Gas pressure biased sealing method for an actuating shaft

Abstract

The propensity for gas leakage around a shaft, which extends through a bore which connects volumes of differing pressures, e.g., a turbocharger turbine housing and the ambient air, is minimized with the addition of a pair of seal rings biased by a gas pressure to provide a continuous gas and soot seal.

I claim: 
     
         1 . A turbocharger with
 a turbine in a turbocharger housing ( 2 ),   a device within the turbocharger housing,   an actuator ( 73 ) located outside the turbocharger for actuating the device within the turbocharger housing,   a pivot shaft ( 63 ) rotatably mounted in a bore ( 70 ) extending through the turbocharger housing for transmitting an actuating movement from the actuating mechanism to the device,   first and second sealing rings ( 80 ) provided in at least one circumferential groove in at least one of said pivot shaft and said bore, and   a means for introducing sufficient pressure between said sealing rings to urge the sealing rings axially apart, under operating conditions, each against a respective sealing groove wall ( 81 ,  83 ).   
     
     
         2 . The turbocharger as in  claim 1 , wherein both sealing rings are provided in the same groove. 
     
     
         3 . The turbocharger as in  claim 1 , wherein each sealing ring is provided in a separate groove. 
     
     
         4 . The turbocharger as in  claim 1 , wherein at least one circumferential groove is provided in the pivot shaft. 
     
     
         5 . The turbocharger as in  claim 1 , wherein at least one circumferential groove is provided in the bore. 
     
     
         6 . The turbocharger as in  claim 5 , wherein the bore is provided in a bushing, and wherein said bushing is seated in said turbocharger housing. 
     
     
         7 . The turbocharger as in  claim 1 , wherein said device is a wastegate valve ( 61 ). 
     
     
         8 . The turbocharger as in  claim 1 , wherein said turbocharger is provided with a variable geometry turbine (VTG) mechanism, and wherein said device is the VTG mechanism. 
     
     
         9 . A method for operating turbocharger with a turbine in a turbocharger housing ( 2 ), a device within the turbocharger housing, an actuator ( 73 ) located outside the turbocharger for actuating the device within the turbocharger housing, a pivot shaft ( 63 ) rotatably mounted in a bore ( 70 ) extending through the turbocharger housing for transmitting an actuating movement from the actuating mechanism to the device, first and second sealing rings ( 80 ) provided in at least one circumferential groove in at least one of said pivot shaft and said bore, said method comprising:
 introducing sufficient pressure between said sealing rings to urge the sealing rings axially apart, under operating conditions, each against a respective sealing groove wall ( 81 ,  83 ).