Conical Polygon Connection in Design of Indexing Gearboxes with Radial Cams

Abstract

Indexing gearboxes are used to convert the uniform rotary motion of the input camshaft into a required non-uniform rotary motion with clearly defined dwell portions of an output shaft. The indexing gearbox with conjugate cam consists of a pair of radial cams and an indexing turret follower fitted with rollers that are mounted on both sides and rolled. The favourable properties of polygon joints are advantageously used in the design of the indexing gearbox with radial cams. The joint profile formed by the polygon has very low, if not negligible, notch effects. For this reason, the fatigue strength of the respective connection is significantly increased. The geometric shape of the follower roller crown in cam mechanisms has also a significant effect on the contact stress due to the load and inertial effects in the surface layers of the general kinematic pair. Together with the design changes of the existing design of indexing gearboxes, modern coating methods can be used, which have become an integral part of industrial practices. Coatings extend the lifetime of sliding and rolling surfaces.