Pre-screening the tribological properties of shock absorbers

WHY

Shock absorber component testing is expensive and time-consuming and this is a limiting factor in developing new materials for this application. There is a need to develop a pre-screening method to get a quick but accurate evaluation of the tribological behavior of materials, without losing too much correlation with the actual conditions (geometry, wear mechanism, load, speed, number of cycles etc.).

HOW

A Cameron Plint TE-77 high frequency friction machine is modified to fit actual components of a shock absorber (rod and bearing). This set-up alloys for a reciprocating motion under variable frequencies, loads and/or displacements. The tests can be performed under dry or lubricated conditions, according to the specifications of the application. During the test, friction is continuously monitored and recorded. This is an important advantage over component test benches: changes in friction can be linked to surface changes (e.g. formation of wear particles) and/or a failure of the lubricating film. Different rod diameters can be tested. The wear on both rod and bearing can be evaluated by optical and confocal microscopy. 

 

 

RESULT 

• A new adapter and test method was developed on a TE-77 high frequency friction machine to evaluate the frictional properties of shock absorbers on component level.
• In situ monitoring of the coefficient of friction of the tribosystem allows to pinpoint changes in surface condition and/or lubricating film.
• The wear mechanisms observed after testing are similar to in-field damage.
• A ranking of different materials and coatings for shock absorber applications is possible.