Turbocharger having variable nozzle device

Abstract

A turbocharger arrangement comprises a vane area formed between a nozzle element ( 21 ) and a floating insert supported on the exhaust housing, wherein the floating insert is urged against the vanes ( 27 ) located in the vane area by a biasing member ( 43 ). By means of this arrangement the turbine efficiency is increased and the risk of vane sticking is avoided to a large extent.

1 . A turbocharger having an exhaust housing ( 7 ;  107 ;  207 ;  307 ;  507 ) and a variable nozzle device comprising vanes ( 27 ;  127 ;  227 ;  327 ;  527 ) interposed in a nozzle between a nozzle element ( 21 ;  121 ;  221 ;  321 ;  521 ) and a floating insert ( 17 ;  117 ;  217 ;  317 ;  517 ) being supported axially slidably with respect to said exhaust housing ( 7 ;  107 ;  207 ;  307 ;  507 ); wherein the floating insert is urged against the vanes ( 27 ;  127 ;  227 ;  327 ;  527 ) by a biasing member ( 43 ;  143 ;  343 ;  543 ),  
     characterised in that 
 the nozzle element ( 21 ) is elastically clamped between a step portion ( 25 ) of an inner periphery of the exhaust housing ( 7 ;  107 ;  207 ;  307 ) and a disc-shaped member supported on a center housing ( 1 ) of the turbocharger:  
 
   
   
       2 . A turbocharger according to  claim 1 , wherein the floating insert is urged against the vanes ( 27 ;  127 ;  227 ;  327 ) of said vane area by a difference in the pressure in an exhaust gas inlet and the nozzle.  
   
   
       3 . A turbocharger according to  claim 2  or  3 , wherein said biasing member is a spring washer ( 43 ;  143 ) placed in a recess ( 41 ;  141 ) formed in a gas outlet shroud portion ( 19 ;  119 ) of the exhaust housing ( 7 ;  107 ;  207 ;  307 ;  507 ).  
   
   
       4 . A turbocharger arrangement according to any one of  claims 1  to  3 , wherein said biasing member is a spring washer placed in a recess ( 341 ) formed in said floating insert ( 317 ).  
   
   
       5 . A turbocharger arrangement according to  claim 4 , wherein said floating insert ( 317 ) is formed of a sheet metal and has a C-shaped cross-section which, together with the exhaust housing ( 7 ;  107 ;  207 ;  307 ), defines said recess ( 341 ).  
   
   
       6 . A turbocharger arrangement according to any of  claims 3  to  5 , wherein said recess ( 41 ;  141 ;  341 ) is communicated to the exhaust gas inlet of said exhaust housing ( 7 ;  107 ;  207 ;  307 ).  
   
   
       7 . A turbocharger arrangement according to one of the preceding claims, wherein the nozzle element ( 21 ;  121 ) is abutted against said exhaust housing ( 7 ;  107 ;  207 ;  307 ;  507 ) by means of first spacer elements ( 145 ;  245 ;  345 ) passing through the floating insert ( 17 ;  117 ;  217 ;  317 ;  517 ).  
   
   
       8 . A turbocharger arrangement according to any of the preceding claims, wherein the floating insert ( 17 ) is abutted against a second spacer element ( 45 ) by said biasing member, said second spacer element ( 45 ) being supported on the nozzle ring ( 21 ).  
   
   
       9 . A turbocharger arrangement according to any of the preceding claims, wherein a piston ring ( 39 ;  139 ;  339 ) is provided between the floating insert and a gas outlet shroud portion ( 19 ;  119 ;  319 ) of the exhaust housing ( 7 ;  107 ;  207 ;  307 ).  
   
   
       10 . A turbocharger arrangement according to  claim 9 , wherein the piston ring ( 39 ;  139 ;  339 ) is received in an annular recess either of said floating insert or said exhaust housing ( 7 ;  107 ;  207 ;  307 ).  
   
   
       11 . A turbocharger having an exhaust housing ( 7 ;  107 ;  207 ;  307 ;  507 ) and a variable nozzle device comprising vanes ( 27 ;  127 ;  227 ;  327 ;  527 ) interposed in a nozzle between a nozzle element ( 21 ;  121 ;  221 ;  321 ;  521 ) and a floating insert ( 17 ;  117 ;  217 ;  317 ;  517 ) being supported axially slidably with respect to said exhaust housing ( 7 ;  107 ;  207 ;  307 ;  507 ), and a spring member ( 543 ) for urging the floating insert ( 517 ) against the vanes ( 527 ),  
     characterised in that 
 said spring member acts on a flange ( 518 ) of said floating insert ( 517 ) which is interposed between the exhaust housing ( 507 ) and a center housing ( 51 ) of the turbocharger in a floating manner.  
 
   
   
       12 . A turbocharger according to  claim 11 , wherein 
 the floating insert ( 517 ) is pevented from rotating relative to said center housing ( 51 ) and relative to said exhaust housing ( 507 ) by a locking means ( 537 ).    
   
   
       13 . A turbocharger according to  claim 11  or  12 , wherein the floating insert is urged against the vanes ( 27 ;  127 ;  227 ;  327 ) of said vane area by a difference in the pressure in an exhaust gas inlet and the nozzle.  
   
   
       14 . A turbocharger according to any one of  claims 11  to  13 , wherein said spring member is a spring washer ( 43 ;  143 ) placed in a recess ( 41 ;  141 ) formed in a gas outlet shroud portion ( 19 ;  119 ) of the exhaust housing ( 7 ;  107 ;  207 ;  307 ;  507 ).  
   
   
       15 . A turbocharger arrangement according to any one of  claims 11  to  14 , wherein said spring member is a spring washer placed in a recess ( 341 ) formed in said floating insert ( 317 ).  
   
   
       16 . A turbocharger arrangement according to  claim 14  or  15 , wherein said recess ( 41 ;  141 ;  341 ) is communicated to the exhaust gas inlet of said exhaust housing ( 7 ;  107 ;  207 ;  307 ).  
   
   
       17 . A turbocharger arrangement according to any one of  claims 11  to  16 , wherein the nozzle element ( 21 ) is elastically clamped between a step portion ( 25 ) of an inner periphery of the exhaust housing ( 7 ;  107 ;  207 ;  307 ) and a disc-shaped member supported on a center housing ( 1 ) of the turbocharger.  
   
   
       18 . A turbocharger arrangement according to any one of  claims 11  to  17 , wherein the nozzle ring ( 21 ;  121 ) is abutted against said exhaust housing ( 7 ;  107 ;  207 ;  307 ;  507 ) by means of first spacer elements ( 145 ;  245 ;  345 ) passing through the floating insert ( 17 ;  117 ;  217 ;  317 ;  517 ).  
   
   
       19 . A turbocharger arrangement according to any one of  claims 11  to  18 , wherein the floating insert ( 17 ) is abutted against a second spacer element ( 45 ) by said spring member, said second spacer element ( 45 ) being supported on the nozzle ring ( 21 ).  
   
   
       20 . A turbocharger arrangement according to any one of  claims 11  to  19 , wherein a piston ring ( 39 ;  139 ;  339 ) is provided between the floating insert and a gas outlet shroud portion ( 19 ;  119 ;  319 ) of the exhaust housing ( 7 ;  107 ;  207 ;  307 ).  
   
   
       21 . A turbocharger arrangement according to  claim 20 , wherein the piston ring ( 39 ;  139 ;  339 ) is received in an annular recess either of said floating insert or said exhaust housing ( 7 ;  107 ;  207 ;  307 ).