At Muncie Power, the objective of noise and vibration testing is to develop
effective ways to eliminate power
take-off (PTO) gear rattle, with specific emphasis on PTO products. The
type of sound of largest concern in this
industry is tonal.
Gear engineers have long recognized the importance of considering system factors when analyzing a single pair of gears in mesh. These factors include important considerations
such as load sharing in multi-mesh geartrains and bearing clearances, in addition to the effects of flexible components such as housings, gear blanks, shafts and carriers for planetary geartrains. However, in recent years, transmission systems have become increasingly complex—with higher numbers of gears and components—while the quality requirements and expectations in terms of durability, gear whine, rattle and efficiency
have increased accordingly.
Investigation of Gear Rattle Phenomena
The article by Messrs. Rust, Brandl and Thien was very interesting in its description of the problem and of some of the interactions which occur.
The acceptance by discerning customers of passenger cars is dependent upon both the actual noise lever and the subjective noise character.
The subjective noise character itself can contain, among other features, undesirable noise phenomena which become apparent at certain points in the vehicle operating range. One such critical phenomenon is gear rattle, which is mainly present under low speed, high load conditions. Due to changes in the angular velocity of the crankshaft, gear rattle under driving conditions occurs at the unloaded gears and splines.
The modern day requirement for
precision finished hobbed gears, coupled
with the high accuracy characteristics of
modern CNC hobbing machines, demands high tool accuracy.
