What is the term that describes the difference between addendum and dedendum in gears?

The term that describes the difference between the addendum and dedendum in gears is clearance. Clearance is crucial in gear design, as it represents the space between the top of the tooth of one gear and the bottom of the tooth of the meshing gear.

The addendum is the radial distance from the pitch circle to the top of the tooth, while the dedendum is the radial distance from the pitch circle to the bottom of the tooth space. Therefore, the clearance is calculated as the difference between the two, ensuring that there is enough space to avoid interference and allow for smooth meshing of the gear teeth during operation. This space prevents the gears from colliding and helps maintain proper function under various operating conditions.

In contrast, terms like fillet space and fillet radius relate more to the shape and curvature of gear tooth profiles, while backlash refers to the play or clearance between mating gear teeth, specifically in the angular direction. These distinctions are important in gear design but do not define the difference between addendum and dedendum.