| 摘要 |
<p>PURPOSE:To prevent automatic machining work from generating a failure while a tool from damage, by holding the tool so as to race for a main spindle, if excessive torque of predetermined value or more is applied to the cutting tool during its machining in a machine tool, and detecting abnormality of the tool. CONSTITUTION:A torque limiter 1, holding a tool 13, is mounted to a machine tool main spindle 20, performing cutting work. If excessive torque is applied to the tool 13, it rotates at a speed lower than that of the main spindle 20 or stops by racing the main spindle 20 and a torque limiter main unit 11 for a tool supporter 12. As a result, the tool 13 relaxes its excessive stress. This is because a ball 16 is dislocated from a recessed part 15 in the tool supporter 12 continuing to rotate and repeats to advance into the next recessed part 15, and a vibration is generated when this ball 16 advances into the recessed part 15. A device, converting this vibration into an electric signal by a vibration detector 2 and inputting the electric signal to a comparator 6 through an ampli fier 3, band pass filter 4 and an envelope detection circuit 5 to be compared with a preset value, detects abnormality of the tool 13.</p> |
