A Fault Monitoring and Diagnosis Method of Electric Spindle Based on Three-phase Instantaneous Power

Abstract

The invention discloses a three-phase instantaneous power based motorized spindle fault monitoring and diagnosing method and belongs to the technical field of motorized spindle fault monitoring. According to the three-phase instantaneous power based motorized spindle fault monitoring and diagnosing method, by means of signal demodulation properties and three-phase symmetry characteristics of three-phase instantaneous power, three-phase input voltage and three-phase stator current signals are collected when a motorized spindle is stably operated, three-phase instantaneous power signals are calculated, the influence of supply frequency modulation, frequency rotating and frequency doubling on monitoring and diagnosing results is eliminated through a design of a junction filter, whether the motorized spindle breaks down is determined according to comparison between a mean value and a root-mean-square (RMS) value of the three-phase instantaneous power signals and standard reference values during the operation process, and a fault type is determined according to generation of fault character frequency during spectral analysis, so that monitoring and diagnosing of faults of the motorized spindle are achieved. According to the three-phase instantaneous power based motorized spindle fault monitoring and diagnosing method, the signal collection and processing process is simple, bearing wearing and rotor broken bar faults of the motorized spindle can be effectively monitored, and the method is applicable to state monitoring and fault diagnosing of the motorized spindle on an industrial scene.

Description

technical field [0001] The invention belongs to the technical field of electric spindle fault detection, and in particular relates to an electric spindle fault monitoring and diagnosis method based on three-phase instantaneous power. Background technique [0002] The electric spindle is a transmission structure that combines the spindle motor and the machine tool spindle into one. The machine tool spindle is directly driven by the built-in motor. It not only has the advantages of compact structure, light weight, small inertia, small vibration, low noise and fast response. It also has the advantages of fast speed, high power, simplified machine tool design, and easy positioning of the spindle. It is an ideal structure in the high-speed spindle unit. With the rapid development of modern industry, the application of electric spindle has been widely promoted, and it is also developing in the direction of high speed, high precision and precise stop. Accounted for more than 40%. ...

AI Technical Summary

Problems solved by technology

[0003] For the fault monitoring and diagnosis of the electric spindle, due to the structural characteristics and high-speed operation characteristics of the electric spindle, there are the following disadvantages when using the vibration method and the stator current method: 1) The electric spindle generally uses hybrid ceramic ball bearings, and the bearing wear is relatively uniform. Uniform pitting of pitting corrosion occurs on the rolling elements and raceways, and the bearing has not yet produced peeling damage, which makes the precision machining not meet the quality requirements, and no obvious fault characteristic frequency components are formed during vibration analysis

2) The early faults of the electric spindle show that the fault characteristics different from the normal state of the motor are usually very weak, and the drive of the frequency converter makes the input voltage signal of the electric spindle have a large number of power frequency modulation and harmonic components, which will appear in the current spectrum A lot of additional interference frequencies are generated in the frequency spectrum. Affected by the interference noise, the fault features in the frequency spectrum are not obvious

3) The speed of the electric spindle is relatively high, generally 10,000rpm and above. The high speed makes the signal frequency relatively high. When analyzing the stator current, not only the sampling requirements are high, but the fault information is more easily interfered by high-frequency noise.

Limited by the spectral resolution, f 1 Spectrum leakage is large, and at f 1 Under the influence of high-frequency noise and high-frequency noise, the fault characteristic components are submerged and difficult to detect

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