Investigation Of Reverse Vibration Characteristics Of Shaft With Symmetrical Embranchment

Shafting with symmetrical embranchment is widely used in engineering, and the abnormal torsional vibration of such shafting happened sometimes because of the symmetrical embranchment, but not yet have been attended. In this thesis, based on a real shafting with three symmetrical embranchments, the gears pair is being combined to moment of inertias and every gear is being simplified as single moment of inertia, the direct mass elastic system and the three symmetrical embranchment annular mass elastic system are built.In this thesis, the torsional mesh stiffness is introduced first which is defined as the torsional stiffness between two meshing gears. By the analysis of the force status between two involute spur gears, the theoretical equation to calculate the torsional mesh stiffness is obtained. With MATLAB, the equation is programmed and its results are compared with ANASYS software's calculations.By the torsional vibration calculation of these two different mass elastic system of the same shafting, it proved that this shafting do exist reverse vibration. Based on the analysis of the reverse vibration characteristics of the shafting, the reverse vibration is explained and methods how to avoid such vibration are also presented. Gear box with three symmetrical embranchments are designed, appropriative test-bed is also built. The existness of reverse vibration and correctness of the theoretical analysis are both proved by experiment.