A hydraulically controlled backing roller includes a mandrel, two cover plates which are installed at two ends of the mandrel through screws respectively, and two screwdown gears which are installed at two end portions of the mandrel respectively. The two screwdown gears are engaged with an output rack of a screwdown hydraulic cylinder, multiple saddle ring sets are sleeved on the mandrel at equal intervals, a saddle ring of each of the saddle ring sets is fixed with a frame through a fan-shaped plate, a backing bearing is provided between two adjacent saddle ring sets; an inner eccentric ring of the each of the saddle ring sets is driven to rotate by hydraulic driving, so that the mandrel has a deflection deformation, and the deflection deformation is transmitted to other adjacent rollers through the backing bearing.

A hydraulically controlled backing roller includes a mandrel, two cover plates which are installed at two ends of the mandrel through screws respectively, and two screwdown gears which are installed at two end portions of the mandrel respectively. The two screwdown gears are engaged with an output rack of a screwdown hydraulic cylinder, multiple saddle ring sets are sleeved on the mandrel at equal intervals, a saddle ring of each of the saddle ring sets is fixed with a frame through a fan-shaped plate, a backing bearing is provided between two adjacent saddle ring sets; an inner eccentric ring of the each of the saddle ring sets is driven to rotate by hydraulic driving, so that the mandrel has a deflection deformation, and the deflection deformation is transmitted to other adjacent rollers through the backing bearing.