tangent to the first engaging flank and a radially inner end of the flank flat being tangent to the first root radius;
a second plurality of sprocket teeth each having a second engaging side tooth profile different from the first engaging side tooth profile, the second engaging side tooth profile including a second engaging flank and a second root radius tangent to a radially inner end of the second engaging flank;
and
the sprocket being adapted for stared meshing with an associated roller chain having a plurality of rollers wherein a first roller of the associated roller chain impacts one of the plurality of first sprocket teeth at a first contact point along the first engaging side tooth profile and wherein a second roller of the associated roller chain impacts one of the plurality of second sprocket teeth at a second contact point along the second engaging side tooth profile spaced from the first contact point.

1 more element

A unidirectional roller chain drive system comprising:

a driving sprocket having sprocket teeth with engaging flanks and coast flanks, the engaging flanks cooperating with the coast flanks of adjacent teeth to define asymmetrical tooth spaces between the sprocket teeth;
a driven sprocket having sprocket teeth with engaging flanks and coast flanks, the engaging flanks cooperating with the coast flanks of adjacent teeth to define asymmetrical tooth spaces between the sprocket teeth;
a roller chain having rollers in engaging contact with the driving sprocket and the driven sprocket;
and
at least one of said driving sprocket and said driven sprocket including:
a first plurality of sprocket teeth each having a first engaging side tooth profile including a first engaging flank, a first root radius, and a flank flat, a radially outer end of the flank flat being tangent to the first engaging flank and a radially inner end of the flank flat being tangent to the first root radius,
a second plurality of sprocket teeth each having a second engaging side tooth profile different from the first engaging side tooth profile, the second engaging side tooth profile including a second engaging flank, and
the at least one of said driving sprocket and said driven sprocket being adapted for staged meshing with the roller chain wherein a first roller of the roller chain impacts one of the plurality of first sprocket teeth at a first contact point along the first engaging side tooth profile and wherein a second roller of the roller chain impacts one of the plurality of second sprocket teeth at a second contact point along the second engaging side tooth profile spaced from the first contact point.

5 more elements

Dependencies are inferred from the claim text.

Random engagement roller chain sprocket having improved noise characteristics

Life of this patent

Random engagement roller chain sprocket having improved noise characteristics

Life of this patent

Abstract

Claims25