A pressure adjustment unit for an adjustment of fluid pressures in at least one first fluid chamber and in at least one second fluid chamber, which at least in the main is separate from the first fluid chamber, within at least one pressure interval, in particular for an at least substantial avoidance of a relative overpressure in one of the fluid chambers, having at least one first pressure expansion element which is provided for modifying a spatial volume of the at least one first fluid chamber, having at least one second pressure expansion element which is provided for modifying a spatial volume of the at least one second fluid chamber, and having at least one pressure coupling unit which is provided for effecting a negative feedback of spatial volume changes of the at least one first fluid chamber and of the at least one second fluid chamber.