Page 135 - Gear Technology Solutions

Figure 21: Comparison of FFT results [7]

A comparison of the Fast Fourier Transformation results, based on the motion
transmission signals of Figure 16, is shown in Figure 21. Diagrams of the
three different torques are arranged in the horizontal direction. The graphics in
the top row are from the forged differential and the bottom row of graphics
®
have been obtained from the Coniflex Pro cut differential. All diagrams show
the first mesh harmonic, which is the frequency where the mesh impact takes
nd
st
th
place, and the higher orders (2 to 6 order). At the low load of 10Nm, the 1
harmonic amplitude of the cut gearset is only 10% compared to the forged
version. In case of 40Nm, the cut gearset has 20% of the forged predecessor
and with a side gear torque of 200Nm the cut gearset still has only 40%
amplitude compared to the forged gearset. The results in Figure 21 basically
confirm the transmission error comparison in Figure 20.

9.9 Test Rig and Field Test Investigations

®
Coniflex Pro is a new development of straight bevel gears which in contrast to the
®
original Coniflex process takes advantage of the geometric and kinematic
®
®
freedoms available in Phoenix free-form machines. Older Coniflex designs can
be duplicated. However, the advantages of conjugate base geometry and the free
control of length and profile crowning with the possibility of a kinematic tip relief
have been compelling facts for manufacturers of differential gears for electric
®
vehicles. The number of Coniflex Pro eDrive differential gear designs is constantly
increasing. This is the reason why already today results from test rigs and field
tests are available. Although the specific results of these tests are confidential
information of the respective manufacturers, it can be stated that the overall
®
performance of surface and root of Coniflex Pro gears is up to twice as strong as
their forged counterparts.

120