Of all the many types of machine elements which exist today, gears are among the most commonly used. The basic idea of a wheel with teeth is extremely simple, and dates back several thousand years. It is obvious to any observer that one gear drives another by means of the meshing teeth, and to the person who has never studied gears, it might seem that no further explanation is required. It may therefore come as a surprise to discover the large quantity of geometric theory that exists on the subject of gears, and to find that there is probably no branch of mechanical engineering where theory and practice are more closely linked. Enormous improvements have been made in the performance of gears during the last two hundred years or so, and this has been due principally to the careful attention given to the shape of the teeth. The theoretical shape of the tooth profile used in most modern gears is an involute. When precision gears are cut by modern gear-cutting machines, the accuracy with which the actual teeth conform to their theoretical shape is quite remarkable, and far exceeds the accuracy which is attained in the manufacture of most other types of machine elements. The first part of this book deals with spur gears, which are gears with teeth that are parallel to the gear axis. The second part describes helical gears, whose teeth form helices about the gear axis.

This revised, expanded edition covers the theory, design, geometry, and manufacture of all types of gears and gear drives. An invaluable reference for designers, theoreticians, students, and manufacturers, the second edition includes advances in gear theory, gear manufacturing, and computer simulation. Among the new topics are: new geometry for gears and pumps; new design approaches for planetary gear trains and bevel gear drives; an enhanced approach for stress analysis; new methods of grinding and gear shaving; and new theory on the simulation and its application. First Edition published by Pearson Education Hb (1994): 0-132-11095-4

The book explores the geometric and kinematic design of the various types of gears most commonly used in practical applications, also considering the problems concerning their cutting processes. The cylindrical spur and helical gears are first considered, determining their main geometric quantities in the light of interference and undercut problems, as well as the related kinematic parameters. Particular attention is paid to the profile shift of these types of gears either generated by rack-type cutter or by pinion-rack cutter. Among other things, profile-shifted toothing allows to obtain teeth shapes capable of greater strength and more balanced specific sliding, as well as to reduce the number of teeth below the minimum one to avoid the operating interference or undercut. These very important aspects of geometric-kinematic design of cylindrical spur and helical gears are then generalized and extended to the other examined types of gears most commonly used in practical applications, such as: straight bevel gears; crossed helical gears; worm gears; spiral bevel and hypoid gears. Finally, ordinary gear trains, planetary gear trains and face gear drives are discussed. Includes fully-developed exercises to draw the reader's attention to the problems that are of interest to the designer, as well as to clarify the calculation procedure Topics are addressed from a theoretical standpoint, but in such a way as not to lose sight of the physical phenomena that characterize the various types of gears which are examined The analytical and numerical solutions are formulated so as to be of interest not only to academics, but also to designers who deal with actual engineering problems concerning the gears

This revised, expanded, edition covers the theory, design, geometry and manufacture of all types of gears and gear drives. This is an invaluable reference for designers, theoreticians, students, and manufacturers. This edition includes advances in gear theory, gear manufacturing, and computer simulation. Among the new topics are: 1. New geometry for modified spur and helical gears, face-gear drives, and cycloidal pumps. 2. New design approaches for one stage planetary gear trains and spiral bevel gear drives. 3. An enhanced approach for stress analysis of gear drives with FEM. 4. New methods of grinding face gear drives, generating double crowned pinions, and improved helical gear shaving. 5. Broad application of simulation of meshing and TCA. 6. New theories on the simulation of meshing for multi-body systems, detection of cases wherein the contact line on generating surfaces may have its own envelope, and detection and avoidance of singularities of generated surfaces.

Over the last several decades, gearing development has focused on improvements in materials, manufacturing technology and tooling, thermal treatment, and coatings and lubricants. In contrast, gear design methods have remained frozen in time, as the vast majority of gears are designed with standard tooth proportions. This over-standardization significantly limits the potential performance of custom gear drives, especially in demanding aerospace or automotive applications. Direct Gear Design introduces an alternate gear design approach to maximize gear drive performance in custom gear applications. Developed by the author, the Direct Gear Design® method has been successfully implemented in a wide variety of custom gear transmissions over the past 30 years. The results are maximized gear drive performance, increased transmission load capacity and efficiency, and reduced size and weight. This book explains the method clearly, making it easy to apply to actual gear design. Describes the origin and theoretical foundations of the Direct Gear Design approach as well as some of its applications—and its limits Details the optimization techniques and the specifics of Direct Gear Design Discusses how this approach can be used with asymmetric gears to further improve performance Describes tolerance selection, manufacturing technologies, and measurement methods of custom gears Compares Direct Gear Design with traditional gear design from both an analytical and an experimental perspective Illustrates the applicability and benefits of this gear design approach with implementation examples Written by an engineer for engineers, this book presents a unique alternative to traditional gear design. It inspires readers to explore ways of improving gear transmission performance in custom gear applications, from higher transmission load capacity, efficiency, and reliability to lower size, weight, and cost.

Presents a Concept That Makes Gear Transmissions Noiseless, Smaller, and Lighter in WeightHigh-conformal gearing is a new gear system inspired by the human skeleton. Unlike conventional external involute gearing, which features convex-to-convex contact, high-conformal gearing features a convex-to-concave type of contact between the tooth fla