on the pressure side the second and the third sleeves 16 and 17 are arranged on the suction side the second sleeve 16 is arranged inside of a wall 18 of the bell shaped rotor 12 while the third sleeve 17 is arranged outside of the wall 18 the end of the sleeve 15 closest to the pressure side is equipped with an inwardly oriented edge 21 whose interior side forms a sliding fit 22 for a first shaft bearing 23 which is located on the pressure side of the shaft 11 additionally the edge 21 of the sleeve 15 forms a receiving region which receives a first o ring 24 which is preferably made of an elastomer material a corresponding receiving region is formed at the connection lid 7 and the connection lid 7 is in turn connected to the housing 2 the receiving regions include grooves angles or the like which are preferably designed so that the first o ring 24 serves both as a sealing element and as the first vibration element 5 that is the first vibration element 5 which supports the rotor stator system 3 on the pressure side is preferably one and the same element as the first sealing o ring 24 as shown in fig1 and 2 of course other elements.