Modeling of oscillations of the undercarriage suspension system of crawler load-lifting machines

Abstract

This paper considers longitudinal vibrations of spring elements of the caterpillar mover and undercarriage support system of crawler load-lifting machines within the framework of the discrete-continuum model. A comprehensive analysis of the wave processes arising during the caterpillar mover operation is carried out. 

Crawler belts of modern hoisting machines are spring-closed chains consisting of movable links with lugs (tracks) of relatively small mass, connected by rigid elements - fingers. By design, the pins can be covered with wear-resistant rubber when pressing into the lugs of the tracks [1]. The effect of the elasticity of caterpillar belts leads to the fact that when the caterpillar machine moves, some parts of the caterpillar mover acquire the properties of oscillating systems in which dynamic processes of wave type are maintained.

One of the effective ways to eliminate the reflected waves on the boundaries of adhesion of caterpillar belts with the teeth of drive wheel crowns is the introduction of a tensioning mechanism with elastic-dissipative elements into the design of the running gear of the caterpillar. The provision of uniform tensioning of the caterpillar belt (using the tensioning mechanism) allows for the exclusion of the possibility of resonance occurrence as a result of the addition of the incident and reflected waves. In this way, it is possible to achieve a uniform distribution of dynamic loads on the teeth of the drive wheel gears as well as in other units and parts of the crawler.

Longitudinal spring oscillations of caterpillar belts are considered a superposition of two weakly damped waves simultaneously moving toward each other. It is theoretically presented that a significant reduction of caterpillar belt oscillations can be achieved by selecting the parameters of a damping device that eliminates reflected waves at the tension and sagging boundaries of the caterpillar belts. Estimated parameters of fixation of caterpillar belts on toothed crowns of driving wheels and boundaries of their final fixation, from which waves are not reflected, are presented.