When screw shaft rotate, due to the friction from materials gravity and shell,making materials only can be forward under the screw blade pushing . This case looks like the fixed screw nut to rotate along the screw shaft to make translation movement. When materials are moved in the middle, which depend on the push force. Therefore,in the whole conveying ,it is a sliding movement. In order to make the screw shaft be a pulling statement, usually we assemble the drive at the position of discharge outlet, and put the end bearing at the inlet. Rotating screw blade can push materials ,the forece to make materials not to touch the screw blades rotate is the gravity and friction from screw conveyor shell to materials. According to the different transported materials feature ,screw blade has different types ,such as solid screw blade,ribbon screw blade, cutting screw blade,etc.
There is an opposite force from the screw shaft to push bearings when materials are under moving. If screw conveyor is long ,there need add hanger bearings in the middle.