Removing text from filename

I'm pretty sure I need to rename my file, but can't figure out the right syntax.
After I run a file through Handbrake, I'm appending _hb to the filename (since Handbrake can't overwrite its source file to give me the same name).
So I end up with Movie Name_hb.mp4 as my completed file.
I want to remove just the _hb from the filename as part of one of my Rules.
Can someone help point me in the right direction?
After I run a file through Handbrake, I'm appending _hb to the filename (since Handbrake can't overwrite its source file to give me the same name).
So I end up with Movie Name_hb.mp4 as my completed file.
I want to remove just the _hb from the filename as part of one of my Rules.
Can someone help point me in the right direction?