How to keep Toddler sleeping in his own bed

We just got my son a car bed. He’s been sleeping in there great for almost a month now. As of Sunday I can keep him in it for naps or at night. He keeps on climbing into my bed. I can’t sleep with him in my bed. I have never had him sleep with me. Suggestions are welcome! I put him back in his bed and closed the door over and over for 4 hours the other night. I’ve tried laying with him in his bed. I’ve let him cry it out. Nothing has worked. Help!?! Thanks