Research On Transmission Of Vibration Of High Speed Train Gear Box And Gear Box Line Test

Gearbox is the key part of transmitting torque, driving locomotive of high speed train, which affects the security and stability of EMU operational reliability directly. However, due to its complicated structure and the poor operational conditions, the gearbox systems tends to generate many problems, such as permeability (leakage), the high temperature of gearbox oil, trash in gearbox-body, crack and so on. The problems, caused by the fatigue and vibration of gearbox-body, would seriously threaten to the safety.Based on the background, this paper, aimed at the gearbox-body cracks in practical applications, analyzes the reasons of crack appeared, finds the weak position of stress test on track, indicates that the different vibration sources affect the dynamic stress of weak positions through vibration analysis.Firstly, find the mainly reasons causing crack, through research the practical operation of the gearbox, is that structure design flaws and Low level of casting process cause stress concentration, abnormal gearbox-body vibration etc.Secondly, based on test data in different lines, calculate the gearbox fatigue damage and life for test points on gearbox-body, analyze that the bottom of gear engagement and the weld of oil injection hole are weak positions.Using FFT and STFT transforms, frequency domain analysis for the dynamic stress signal of key points and acceleration signal of key points focusing on operating condition and velocity condition, indicates that, wheel tread emerge polygon during wheel repaired, gearbox-body resonate when Wheel rotation frequency of the polygon is closed to the inherent frequency of gearbox-body and vibrating violently.Finally, study the four kinds of gearbox-body vibration transfer characteristic, which finds that gearbox vibration caused mainly by crankcase vibration, motor vibration and its own gearing mesh vibration etc. Gearbox-body low-frequency vibration derives from the crankcase vibration transmission, high-frequency vibration is mainly affected by gearing mesh vibration.