Gears gear noise

Some faetors eausing gear noise ean be attributed to, but not limited to, the following ... 

Gears and Their Vibration A Basic Approach to Understanding Gear Noise, J. Derek Smith... 

AGMA 299.01, Gear Sound Manual Sec. 1, Fundamentals of Sound as Related to Gears Sec. 2, Sources, Specifications, and Levels of Gear Sound Sec. 3, Gear-Noise Control. 

The spur gear is the least expensive of all gears to manufacture and is the most commonly used. It can be manufactured to close tolerances and is used to connect parallel shafts that rotate in opposite directions. It gives excellent results at moderate peripheral speeds and the tooth load produces no axial thrust. Because contact is simultaneous across the entire width of the meshing teeth, it tends to be noisy at high speeds. However, noise and wear can be minimized with proper lubrication. 

Bevel, zerol Same ratings as straight bevel gears and use same mountings, permits slight errors in assembly, permits some displacement due to deflection under load, highly accurate, hardened due to grinding Limited to speeds less than 1000 fpm due to noise... 

To quiet a noise-generating mechanism, the first impulse is often to enclose it. Sometimes an enclosure is in fact the best solution, but not always. If it can be determined what is causing the noise, appropriate action can be taken to be more specific and provide a cost-effective fix. In some cases the problem is caused by a component such as a stepper motor or gear set that does not produce objectionable noise by itself. The trouble typically develops because a small noise is transmitted to a metal frame or cabinet that then serves to amplify the sound using a plastic cabinet can isolate the noise problem. 

---