Modal Analysis And Vibration Reduction Of The Main Structure On A Forklift

Vibration is a very important factor of the performance of a forklift.Severe vibration greatly reduces the workers’ comfort, and would lead to a series ofproblems. As market competition intensifies, as well as the technology of vibrationcontrol continues to evolve, lower vibration level is required in forklift industry.However, the domestic forklift manufacturing enterprises usually design thestructures without considering the dynamics, which lead to obvious vibration. As aresult, local forklifts have a large gap with similar foreign products. In order to avoidresonance, this paper researches the dynamic characteristics of a forklift, and usestructure dynamics modification to reduce forklift vibration.The main structure of forklift includes Frame and Overhead Guard, Frame is themain load bearing matrix, and overhead guard is the largest structure which combinedwith the Cab. Modal parameters of these two structures not only reflect the overalldynamic performance of the forklift but also become the key factors in controllingforklift vibration characteristics. Engines and uneven road is the main source offorklift vibration. In this paper, we diagnose the vibration of the Frame and OverheadGuard of a forklift. Firstly, vibration signals when the forklift is working is collected,and we focus on the signals when the subjective evaluation is worst. Then modal testof both Frame and Overhead Guard is done, and the results are compared withvibration signals. Based on these work, the main reason of Forklift vibration isdetermined as the resonance of Frame and Overhead Guard excited by engine. Sincethe nature frequency of the Frame is close to the nature frequency of the OverheadGuard, resonance is caused on both of these two structures, which is a serious impacton comfort of forklift. Finally, a plan for reducing the vibration is proposed.