Remanufactured Center Housing and Method

Abstract

A system and method for remanufacturing a turbocharger center housing include performing a machining operation on an original center housing to remove a portion of a parent material from the original center housing. A ring having a generally rectangular cross section is attached to the center housing blank in place of the removed material to produce a rebuilt center housing. In one embodiment, the ring forms an annular surface onto which a seal is engaged to avoid external leakage of turbine exhaust gas through an interface between a turbine housing and the remanufactured center housing.

We claim: 
     
         1 . A rebuilt turbocharger, comprising:
 a shaft having a turbine wheel connected at a first shaft end, and a compressor wheel connected at a second shaft end;   a compressor housing disposed around the compressor wheel;   a turbine housing forming a central bore and disposed around the turbine wheel, the turbine housing forming an internal scrolled passage that surrounds the turbine wheel and carries gasses during operation;   a heat shield disposed at least partially within the central bore and around the shaft between the compressor and turbine wheels, the heat shield being generally cup-shaped, the heat shield including an outer flange;   a center housing disposed between and connected with the compressor housing and the turbine housing, the center housing forming a bore, through which the shaft extends, and including at least one bearing that rotatably supports the shaft;   a protrusion formed on the center housing, the protrusion extending within the central bore such that the heat shield is disposed between the turbine wheel and the protrusion;   a seal formed by engagement of the outer flange of the heat shield between the center housing and the turbine housing along an annular area of the center housing that extends radially relative to the shaft and is disposed radially inwardly from an interface between the center housing and the turbine housing; and   a ring having a generally hollow cylindrical shape with a generally rectangular cross section, the ring being connected to the center housing around a base of the protrusion and forming the annular area onto which the outer flange of the heat shield is engaged to form the secondary seal.   
     
     
         2 . The rebuilt turbocharger of  claim 1 , wherein the ring is made from a same parent material as the center housing. 
     
     
         3 . The rebuilt turbocharger of  claim 1 , wherein the ring is made from a different material than a parent material of the center housing. 
     
     
         4 . The rebuilt turbocharger of  claim 1 , wherein the ring has an inner diameter that is configured for a press-fit engagement between the ring and the center housing at an area adjacent the base of the protrusion. 
     
     
         5 . The rebuilt turbocharger of  claim 1 , wherein the ring includes two diagonally opposite chamfers or fillets disposed along respective diagonally opposite edges of the ring, a first chamfer or fillet disposed at an inner, lower edge, and a second chamfer or fillet disposed at an outer, upper edge of the ring. 
     
     
         6 . The rebuilt turbocharger of  claim 1 , wherein the interface between the center housing and the turbine housing forms an annular mechanical face seal between cooperating annular surfaces of the center housing and the turbine housing on corresponding flanges that are secured by a clamp. 
     
     
         7 . The rebuilt turbocharger of  claim 1 , wherein the ring has a width in a radial direction relative to the shaft that is larger than an corresponding width of the outer flange such that an entire width of the outer flange of the heat shield is accommodated within the width in the radial direction of the ring. 
     
     
         8 . A center housing for a turbocharger for use on an internal combustion engine, the center housing being configured to interconnect a compressor housing with a turbine housing in the turbocharger, the center housing comprising:
 a bore formed in the center housing, the bore configured to rotatably support a shaft having a compressor wheel at one end and a turbine wheel at another end;   a protrusion formed on the center housing, the protrusion configured to extend within a central bore of the turbine housing;   an annular area that extends radially relative to the shaft and is disposed radially inwardly from an interface between the center housing and the turbine housing; and   a ring having a generally hollow cylindrical shape with a generally rectangular cross section, the ring being connected to the center housing around a base of the protrusion and forming the annular area onto which a gasket may be engaged to form a seal between the center housing and the turbine housing.   
     
     
         9 . The center housing of  claim 8 , wherein the ring is made from a same parent material as the center housing. 
     
     
         10 . The center housing of  claim 8 , wherein the ring is made from a different material than a parent material of the center housing. 
     
     
         11 . The center housing of  claim 8 , wherein the ring has an inner diameter that is configured for a press-fit engagement between the ring and the center housing at an area adjacent the base of the protrusion. 
     
     
         12 . The center housing of  claim 8 , wherein the ring includes two diagonally opposite chamfers or fillets disposed along respective diagonally opposite edges of the ring, a first chamfer or fillet disposed at an inner, lower edge, and a second chamfer or fillet disposed at an outer, upper edge of the ring. 
     
     
         13 . The center housing of  claim 8 , wherein the interface between the center housing and the turbine housing forms an annular mechanical face seal between cooperating annular surfaces of the center housing and the turbine housing on corresponding flanges that are secured by a clamp. 
     
     
         14 . The center housing of  claim 8 , wherein the ring has a width in a radial direction relative to the shaft that is larger than an corresponding width of the gasket such that an entire width of the gasket is accommodated within the width in the radial direction of the ring. 
     
     
         15 . A method for rebuilding a center housing for a turbocharger, comprising:
 dis-assembling an original turbocharger to separate an original center housing from remaining turbocharger components;   mounting the original center housing on a machining device;   performing a machining operation using the machining device, the machining operation including at least one of cutting and grinding to remove a portion of a parent material from the original center housing, the portion of the parent material disposed within a hollow cylindrical cutting area and, when the parent material has been removed, producing a center housing blank from the original center housing, the center housing blank including a radially extending annular surface and an axially extending cylindrical surface that orthogonally intersect and are formed by the machining operation; and   attaching a ring having a generally rectangular cross section to the center housing blank to produce a rebuilt center housing, the ring including an inner cylindrical surface disposed at an inner diameter, and a generally flat, annular base, such that the annular base of the ring abuts the radially extending annular surface and the inner cylindrical surface engages the axially extending cylindrical surface of the center housing blank at a press-fit clearance.   
     
     
         16 . The method of  claim 15 , further comprising performing an additional machining operation to grind or cut portions of the ring such that an overall structure and dimensions of the rebuilt center housing duplicate those of a new, original center housing. 
     
     
         17 . The method of  claim 16 , wherein the additional machining operation is performed to at least one of (a) clean, flatten or deburr an outwardly facing annular face of the ring, and (b) refine an outer diameter of an outer peripheral surface of the ring. 
     
     
         18 . The method of  claim 15 , further comprising cleaning the original center housing by chemical and/or mechanical agents to remove loose debris. 
     
     
         19 . The method of  claim 15 , wherein attaching the ring to the center housing is accomplished by a press-fit operation. 
     
     
         20 . The method of  claim 15 , further comprising reassembling a rebuilt turbocharger using the rebuilt center housing.