Study On Vibration And Noise Characteristics Of Hydraulic Gearbox Based On Partial Coherence Analysis

Hydraulic gearbox is one of the most important parts of industrial vehicles. The noise of hydraulic gearbox has great affect on industrial vehicles when it works. So it's important to reduce the noise of hydraulic gearbox.The noise of hydraulic gearbox is lounder than the noise of engine was found in a noise test about a folklift produced by HeLi. That means hydraulic gearbox is the most important noise source in the folklift. So it's necessary to research vibration and noise characteristics of hydraulic gearbox. And according to these characteristics, low-noise design and modify of hydraulic gearbox could be carried out.By means of a test-bed, the vibration and noise of the gearbox was tested. The waterfall chart was used to analyse data, the result means that the dominative noise sourses are near to torque converter. A separate-test was used to look for the position of noise sourses exactly and partial coherence analysis was used to analyse the data. It's concluted that dominative noise sourses are the gear of torque converter and the hydraulic pump(a internal-mesh gear pump) possibly. Then, specturm analysis was used to check the result of partial coherence analysis. The result of specturm analysis was the same as the result of partial coherence analysis. It confirms that dominative noise sourses of the gearbox are the gear of torque converter and the hydraulic pump. Further more, it also proves that partial coherence analysis has been properly used in this issue.