High performance air journal bearing

An air journal bearing for a rotatable shaft of an air handling machine, comprising:

• a journal sleeve having an inner cylindrical surface and a central axis defining longitudinal and radial directions;
• a top foil disposed radially inboard of the journal sleeve and configured to receive the rotatable shaft;
• and
• a bump foil disposed between the top foil and the journal sleeve and configured to bias at least a portion of the top foil against an outer surface of the rotatable shaft;
• wherein the journal sleeve, the top foil and the bump foil are formed as a single piece made of selectively sintered ceramic-metal powder, and wherein at least one of the bump foil and a radially extending segment of the top foil is formed contiguous with the inner cylindrical surface.

A method of manufacturing a one-piece air journal bearing for a rotatable shaft of a turbomachine, comprising:

• presenting a plurality of successive deposition layers of a ceramic-metal powder comprising a mixture of ceramic powder and metal powder, wherein the ceramic and metal powders are sinterable by absorption of laser energy at first and second wavelengths, respectively;
• and
• after the presenting of each deposition layer, laser scanning a respective pattern on each deposition layer, using a respective combination of the first and second wavelengths, to produce a respective product layer of the one-piece air journal bearing made of selectively sintered ceramic and/or selectively sintered metal and corresponding to the respective pattern;
• wherein an accumulation of the respective product layers produces the one-piece air journal bearing comprising:
• a journal sleeve having an inner cylindrical surface;
• a top foil disposed radially inboard of the journal sleeve and configured to receive the rotatable shaft;
• and
• a bump foil disposed between the top foil and the journal sleeve and configured to bias at least a portion of the top foil against an outer surface of the rotatable shaft;
• wherein at least one of the bump foil and a radially extending segment of the top foil is formed contiguous with the inner cylindrical surface.