In the Steering System of a Car

Electric power steering systems (EPS) are used in today‘s all-new generation automobiles, including electric cars, and still need to be improved due to different application requirements. Proper design and a clear understanding of the dynamic interactions between all components in the steering system are essential to enhance system performance and prevent vibration and noise caused by uneven roads, such as cobblestones. Developing sophisticated dynamic models and verifying them through experiments is necessary to achieve these improvements.

The Research Unit for Technical Dynamics and Vehicle Dynamics investigated the effects of various parameters on possible vibration and clanking noise in an axis parallel (APA) type EPS system to further improve the overall system design. For this purpose, basic and multibody dynamic system models were developed, and simulation results were compared with related measurement results from test rigs and vehicle tests.

Figure 1 presents samples of the local models for the yoke-rack-pinion interaction and the assumed contact surfaces on the rack teeth through its interaction with the pinion gear in a simplified contact model. Figure 2 shows the multibody dynamics model of the steering system including user routines to map the complex contact conditions between all parts of the steering system. Experiments were evaluated for various loading cases that may cause noise in the steering system.

Figure 1: (a) Local model of yoke-rack-pinion interaction; (b) Contact between rack and pinion

Figure 2: Multibody dynamics model of steering system

References

Härtel, Alexander. "Ableitung objektiver Anforderungen für impulshafte Störgeräusche bei elektrischen Lenksystemen., opens an external URL in a new window" PhD Thesis, Technische Universität Wien, 2022.

Researchers

• Alexander Härtel
• Eray Arslan

Project Funding

Industrial