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.

Vibration Analysis and Modeling of an Off-Road Vibratory Roller Equipped with Three Different Cab’s Isolation Mounts

“…The reference parameters of the vehicle are given in Table 2. In addition, for the lumped parameters of three cab's isolation mounts, as listed in Table 3, herein, the traditional rubber mounts and the main rubber of hydraulic mounts are the same stiffness and damping constants [21]. The static stiffness constants of pneumatic mounts are also equivalently calculated with the above two isolation mounts.…”

“…A six-degreeof-freedom (DOF) cab model of earth-moving machinery with the hydraulic mounts involving quadratic damping was also investigated under the road roughness excitation within a frequency range below 10 Hz [21]. The results showed that the root mean square (RMS) of acceleration responses and the power spectral density (PSD) of displacement responses of the cab's mass centre are all reduced remarkably with the comparison between hydraulic and rubber mounts.…”

“…Among these three indices, the ride comfort performance evaluated via the weighted RMS acceleration response was considered to be the most important index [21]. In addition, in the international standard ISO 2631-1 [34], the acceleration PSD response was also applied to estimate the effect of vibration on the endurance limit of the human body in the frequency domain.…”

Study on Vibration Characteristics and Human Riding Comfort of a Special Equipment Cab

“…Then, they analyzed the effect of the device active suspended cab on the human body vibration and did the study of the operators' comfort [1]. Aiming at improving operating conditions, Sun and Zhang had done the low-frequency vibration study of the bulldozer cab vibration; then, the structure design and improvement scheme of the equipment had been proposed [2]. Xu et al had established a comprehensive model of a cab and an operator; then, the damping layout way had been researched [3].…”

Ride Comfort Analysis of Vibratory Roller via Numerical Simulation and Experiment

“…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 [2]. The ride dynamics of typical North-American soil compactors were investigated via analytical and experimental methods.…”