What is a root diameter ?
The line connecting the roots of the teeth of the cylindrical gear is the root circle and its diameter is the root diameter.
If the pitch diameter (reference diameter) is d and the module is m, the root diameter df can be expressed by the formula :
df = d - 2.5m
In the diagram below, the root diameter is shown enclosed in a red box.
相关链接 - 齿根圆直径