ABSTRACT
This chapter discusses the purposes, designs, and functions of spur, planetary, rack and pinion, helical, bevel, and worm gears. It explains criteria for optimal gear operation and its relationship with gear design variables and design equations. The chapter describes equations and solution methods for the kinematics of spur, planetary, rack and pinion, helical, bevel, and worm gears. The circular pitch is the distance measured along the pitch circle from one point on a gear tooth to the corresponding point on an adjacent gear tooth. The addendum is the radial distance from the pitch circle to the top of a gear tooth and the dedendum is the radial distance from the pitch circle to the bottom of a gear tooth. The pressure angle is the angle between the line tangent to both pitch circles of mating gears and the line perpendicular to both gear-tooth surfaces at the contact point.
