Rotary gear machine with commutator and shaft in flange housing

A rotary piston machine comprising:

• a housing;
• flange housing means on said housing for mounting the machine on suitable support means;
• a shaft rotatably supported within said housing;
• a rotor fixedly mounted on said shaft and adapted to rotate together with said shaft;
• a hollow gear for forming compressing chambers in cooperation with said rotor;
• a commutator fixedly mounted within said housing and adapted to supply pressure medium to, and to remove pressure medium from, said compressing chambers;
• wherein said shaft extends out of said flange housing means and said commutator is located in said flange housing means and is fixedly mounted therein against rotation, wherein the commutator has a flat side and is press-fit into an axial bore of said flange housing means and sealingly abuts with the flat side against the bottom of the bore;
• a control disc arranged between the commutator and the rotor, and a safety element provided between the control disc and the rotor, said safety element being fixedly secured with respect to displacement in the axial direction of said shaft, said safety element being located in relief means of said control disc, and wherein said safety element further abuts at a face of the rotor which faces towards said flange housing means.