Transmission Error and NVH Comparison

With the ANSYS Finite Element software, the sample gear sets (cut and forged) have also been analyzed regarding motion transmission error under load. Figure 10 shows the results of the transmission error for the noise critical side gear torque of 40 Nm. The solid blue graph shows the transmission errors of the Coniflex Pro differential, and the dotted red graph shows the results of the forged differential. The cut differential (blue graph) has a maximum transmission error of 155 µrad. For the forged counterpart, the maximal transmission error is 740 µrad which is about 5 times the amount of the cut differential. Fast Fourier Transformations (FFT) were performed from the motion transmission graphs in Figure 10. The results shown in Figure 11 present transmission error amplitudes versus orders of mesh. The forged gear set (right side) has 295 µrad amplitude at the first mesh harmonic, which is also more than 5 times the value of the Coniflex Pro cut gear set ( left side). FFT results reflect operating noise and vibration (NVH) rather well, which confirms that the sample Coniflex Pro differential has the potential to operate quietly in contrast to the forged version.