Fluid flow machine

1. A system comprising:

a fuel cell having a cathode;

a fluid flow machine comprising:

a housing with a compression chamber inside of the housing;

a connecting piece for receiving a working fluid on an intake side of the compression chamber;

a shaft that is held in the housing by radial and axial bearings;

at least one impeller mounted on said shaft and configured in the compression chamber inside of the housing; and

a cooling arrangement for at least one of the radial and axial bearings, comprising:

a cooling fluid transport device that comprises a revolving part of the axial bearing;

cooling channels arranged in the housing; and

a suction connection of said revolving part leads to the intake side of the impeller;

wherein the radial and axial bearings are located outside of the compression chamber,

wherein the revolving part comprises a disk that is arranged on the shaft in a torque-proof manner,

wherein the disk comprises radial bores and axial bores connected to the radial bores for transporting the cooling fluid, and

wherein the cooling channels receive the cooling fluid from the disk of the axial bearing and provide the cooling fluid as an oxidant to the cathode of the fuel cell.

2. The system according to claim 1 , wherein the disk has channels which transport the cooling fluid.

3. The system according to claim 2 , wherein the channels are disposed substantially radially in said disk.

4. The system according to claim 1 , wherein the shaft is hollow and its interior acts as a cooling fluid duct.

5. The system according to claim 1 , wherein the impeller is driven by an electric machine.

6. The system according to claim 5 , wherein the cooling fluid also cools the electric machine.

7. An electric turbocharger comprising:

an electric machine and a turbine wheel; and a system according to claim 1 .

8. A system comprising:

a fuel cell having a cathode;

a fluid flow machine comprising:

a housing;

a shaft which is rotatably supported on radial and axial bearings in said housing;

an impeller mounted on said shaft; and

an intake port through which said fluid flows to said compression chamber;

wherein,

said axial bearing includes a disk, which is mounted on said shaft in a torque proof manner;

said shaft has a longitudinal bore which is open to the intake port at one end thereof, as well as radial bores which connect with the axial bore;

said disk has substantially radially disposed channels which connect at one end thereof with the radial bores in the shaft, and which open at a radial extremity thereof to cooling channels which are arranged in said housing along bearing surfaces of the radial and axial bearings, whereby cooling gas flows from said intake port, through the longitudinal and radial bores of the shaft, and through the channels of said disk, to said cooling channels, and said disk includes radial bores and axial bores connected to the channels of the disk for transporting the cooling gas; and

said cooling channels supply the cooling gas received from the channels of the disk as oxidant to the cathode of the fuel cell.