Friction Phenomena on Microscale in Technical Contacts With Rubber

The focus of this work is the friction of reciprocating seals. In most cases the counter face of sealing contacts is metallic. The machining process of these parts results in an upper boundary of surface roughness wavelength in the range of micro meter. Usually a lubricant is used to reduce friction and wear and thus increase the lifetime. Different mechanisms contribute to the friction in these systems: Viscous friction resulting from the shear of the lubricant, hysteresis friction caused by internal damping when the rubber material is excited while sliding on the rough counterpart. Adhesion is considered as having no large influence due to the lubricant preventing to build up bondings. The lubricant can establish a boundary layer on the surface of the contact partners. The shear resistance of this film contributes to the friction. The investigations presented in this paper focus on the hysteresis friction in dependence on the surface topography, sliding velocity, temperature and load. Furthermore the effect of a lubricant is studied: The experimental identification of boundary lubrication is presented together with its influencing parameters.