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## 9.1 INTRODUCTION

Computerized simulation of meshing and bearing contact is a significant achievement that could substantially improve the technology and quality of gears. Computer programs known as tooth contact analysis (TCA) programs are directed at the solution of the following basic problem:

The equations of pinion and gear tooth surfaces, the crossing angle, and the shortest distance between the axes of rotation are given. The pinion and gear tooth surfaces are in point contact. It is necessary to determine (i) the transmission errors, (ii) the paths of contact points on the gear tooth surfaces, and (iii) the bearing contact as the set of instantaneous contact ellipses.

In the case of determination of the bearing contact, it is considered that due to the elasticity of gear tooth surfaces their contact is spread over an elliptic area, and the center of the contact ellipse is the theoretical point of contact. It is also considered that the surface elastic approach is known (for instance, from the experimental data), and the problem of bearing contact can be solved as a geometric problem (see Section 8.7).

The main idea of TCA is based on simulation of tangency of tooth surfaces that are in mesh. The determination of the instantaneous contact ellipse requires knowledge of the principal directions and curvatures of the tooth surfaces that are in tangency. A substantial simplification for the solution to this problem has been achieved due to the expression of principal curvatures and directions for the generated surface by the principal...

Copyright Faydor L. Litvin and Alfonso Fuentes 2004 under license agreement with Books24x7

##### Products & Services
Bevel and Miter Gears

Bevel gears are gears designed to transmit motion between intersecting axes. Perpendicular arrangements are most common, but bevel gears can be manufactured for nearly any angle. The teeth bearing surface of the gear, or surface pitch, is conically shaped or tapered. Miter gears are bevel gears manufactured in a 1:1 ratio, with the same number of teeth on mating gears and with perpendicular axes.

Worms and Worm Gears

Worms and worm gears are gear sets that offer high gear reduction and torque multiplication with a small footprint. A worm drive is a cylindrical gear with a shallow spiral thread that engages the worm gear in a non-intersecting, perpendicular axes configuration.

Spur Gears

Spur gears are the simplest type of gear. Transmitting power between parallel axes, the teeth project radially on the disc.

Rack and Pinion Gears
Rack and pinion gears are used to convert rotation into linear motion.
Metric Gears
Metric gears are defined by module, which designates the center-to-center distance between successive teeth. This criteria of gear selection is used in countries which have adopted the metric system and is intended to standardize gear selection.

##### Topics of Interest

10.1 INTRODUCTION The involute gearing, first proposed by Euler, has found widespread application in the industry due to its many advantages: (i) the tools for generation of involute gears can be...

7.1 INTRODUCTION The information on surface curvatures is required for computerized simulation of contact of gear tooth surfaces (see Chapter 9), and grinding of ruled undeveloped surfaces (see...

14.1 INTRODUCTION Cycloidal gears (Chapter 13) and involute gears (Chapters 10, 11, 14, 15, and 16) have different areas of application. This chapter covers involute gears with parallel axes, whose...

18.1 INTRODUCTION A conventional face-gear drive is formed by an involute spur pinion and a conjugated face-gear (Fig. 18.1.1). Such a gear drive may be applied for transformation of rotation...

17.1 INTRODUCTION Wildhaber [1926] and Novikov [1956] have proposed helical gears based on generation by circular arc rack-cutters. The difference between the two inventions is that the gear tooth...

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