Design and research of structural elements of the elbow orthosis planetary gearbox

Abstract

A variety of mechanisms, each designed with distinct specifications, find application in diverse sectors of the machine engineering industry. The utilisation of apparatuses comprising mechanical components in the field of medicine is also evident in the context of patient rehabilitation. These mechanisms are orthoses. The design of such systems is subject to a stringent set of specifications, which include compactness, light weight, and reliability. The purpose of orthoses is to replicate lost functions as closely as possible to a healthy human. It is evident that planetary gears satisfy the criteria for compactness and the requisite technical characteristics. The present paper sets out to model and analyse the stress-strain state of components of a planetary gearbox in the context of an elbow orthosis. The KISSsoft software package was utilised for the design and 3D modelling of components, as well as for determining the stress-strain state. In the course of the design process, the KISSsoft software displays the gear tooth profiles and the line of contact, thus enabling further correction if required. In the modelling of the transmission, the connecting elements were made of 45 steel. The paper provides a detailed analysis of the characteristics of meshing for both cylindrical and bevel gears. The results of the simulation pertaining to the distribution of contact temperature are also presented herein, as are the findings regarding the dependence of reliability and safety factor on service life.