overpairs on flop - how much do you bet?

[montauk]

hi all, id probably be better off posting this in a hand history thing, but can't convert from the poker site i use so, here's the general question.

You raise with QQ-AA pre flop, get 2 callers and are first to act on the flop with overpairs on a non-threatening board.

In a couple of hands I have raised the pot, only to be called with opponents with 1 overcard, and on another occasion with a flush draw. Both these times I raised the pot half my money was in the pot, while half was still in my stack.

Do I need to AI my JJ-AA on the flop to stop chasers with overpairs? Or is a pot sized bet standard? Even if they are chasers, should i mind since i have pot odds significantly in my favour.

thanks.