Investigation of the stress–strain state of the planet gear shaft and carrier of the planetary gearbox of an elbow orthosis

Abstract

Mechanical transmissions are widely used in various types of structures and mechanisms in different branches of the machine-building industry. One such branch is medicine. Devices with mechanical components are also used for patient rehabilitation in the postoperative period. Such mechanisms are known as orthoses. Structures of this type must meet several strict requirements–for example, compactness, light weight, safety, reliability, and others. Orthoses must reproduce the lost functions of a healthy person as accurately as possible. As previous work has shown, planetary gears meet the requirement for compactness. Planetary gears provide the necessary technical characteristics. This article presents the simulation and analysis of the stress-strain state of the components of a planetary gearbox for an elbow orthosis. KISSsoft and Ansys software packages were used for the design and 3D modeling of components, as well as for determining the stress-strain state. During the design process, KISSsoft software displays the profiles of the gear teeth and the contact line, allowing further adjustments to be made if necessary. When modeling the gears, the connecting elements were made of 45 steel. The article presents the basic formulas used for the analytical calculation and shows the stress and displacement fields obtained using the Ansys software product.