Modeling of trochoidal gearing with respect to the uniform teeth wear

Abstract

The paper presents theoretical model of the gearing with modified trochoidal profile which is applied to Gerotor pumps. Gerotor pumps belong to the category of rotating machines whose kinematics is based on the principles of planetary mechanism with internal gearing. Using geometrical and kinematical models of the trochoidal gearing, we provide detailed analysis of specific sliding at the contact points of the profiles, as well as the relations for its determination. Specific sliding is one of the most significant constraining factors in the selection of the geometrical parameters of the gearing profile, which indicates conditions for appearing friction and wear of the tooth contact surface. The key objective in optimal gerotor pump design is to provide appropriate selection of geometrical parameters of the gearing, leading to the uniform wear of meshing gears teeth profiles. This requires ensuring the uniform wear of meshing profiles at the point with highest value of sliding velocity, i.e. at the contact points the most distant from the pitch point. Consequently, the methodology described in the paper defines the constraints to enable for uniform wear of meshing gears teeth profiles from the kinematical point of view.