Grinding method of crank pin and grinding machine

Abstract

A grinding method of a crank pin that grinds an outer circumferential surface of the crank pin of a crankshaft having a crank journal and the crank pin eccentric to the crank journal by rotating a crankshaft around a central axis (a center of the journal) of the crank journal and moving a rotating grinding wheel in a diametric direction of the crankshaft according to rotation phase angle of the crankshaft, in which a rotation number of the crankshaft is changed in one revolution of the crankshaft to perform a grinding process.

1 . A grinding method comprising: 
 rotating a crankshaft comprising a crank journal and a crank pin eccentric to the crank journal around a central axis of the crank journal;    moving a rotating grinding wheel in a radial direction of the crankshaft according to a rotation phase angle of the crankshaft; and    grinding an outer circumferential surface of the crank pin by the moving of the rotating grinding wheel and the rotation of the crankshaft while a rotation speed of the crank shaft is changed in one revolution of the crankshaft    
   
   
       2 . The grind method according to  claim 1 , further comprising: 
 rotating the crankshaft and the grinding wheel in the same direction;    making slow the rotation speed of the crankshaft when the crank pin is located closer to the grinding wheel than the center of the crank journal; and    making fast the rotation speed of the crankshaft when the crank pin is located farther from the grinding wheel than the center of the crank journal.    
   
   
       3 . A grinding machine comprising: 
 a grinding wheel capable of rotating; and    a crankshaft having a crank journal and a crank pin eccentric to the crank journal, wherein an outer circumferential surface of the crank pin is grinded by rotating the crankshaft around a central axis of the crank journal and moving the rotating grinding wheel in a radial direction of the crankshaft according to a rotation phase angle of the crankshaft, and    wherein a rotation speed of the crankshaft is changed in one revolution of the crankshaft to perform a grinding process.