A Fault Diagnosis Method of Variable Speed/Variable Load Rolling Bearing Based on Mode Conversion

Abstract

The invention discloses a variable speed / variable load rolling bearing fault diagnosis method based on mode conversion, which includes the following steps: establishing a bearing vibration signal model by assuming that the fault rolling bearing vibration signal is composed of at least two signal sources with different distribution characteristics, Then based on the threshold technology and the tail estimation method, the signal is preliminarily separated and analyzed to obtain signal patterns with different distribution characteristics, and then combined with the expectation-maximization theory to establish a hidden Markov model of the signal to obtain the noise pulse, and compare the original signal with it Subtraction to further improve the signal-to-noise ratio of the signal, and finally use the traditional envelope spectrum to analyze the signal to evaluate whether the rolling bearing has a fault and the type of the fault. On the one hand, the present invention overcomes the problem that the vibration signal is difficult to diagnose under the condition of variable load / rotating speed; on the other hand, it solves the problem that the traditional envelope method cannot application problem.

Description

technical field [0001] The invention belongs to the technical field of fault diagnosis of mechanical equipment, in particular to a method for diagnosing faults of rolling bearings with variable speed and variable load based on mode conversion. Background technique [0002] The demand for mechanical equipment in modern society is increasing day by day. Rolling bearings, as the key core components of mechanical equipment, are widely used in electric power, petrochemical, metallurgy, machinery, aerospace and some military industrial sectors, and are also one of the most vulnerable components . According to relevant statistics, 70% of mechanical failures are vibration failures, and 30% of vibration failures are caused by rolling bearings. This is because rolling bearings play the role of bearing and transmitting loads in mechanical equipment, and the working conditions are relatively harsh. Its operating status has a great impact on the safe operation of the entire machine. On...

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Problems solved by technology

[0004] In recent decades, with the continuous development of signal processing theory, relevant researchers have proposed a variety of noise reduction methods. However, for the mechanical system under variable load / variable speed conditions, which makes the vibration signal unstable and difficult to diagnose, there has been a lack of applicable methods. Methods

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