Optimization Design And Limited Working Life Evaluation Of Counter-Rotating Epicyclic Gearbox

There are two types of propulsion system used by Underwater Unmanned Vehicles(UUV): thermo-motive and electric-motive propulsion system.The electric-motivepropulsion system has been receiving considerable attention, the reason is that it offerssignificant advantages as inherently silent, less pollution, no change in weight and easyto use and maintain over conventional systems. Nowadays, a new choice of electricpropulsion system for UUV Propulsion System, was high speed permanent magnetsynchronous motor combined with reducer propulsion system. In this work, the powerflow and bending fatigue under limited life-time of reducer were studied by choosingcounter-rotating epicyclic gearing of an Underwater Unmanned Vehicle as the researchobject, and using theoretic analysis method. All the work shown as follows:â‘ A novel compound epicyclic gearing that combines a planetary gear train witha differential gear train is designed for an electrical propulsion system of UUV. Thisepicyclic gearing can transform a single input into two counter-rotating outputs withequal torque amplitudes and speeds. Based on the analysis method of power-flow in thedifferential gear train, the character of the power flow of the compound epicyclicgearing was determined. After comparing with the power distribution of input flow, thecondition of this mechanism without power recirculation was investigated.And Someuseful results are obtained.â‘¡Based on the compound epicyclic gearing, the geometric conditions and gearstrength conditions of double planets epicyclic gearing and a differential planetary geartrain must are analyzed. Two single-stage planetary gear drive system optimizationdesign models are established, and are applied to get the minimum volume.â‘¢The Boundary Element Analysis Software-FRANC3D is used to evaluate theinfluence of force, rim thickness, pressure angle and tooth fillet to the speed ofpropagation, getting the crack shape after it reach half of the tooth width and therelationship of load cycles versus crack length under different load conditions andlife-stress curve.