An Overview of Gear Vibration Analysis

Gears are important features of various industrial applications such as machine tools, and gearboxes. This why a gearbox failure can be a severe issue and may bring significant financial losses. For this reason, gear fault diagnosis has gathered importance, since a last few years. Vibration analysis is one of the widely used fault analysis techniques, which aids in early fault detection, and allows a user to take all necessary precautions. In this post, we will discuss some prominent vibration analysis techniques.

A Brief Introduction to Vibration Analysis

As the name suggests, this method refers to listening to the vibration of the machine. Each component of the gear vibrates differently and creates a characteristic noise pattern. In case of damage, the noise pattern differs. This helps an analyst recognize the damage. For example, the noise differs if the problem occurs due to misalignment, unbalance, or damage.

Gearbox Failure and Common Vibration Analysis Methods Discussed

Gear failure may be caused due to any of the following:

Improper Design: The errors of this type are caused due to improper gear geometry, use of wrong materials or inferior quality materials, lubrication, and more.
Application Errors: These errors are caused due to problems such as mounting, vibration, cooling and maintenance, and installation.
Manufacturing Errors: The errors of this type are caused due to heating, or mistakes in the machining.

Following are a few common types of vibration analysis techniques employed by operators and machine technicians to detect gear faults.

Time Domain Analysis: These methods are employed to analyze the amplitude, as well as the phase information of the vibration time signal to detect the faults in gear-rotor bearing system. The time domain analysis techniques help detect impulsive signals arising from bearing or gear. Time Waveform analysis is one of the important techniques in this category, which is employed to detect beats, as well as transients.
Resonance Analysis: This type of analysis is performed for identification of natural vibrations and frequencies in a gear. Resonance analysis may be conducted through techniques including impact tests, recording of the run-up, and coast-down curve, as well as measurement of the bending lines on the shaft.
Frequency Domain Analysis: These methods include Fast Fourier Transform (FFT), Hilbert Transform Method, as well as Power Cepstrum Analysis. All these FFT techniques use the difference of power spectral density to identify the faulty parts. FFT analysis techniques are used for identifying the common machine faults like unbalance, misalignment, etc.
Envelope Analysis: This analysis is performed for diagnosis of damaged gear toothing, as well as roller bearings.
Phase Measurement Analysis: These methods are often used with the FFT to differentiate machine faults such as misalignment of loose parts, or unbalance, etc.
Order Analysis: This is the technique used for analyzing vibration signals and noise in reciprocating or rotating machinery. Some of the examples of these machinery include automotive engines, turbines, compressors, and pumps.
Orbit Analysis: This method is used to analyze shaft vibrations.

The above-mentioned are only a few gear vibration analysis methods discussed. Are you planning to conduct a gear vibration analysis for your gears? You need to discuss it with an expert and understand benefits of all the above mentioned methods in detail. Motor & Gear Engineering, Inc. – a well-known gear and gearbox services company is one such industry expert, whom you can contact for your gear vibration analysis.