Problem: Audible and perceptible vibrations

Goal:  Increase in ride comfort

The e-axle drive is becoming increasingly popular for use in e-vehicles: With its lower weight, it promises more power and range.
In the e-axle drive, the three drive components – electric motor, transmission and inverter electronics – are combined to form a compact unit. Due to limited space, the individual components of the entire drive unit must be optimally matched in terms of strength, weight and sound transmission. Otherwise, audible and perceptible vibrations can occur that affect ride comfort. The investigation of torsional vibrations in the e-axle drive is therefore fundamental for the analysis of noise excitation as well as NVH (noise, vibration, harshness) behavior.

In the diagram, the speeds at the electric motor, at the gearbox output and at the intermediate shafts are recorded in high resolution. The clock frequency of the ROTEC speed card is 12.3 GHz. Thus, the torsional vibration of the shafts as well as the torsional angle between two shafts can be measured in the µrad range. The transmission error (TE) of the gears can thus be displayed with the highest accuracy. This parameter is important for describing the excitation of the gear howling (GWN) and indispensable for a deeper understanding of NVH behavior. At the same time, structure-borne sound signals are recorded with an accelerometer and microphones and then jointly evaluated in the order and frequency ranges. For the measurement of electrical quantities such as currents and voltages, we use the high-precision HV measuring probes of our partner company KLARIC.

The recorded measured values are evaluated in the time domain. At the same time, the acoustic behavior is analyzed.

Furthermore ROTEC ENGINEERING provides you with support and technical engineering know-how for problems related to vibration analysis of engines, transmissions and drive trains. With our know-how, we make a valuable contribution to your product in the areas of timing gear validation, valve train optimization, clutch design, transmission errors (TE), transmission optimization, oil supply optimization, powertrain measurement and optimization, current and voltage analysis, and the application of measurement technology.