Dynamic Modeling of the Torsional Vibration of the Slewing Mechanism of a Hydraulic Excavator

Abstract

A torsional vibration model of the slewing mechanism of a hydraulic excavator is developed to predict its free vibration characteristics with consideration of many fundamental factors, such as the mesh stiffness of gear pairs, the coupling relationship of a two stage planetary gear trains and the variety of moment of inertia of the input end caused by the motion of work equipment. The natural frequencies are solved using the corresponding eigenvalue problem. Taking the moment of inertia of the input end for example to illustrate the relationship between the natural frequencies of the slewing mechanism and its parameters, based on the simulation results, just the first order frequency varies significantly with the moment of inertia of the input end of the slewing mechanism.

Dynamic Modeling and Response Analysis of Lateral-Torsional Coupling Vibration of the Slewing Mechanism of a Hydraulic Excavator

“…The slewing mechanism of a hydraulic excavator comprises slewing motor,reducer with two stage planetary gear trains and slewing support equipment, based on the torsional vibration model of the slewing mechanism [11],with consideration of the lateral vibration and lateral-torsional coupling relationship,its undamped lateral-torsional coupling dynamic model is shown in Fig. 1.…”

“…Generally speaking, the torque and velocity of the slewing mechanism of a hydraulic excavator in the operation fluctuates in some degree, especially in starting and braking conditions, and the fluctuation is very complex, for simplification, taking harmonic excitation for example to illustrate the difference between the lateral-torsional coupling vibration and pure torsional vibration [11], and the excitation frequency is rotation frequency. As an example, consider a hydraulic excavator with the following parameters:…”

“…The dynamic study of the slewing mechanism of a hydraulic excavator and its inner parts has been studied [3][4][5][6][7][8][9][10][11], such as study of the contact stress of hydraulic excavator slewing bearing [3]; developing a general-purpose dynamic model of an N-stage planetary gear train consisting of single-planet, double-planet or complex-compound planetary gear sets [5]; modeling and analysis of the slewing mechanism using software [8], dynamic modeling of the pure torsional vibration of the slewing mechanism of a hydraulic excavator [11],These studies play important roles in revealing the dynamic performance of the slewing mechanism. However, these studies are mostly about the partial structure of the slewing mechanism, and the whole analysis of the slewing mechanism are mainly based on software, which hardly reflect the inherent relationship between the dynamic characteristics of the whole slewing mechanism and its parameters, and the mathematical dynamic model of the pure torsional vibration of the whole slewing mechanism doesn't consider the lateral vibration and lateral-torsional coupling relationship.…”