Reach On Cab Vibration Isolation Problem Of HXN3Diesel Locomotive

Research on isolating the diesel locomotive cab from the vibration coming from the high-power diesel engine has received increased attention in recent years in the field of NVH(Noise、Vibration&Harshness). Excessive noise and vibration will reduce the ride comfort, make driver fatigue, and shorten the service life of the instruments. The vibration of the operating handle and display device will effect the operation. The extended Ruzicka isolation system is applied by most diesel locomotives for separating the low-frequency vibration coming from the interaction of the rail and the wheel, while additional vibration isolation system is also required to separate the cab from the high-frequency vibration excited by the engine and the generator.Different from the domestic DF series diesel locomotive, a pivot-mount isolation system is applied to the HXN3diesel locomotive for separating the cab from the underframe. While as a matter of fact, the vibration of the cab isn’t kept within acceptable limits. For solving this problem, the vibration isolation properties of the HXN3locomotive cab isolation system is assessed, the relation between the transmissibility and the suspension parameters is derived, and finally the isolation system is optimized.This paper will discuss this problem by following sections:The differences between the isolation systems applied by domestic and overseas locomotives are compared. And so it is with overseas and domestic research status on isolation system which is applied on the diesel locomotive.The theory of vibration isolation and the isolation assessment method are presented.2different vibration isolation systems are analyzed with the theory of frequency response function. The application of the frequency response function is presented.Acceleration and running stabilities of the cab at different speed are derived via establishing the kinetic model of the HXN3diesel locomotive with the cab isolation system.The rigid-flexible coupling vibration analysis of HXN3cab isolation system is conducted via importing the finite element model of the cab structure into the isolation system.The governing equations of the6-DOF cab isolation system are established, the frequency response function (FRF) matrix is modeled, and transmissibility at different direction is derived. The property of this cab isolation system is assessed.The relationship between the lateral, vertical transmissibility and the suspension stiffness characteristic parameters is derived by comparing the frequency response function curve with different suspension stiffness characteristic parameters. The optimal suspension parameters are decided.Study results show that:In the HXN3cab isolation system, the vertical low frequency isolation property is decided by the stiffness of the front spring, the vertical high frequency isolation property is decided by the radial stiffness of the rubber, the lateral low frequency isolation property is decided by the stiffness of the lateral link, and the lateral high frequency isolation property is decided by the axial stiffness of the rubber. After optimization, the HXN3cab vibration isolation system is improved significantly.