Turbo machine, stator vanes and assembly ring

The turbo machine, and especially a turbocharger, has a guide baffle which has a vane support ring upon which is mounted around the rotor a number of adjustable vanes in a defined vane chamber. An additional ring (16) lying axially opposite the vane support ring forms the other boundary of the vane chamber. At least one of the rings, especially at least the additional ring and/or the side face of the vanes facing the ring, have a surface section (19a) receding in the axial direction of the vane chamber, whereby in the case of one ring the axially receding surface section reaches as far as the movement range of the vanes. Independent claims are also included for the following: (A) a guide baffle of variable geometry for a turbo machine; and (B) an additional mounting ring for a turbocharger.