Enhanced capacity bearing

Abstract

A bearing is provided particularly suitable for a turbine and turbine related components used in the aerospace industry. More particularly, the bearing is suitable for such applications as pneumatic starters for turbines. The bearing is preferably constructed from a M50 steel, which typically has a pre-treated hardness in the range of approximately 60 to 64 Rc. With the present invention, the bearing is nitrided to obtain a case hardness of approximately 74 Rc. To achieve such a case hardness, the bearing may require nitriding over several days. In one preferred embodiment of the present invention, a pneumatic starter includes a shaft, preferably constructed from M50, that has a portion of its outer surface nitrided. The nitrided surface functions as an inner race of a bearing assembly. Nitriding the portion of the shaft extends the bearing life of the bearing due to its increased hardness.

What is claimed is:  
     
         1 . A bearing component constructed from an M50 alloy with a nitrided case having a case hardness of approximately 74 Rc.  
     
     
         2 . The bearing component according to  claim 1 , wherein said thru hardened M50 alloy has a pre-treated hardness in a range of approximately 60 to 64 Rc.  
     
     
         3 . The bearing component according to  claim 1 , wherein said bearing component is an inner race.  
     
     
         4 . The bearing component according to  claim 3 , wherein said inner race is a shaft of a pneumatic starter for a turbine engine.  
     
     
         5 . A method of manufacturing a bearing comprising the steps of: 
 a) providing a bearing component constructed from a an M50 alloy;    b) nitriding the bearing component to increase the nitrogen content of an exterior portion of the bearing component; and    c) achieving a case hardness of approximately 74 Rc.    
     
     
         6 . The method according to  claim 5 , wherein said bearing component is an inner race.  
     
     
         7 . The method according to  claim 6 , wherein said inner race is a shaft of a pneumatic starter for a turbine.  
     
     
         8 . A starter comprising: 
 a housing;    planetary gear assembly supported within said housing;    a bearing assembly arranged within said planetary gear assembly wherein a portion of said bearing assembly is constructed from a nitrided high speed steel.    
     
     
         9 . The starter according to  claim 8 , wherein said high speed steel is an M50 alloy.  
     
     
         10 . The starter according to  claim 8 , wherein said bearing component is an inner race.  
     
     
         11 . The starter according to  claim 9 , wherein planetary gear assembly includes a shaft with a portion of said shaft providing said inner.