Cross shaft design from the aspect of capacity

Abstract

A cross shaft is one of the most important parts of the Cardan joint. In most cases, the size and lifetime of the Cardan joint depend on the cross shaft. To ensure the quality of mechanical parts, it is necessary to fulfill the basic constructional requirements related to the form, function, material and manufacturing procedure. The form of mechanical parts is the result of adjusting all of these requirements, and the task of a constructor is to develop forms with the aim of finding the best solution. This paper describes the procedure of determining the effect of geometry changes on the stress level in the cross shaft of the Cardan joint. The task of the Cardan joint is mechanical transmission of power and motion between shafts that change the position of their axes in the process of exploitation or are placed at a certain angle. The critical stress at the cross shaft was calculated by the analytical method and tested by a numerical solution. It is shown how small changes in the geometry of the cross shaft can lead to a significant reduction of critical stress. The most favorable ratio between the geometry of the cross shaft and the extreme stress values has been obtained by the means of the iterative correction of the form and the repetition of the numerical stress calculation.