Figure 1 shows the measurement curve of tooth profile deviation of aa-1 gear after 8 million times of operation. The measurement results show that the maximum total tooth profile deviation is 15.7 μ m and the maximum tooth profile shape deviation is 12.3 μ M. By observing the tooth surface features recorded in the photos, there are pitting features near the end face of the gear, and there are large initial pitting traces near the pitch line and along the middle of the tooth width, as shown in the dotted rectangular box marking the position in the figure. At the same time, there are weak early pitting features in the unmarked area of the tooth surface by naked eye observation, indicating that with the gear running cycle With the increase of the number of times, the characteristics of fatigue pitting are more and more prominent.
The dynamic response analysis of the measurement system signal is still carried out in three stages within one million cycles. The time domain signal of vibration acceleration in each stage is shown in Figure 2. The time domain spectrum trend of vibration signal in the figure is basically stable, and there is no local vibration mutation phenomenon, but there are still obvious characteristics of vibration amplitude staggering. For example, the overall height distribution of the time domain signal along the Y vector in Figure 2 (b) presents the phenomenon of “hedgehog peak”, and the amplitude change is obvious, which is different from the more balanced height distribution of the time domain signal along the X vector in Figure 2 (c)“ “Plump wings” phenomenon. In terms of the overall vibration acceleration amplitude distribution, the vibration amplitude distribution along the X vector in the three stages fluctuates around 1.50 and is relatively balanced. For the vibration amplitude characteristics along the Y vector, the concentration region of vibration amplitude within 100000-200000 times is smaller than that in the latter two stages, which may be caused by the unbalanced dynamic response characteristics caused by the different wear amount of tooth surface geometric characteristics or the initial characteristics of tooth surface fatigue phenomenon.
The results show that the average temperature of the three stages is almost the same, which indicates that the wholesystem is in the state of thermal equilibrium temperature. The comparison of the statistical indexes along the X vector in each stage shows that the vibration acceleration basically remains at the same level, and the difference between the three is very small. The difference is that the statistical indexes have different skew effects, such as 100000-200000 times are positive skew, and the latter two are negative skew. The statistical index value of vibration acceleration along y vector has slight amplitude change effect, and has different performance characteristics in skewness and kurtosis. According to the vibration acceleration amplitude increase percentage analysis, the acceleration maximum index g and average index G3 are still used to analyze the amplitude increase percentage. The increasing percentages of index ＆ and index ft are 37.6% and 37.5% respectively, and 39.2% and 38.3% respectively, which further indicates the overall increasing effect of system dynamic response.