Study On The Characteristic Of Vibration Of The Sun Gear For Planetary Gear Trains With Or Without Phase Difference

With the development of automobile industry and road transportation,automatic transmissions are applied in America, Japan . There are more automatictransmissions in the automobiles made in China. Planetary gear transmission is oneof main parts, and the vibration and noise of it have a great effect on the comfort ofdrive. Doctor Yong Cheng brings forward a theory about phase difference designfor transmission system of planetary gear. It has been proved by experimentationthat there is a great improve in vibration and noise of the transmission system ofplanetary gear with Phase difference. But it is not discussed in-depth about thefunction mechanism. On the base of the predigesting model of concentrateparameter in transmission system of planetary gear, the paper try to clarify thecharacteristic of the meshing phase in common transmission system of planetarygear, set up a parameter description for analyze model about the planetary gear .Thus it will prove theoretically the effect on vibration characteristics oftransmission system of planetary gear caused by phase difference. The paperincludes seven chapters.Chapter one provides a summary of the development of planetary geartransmission, planetary gear transmission characteristics and applications in the car,because of the uneven distribution of load among the planet gears and the meanswithin floating sun gear. The current planetary gear transmission related researchleads the concept of phase difference design and the research presented this paperspurpose and content.In chapter two, we first particularly introduce the concept of phase differencein planetary gear transmission and the designing theory of phase difference inplanetary gear transmission. By using the parameter simplified model in theplanetary gear transmission, We use the spring replace the mesh between the gears,The stiffness of spring (meshing stiffness) never-endingly changing with therotating of gears and the number of the meshing gear (for spur gear) or the lengthof meshing line (for bevel gear) in the gear meshing zone, and indicate that themeshing stiffness function is the base of phase difference. For all kinds of meshingof planetary gear, it is very important to correctly define the phase relationshipbetween the gears in the rotating process, the mainly phase relationship concernedis:1. Each planet gear meshing with the sun gear and the relationship ofmeshing phase;2. Each planet gear meshing with the inside gear and the relationship ofmeshing phase;3. For every planet gear, the meshing phase relationship between sun gearand planet gears with the inside gear.By analyzing the parameter description that suit to the analyzing model of theplanetary gear train, we lead the phase relationship specialty to each meshing partin the gear transmission .And fully concerned to the meshing specialty of spur gearand bevel gear;we give the mathematic description to the phase difference and thegears meshing stiffness function separately.In chapter three, We analyze the factor to influence the vibration to theplanetary gear transmission, through the analysis to the vibration of the phasedifference, and simplified the every influencing factor, We induce the hypothesis tothe analyzing model to planetary gear train and the sun gear phase difference, andon this conditions, We establish the vibration analyzing model to phase differenceon the planet gears and the floating sun gear.Chapter four and the chapter five use Dr. Chen Yong's test equipment basicparameter in vibration analysis model. By analyzed quantificationally the first-andsecond-order component on the vibration response on sun gear of planetary geartrain with or without phase difference that are main influence factors to thevibration characteristics of transmission system, the conclusion is confirmed thatincrease gear meshing degree of superposition to be helpful in reduces vibration ofthe gear system.Chapter six has separately analyzed contrastively the vibration response of thesun gear on transmission system of planetary gear with or without phasedifference on the condition of the gear pairs to transmit the same meshing forcesand the system to transmit the same torque. And it points out the system stiffnesson analyzing model be transformed the constant from the periodic functionbecause the system apply phase difference design, thus the system vibrationdifferential equation is transformed linear differential equation on the conditionwith phase difference form nonlinear differential equation on the conditionwithout phase difference, thereby the system vibration response transforms thestably cycle vibration from representative nonlinear vibration. Therefore thevibration response of sun gear is more stably and the vibration of transmissionsystem is remarkably reduced.As the sum up of the papers, Chapter seven expatiate the main work and theconclusion of research.