Performance of earth-moving machinery cab with hydraulic mounts in low frequency

Abstract

The purpose of this study is to explore the low-frequency advantages and characteristics of the hydraulic mounts used for vibration isolation of an earth-moving machinery cab. For the feature of the cab’s center of mass being relatively high above the cab’s supporting surface, the pitch and roll vibrations of the cab are prone to generate in the low frequency range. A six-degree-of-freedom (d.f.) model of the cab supported by hydraulic mounts with quadratic damping is set up in this paper. And the simulation which compares performance of the hydraulic mounts and the rubber mounts used in the cab is carried out. It shows that the cab system with quadratic damping hydraulic mounts has remarkable efficiency to mitigate the vibrations and in turn to enhance the cab comfort, but its nonlinear damping characteristic has almost no effect on the natural frequencies of the cab system. A new approach is also proposed, which considers the absolute displacement of the pitch motion of the cab besides the traditional absolute accelerations, to improve the indications of the ride comfort for the suspended cab with a high-positioned mass center in the isolation design of the earth-moving machinery cab.