Patent ID: 8365564

Claim:
A ring rolling mill comprising: a main roll that is rotated around its center axis and is supported by a fixed frame; a mandrel that is rotated around its center axis; and a mandrel inclining and supporting mechanism that comprises at least one supporting frame, at least one pin, and a driving section; wherein the supporting frame extends from the mandrel toward the main roll and supports upper and lower ends of the mandrel, the pin is inserted through the supporting frame in a direction perpendicular to the center axis of the mandrel such that the supporting frame becomes rotatable about the pin, the driving section inclines the supporting frame about the pin and brings the main roll and mandrel close to or away from each other, the ring rolling mill rolls a peripheral portion of a ring-shaped body in a radial direction of the ring-shaped body while the ring-shaped body is rotated along its peripheral direction in a state where the peripheral portion of the ring-shaped body is pinched in the radial direction between an outer peripheral surface of the main roll which is rotationally driven and an outer peripheral surface of the mandrel which is rotatable, and during rolling of the ring-shaped body the mandrel inclining and supporting mechanism is arranged so as to incline and support the mandrel with respect to the center axis of the main roll such that a gap between the outer peripheral surface of the mandrel and the outer peripheral surface of the main roll differs between an upper and lower portion of the gap in a direction along the center axis of the main roll.