| 摘要 |
PURPOSE:To maintain a displacement detection accuracy higher than a certain level and improve a cutting accuracy regardless to the diameter of a work by providing two displacement detecting means at both the ends of a cross section on the cutting start side and the cutting end side of a rotary cutting blade. CONSTITUTION:First and second displacement sensors 54a and 54b which are composed of, for instance, magnetosensors are positioned at the cutting start side and the cutting end side of a blade 44 along the radial direction of a work Si and so provided as to face both the respective sides of the blade 44 to constitute a displacement detector 54. The displacement sensors 54a and 54b detect the change of the distances between the sensors 54a and 54b and the corresponding surfaces of the blade 44. The outputs of the sensors 54a and 54b are inputted to a comparator 56 to detect the deviation between the two outputs. In order words, the bend of the blade 44 at the cutting start side position of the work diameter is detected by the first displacement sensor 54a and, at the same time, the bend of the blade 44 at the cutting end side position of the work diameter is detected by the second displacement sensor 54b. Therefore, by comparing both the detected values with each other, the bend and bending state over the approximately whole cross section can be detected relatively easily and with a high accuracy. Moreover, even if noise is contained in the outputs of the respective displacement sensors 54a and 54b, the noise is cancelled by the comparator 56 and eliminated from the detected value. |
