Structural Stress Analysis and Reliability Evaluation for a New Speed Reducer

Reducers are extensively used in many machines for reducing the speeds of mechanism. This paper proposed a new design of speed reducers to meet the performance requirements in high rigidness and large speed-reduction ratios. The movements of the reducer are designed based on the principles of differential displacements of the deceleration gear rings. The geometric models of the related components were designed using CAD software. The motions of mechanism were simulated for identifying the feasibility of designing including acquiring the kinematic properties. The mathematical models of structural stresses analysis were proposed so that the bending and contact stresses of the gear rings could be evaluated, accordingly. Finite element methods (FEM) were also used to analyze the structural stresses of the reducer. The studied results showed that the bending fracture of the gear rings would prior to its contacting fracture. The allowable loading of the reducer was then established according to the analyzed results of the maximum stresses on various transmitted torques. The methods of reliability evaluation were reported for considering the strength variation and calculating the reliabilities of the reducer at various loadings. The studied results are useful in structural design, stress analysis and reliability evaluation for developing high speed-reduction mechanisms.