Fault Diagnosis and Analysis of Gear Rattle of Construction Machinery
In order to reduce the serious abnormal noise of a construction machinery gearbox,the vibration,rotating speed and pressure of the gearbox are tested and analyzed.By analyzing the speed signals of the engine and gearbox,it is found that the rotating speed of the engine is unlikely to cause the noise.Based on the vibration and pressure signals and the parameters of the transmission system,it is identified that the auxiliary reversing oil pump is the reason of the battle noise.That is,the pump produces a larger amplitude of the harmonic pressure,which forces the transmission system to produce a large torsional displacement at the specific frequency,and the displacement exceeds the clearance of the unloaded gear in the gearbox which causes the rattle.The validity of the diagnosis is proved by the two schemes of installing the hydraulic buffer accumulator and replacing the the reversing oil pump by the one of different brands.This work may provide a guidance for diagnosis of gear-box rattle.