US Patent 7993204 Torsional vibration damper arrangement

A torsional vibration damper with a primary side and a secondary side, wherein rotation of the primary side relative to the secondary side causes displacement of hydraulic fluid from at least one displacement chamber and compression of pneumatic fluid in at least one compensating chamber. A first displacement chamber assembly includes a pair of axially opposed end walls bounding each displacement chamber in both axial directions and a circumferential wall bounding it in one radial direction, and a second displacement chamber assembly bounds it in the other radial direction. At least one circumferential recess provided in one of the first and second displacement chamber assemblies is engaged by at least one projection provided on the other of the first and second displacement chamber assemblies to limit the relative rotation.