In a pair of gears, what is the plane perpendicular to the axial plane and tangent to the pitch surface called?

The correct term for the plane that is perpendicular to the axial plane and tangent to the pitch surface of a gear pair is the pitch plane. This plane plays a crucial role in understanding the geometry and kinematics of gears.

In gear design, the pitch plane is an imaginary surface where the effective contact between the gears occurs. It is essential for defining the relationships between the gears' dimensions and their motion during meshing. The pitch circle, while related, is a different concept; it refers to the circular boundary on each gear where the teeth theoretically engage.

The pitch point is the point on the pitch circles of two gears where they are tangential to each other, indicating the point of contact during meshing and where the rotational motion is transferred. These distinctions are critical in gear design and analysis, as they influence factors such as gear ratio, efficiency, and load distribution.

Understanding the pitch plane helps engineers develop accurate models for gear systems, ensuring proper functioning and longevity of mechanical assemblies.