Reibung und verschleisserscheinungen an festgeklemmten kolben

Abstract

Damage has been observed in pistons that have jammed as a result of thermal expansion and have retained this state prima facie. A full description is given of these phenomena, together with illustrations of surface views and sections. High normal pressures brought about by thermal expansion may provoke on the deformed parts with diminished radius of curvature shearing stresses of such magnitude that they are able to destroy the structural connection, causing detachment of piston material particles. These experiences are in agreement with the rules of statics in structural mechanics. This damage provides proof of the fact that, in spite of the oil film, mechanical dislocation of surface particles and surface roughnesses may be provoked as soon as the local load becomes sufficiently high. Comparison with electron-microscopic magnifications taken by various authors proves that a similar state of affairs also prevails in the submicroscopic wear region. This confirms, therefore, the conception that wear is brought about not only by abrasion owing to mechanical contact, but also as a result of surface fatigue.