Analysis and comparision of noise and vibration of straight Bevel gears finished by advanced processes

Abstract

Gears are toothed wheels used for the transmission of power in many mechanical systems. Gears are typically used for short distance power transmission. They are compact and have efficient and smooth transmission of power and/or motion between two parallel shafts (e.g. spur and helical gears), intersecting shafts (e.g. bevel gears) or non-parallel non-intersecting shafts (e.g. hypoid gears and worm and worm wheel). Bevel gears is a cone-shaped gear which transmits power between two intersecting axels/shafts. Performance characteristics of a gear include its load carrying capacity, service life, operating performance, surface characteristics, wear characteristics, transmission characteristics and noise-vibration generation characteristics. The noise and vibration caused by the rotation of the gears is considered a big problem especially at high loads and speeds. However, since noise and vibration problems tend to happen due to several causes in combination. The following are causes of noise and vibration; Gear material, Gear design, alignment of the shafts on which gears are mounted, Configuration of the gear box, Surface damage to the gears during their manufacturing (finishing, heat treatment and other processing), Surface finish of flank surfaces of the gear teeth, Errors in microgeometry of gear teeth such as errors in their form (i.e. tooth profile, lead), location errors (i.e. pitch and runout), and topography, Accuracy in assembly of gears, Operating conditions such as temperature, friction, running speed, type of unexpected load, type of lubrication, use of coolant, Wear of gears. Surface characteristics has two major components namely (i) surface quality which includes surface finish, micro-geometry (i.e. form and location errors) and wear characteristics; and (ii) surface integrity that encompasses microstructure, micro-hardness and residual stress. In which surface quality and surface integrity of gears depends on finishing of the gears. Here we have done analysis and comparison of noise and vibrations of bevel gears finished by some advanced processes viz. electrochemical honing (ECH), pulsed-electrochemical honing (PECH) with unfinished gear. It has been noted that gears which have better finish results have low level of noise and vibrations.