Determination of rigidity of the radial-axial bearing undercarriage frame in hydraulic excavators

Abstract

Rotating superstructure and undercarriage frame in construction machines are usually connected via large-diameter radial-axial bearing. Manufacturers of those bearings define the necessary conditions for their proper operation and a long lifetime. The main condition to be fulfilled is the necessary rigidity of the undercarriage frame of the machine, because the bearing itself, having small cross-section dimensions compared to its diameter, is not rigid enough to prevent distortion of the bearing raceway. The paper presents the analytical method for the determination of rigidity of the radial-axial bearing undercarriage frame in hydraulic excavators. A certain displacement is imposed on one undercarriage frame support which induces reactions in the others and distortion of the structure. A Maxwell-Mohr integrals and Vereshchagin rule were used to form and solve a system of canonical equations for the unknown forces and moments. The derived relations were tested by the results obtained from the finite element method analysis conducted in ANSYS package. The comparison revealed a good accuracy of the proposed model for the real-life spectrum of design parameters.