I use these gloves if I'm not going bare-knuckle on the heavy bag.
They come with a foam insert sew into the center of the palm to help protect the hand (you can see it in the video in the link I've provided, ignore the shitty shadow boxing, LOL. I've taken it out and use them for sparring as well). I rarely use them on the bag as I do a lot of makiwara training as well.
Just another option for ya.