Nobuaki Kurita

Correlation factor in diffusion in the L12 structure for atomic migration via triple defects

Abstract Expressions for the diffusion coefficients and correlation factors for diffusion by means of divacancies in compounds A3B with the L12 structure are calculated. The divacancy is assumed not to dissociate and migrate via a triple-defect configuration. By applying a matrix method proposed by Howard [Phys Rev 1996;144:650], values for the correlation factors are calculated as a function of the ratio of the defect-atom exchange frequencies. The ratio of the diffusion coefficients of A and B atoms, DA/DB, will lie between 0.061 and 4.9.

Calculation Model for Internal Gear Skiving With a Pinion-Type Cutter Having Pitch Deviation and a Run-Out

As the emerging economies expand, demand for low cost production of internal gears has been increasing. And skiving is in focus as a potential method than can meet this demand.Skiving was invented in 1910, since then, mechanical machine has been developed to NC machine and cutter design technologies have developed dramatically. As a result, several machine and tool manufacturer started to release their skiving machine and skiving cutter as well.Furthermore, many studies on the kinematics have been conducted both in research institutions and private companies. However, most of these studies are subject to understanding the cutting mechanisms as a basic research and establishing cutter design methods.For further improvement and boost widespread application of the process, optimization of the manufacturing process is an issue. Particularly, the effects of cutter accuracy and cutter set up deviations on the skived gear are important to ensure reliability of the process. Unfortunately, few studies on those effects can be found.In this paper, geometrical model that can predict the effect of pitch deviation and of run out of a cutter on a skived gear is proposed. Experiments were also carried out to verify the validity of the model, and the results were in good agreement with the simulated ones.Copyright