1、 Common methods for micro inspection of gear surfaces
1) Profile tooth shape and tooth direction lead detection.
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Traditional gear quality inspection can only be used to analyze faults related to low order harmonics.
2) FFT detection of tooth surface using Fourier transform.
Using Fast Fourier Transform (FFT) to balance high-order and low order harmonic data, associating detection results with noise analysis, suitable for high-performance gear tooth surface quality analysis.
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The impact of low order amplitude on noise is very small. The first order corresponds to gear eccentricity, while the second order is equivalent to gear elliptical motion. Therefore, the low order spectrum is generally filtered out and only the high order spectrum is considered.
If a large amplitude is generated in the meshing order and frequency doubling order of the gear pair, it is considered as poor gear alignment, caused by the large impact of the gear pair during meshing in and out. The generation of large amplitudes in non integer multiples, known as "ghost orders," is caused by poor tooth surface waviness.
3) Topology detection.
The three-dimensional morphology of the surface microstructure of a single tooth is shown in the figure, and the gear was measured using the Klinberg gear measuring machine P65. In the figure, the black line represents the meshing line of the tooth surface, with an angle of β b; The red line represents the ripple trend line, with an angle of β w.
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The smaller the angle between the contact line and the corrugation line of the driving surface, the higher the probability of generating noise. During the meshing process, the driving surface of the gear will regularly contact the valleys and peaks of the tooth surface corrugation, causing impact and generating noise. The three-dimensional morphology when β w=β b is shown in the figure. When the ripple line is parallel to the contact line, the probability of generating noise is highest.