Dual-mass flywheel

A dual-mass flywheel comprising a primary mass adapted to be attached to a crankshaft of an internal-combustion engine in a position centered on an axis of rotation;

• a secondary mass supported for rotation around the axis of rotation relative to the primary mass and adapted to be coupled to a friction clutch;
• and a torsion-damping arrangement which couples in a rotationally elastic manner the secondary mass with the primary mass;
• and wherein the primary mass includes two formed sheet-metal parts positioned concentric with the axis, one of said parts being a first formed sheet-metal part and having the shape of a pan and having a base wall portion which extends in an essentially radial direction and is adapted to be attached to the crankshaft and a peripheral flange portion which connects radially outward to the base wall portion and runs essentially axially away from the crankshaft, and the other of said parts being a second formed sheet-metal part and being connected to the peripheral flange portion of the first formed sheet-metal part and, together with the first formed sheet-metal part, defining in the radially outer region of the primary mass, concentric with the axis of rotation, a cavity, in which cavity there are arranged springs of the torsion-damping arrangement, wherein the second formed sheet-metal part also has the shape of a pan and includes a base wall portion which extends in an essentially radial direction and defines the cavity and a peripheral flange portion which is attached radially outward to the base wall portion and extends in an essentially axial direction away from the crankshaft, wherein the peripheral flange portions of the two formed sheet-metal parts run concentrically into each other in the region of the mass-ring extension and the formed sheet-metal parts are attached to each other in this region in a tight and rigid manner, wherein the peripheral flange portion of the first formed sheet-metal part includes a ring-shaped step and has on the side of the step which side faces away from the crankshaft a diameter that is larger than that of the side that is close to the crankshaft, wherein a juncture of the base wall portion and the peripheral flange portion of the second formed sheet-metal part is received proximate to the step, and wherein the peripheral flange portions of the two formed sheet-metal parts together form on the primary mass in the region of its outer perimeter an axially extending centered mass-ring extension which axially extends at least in part into a region radially outwardly of the secondary mass.