Question

Can the function of brushes be that it make movement of split rings easy

Answer 1

Slip rings and brushes are generally a part of a DC machine and serve as a tool for mechanical rectification (although, Rectification is generally done with electronic AC to DC converters).

Let us consider a dc generator. The electric current generated in the armature of the dc generator is alternating in nature because of the opposite polarity of magnetic poles that exist (for simplicity take a two pole magnet with a N and S pole), and when the armature rotates, the conductors wounded around the armature come into effect of those two different poles in one rotation.

Answer 2

Brushes act as a connecting link between the split rings and the external circuit and the coil.