Process and apparatus for grinding work for non-circular rotor, as well as camshaft

Abstract

To grind an outer peripheral surface of a work ( 10 ) for a non-circular rotor by a rotary grindstone ( 22 ) advanced and retreated by an NC control depending on the profile of the work ( 10 ), while rotating the work ( 10 ) about its axis, the following steps are carried out: a first step of detecting a predetermined lift amount of the outer peripheral surface of the work ( 10 ) at a given point to index a standard phase of the work ( 10 ); and a second step of advancing or retreating a grindstone 22 by the NC control depending on a standard phase of the work ( 10 ) indexed at the first step to grind the outer peripheral surface of the work ( 10 ). Thus, even if a special recess is not formed in the outer periphery of the work, the indexing of the standard phase of the work can be achieved properly.

1 . A process for grinding a work for a non-circular rotor for grinding an outer peripheral surface of said work ( 10 ), which includes a base circle portion ( 50 ) having a constant curvature radius, and a cam lobe ( 51 ) leading to circumferential opposite ends of said base circle portion ( 50 ), by a rotary grindstone ( 22 ) advanced and retreated by an NC control depending on the profile of said work ( 10 ), while rotating said work ( 10 ) for the non-circular rotor about an axis thereof, characterized in that the following steps are carried out: a first step of detecting a predetermined lift amount, between said base circle portion ( 50 ) and said cam lobe ( 51 ) of the outer peripheral surface of said work ( 10 ) at a given point to index a standard phase of said work ( 10 ), and a second step of advancing or retreating the rotary grindstone ( 22 ) by the NC control based on the standard phase of said work ( 10 ) indexed at said first step to grind the outer peripheral surface of said work ( 10 ).  
   
   
       2 . (canceled)  
   
   
       3 . An apparatus for grinding a work for a non-circular rotor, comprising a work-rotating means ( 8 ) for rotating the work ( 10 ), which includes a base circle portion ( 50 ) having a constant curvature radius, and a cam lobe ( 51 ) leading to circumferential opposite ends of said base circle portion ( 50 ), for the non-circular rotor about an axis thereof, while supporting said work ( 10 ), a rotary grindstone ( 22 ) capable of grinding an outer peripheral surface of said work ( 10 ), grindstone-rotating and reciprocally moving means ( 18 ,  12 ) capable of being advanced and retreated with respect to the outer peripheral surface of said work ( 10 ), while driving said rotary grindstone ( 22 ) in rotation, a standard phase-indexing means for indexing a standard phase of said work ( 10 ), and an NC control unit ( 33 ) for advancing and retreating said rotary grindstone ( 22 ) to grind the outer peripheral surface of said work ( 10 ) based on the standard phase of said work ( 10 ) indexed by said standard phase-indexing means and previously input data for the profile of said work ( 10 ), characterized in that said standard phase-indexing means comprises a standard phase sensor ( 35 ) for detecting a predetermined lift amount, between said base circle portion ( 50 ) and said cam lobe ( 51 ), of the outer peripheral surface of said work ( 10 ) at a given point.  
   
   
       4 . (canceled)  
   
   
       5 . A camshaft which includes cams ( 10   a ,  10   b  - - -  10   n ) each comprising a base circle portion ( 50 ) ground by the process for grinding a work for a non-circular rotor according to  claim 1 , and a cam lobe ( 51 ) leading to circumferential opposite ends of said base circle portion ( 50 ), said camshaft having no recess indicating a standard phase in an outer peripheral surface thereof.