Abstract: The seal or pattern between two machine parts has on one of the sealing gap-forming, facing surfaces (5) a plastic layer (1) with closely juxtaposed depressions (8) which have the form of partly cut off voids of an expanded plastic structure. They are formed by the removal of a plastic layer (3) expanded on the machine part, the layer thickness being so uniformly reduced that the voids (4) of the bottom void layer (4) adjacent to the base surface (5) of the machine part are open. This avoids the insulating action of the closed voids of an expanded plastic layer and the latter has a very limited weight, which avoids any risk of the layer being detached or separated due to centrifugal forces. Moreover, in simple manner, a honeycomb-like, open surface structure is obtained, so that there is a labyrinth effect in the sealing gap.

Abstract: For improving the gap sealing between the circumferential surfaces of rot of a rotary piston machine and circular cylindrical inner surfaces (9) of the surrounding casing, rib-like protuberances (11) are displaced from the casing inner surfaces by cold working. On running in the rotary piston machine the external cross-sectional area of the protuberances (11) is removed by wear, so that between the protruberance (11) and the inner surface (9) a minimum sealing gap is obtained without corresponding manufacturing costs being involved in the formation thereof.

Abstract: The rotary piston machine has two internal rotors (2, 3) fixed to a common shaft (12) and two external rotors (4, 5) rigidly interconnected by means of an annular rotor disk (9). The working spaces (16) between the engagement parts of both external rotors (4, 5) extend a maximum extension (19) radially inward past the inner boundary of rotor disk (9). For the axial sealing of the working spaces (16), also in the area of said extension (19), the rotor disk (9) encloses a partition body (15), which surrounds the shaft (12) of the internal rotors (2, 3) by means of a bearing (43). A further bearing (13) is provided between rotor disk (9) and partition body (15). Partition body (15) is prevented from concomitant rotation with one of the two rotary machine parts (9, 12) adjacent thereto as a result of the radial displacement of the shaft (12) engaging therein relative to the rotation axis of rotor disk (9).