Process for Lobe and Journal Preparation and Weld Repair

Abstract

A process for repairing a section of a rotatable shaft is disclosed. The section of the rotatable shaft has a surface portion having a surface parallel to an axis of rotation of the rotatable shaft and axial ends perpendicular to the axis of rotation of the rotatable shaft. The process includes preparing a well region extending over a perimeter of the section and extending downward in the surface portion, depositing material into the well region to fill the well region using a welding process and displacing a portion of the material that was deposited in the well region. The well region has a bottom portion that is substantially parallel to the axis of rotation and includes opposing sidewalls. Each sidewall extends proximate to the axial ends of the rotatable shaft and directly adjoins a remaining portion of the surface portion.

We claim: 
     
         1 . A process of repairing a section of a rotatable shaft, wherein the section includes a surface portion having a surface parallel to an axis of rotation of the rotatable shaft, the section includes axial ends perpendicular to the axis of rotation of the rotatable shaft, the process comprising:
 (a) preparing a well region extending over a perimeter of the section and extending downward in the surface portion, the well region having a bottom portion that is substantially parallel to the axis of rotation and includes opposing sidewalls, wherein each sidewall extends proximate to the axial ends of the section and directly adjoins a remaining portion of the surface portion;   (b) depositing material into the well region to fill the well region using a welding process; and   (c) displacing a portion of the material that was deposited in the well region.   
     
     
         2 . The process of  claim 1 , wherein the section is one of the following: a lobe or a journal. 
     
     
         3 . The process of  claim 2 , wherein the rotatable shaft is a camshaft. 
     
     
         4 . The process of  claim 1 , wherein the preparing includes forming fillets between the bottom portion and the sidewalls. 
     
     
         5 . The process of  claim 1 , wherein the preparing utilizes a milling process. 
     
     
         6 . The process of  claim 5 , wherein the preparing includes at least one of the following: milling with a key slot cutter or milling with a ball nose end mill. 
     
     
         7 . The process of  claim 1 , wherein the depositing includes depositing using Laser Beam (LB) Welding. 
     
     
         8 . The process of  claim 7 , further comprising providing argon gas during the depositing. 
     
     
         9 . The process of  claim 1 , wherein the depositing includes depositing with at least one of the following: Plasma Transfer Arc (PTA) Welding, Electron Beam (EB) Welding, Metal Inert Gas (MIG) Welding or Tungsten Inert Gas (TIG) Welding. 
     
     
         10 . The process of  claim 1 , wherein the depositing includes providing one of the following gases proximate to the welding process: argon, carbon dioxide or helium. 
     
     
         11 . The process of  claim 1 , wherein the displacing includes displacing utilizing at least one of the following: a grinding process or a machining process. 
     
     
         12 . The process of  claim 1 , wherein the material deposited is steel. 
     
     
         13 . The process of  claim 1 , wherein the depositing includes depositing a powder material. 
     
     
         14 . The process of  claim 1 , wherein the depositing includes depositing a wire material. 
     
     
         15 . The process of  claim 1 , wherein the rotatable shaft is a component of one of the following: a turbine, a turbocharger, a starter, a motor, an alternator, a water pump, a hydraulic pump, a fuel pump, a coolant pump, an oil pump, a transmission, an auxiliary system for a vehicle, or a drivetrain. 
     
     
         16 . The process of  claim 1 , further comprises pre-weld heat treatment of the section after the preparing and prior to the depositing. 
     
     
         17 . The process of  claim 1 , further comprises post-weld heat treatment of the section after the depositing and prior to the displacing. 
     
     
         18 . The process of  claim 1 , wherein the section extends eccentrically from the rotatable shaft. 
     
     
         19 . A process of repairing a section of a rotatable shaft, wherein the section extends eccentrically from the rotatable shaft and includes a surface portion having a surface parallel to an axis of rotation of the rotatable shaft, the section includes axial ends perpendicular to the axis of rotation of the rotatable shaft, the process comprising:
 (a) milling a well region extending over a perimeter of the section and extending downward in the surface portion, the well region having a bottom portion that is substantially parallel to the axis of rotation, and opposing sidewalls, wherein each sidewall extends proximate to the axial ends of the section and directly adjoins a remaining portion of the surface portion;   (b) depositing material into the well region to fill the well region by using laser beam welding; and   (c) grinding a portion of the material that was deposited in the well region.   
     
     
         20 . The process of  claim 19 , wherein the preparing includes forming fillets between the bottom portion and opposing sidewalls and the depositing includes at least one of the following: depositing a powder material or a wire material.