International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This paper presents a study of some geometric characteristics of conic spatial rack drives with linear helicoids. Three variants of the conic configuration are considered — with convolute, involute, and Archimedean helicoids — and their action surface properties are analyzed in relation to the distribution parameter. The role of the distribution parameter in determining the geometry of the action surface and the position of each variant in the design parameter space is discussed.

This research deals with the study of some kinematic characteristics, which can be used to ensure the loading capacity of the rack drives, including its hydrodynamic component. A brief analysis of the spatial rack drives in terms of their load capacity is realized. When mutually enveloping tooth surfaces are synthesized, it is possible to appear singular contact points appear on the active tooth surfaces. Two kinds of singular points exist, depending on the normal vector to the meshed tooth surfaces in their common points: singular points of firstorder (called ordinary nodes), and singular points of second-order. Singular points of first order should be registered and eliminated from the mesh region since increased specific friction, worsen lubrication, and heat transfer are present, which result in a decreased loading
capacity of the gear set A special accent is placed on the registration and elimination of singular points on the tooth surfaces of the synthesized rack drives. Analytical expressions are written defining total transference velocity and its normal component to an instantaneous contact line at an arbitrary contact point.