oth ends Types HS HS HS BS BS BS HC B4-VV-13B Bevel-helical gear boxes B4

Flender/Flender Gear Units/Bevel-helical gear boxes B4

tatic transmission error of cylindrical gear pair with involute proles. It is apparent from the shape of the prole deviation that the two exact proles make contact only around the pitch circle. At this point the transmission error becomes zero. Prole deviations in areas above and below the pitch circle cause parabolic curve as transmission error per each tooth mesh (Item 1 of Fig.5.. Item 2 in Fig. 5.3depicts the inuence of pitch deviation on the load-free transmission error. Since the tooth prole is not affected by the pitch deviation, the transmission error changes in the form of step-shaped leap, whose amplitude corresponds to the pitch deviation converted to an angle. The resulting discontinuity in transmission error at the transfer point causes enormous accelerations, even in the load-free state. In operation, this leads to pulsatile loads on the tooth anks. The term pulse is therefore preferred to the term path-induced excitation. The Fig. 5.3 Excitation mechanisms for gear noise. 1 Path-induced excitation, caused by ank modication, load- or assembly-induced topography deviations. 2 Impact excitation: pulsatile path-induced excitation, caused by manufacturing- or load-induced pitch deviations. 3 Parameter excitation: stiffness variation, caused by variable meshing tooth pair stiffness along the path of contact5.1 Causes of Noise Generation 1 importance of the pulse effect may be affected by form and pitch deviations. More thorough investigations in the relationships between variations in gear tooth geom-etry and load-free transmission error have been carried out, particularly by [FAUL6 ], [OPIT6 ] and [ NAUM6 ]. Apart from pitch and tooth ank topography deviations which may excite vibrations in gear set, stiffness variation of the kindshown in Item 3 of Fig. 5.3constitute third cause in tooth mesh noise generation. The depth wise variation in tooth thickness causes variations in mesh stiffness of atooth pair, which in turn leads to the cyclical excitat