stochastic structures

The influence of stochastic shaft surface defects on the rotary shaft seal function is being investigated within the project “stochastic structures”. Two research centres are taking part in the project: Institute of Measurement and Automatic Control (IMR) and Institute of Machine Elements and Engineering Design (IMKT), Leibniz University in Hannover. The common purpose of the project is the investigation of stochastic surface defects with the view to the operation of rotary shaft seals. In this context, the influence of such defects on the leakage and wear is especially interesting. It is important to determine the limits for stochastic defects that are not critical and permissible for the further practical use. In other words, it is desirable to find the boundary between critical and non-critical shaft surface defects. An additional goal of IMR is the development of a production–related multi sensor system for the detecting critical surface defects.

To detect and to measure stochastic defects on the shaft contact surfaces the measuring methods, those are able to measure the lateral size of defects in the range of some millimeters (dents) as well as in the range of few tenths of millimeters (scratches), are needed. After the comparison of different methods, two measuring systems were chosen: light scattering sensor for the long-wave form deviations (dents) and chromatic sensor for the short-wave deviations (scratches). It was as well noted, that the light scattering sensor is able to detect the small scratches.

Funding and Partners

• Alliance Industry Research (AiF)
• Volkswagen AG (VW)
• SKF Group
• Driveline and Chassis Technology (ZF)
• Instituts für Maschinenelemente, Konstruktionstechnik und Tribologie (IMKT)