ROTARY TOOL SUCH AS SMALLLDIAMETER DRILL

摘要

PURPOSE:To enable perfect cutting or grinding, by detecting a rotational frequency in a loaded state and compensating the frequency to a value in a prescribed range. CONSTITUTION:A reacting element 14 such as a magnet is provided in the journal 9 of a spindle 4. A detector 15 such as a magnetic detector is provided to correspond to the reacting element. A rotational frequency detected by the detector 14 is adaptively controlled by a calculation unit. The pneumatic circuit of a driving unit accelerates or decelerates the spindle 4 depending on judgement by the calculation unit. The actual rotational frequency of a drill 13 is indicated in an analogue or digital manner. The rotational frequency in a loaded state is compensated in a prescribed range to improve the efficiency of cutting-off or grinding.