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US 5,848,948 AGranted
Roller chain timing drive having reduced noise
AssigneeCloyes Gear and Products, Inc.
InventorTimothy R. Allen
Life of this patent
Estimating the term…
Abstract
A roller chain timing drive reduces noise by thinning the teeth and elongating the root land in between each pair of teeth. Specifically, through detailed calculation, the root land is elongated resulting in a reduced thickness of the teeth as measured across itself from a drive flank to a coast flank. The result is maintained contact of all rollers wrapped around a sprocket throughout the entire design life of the chain and sprockets which reduces noise.
Claims14
A chain drive assembly comprising:
- a sprocket including a plurality of sprocket teeth each having a drive flank and a coast flank, and having a thickness measured along a pitch circle from the drive flank to the coast flank;
- each drive flank cooperating with an adjacent coast flank to define a tooth space having an arcuate surface that is concentric with a rotational axis of the sprocket;
- a root diameter value of the sprocket being defined as the diameter of a circle having a circumference laying on each arcuate surface, the root diameter value satisfying at least one of ANSI, ISO, British, and DIN standards;
- a chain including rollers for engaging the sprocket teeth, the chain having a initial chain pitch value defined as a distance between the centers of adjacent rollers thereof, and having a worn chain pitch value which is greater than the first chain pitch value, the worn chain pitch value being the anticipated chain pitch when the chain reaches the end of its useful life;
- and
- the thickness of each sprocket tooth being determined based on at least a difference between the initial chain pitch value and the worn chain pitch value, the thickness of each sprocket tooth permitting the rollers to maintain contact within the respective tooth spaces as the chain pitch varies from the initial chain pitch value to the worn chain pitch value.
3 more elements
A chain drive assembly comprising:
- a first sprocket and a second sprocket each including a plurality of sprocket teeth each having a drive flank and a coast flank, and having a thickness measured along a pitch circle from the drive flank to the coast flank wherein adjacent sprocket teeth cooperate to define tooth spaces;
- the tooth spaces of at least one of the first and second sprockets having an arcuate surface that is concentric with a rotational axis of the at least one of the first and second sprockets, a root diameter value of the at least one of the first and second sprockets being defined as the diameter of a circle having a circumference laying on each of the arcuate surfaces, the root diameter value satisfying at least one of ANSI, ISO, British, and DIN standards;
- a closed-loop chain including rollers for engaging the sprocket teeth, the chain having an initial chain pitch defined as the distance between the centers of adjacent rollers thereof and having a worn chain pitch value which is greater than the initial chain pitch value, the worn chain pitch value being the anticipated chain pitch when the chain reaches the end of its useful life;
- and
- the thickness of the sprocket teeth of the at least one of the first and second sprockets being determined based on at least a difference between the initial chain pitch value and the worn chain pitch value to permit the rollers to maintain contact within the respective tooth spaces as the chain pitch varies from the initial chain pitch value to the worn chain pitch value.
2 more elements
Dependencies are inferred from the claim text.