Thrust bearing shaft for thrust and journal air bearing cooling in an air machine

An air cycle machine comprising:

• a compressor rotor and a turbine rotor secured to rotate together;
• and
• an air bearing system including an inlet for supplying air into a housing, air flowing through a chamber in the housing along two thrust bearing surfaces, said thrust bearing surfaces being defined between a housing, and a disk on a thrust bearing shaft, said thrust bearing shaft including the disk, a first portion of the thrust bearing shaft extending from one face of said disk, a second portion of the thrust bearing shaft extending from an opposed second face of said disk, and said second portion having sealing ribs, and six holes extending through a body of said thrust bearing shaft to a hollow interior, said sealing ribs being spaced closer to said disk than said holes;
• and
• a ratio of a distance from an end of said second portion remote from said disk to a center of said holes to a distance from the end of said second portion to the second face of said disk being between 0.20 and 0.22.

A method of assembling a thrust bearing shaft into an air cycle machine comprising the steps of:

• providing a thrust bearing shaft having a radially enlarged thrust disk to be mounted between two static housing surfaces in an air cycle machine, a first portion of the thrust bearing shaft extending from one face of said thrust disk, a second portion of the thrust bearing shaft extending from an opposed second face of said thrust disk, and said second portion having sealing ribs, and six holes extending through a body of said thrust bearing shaft to a hollow interior, said sealing ribs being spaced closer to said thrust disk than are said holes, a ratio of a distance from an end of said second portion remote from said thrust disk to a center of said holes to a distance from the end of said second portion to the second face of said thrust disk being between 0.20 and 0.22;
• inserting said thrust bearing shaft into a housing with said thrust disk being positioned between housing portions to define the thrust bearing surfaces;
• and
• securing the first portion of said thrust bearing shaft to an end of a second shaft.