Grinding machine and grinding method

Abstract

A grinding machine includes a wheel spindle stock in which a wheel spindle is rotatably provided. The wheel spindle moves between first and second spindles so that a third rotation axis of the wheel spindle moves in the direction perpendicular to first and second rotation axes on an XZ plane extending through the first and second rotation axes. The grinding wheel that is held by the wheel spindle grinds a first workpiece as the wheel spindle stock moves toward a first headstock, and grinds a second workpiece as the wheel spindle stock moves toward a second headstock.

What is claimed is: 
     
         1 . A grinding machine, comprising:
 a first headstock having a first spindle that can rotate about a first rotation axis extending in a vertical direction and that rotatably supports a first workpiece;   a second headstock having a second spindle that can rotate about a second rotation axis separated from the first rotation axis at a predetermined interval and extending parallel to the first rotation axis, and that rotatably supports a second workpiece different from the first workpiece;   a wheel spindle stock that has a third rotation axis extending parallel to the first and second rotation axes and that moves between the first and second headstocks so that the third rotation axis moves in a direction perpendicular to the first and second rotation axes on a plane extending through the first and second rotation axes;   a wheel spindle that is rotatably provided in the wheel spindle stock; and   a grinding wheel that is provided on the wheel spindle, that grinds the first workpiece as the wheel spindle stock moves toward the first headstock, and that grinds the second workpiece as the wheel spindle stock moves toward the second headstock.   
     
     
         2 . The grinding machine according to  claim 1 , further comprising:
 a control device that controls grinding of the workpieces; wherein   the control device controls the grinding of the workpieces so that the grinding wheel rotates in the same direction both when grinding the first workpiece and when grinding the second workpiece.   
     
     
         3 . The grinding machine according to  claim 1 , further comprising:
 a truing device that performs truing of the grinding wheel; wherein   the truing device is disposed between the first and second headstocks so that a direction in which the truing device moves to measure an outside diameter of the grinding wheel matches a direction in which the wheel spindle stock moves, and that a measurement point for measuring the outside diameter of the grinding wheel is located on the plane extending through the first and second rotation axes.   
     
     
         4 . The grinding machine according to  claim 2 , further comprising:
 a truing device that performs truing of the grinding wheel; wherein   the truing device is disposed between the first and second headstocks so that a direction in which the truing device moves to measure an outside diameter of the grinding wheel matches a direction in which the wheel spindle stock moves, and that a measurement point for measuring the outside diameter of the grinding wheel is located on the plane extending through the first and second rotation axes.   
     
     
         5 . The grinding machine according to  claim 3 , wherein
 the first and second headstocks are placed so that a distance between outer peripheries of the first and second headstocks on the plane extending through the first and second rotation axes is at least a sum of a diameter of the grinding wheel and a maximum length of the truing device in the direction in which the wheel spindle stock moves.   
     
     
         6 . The grinding machine according to  claim 4 , wherein
 the first and second headstocks are placed so that a distance between outer peripheries of the first and second headstocks on the plane extending through the first and second rotation axes is at least a sum of a diameter of the grinding wheel and a maximum length of the truing device in the direction in which the wheel spindle stock moves.   
     
     
         7 . The grinding machine according to  claim 3 , further comprising:
 a moving device that moves the truing device in the vertical direction; wherein   the grinding machine grinds the workpieces each having a noncircular shape.   
     
     
         8 . The grinding machine according to  claim 2 , wherein
 the control device includes an adjusting unit that adjusts the second workpiece to a preset machining start phase during grinding of the first workpiece or while the wheel spindle is moving from the first headstock toward the second headstock.   
     
     
         9 . The grinding machine according to  claim 2 , further comprising:
 a load/unload device that can load and unload the workpieces to and from the first and the second spindles; wherein   the control device includes a command unit that sends a command to unload the second workpiece or the first workpiece and load a new workpiece onto the second workpiece or the first workpiece to the load/unload device during grinding of the first workpiece or the second workpiece.   
     
     
         10 . The grinding machine according to  claim 1 , further comprising:
 a discharge device having two nozzles that can discharge grinding fluid during grinding of the first or second workpiece.   
     
     
         11 . The grinding machine according to  claim 10 , wherein
 the two nozzles are placed so that a direction in which the grinding fluid is discharged to the first or second workpiece is the same as a direction of a circumferential speed of the grinding wheel at a grinding point of the first or second workpiece.   
     
     
         12 . A grinding method for grinding the workpieces by the grinding machine according to  claim 1 , comprising:
 grinding the workpieces by controlling the grinding machine so that the first and second workpieces rotate in the same direction and the grinding wheel and the workpieces rotate in opposite directions.