Load Sharing Character Research On Planetary Gear Train Of Hydraulic Automatic Transmission

Currrently,researches on load sharing character of planetary gear train are mainly about the theoretical study of factors,researches about tests and influences laws of load sharing are deficient.Load sharing character of Ravigneavx planetary gear train are studied in this paper taking gear mesh stiffiness,damping,manufacturing errors,installation errors and so on into account.Quasi static model of planetary gear train and that model of automatic transmission are built.Influence that load sharing character has on transmission performance are analyzed by these models based on load sharing test of planetary gear train and modal test of transmission shell.The following four aspects are mainly studied in this paper.Quasi static model of Ravigneavx planetary gear train of one 4 AT transmission is built,the order of 11 factors are determined by use of this model and orthogonal experiment mathod.The laws of main factors affecting planetary gear train load sharing character are thus studied on the base of the orthogonal experiment results.Load sharing test is carried out on the specially designed test bench.Strain of area about the pin support holes on planetary carrier is measured,which is then converted to the principal stress by taking account of material properities of planetary carrier.Load sharing cofficient is calculated by the principal stress.Results show that load sharing cofficient decreases with the input toeque increasing,at the same time,test results are well agree with the simulation results.Analysis results of effcets that pin position errors,support stiffiness of ring gear and support stiffiness of needle bearings have on load sharing cofficient show that above three factors have significant influence on load sharing cofficient.Reducing support stiffiness of ring and needle bearings properly and reducing pin position errors as much as possible can improve load sharing performance of planetary gear train.Gear strength,bearing load,transmission efficiency and gear whine are analyzed by quasi static model of AT transmission.Results show that uneven load of planetary gear train influences the strength of planetary gear train’s gears significantly,yet has little influence on other fixed-axle gears.Meanwhile uneven load also leads to differences of support bearings’ loading condition.Load sharing performance affects transmission efficiency and gear whine,yet such influence is not much significant.