Research On Dynamic Characteristics And Fault Simulation Of Helicopter Tail Transmission Support Bearing

The tail drive system is an important part of the helicopter transmission system.The rolling bearing is the key support part of the tail drive,whose performance is a direct impact on the performance of the tail drive system.The complex flight status of helicopter lead to poor working environment and influence the dynamic characteristics of the support bearings,making the support bearing prone to failure.Once support bearing failure happens,it will directly threaten the helicopter flight safety.Take a certain type of helicopter tail drive support bearings,double row deep groove ball bearing as an example in this paper.The dynamic characteristics under typical operating conditions and vibration characteristics in typical fault of the tail drive support bearing were studied.The research work provides a theoretical reference basis for structure optimization design,vibration and noise reduction and operation condition monitoring of the helicopter tail drive support bearings,it is of great significance.The main research work is as follows:(1)Load analysis and calculation of the helicopter tail drive support bearings.Taking a helicopter tail drive system as an example,it analyzes the support characteristics of tail drive support bearings,load and tail rotor required power of the tail drive system in several kinds of typical working conditions are calculated on the basis of the theory of aerodynamic and engineering algorithm.On this basis,according to the support characteristics of the tail drive bearing,the load values of the bearing was calculated,which provide the load basis for the dynamic characteristics and fault modeling analysis of the support bearing.(2)Multi-body contact modeing and dynamic characteristics analysis of support bearings in basis of the elastic hydrodynamic lubrication theory and Hertz contact theory.In this paper,the contact characteristics between ball and raceway was discussed,and the equivalent stiffness between the ball and raceway was obtained by combining of Hertz contact stiffness and lubrication contact stiffness.Based on the theory of multi-body dynamics analysis,the multi-body contact dynamic model of tail drive support bearing was established.The dynamic response under different flight conditions of the support bearing were analyzed.(3)Fault modeling and vibration characteristics analysis of helicopter tail drive support bearing.According to the typical failure mode of the tail drive bearing,based on load analysis and multi-body contact modeling of the bearing,the fault simulation model of tail drive support bearing for different fault locations,different sizes and different composite fault were established by using ADAMS fault modeling method model,the fault simulation and vibration characteristics analysis were carried out.The vibration acceleration signal under different fault conditions was obtained,and the change rule of typical statistical feature quantity during fault evolution was analyzed.(4)Experimental analysis and verification.The fault simulation experiment platform of double row deep groove ball bearing was built,and the vibration signal was collected by B &K system,and the experimental signal was processed.The accuracy of the simulation model of the double row deep groove ball bearing was verified by the comparison of the experimental signal and the simulation signal.