Thrust shaft for ram air fan

Abstract

A thrust shaft contains a shaft body having a disk at one axial end to provide a rotating surface in a thrust bearing, the disk having a first side and an opposite second side. The thrust shaft also contains a first section extending from the first side of the disk, the first section cylindrical in shape and having eleven holes uniformly spaced circumferentially about the first section, the holes being substantially axially equidistant from the first side of the disk. The thrust shaft also contains a second section cylindrical in shape having a smaller diameter than the first section, the second section extending from the first section to an end of the shaft remote from the disk.

1 . A thrust shaft comprising:
 a shaft body having a disk at one axial end to provide a rotating surface in a thrust bearing, the disk having a first side and an opposite second side;   a first section extending from the first side of the disk, the first section cylindrical in shape and having eleven holes uniformly spaced circumferentially about the first section, the holes being substantially axially equidistant from the first side of the disk; and   a second section cylindrical in shape having a smaller diameter than the first section, the second section extending from the first section to an end of the shaft remote from the disk.   
     
     
         2 . The thrust shaft of  claim 1 , wherein a third section cylindrical in shape is attached to the second side of the disk. 
     
     
         3 . The thrust shaft of  claim 1 , wherein a ratio of a diameter of each of the holes to the distance measured from the first side of the disk to the center of the holes is between approximately 1.04 and approximately 1.14. 
     
     
         4 . The thrust shaft of  claim 1 , wherein a ratio of an axial length of the first section to an outer diameter of the first section is between approximately 1.36 and approximately 1.37. 
     
     
         5 . The thrust shaft of  claim 1 , wherein the holes allow airflow to cool a thrust bearing adjacent to the disk. 
     
     
         6 . A thrust shaft comprising:
 a body having a disk, the disk having a first side and an opposite second side, the disk having a circular hole located at the center of the disk;   a first section of the thrust shaft, the first section cylindrical in shape and having a first end and a second end, the first end attached to the first side of the disk;   a second section of the thrust shaft, the second section cylindrical in shape and having a first end and a second end, the first end of the second section attached to the second end of the first section; and   a plurality of holes, the holes uniformly spaced apart and located circumferentially about the first section,   wherein a ratio of a diameter of each of the holes to the distance measured from the first side of the disk to the center of the holes is between approximately 1.04 and approximately 1.14.   
     
     
         7 . The thrust shaft of  claim 6 , wherein the second section has a smaller outer diameter than an outer diameter of the first section. 
     
     
         8 . The thrust shaft of  claim 6 , wherein the holes are located substantially axially equidistant from the first side of the disk. 
     
     
         9 . The thrust shaft of  claim 6 , wherein the thrust shaft is supplied with air by the holes. 
     
     
         10 . The thrust shaft of  claim 6 , wherein the first section has eleven holes uniformly spaced circumferentially about the first section. 
     
     
         11 . The thrust shaft of  claim 6 , wherein a ratio of an axial length of the first section to the outer diameter of the first section is between approximately 1.36 and approximately 1.37. 
     
     
         12 . The thrust shaft of  claim 6 , wherein the holes allow airflow to cool a bearing adjacent to the disk. 
     
     
         13 . The thrust shaft of  claim 6  and further comprising: a third section that is cylindrical in shape and is attached to the second side of the disk. 
     
     
         14 . The thrust shaft of  claim 13 , wherein a ratio of an inner diameter of the third section to an inner diameter of the second section is between approximately 1.12 and approximately 1.13. 
     
     
         15 . A ram air fan assembly comprising:
 a fan housing;   a fan motor attached to the fan housing;   a fan rotor;   a main shaft connecting the fan motor to the fan rotor;   a thrust shaft centered about the main shaft, the thrust shaft having a disk at one axial end, the disk having a first side and a second side, a first section cylindrical in shape and having a first end and a second end, the first end of the first section enjoining the first side of the disk, a second section cylindrical in shape and extending from the second end of the first cylindrical section to an end of the thrust shaft remote from the disk, the second section having a smaller outer diameter than an outer diameter of the first section,   wherein a ratio of the length of the first section to the outer diameter of the first section is between approximately 1.36 and approximately 1.37,   wherein the first section includes a plurality of holes uniformly spaced circumferentially about the first section and substantially axially equidistant from the disk.   
     
     
         16 . The ram air fan of  claim 15 , wherein the holes allow airflow to cool a bearing adjacent to the disk. 
     
     
         17 . The ram air fan of  claim 15 , wherein the first section has eleven holes. 
     
     
         18 . The ram air fan of  claim 15 , wherein a ratio of a diameter of the holes to a distance from the disk to the center of the holes is between approximately 1.04 and approximately 1.14. 
     
     
         19 . The ram air fan of  claim 15 , the thrust shaft further comprising: a third section cylindrical in shape and extending from the second side of the disk. 
     
     
         20 . The ram air fan of  claim 19 , wherein the thrust shaft has a ratio of an inner diameter of the third section to an inner diameter of the second section is between approximately 1.12 and approximately 1.13.