Spline rumble is characterized by a multiple low shaft order droning noise.

It arises in electrified vehicle (EV) powertrains due to excitation at the spline connection between the motor rotor and the transmission input. It is caused by the interactions between manufacturing errors.

In this article SMT will be looking at how MASTA can be used to predict rumble in a modern EV gearbox with a three-bearing input assembly layout.

SMT uses a quasi-static analysis in MASTA Advanced System Deflection to understand the fundamental mechanism and predict the excitation force at the spline.

Then they’ll use a time stepping analysis using MASTA’s DRIVA modules to fully model the non-linear dynamics.

Finally, they will perform a sensitivity study on the manufacturing errors to see how different errors contribute to rumble.