ANALYSIS OF THE INSTANTANEOUS FRICTION COEFFICIENT OF THE TROCHOIDAL GEAR PAIR

Abstract

Wear of contact surfaces is one of the most common causes of gear failure. In addition to physical and chemical processes that occur in the contact zone, kinematic meshing parameters have a great effect on the wear process. This paper analyses the influence of geometric and kinematic parameters of the gear profile on the instantaneous friction coefficient of the trochoidal gearing in the gerоtor pump. The friction coefficient is not a constant value and it varies during the teeth meshing as a result of a constant change in the lubrication regime. There are many empirical expressions for calculation of the instantaneous friction coefficient, but due to numerous limitations, many of these expressions can be applied only to certain operating conditions and loads. The analysis of the friction coefficient was performed through two contact periods defined by the change in direction of the rolling velocity of the meshing profiles contact point. The obtained results enable identification of dominant factors that influence the instantaneous friction coefficient and show possibilities for further development of analytical models of mechanical losses in the gerоtor pump.