Wear mechanisms in oscillating bearings

Surface examination of dry oscillating bearings reveals three different contact zones and indicates that various frictional behaviours take place during the process. The relation between wear and applied conditions such as load and amplitude of oscillation is obscured by the complex behaviour of most frictional materials. Studies of initial destruction, transfer and elimination are easier with materials that show simple behaviour. Friction and wear are governed by load-carrying third bodies transported in the contact. Transport was confirmed during observation through a hollow glass ring rubbing on a chalk sector. Wear debris motion explains the manner in which geometry modification occurs with time. Circumferential debris transport due to ring motion is modified at the centre of the sector where transverse flow takes place. The initial O-shaped sector can change into an ω configuration. Thus the calculation of wear or of eliminated material must allow for the new ω shape. The new shape also controls bearing clearance. The effects of load and oscillating motion on wear parameters are presented. More than one wear mechanism can exist in a single contact.