Macro Photography lenses?

I just bought a Nikon 85mm macro lens. (AF-S DX Micro Nikkor 85mm f/3.5G ED VR). The lens works great but I have one question about the focus ring. Once the lens reaches its maximum or minimum focus the ring can still be turned. You can feel when the focus ring maxes out but it still turns after that. Its very smooth so I wonder if there's some kind of damper on the focus ring or maybe a safety. The auto focus motor works fine and its virtually silent. Its also the fastest focus motor I've ever worked with. The instructions don't say anything about this and I couldn't find anything on the internet. Its my first Macro lens so I have no idea.

Added (1). Thanks but I still want to know about the focus ring. Is it supposed to stop once you reach the maximum or minimum focus. Or is it supposed to continue moving. The focus rings on all my other lens stop once you reach the maximum or minimum focus. I want to know if its some kind of damper or safety.

Make sure that you have the lens in the manual focus mode.

To practice the maximum macro mode on that lens, set the lens to 1:1 and then move the camera in and out until the subject is in focus. By adjusting the lens aperture, you can increase the depth of field

It is probably some sort of friction clutch. When you get past maximum, it keeps spinning, but it does not engage the internal focusing mechanism.