Abstract

With the increasing demand for electric vehicles to meet environmental requirements, the continuous development of electric drive systems is essential. Electric machines, which operate at higher speeds than combustion engines, require high gear ratios and high power density of the drive unit. Planetary gearboxes fulfill these requirements, but pose challenges due to their geometric constraints, system stiffness and dimensional tolerances. Gear meshing and power splitting create a statically overconstrained system and therefore place high demands on modeling. The intended presentation will focus on the effects of dimensional tolerances and electrical machine parameters on the acoustics of integral housings and gearboxes, aiming to derive solutions for noise reduction.
 

The methodology follows an interdisciplinary CAx process chain: vehicle system simulations derive component requirements, electromagnetic simulations determine force densitites of the electric machine and 3D tolerance analyses with Catia 3DCS evaluate component tolerances. The acoustics are evaluated using transmission error, acceleration measurements at sensor positions and Equivalent Radiated Power (ERP). A sensitivity analysis identifies key modeling techniques affecting acoustic behavior, offering targeted strategies for noise reduction.

The presentation highlights modeling and simulation details of a multi-body system in Simpack combining electric machine components and a planetary gear set with stepped planetary gears. Various modeling techniques for gear meshing and bearings are evaluated for their impact on simulation accuracy and computational efficiency. Emphasis is placed on implementing dimensional tolerances in Simpack and analyzing their effects on drivetrain acoustics. Additionally, the role of electric machine adjustments, such as reducing torque ripple or electromagnetic forces, is explored. The combined optimization of electromagnetic and mechanical factors demonstrates a viable approach to reduce noise emissions in electric drivetrains.

Slide deck

Presenter Bio

Alexander Fischer studied Car and Utility Vehicle Engineering as well as Lightweight Construction & Simulation at Landshut University of Applied Sciences. After 4.5 years as a student and CAE engineer specializing in structural mechanics and multi-body simulation of powertrain and chassis at ARRK-Engineering, Alexander Fischer turned to research. As a research associate for about 6 years at the Landshut University of Applied Sciences, he worked on the manufacturing, characterization and modeling of composite materials and multi-curved sandwich elements with reactive thermoplastic matrix. Since April 2022, Alexander Fischer has been working as team leader at ARRK Engineering for powertrain simulations with focus on system, multi-body system and electromagnetic simulation.