External versus internal gearsExternal gears are gears with teeth formed on the outer surface of a cylinder or cone. In contrast, an internal gear is a gear with teeth formed on the inner surface of a cylinder or cone. As with bevel gears, internal gears are gears with pitch angles greater than 90 d

The distinctive feature of the kinematic geometric measurement method is that it vividly reflects the gear meshing transmission process and accurately reveals the variation law of the gear single error and the relationship between the errors, which is especially suitable for gear technology error analysis and dynamic performance prediction.