The friction down core idler set includes a lower crossbeam, an upper crossbeam, and idlers. Trumpet-shaped friction wheels are installed at the contact points between both ends of the idlers and the edges of the conveyor belt. It also includes slide rails, rollers, and roller supports. The lower ends of the roller supports are fixed on the lower crossbeam, the rollers are installed at the upper ends of the roller supports, one end of the slide rail is fixed at the bottom of the upper crossbeam, and the other end cooperates with the rollers. Limit stops are installed on the base to restrict the rotation range of the upper crossbeam. Through the cooperation of friction wheels, slide rails, rollers, etc., the down self-aligning idler set not only has the advantages of low resistance generation and low wear on idlers and conveyor belts like friction down self-aligning idlers, but also has the advantage of being insensitive to eccentric loads like conical down self-aligning idlers.