Impact of viscoelastic characteristics of built-in dampers on the dynamic state of cylindrical hinges with excessive backlashes

During the operation of cargo manipulators of mobile transport and technological machines for various purposes, having an open kinematic scheme with the articulation of sequentially installed links using cylindrical hinges, wear of their contact surfaces is observed. This type of damage is a typical defect in the metal structure of manipulators. The main cause of wear is the small contact surface of the «eyelet-hinge pin» pair, which leads to high pressure on the contact surface of the eyelet or sleeve opening and subsequent frictional wear. The article presents a mathematical model and a technique for modeling the dynamic state of hydraulic manipulators of mobile transport and technological machines in the presence of increased gaps in cylindrical articulated joints of links. The designs are considered and a mechanism is proposed to reduce the additional shock load in the hinges by using built-in hinge dampers that provide both purely elastic and combined viscoelastic damping of oscillatory processes. Based on computer simulation of a three-link manipulator of a specific mobile machine, a quantitative analysis of the effectiveness of reducing dynamic stresses in a metal structure was performed. The impact of the viscoelastic characteristics of the built-in dampers on the dynamic state of cylindrical hinges with increased clearances is analyzed.