Torsional Vibration Model And Vibration Characteristics Of Non-circular Face Gear Differential Under The Condition Of Breakaway

Non-circular face gear(NFG)differential is a new type of variable transmission ratio limited slip differential.With the advantages of simple structure,high reliability and good slip-limiting performance,NFG differential can be widely applied in the field of vehicles.However,the lacking of the theoretical support about related dynamic research and performance evaluation methods limits the development of NFG differential.Therefore,the analysis method of torsional vibration of NFG differential under slip-limiting process is proposed which provides a theoretical foundation for the dynamic design and optimization of NFG differential.Firstly,the transmission principle of NFG pair and the configuration of NFG differential are expounded.The working state of NFG differential on different road surfaces is analyzed and the static/dynamic slip-limiting principle is discussed.The dynamic sliplimiting of the differential plays an important role in getting the vehicle out of trouble.With the increase of the input speed and eccentricity,the slip-liniting performance is also greatly improved.Then,the equivalent mechanical model of the gear meshing process considering a variety of internal excitations is established based on the elastic angle separation method.The motion state of the NFG differential gear train under the condition of getting out of trouble is mathematically described.The torsional vibration model and kinematic model are established which provides a theoretical basis for studying the vibration response law of the differential during the slip-limiting process.Then,the Runge-Kutta method is used to calculate the numerical simulation.The effects of four system parameters including in eccentricity,input speed,ground adhesion condition and meshing error on the vibration response and performance of the differential are analyzed.The simulation results show that increasing the eccentricity of NFG can improve the slip-limiting performance of the differential but it will lead to system vibration enhancement so that eccentricity should be selected reasonably.Increasing the input speed can improve the slip-limiting performance but the vibration of the system will be significantly improved when the speed is close to the super-harmonic resonance frequency of the system.Improving the adhesion condition of the slipping wheel can effectively help the vehicle get out of trouble but the vibration of the system also increases.The increase of meshing error will aggravate the vibration of the system and has no positive effect on improving the slip-limiting performance.The error should be minimized as possible.Finally,the vibration test bench of NFG differential under slip-limiting condition is built.The influence of input speed and ground adhesion condition on the vibration state of the system is tested by the Variable-controlling approach.The frequency components and variation of frequency domain curves of simulation and experiment are basically consistent which verifies the correctness of dynamic analysis method of NFG differential.