| 摘要 |
PURPOSE:To improve the reliability of a detection by constituting a titled device so that an output of an acoustic emission (AE) sensor is provided to a signal processing part only in the course of an actual work. CONSTITUTION:At the time of a regular cutting, a power spectrum distribution of an AE signal from an AE sensor 9 is concentrated to around 50kHz, and a power spectrum distribution of the time when a tool is broken has a peak in the vicinity of 300kHz. Therefore, when only the AE signal of the vicinity of the respective frequency components is fetched by two BPFs 13, 14, detected by detectors 16, 17, and its output levels are compared by a comparator 19, the normal time and the time when the tool is broken can be discriminated exactly. Therefore, by applying a signal to a breakage detecting circuit 21 only when the tool is broken, a wrong detection is eliminated, and the reliability for detecting a breakage is improved. |
