Turbo compressor assembly of a cooling machine

A turbo compressor assembly of a cooling machine, comprising:

• a compressor comprising an impeller;
• an electric motor comprising a rotor;
• a turboexpander comprising a turbine with an impeller;
• the compressor, electric motor, and turboexpander all arranged in a common housing, the common housing comprising a body of the compressor, a body of the electric motor, and a body of the turboexpander;
• a shaft mounted in the common housing;
• the compressor impeller, the turbine impeller, and the electric motor rotor all fixedly mounted on the shaft;
• the compressor impeller and the turbine impeller placed at opposite ends of the common shaft, and the electric motor rotor being placed between the compressor impeller and the turbine impeller;
• the shaft mounted in the common housing between the compressor impeller and the electric motor rotor with a first radial dynamic gas bearing, and mounted between the turbine impeller and the electric motor rotor with a second radial dynamic gas bearing;
• the shaft mounted between the second radial dynamic gas bearing and the turbine impeller with a thrust dynamic gas bearing, wherein a supply stream of working gas from the turbo compressor assembly supplied to the first radial bearing is formed between an inner wall of the compressor body and the shaft, and a supply stream of working gas from the turbo expander supplied to the second radial bearing and to the thrust bearing is formed between an inner wall of the turboexpander body and the shaft;
• the first radial dynamic gas bearing sealed towards the electric motor rotor by a shaft seal;
• and
• a surface in a shape of an annulus formed on the shaft between the first radial bearing and the shaft seal, the annulus perpendicular to an axis of the shaft and functioning as a piston for balancing an axial force acting on the shaft.