Hello, I'm designing a rotary brush based on the idea of Gerotto The bull excavator robot. There are 2 brushes, each weighs 16kg with outside diameter 320mm, the inside diameter is 170mm. I want to attach the brush to the electric motor so I intend to make a bushing inside the tube and mount the brush directly on the motor shaft. The problem is the motor shaft diameter is only 19mm, although the loading force is still in the range but may I ask, does the idea of mounting something directly on motor shaft a good design. I'm concerned that if the brush hit something the motor shaft will break. Anyone have experience in designing mechanical part please help me.