Non-magnetic camshaft journal and method of making same

Abstract

A camshaft journal and method of producing the same. The method uses dynamic magnetic compaction in conjunction with austenitic manganese steel powder metal precursors. Journals formed along the camshaft are configured to cooperate with complementary bearing surfaces, and can be used in cooperation with one or more sensors such that the journal does not magnetically interfere with signals travelling to such sensors. The journals may also be subjected to machining, sintering or both once the dynamic magnetic compaction has been completed.

1 . A method of fabricating a camshaft journal using dynamic magnetic compaction, said method comprising:
 providing a camshaft die with an interior profile that substantially defines an exterior profile of said journal;   placing, within at least a part of said interior profile a powdered austenitic manganese steel such that upon formation of said journal with said camshaft die, at least the portion of said exterior profile that corresponds to said journal is made from said austenitic manganese steel; and   subjecting said powdered austenitic manganese steel in said camshaft die to said dynamic magnetic compaction.   
     
     
         2 . The method of  claim 1 , wherein said dynamic magnetic compaction comprises compacting said powdered austenitic manganese steel into a green precursor. 
     
     
         3 . The method of  claim 2 , further comprising consolidating said green precursor. 
     
     
         4 . The method of  claim 3 , wherein said consolidating said green precursor comprises sintering. 
     
     
         5 . The method of  claim 3 , wherein said consolidating said green precursor comprises machining. 
     
     
         6 . The method of  claim 3 , further comprising forming an additional shape in said journal prior to said sintering. 
     
     
         7 . The method of  claim 1 , further comprising arranging a position sensor in signal cooperation with said journal such that said journal's substantially lack of magnetic properties prevent it from substantially causing any degradation to a signal extending between a rotated camshaft to which said journal is coupled and said sensor. 
     
     
         8 . A camshaft journal made by the method of  claim 1 . 
     
     
         9 . A method of fabricating a camshaft journal, said method comprising:
 providing a die with an interior profile that substantially defines an exterior surface of said journal;   placing a compactable austenitic manganese steel within at least a portion of said interior profile of said die; and   forming said journal using dynamic magnetic compaction.   
     
     
         10 . The method of  claim 9 , wherein said austenitic manganese steel is in powder form prior to placement into said die. 
     
     
         11 . The method of  claim 9 , further comprising heat treating said journal after said forming. 
     
     
         12 . The method of  claim 11 , wherein said heat treating comprises sintering. 
     
     
         13 . The method of  claim 9 , further comprising machining said journal after said forming. 
     
     
         14 . The method of  claim 13 , further comprising sintering said journal after said machining and forming. 
     
     
         15 . The method of  claim 13 , wherein said machining said journal after said forming takes place prior to sintering in a protective atmosphere. 
     
     
         16 . The method of  claim 9 , further comprising machining and heat treating said journal after said forming. 
     
     
         17 . A method of making a camshaft journal, said method comprising:
 providing a die with an interior profile that substantially defines an exterior surface of said journal;   placing a compactable austenitic manganese steel within at least a portion of said interior profile of said die; and   forming at least said journal using dynamic magnetic compaction.   
     
     
         18 . The method of  claim 17 , wherein said compactable austenitic manganese steel is in powdered form prior to said forming. 
     
     
         19 . The method of  claim 18 , further comprising performing at least one of machining and heat treating said journal after said forming. 
     
     
         20 . A method of making a camshaft journal from multiple precursor compositions, said method comprising:
 defining a form that substantially corresponds to a shape of said journal;   arranging a first steel precursor in a first portion of said form, said first steel precursor configured such that said portion of said journal that corresponds thereto possesses relatively machinable properties;   arranging a second steel precursor in a second portion of said form, said second steel precursor configured such that said portion of said journal that corresponds thereto possesses substantially non-magnetic properties; and   applying dynamic magnetic compaction to said first and second steel precursors in said form.   
     
     
         21 . The method of  claim 20 , further comprising connecting said journal onto a camshaft. 
     
     
         22 . The method of  claim 20 , wherein said first portion of said form corresponds to at least a portion of the outer surface of said journal and said second portion of said form corresponds to at least a portion of the inner surface of said journal. 
     
     
         23 . The method of  claim 20 , wherein said first and second portions of said form are situated along a rotational axis of said journal such that said first and second steel precursors occupy substantially distinct axial portions of said journal. 
     
     
         24 . The method of  claim 23 , further comprising forming at least one signal-generating interruption in a portion of said journal that corresponds to said first portion of said form. 
     
     
         25 . The method of  claim 24 , wherein said at least one signal-generating interruption corresponds to a cutout in a peripheral portion of said journal.