Since I do not know if the hole is tapered or straight through, nor the diameter of the hole, all I did was to type rubber bushing/with hole, and this popped up.
https://www.google.com/search?q=rubb...w=1263&bih=853
Since it's articulating I'm guessing things need some twisty movement, thus the large diameter hole with a bolt through it, well that is how I'm supposing, anyway.
Good luck in your search.
Just know both sides of that diameter, and the metric size of the diameter of the bolt and how long it needs to be. The nut looks to be a type with a nylock insert maybe.