Lubricated Hirth serration coupling

Abstract

Apparatus and methods for coupling components of dissimilar materials via a Hirth serration coupling, wherein an interfacial layer at a Hirth teeth interface allows radial sliding motion of a first set of Hirth teeth relative to a second set of Hirth teeth. The interfacial layer may be a solid lubricant coating, or a compliant multi-layered metal sheet.

1 . An apparatus, comprising: 
 a first component;    a second component coupled to said first component via a Hirth serration coupling, said Hirth serration coupling defining a Hirth teeth interface between said first component and said second component; and    an interfacial layer disposed at said Hirth teeth interface, wherein said interfacial layer is adapted for allowing radial sliding motion of said second component relative to said first component at said Hirth teeth interface.    
   
   
       2 . The apparatus of  claim 1 , wherein: 
 a first coefficient of thermal expansion (CTE) of said first component is less than a second coefficient of thermal expansion (CTE) of said second component.    
   
   
       3 . The apparatus of  claim 2 , wherein: 
 said first component is a ceramic rotor, and    said second component comprises a metal rotor.    
   
   
       4 . The apparatus of  claim 1 , wherein: 
 said first component is a first rotor, and    said second component is a second rotor axially aligned with said first rotor.    
   
   
       5 . The apparatus of  claim 1 , wherein said interfacial layer is selected from the group consisting of a solid lubricant coating and a compliant metal layer.  
   
   
       6 . The apparatus of  claim 5 , wherein: 
 said compliant metal layer comprises a pre-formed metal sheet,    said pre-formed metal sheet comprises a plurality of layers including: 
 an inner substrate layer,  
 a first lubricant layer disposed on a first surface of said substrate layer,  
 a soft metal layer disposed on a second surface of said substrate layer, and  
 a second lubricant layer disposed on said soft metal layer.  
   
   
   
       7 . The apparatus of  claim 6 , wherein: 
 said substrate layer comprises a superalloy, and    said first lubricant layer comprises a metal oxide.    
   
   
       8 . The apparatus of  claim 6 , wherein said first lubricant layer comprises cobalt oxide.  
   
   
       9 . The apparatus of  claim 6 , wherein said soft metal layer is selected from the group consisting of nickel, cobalt, platinum, rhodium, nickel oxide, cobalt oxide, and mixtures thereof.  
   
   
       10 . The apparatus of  claim 6 , wherein said second lubricant layer is selected from the group consisting of gold, silver, platinum, boron nitride, boron oxide, and mixtures thereof.  
   
   
       11 . The apparatus of  claim 6 , wherein said first lubricant layer comprises boron nitride, and said second lubricant layer comprises gold or silver.  
   
   
       12 . The apparatus of  claim 6 , wherein: 
 said first component comprises a ceramic,    said first component includes a first set of Hirth teeth, and    said second lubricant layer lies adjacent to said first set of Hirth teeth.    
   
   
       13 . The apparatus of  claim 6 , wherein said pre-formed metal sheet has a thickness in the range of from about 100 to 325 microns.  
   
   
       14 . The apparatus of  claim 1 , wherein: 
 said interfacial layer comprises a solid lubricant coating,    said second component comprises a metal,    said second component includes a second set of Hirth teeth,    said solid lubricant coating is disposed on said second set of Hirth teeth, and    said solid lubricant coating is adhered to said second component.    
   
   
       15 . The apparatus of  claim 14 , wherein said solid lubricant coating is deposited on said second component by a sputtering process to a thickness of from about 2 to 3 microns.  
   
   
       16 . The apparatus of  claim 14 , wherein solid lubricant coating comprises a material selected from the group consisting of gold, silver, platinum, cobalt oxide, boron nitride, boron oxide, and mixtures thereof.  
   
   
       17 . The apparatus of  claim 1 , wherein: 
 said first component comprises a ceramic rotor having a first set of Hirth teeth,    said second component comprises a metal rotor having a second set of Hirth teeth engaging said first set of Hirth teeth,    said first component is axially aligned with said second component, and    said interfacial layer comprises a solid lubricant coating disposed on said second set of Hirth teeth.    
   
   
       18 . An apparatus, comprising: 
 a ceramic component; and    a metal component rotatably coupled to said ceramic component via a Hirth serration coupling.    
   
   
       19 . The apparatus of  claim 18 , wherein: 
 said Hirth serration coupling defines a Hirth teeth interface between said ceramic component and said metal component, and the apparatus further comprises:    an interfacial layer disposed at said interface.    
   
   
       20 . The apparatus of  claim 19 , wherein said interfacial layer comprises a solid lubricant coating or a multi-layered pre-formed metal sheet.  
   
   
       21 . The apparatus of  claim 20 , wherein said solid lubricant coating comprises a noble metal layer sputter coated on said metal component.  
   
   
       22 . The apparatus of  claim 20 , wherein said multi-layered pre-formed metal sheet comprises: 
 an inner substrate layer,    a first lubricant layer disposed on a first surface of said substrate layer,    a soft metal layer disposed on a second surface of said substrate layer, and    a second lubricant layer disposed on said soft metal layer, wherein: 
 said first lubricant layer lies adjacent to said metal component, and  
 said second lubricant layer lies adjacent to said ceramic component.  
   
   
   
       23 . An apparatus, comprising: 
 a first component comprising a ceramic rotor and having a first set of Hirth teeth;    a second component comprising a metal and having a second set of Hirth teeth for engaging said first set of Hirth teeth to provide a Hirth serration coupling of said first component to said second component; and    an interfacial layer disposed at said Hirth teeth interface, wherein said interfacial layer comprises a solid lubricant coating or a compliant metal layer.    
   
   
       24 . The apparatus of  claim 23 , wherein said compliant metal layer comprises a multi-layered pre-formed metal sheet including: 
 an inner substrate layer, a first lubricant layer disposed on a first surface of said substrate layer,    a soft metal layer disposed on a second surface of said substrate layer, and    a second lubricant layer disposed on said soft metal layer.    
   
   
       25 . The apparatus of  claim 23 , wherein: 
 said Hirth serration coupling defines a Hirth teeth interface between said first set of Hirth teeth and said second set of Hirth teeth,    a coefficient of thermal expansion (CTE) mismatch exists between said first component and said second component, and    said interfacial layer is adapted for allowing radial sliding motion of said second component relative to said first component at said Hirth teeth interface.