H4VV-17-C Bevelhelical gear unit BNominal torq Helical speed reduction gearboxes H4

Flender/Flender Gear Units/Helical speed reduction gearboxes H4

gear mesh frequency often signicantly contributes to (or dominates) the overall energy in the vibration signal. Signal segments with periodicities which correspond to the gear mesh frequency are generally much more similar, compared to signal segments selected at random. These segments may subsequently be used to obtain density distribution which is subject to less variance, and which may subsequently result in more sensitive NLL discrepancy values. Figure 2 illustrates the implemented windowing methodology. Gear Pinion Fixed shaft angular intervals Figure 2: Representation of the xed window intervals which correspond to approximate pinion-gear meshing periods. Let the angular domain resampled vibration signal be denoted = [p1p2:::pN:::prN]Twhere Nis the number of resampled datum points per rotation of the shaft on which the tachometer is mounted The vibration signal is truncated so that all the data before the rst and after the last tacho pulses are discarded. Let rrepresent the integer number of complete shaft rotations during the measurement, so that rNis the length of the resampled vibration signal. Let Tgrepresent the number of teeth on the gear, and let Tprepresent the number of teeth on the pinion. If the tachometer is mounted on the gear shaft, then the window length Lwis obtained as the number of datum points per rotation of the gear, divided by the number of gear teeth Lw==Tg. Similarly if the tachometer is mounted on the pinion shaft then the window length is obtained as Lw==Tp. Let the rst signal segment be represented by the column vector s1= [p1p2:::pLw]Tand the second segment by s2= [pLw+1pLw+2:::p2Lw]. This is repeated until rN=Lwsignal segments have been obtained. The signal segments are collected in the matrix Xs, where Xs= [s1s2:::srN=Lw]. Each column in Xsrepresents pinion-gear meshing period. measure of discrepancy (NLL value) will be computed for each column in Xs. The resulting NLL discrepancy signal will have much lower sampling rate th