What is the difference between gearbox, the reducer?

In general, there is no difference between the gearbox, the reducer. The others are just different names, and they all refer to the same thing. In fact, it cannot be completely equivalent. The reducer is a reducer with a motor installed, called a geared motor, or a three-in-one reducer (including motor, reducer, and brake). However, in general conversations, the reducer and the reducer default Refers to the same thing.
The reduction gearbox is divided into a reduction gearbox, an increase gearbox, and a transmission gearbox. The reducer is one of the reduction gearboxes. However, the reducer should also include a non-gear drive (or completely non-gear drive) reducer. As long as the deceleration effect can be achieved, gear transmission is not necessary. Sprockets, pulleys, etc., can be used for reduction transmission. In this case, the reducer cannot be completely equivalent to the gearbox.
Because the transmission efficiency of the reducer is higher than other transmission methods, and the transmission ratio is accurate, in most cases the reducer is manufactured by gear transmission, so it is customary to treat the reducer and the gearbox as one thing.