Looks like you pulled the guts out of your vending motor ( called the rotor, as opposed to the non-rotating portion called the stator) you are correct, it is part of the units brake-assembly ( it prevents the rotor from spining after a vend ( bottle or can) is delivered. you need to replace the entire vending motor assembly, unless you find someone with a good spare to part-out.
You may also wish to look over at
www.VEII.com they have parts for more "modern" machines, but you may find a vending motor that's close to yours,
PS... you never mentioned WHAT machine you are dealing with, this sites a little light in the mind-reading talent department...