Common Rail Valve Seat Refurbishing Tool and Apparatus

Abstract

A tool and apparatus to refurbish a valve seat having a compound geometry, such as a valve seat in a valve body for a common rail fuel injector is disclosed. The tool includes a body with a head portion having substantially the same geometry as the valve seat to be refurbished. The tool further includes a radiused portion located between two angled surfaces of the tool that functions to provide a chamfered cut at the intersection of the valve seat and diffuser passage to be refurbished. The apparatus includes a collet to secure the tool, and the collet may be mounted or secured to a fixture which is in turn mounted on a preloaded biased base so movement of the tool in the Z axis is controllable. The apparatus also comprises a slide moveable in an X and Y axis for adjustment of the tool.

What is claimed as new and desired to be protected by Letters Patent of the United States is: 
     
         1 . A lapping tool to refurbish a valve seat having a compound geometric profile, said lapping tool comprising:
 a body having a length and a width;   said length longer than said width;   said body having a first end and a second end, said first and second ends opposed to each other;   said first end insertable into a unit for lapping tool motion in an X axis, a Y axis and a Z axis;   said second end terminating in a head portion, said head portion equipped with an abrasive surface; and   said head portion comprising:   an angled work portion extending at a first angle, said first angle substantially complimentary to said compound geometric profile of said valve seat;   an angled end diameter portion protruding outward from said angled work portion at a second angle, said angled end diameter having a proximal diameter and a distal diameter, said distal diameter shorter than said proximal diameter, said angled end diameter portion extending at said second angle from said proximal diameter to said distal diameter; and   a radiused head portion separating and contiguous with said angled work portion and said angled end diameter portion.   
     
     
         2 . The lapping tool of  claim 1 , wherein said body and said head portion are separated by a tapered portion. 
     
     
         3 . The lapping tool of  claim 1 , wherein said abrasive surface includes at least one of diamond, cubic boron, or silicon carbide abrasive having a grit in the range of about 30 microns. 
     
     
         4 . The lapping tool of  claim 3 , wherein said head portion comprises a nickel plated layer with said grit impregnated in said nickel plated layer. 
     
     
         5 . A lapping tool to refurbish a valve, said valve comprising a valve seat having a valve seat angle and a diffuser passage having a diffuser angle, said lapping tool comprising:
 a body having a length greater than a width;   said body having opposed first and second ends;   said first end insertable in a lapping unit for motion of the tool in an X axis, a Y axis and a Z axis, said second end equipped with a head portion having an abrasive surface;   said head portion having an angled work portion having a first angle, and an angled end diameter portion having a second angle, said angled work portion and said angled end diameter portion separated by and contiguous with a radiused portion;   said first angle of said head portion substantially the same angle as said valve seat angle, and said second angle of said head portion substantially the same angle as said diffuser angle; and   said radiused portion forming a radiused intersection between said angled work portion and said angled end diameter portion, said radiused intersection configured to facilitate a chamfered cut at an intersection of said valve seat angle and said diffuser angle of said valve.   
     
     
         6 . The lapping tool of  claim 5 , wherein said body and said head portion are separated by a tapered portion. 
     
     
         7 . The lapping tool of  claim 5 , wherein said abrasive surface includes at least one of diamond, cubic boron, or silicon carbide abrasive having a grit in the range of about 30 microns. 
     
     
         8 . The lapping tool of  claim 7 , wherein said head portion comprises a nickel plated layer with said grit impregnated in said nickel plated layer. 
     
     
         9 . An apparatus to refurbish a ball check valve in a single operation, said ball check valve comprising a valve seat having a valve seat angle and a diffuser passage having a diffuser angle, said apparatus comprising:
 a fixture configured to accept said ball check valve;   said fixture mountable in an precision slide machining apparatus for movement of said fixture in an X axis and a Y axis;   said fixture supported by a preloaded biaser to control movement of the fixture in a Z axis;   a rotary power unit suitable to rotate a lapping tool at various speeds;   said lapping tool equipped with a body having a length greater than a width;   said body having opposed first and second ends;   said first end insertable in said rotary power unit for motion of said lapping tool in an X axis, a Y axis and a Z axis, said second end equipped with a head portion having an abrasive surface;   said head portion further comprising:   an angled work portion having a first angle;   an angled end diameter portion having a second angle and protruding outward from said angled work portion, said angled end diameter portion having a proximal diameter and a distal diameter, said distal diameter shorter than said proximal diameter; said angled end diameter extending at said second angle from said proximal diameter to said distal diameter;   said first angle of substantially the same angle as said valve seat angle, and said second angle of substantially the same angle as said diffuser angle; and   said angled work portion and said angled end diameter portion separated by and contiguous with a radiused portion, said radiused portion configured to form a chamfered intersection between said valve seat angle and said diffuser angle.   
     
     
         10 . The apparatus of  claim 9 , wherein said apparatus is a Computer Numerically Controlled (CNC) machine center. 
     
     
         11 . The apparatus of  claim 9 , wherein said lapping tool further comprises a tapered portion separating said body and said head portion. 
     
     
         12 . The apparatus of  claim 9 , wherein said abrasive surface includes at least one of diamond, cubic boron, or silicon carbide abrasive having a grit in the range of about 30 microns. 
     
     
         13 . The apparatus of  claim 12 , wherein said head portion comprises a nickel plated layer with said grit impregnated in said nickel plated layer.