Chain wheel broke somehow off

[lapka]

Hi all. i am new here and generally also pretty new to doing anything with my bicycle myself.

I was driving my bicycle today and suddenly noticed that the rear chain ring got completely detached
from the hub and was just free rotating. I never before had a closer look at how it looks like, so I have no idea, what exactly got broken. Now it looks like that:

[img][/img]

After some research on the inet, I think that there is something like a lockring or so missing, where the
red arrow is pointing. But again I have no idea how it could come off.

Someone an idea what is broken or where I could research that?

The bike was bought second hand, so I can't go to a dealer. And it seems that there is no repair shop here around.  

[Painkiller]

try this, cannot tell from the pic. maybe there is a co-op in your area that help in person and have a spare pare part if need be. It could be broken beyond repair and they may have a wheel to work for cheap.
http://www.parktool.com/blog/repair-help/coaster-hub-overhaul-pedal-brake-hub

[lapka]

(09-13-2015, 05:25 PM)painkiller Wrote:  try this, cannot tell from the pic. maybe there is a co-op in your area that help in person and have a spare pare part if need be. It could be broken beyond repair and they may have a wheel to work for cheap.
http://www.parktool.com/blog/repair-help/coaster-hub-overhaul-pedal-brake-hub

Tx guys. Problem resolved. That is a split ring that came off. So I am gonna to clean that all as first and then try to put it back on.