Hydrodynamic foil bearing shaft

An air cycle machine (ACM), comprising:

• first and second rotors, each comprising a rotor hub and each rotor hub comprising:
• rear and forward faces;
• a central portion axially interposed between the rear and forward faces;
• and
• blades extending radially outwardly from the central portion,
• each rotor hub defining a pocket having an open end and forming a foil bearing shaft;
• an outlet housing comprising first and second bearing support elements, which are respectively receivable in the respective pockets of the respective bodies of the first and second rotors;
• and
• one or more first and one or more second bearings supportively disposed within the first and second bearing support elements, respectively, to support rotation of the respective foil bearing shafts of the respective bodies of the first and second rotors.

A method of assembling an air cycle machine (ACM), the method comprising:

• forming a rotor to comprise a rotor hub, the rotor hub comprising:
• rear and forward faces;
• a central portion axially interposed between the rear and forward faces;
• blades extending radially outwardly from the central portion;
• and
• a foil bearing shaft,
• the method further comprising:
• machining a pocket into the rotor hub from the rear face;
• supportively disposing one or more bearings within a bearing support element of an outlet housing;
• and
• inserting the bearing support element into the pocket whereby the one or more bearings are supportively disposed within the bearing support element to support rotation of the foil bearing shaft.