Shaft boss best connection

[cast16]

Hi all
I need to design an engine conveyor like that in the attached pictures.
I just have some pictures taken from my colleagues.
My problem for the moment is understand which would be the best connection to the shaft of the end hardened boss/sleeve. I know it need to be keyed for the transmission of the movement, but how to prevent the boss sliding out of the shaft? The only way I guessed is to use a grub screw. Is there any better, more adequate system?
Thank you.

 

[Sparweb]

This shaft can have a shoulder (a step-change in diameter) designed to rest against the inner race of the bearing, preventing the shaft from sliding through.
Also, the sprockets for the chain drive are probably on a sleeve, keyed to the shaft as you say. The inner diameter of the sleeve is not determine by the ID of the bearings, it is determined by the outer diameter of the shaft between the bearings. The sleeve fits on the part of the shaft that is between the bearings - mutually defining the diameter of the middle of the shaft and the sleeve, actually. Tell me why the shaft must have only one diameter, such as the diameter to slide through the bearings? Ask yourself "can the shaft cannot have an increased diameter between the pillow block bearings? The answer is (often) yes. By having a larger diameter than the ID of the bearing, how would the shaft slide out of the bearings?

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