Vane assembly and method of assembling a vane assembly for a variable-nozzle turbocharger

Abstract

A vane assembly includes vanes each having an axle and an arm immovably connected with the vane prior to assembling the vane assembly. The vane, axle, and arm can be an integral one-piece structure formed by casting, machining, or metal injection molding. The axles engage apertures in a nozzle ring and are rotatable in the apertures about axes of the vanes. An actuator ring is assembled with the nozzle ring and is rotatable relative thereto. The actuator ring defines connecting elements that connect with cooperative connecting elements on the vane arms. Rotation of the actuator ring causes the vanes to rotate for adjusting the angles of the vanes. During assembly, the motion of inserting the axles into the apertures is also effective for placing the arms in position for connection with the actuator ring.

1 . A variable-nozzle turbine, comprising:
 a turbine wheel connected with a shaft for rotation therewith;   a turbine housing enclosing the turbine wheel, the turbine housing defining a generally annular chamber surrounding the turbine wheel for receiving exhaust gas, and comprising a nozzle defining a flow path for passage of exhaust gas from the chamber radially inwardly to the turbine wheel, the flow path being defined between axially spaced first and second walls;   a fixed nozzle ring encircling an axis, the nozzle ring having a flow side and an opposite back side, the flow side defining an annular surface that is generally perpendicular to the axis and at least partly forms the first wall, the nozzle ring defining a plurality of circumferentially spaced apertures extending axially through said annular surface;   an actuator ring disposed adjacent to the flow side of and concentric with the nozzle ring, the actuator ring being rotatable about said axis relative to the nozzle ring, the actuator ring defining a plurality of circumferentially spaced first connecting elements;   a ring of circumferentially spaced vanes each comprising an airfoil portion that extends axially from a first end proximate the annular surface of the nozzle ring to an opposite second end, and an axle immovably connected with the first end of the airfoil portion and extending axially therefrom in a direction away from the second end, the axle defining a rotation axis of the vane, the axles of the vanes being disposed in the apertures of the nozzle ring such that the axles are rotatable in the apertures; and   each vane further including an arm having a proximal end immovably connected with the vane proximate the first end of the airfoil portion, a distal end of the arm being offset from the rotation axis of the vane and defining a second connecting element removably connected with one of the first connecting elements of the actuator ring, the arms of the vanes being on the flow side of the nozzle ring.   
   
   
       2 . The variable-nozzle turbine of  claim 1 , wherein the arm of each vane is immovably connected with the axle proximate the first end of the airfoil portion of the vane. 
   
   
       3 . The variable-nozzle turbine of  claim 1 , wherein the arm of each vane is immovably connected with the airfoil portion of the vane. 
   
   
       4 . The variable-nozzle turbine of  claim 1 , wherein each vane and associated axle and arm comprise an integral one-piece structure. 
   
   
       5 . The variable-nozzle turbine of  claim 1 , wherein the actuator ring surrounds a portion of the nozzle ring, and the actuator ring and nozzle ring collectively form at least part of the first wall of the nozzle. 
   
   
       6 . The variable-nozzle turbine of  claim 5 , wherein respective surfaces of the actuator ring and the portion of the nozzle ring that form at least part of the first wall of the nozzle are substantially flush with each other. 
   
   
       7 . The variable-nozzle turbine of  claim 1 , wherein the first connecting elements of the actuator ring comprise female connecting elements, and the distal end of the arm of each vane defines a male connecting element that is engaged in one of the female connecting elements for connecting the arm to the actuator ring. 
   
   
       8 . The variable-nozzle turbine of  claim 7 , wherein the female connecting elements of the actuator ring comprise recesses in a radially inner surface of the actuator ring. 
   
   
       9 . The variable-nozzle turbine of  claim 7 , wherein the female connecting elements of the actuator ring comprise recesses in a radially outer surface of the actuator ring. 
   
   
       10 . The variable-nozzle turbine of  claim 1 , wherein the nozzle ring is of stepped configuration having a larger-diameter portion joined to a smaller-diameter portion, the actuator ring surrounding the smaller-diameter portion, the larger-diameter portion being disposed axially adjacent the actuator ring. 
   
   
       11 . The variable-nozzle turbine of  claim 1 , further comprising a plurality of spacers connected between the nozzle ring and the second wall of the nozzle. 
   
   
       12 . A variable vane assembly for a turbine nozzle, comprising:
 a fixed nozzle ring encircling an axis, the nozzle ring having a flow side and an opposite back side, the flow side defining an annular surface that is generally perpendicular to the axis and at least partly forms the first wall, the nozzle ring defining a plurality of circumferentially spaced apertures extending axially through said annular surface;   an actuator ring disposed adjacent to the flow side of and concentric with the nozzle ring, the actuator ring being rotatable about said axis relative to the nozzle ring, the actuator ring defining a plurality of circumferentially spaced first connecting elements;   a ring of circumferentially spaced vanes each comprising an airfoil portion that extends axially from a first end proximate the annular surface of the nozzle ring to an opposite second end, and an axle immovably connected with the first end of the airfoil portion and extending axially therefrom in a direction away from the second end, the axle defining a rotation axis of the vane, the axles of the vanes being disposed in the apertures of the nozzle ring such that the axles are rotatable in the apertures; and   each vane further including an arm having a proximal end immovably connected with the vane proximate the first end of the airfoil portion, a distal end of the arm being offset from the rotation axis of the vane and defining a second connecting element removably connected with one of the first connecting elements of the actuator ring, the arms of the vanes being on the flow side of the nozzle ring.   
   
   
       13 . The variable vane assembly of  claim 12 , wherein the arm of each vane is immovably connected with the axle proximate the first end of the airfoil portion of the vane. 
   
   
       14 . The variable vane assembly of  claim 12 , wherein the arm of each vane is immovably connected with the airfoil portion of the vane. 
   
   
       15 . The variable vane assembly of  claim 12 , wherein each vane and associated axle and arm comprise an integral one-piece structure. 
   
   
       16 . The variable vane assembly of  claim 12 , wherein the apertures in the nozzle ring comprise blind holes. 
   
   
       17 . The variable vane assembly of  claim 12 , wherein each aperture in the nozzle ring has a relatively small-diameter portion that receives one of the axles and forms a bearing surface therefor, and a relatively larger-diameter countersunk portion surrounding the small-diameter portion at the annular surface of the nozzle ring, a lengthwise portion of the arm of each vane adjacent the proximal end of the arm being accommodated in the countersunk portion of the respective aperture. 
   
   
       18 . A method for assembling a variable vane assembly for a variable-nozzle turbine, comprising the steps of:
 providing a nozzle ring encircling an axis, the nozzle ring having a flow side defining an annular surface generally perpendicular to the axis and defining a plurality of circumferentially spaced apertures extending through the annular surface;   assembling an actuator ring with the nozzle ring such that the actuator ring is adjacent to the flow side of and concentric with the nozzle ring, the actuator ring defining a plurality of circumferentially spaced first connecting elements and being rotatable relative to the nozzle ring;   providing a plurality of vanes each having an airfoil portion that extends axially from a first end to an opposite second end, and an axle immovably connected with the first end of the airfoil portion and extending axially therefrom in a direction away from the second end, the axle defining a rotation axis of the vane, each vane further comprising an arm having a proximal end immovably connected with the vane proximate the first end of the airfoil portion, a distal end of the arm being offset from the rotation axis of the vane and defining a second connecting element configured to connect with one of the first connecting elements of the actuator ring; and   inserting the axle of each of the vanes into one of the apertures in the nozzle ring, the motion of inserting the axle being effective also to place the second connecting element of the vane in position for connection with one of the first connecting elements of the actuator ring.   
   
   
       19 . The method of  claim 18 , wherein the actuator ring is assembled with the nozzle ring prior to inserting the axles into the apertures, and the motion of inserting the axles is also effective to connect the second connecting elements of the vanes with the first connecting elements of the actuator ring. 
   
   
       20 . A vane for a variable nozzle of a turbocharger, comprising:
 an airfoil portion having a proximal end and an opposite distal end;   an axle having a proximal end connected to the proximal end of the airfoil portion so as to form an airfoil/axle assembly, the axle having an opposite distal end, the axle defining a rotation axis for the vane; and   an arm connected to the airfoil/axle assembly intermediate the distal end of the airfoil portion and the distal end of the axle, the arm extending outward from the axle for engaging an actuator for rotating the vane about the rotation axis.   
   
   
       21 . The vane of  claim 20 , wherein the arm is connected to the axle proximate the proximal end thereof.