Measurements of gear noise, acceleration and DTE (Dynamic Transmission Error) have been performed on a complete truck gearbox. DTE, acceleration and noise were measured using both speed sweeps and constant speeds. The speed sweeps were used to analyse the dynamic properties of the system. When the amplitude of the noise or DTE was of interest, the constant speed measurements were used to ensure steady state condition. The correlation between noise and DTE is examined. The method uses a fixed speed and calculates the correlation as the torque is increased. Eight different speeds typical of the operating conditions of the gearbox was used during the measurements. At each speed the torque was varied between 600 to 2000 Nm in 200 Nm increments. The correlation between noise and DTE varies for different gear pairs. The highest correlation is found for the low split gear pair, which is located closest to the gearbox housing. The correlation also seems to increase for the higher torques used in the measurements. There can be number of reasons for a drop in the correlation between noise and DTE. Some resonances can be found where the correlation is low, but not all resonances result in low correlation. If the correlation between noise and DTE for the gear mesh order of the first gear pair is analysed, the DTE for the first gear pair gives the best correlation coefficient in general. In some measurements, the total DTE or the DTE of the second gear stage results in a higher correlation coefficient. This indicates that the second gear stage is involved in the noise generation for this frequency, something that is not visible in the DTE for the first gear stage. Comparing the measured DTE and calculated static TE (Transmission Error) for the gear teeth shows an increase in DTE and noise but a decrease in calculated TE as the torque is increased. If the system is linear and the static TE is considered to be the excitation, the dynamic TE should follow the same pattern. Non-linear effects and other sources can be an explanation to the lack of correlation between the calculated static TE and measured dynamic TE. The measurements show that there is a connection between DTE and noise, although further investigation is needed to better understand the dynamic properties of the gear system. The measurements can also become an important input in a dynamic model of the gear system. More research is needed to determine the possibilities and limitations of DTE as a prediction of gear noise.
Analysis of gear noise and dynamic transmission error measurements
Analyse des Getriebegeräusches und Messung des dynamischen Übertragungsfehlers
2004
9 Seiten, 14 Bilder, 16 Quellen
Conference paper
English
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