blender to unity animation problem

I have animated a chest in blender that consists of a single bone. It looked fine in blender but when I exported the fbx into unity the whole chest moved with the bone and not just the lid. Does anyone know why this is?

The problem was that I needed to create two bones. Animating with one bone for the lid works fine in blender but does not work at all in unity. You have to make one bone to keep the base of the chest still while the other bone opens the lid.