Are gears and gear rings a kind of thing?
A cylindrical or conical gear is obtained when the teeth are machined on the outer surface of a cylinder or cone;The teeth are machined on the inner surface of the hole to obtain the gear ring;When the teeth are machined on the plane, the rack is obtained;
A relatively thin gear can be either an internal or an external gear, not a gear ring, especially an internal one.
Gear generally refers to the external gear, the diameter is relatively small; gear ring, custom means that the diameter is very large
