16-03-2017, 01:03 PM
In ideal or transmission power systems using rotating parts, not only the applied or reacted pairs are "smooth" leading to constant speeds, but also the rotational plane where the power and the plane are generated (or input) That are extracted (Output) are the same. Actually, this is not the case. The generated torques may not be smooth (for example, internal combustion engines) or the component being driven may not react to the torque smoothly (eg, reciprocating compressors), and the power generation plane is normally at some distance Of the power take-off plane. In addition, components that transmit the torque can generate non-smooth or alternating pairs (eg, elastic drive belts, worn gears, misaligned shafts). Because no material can be infinitely stiff, these alternating pairs applied at a certain distance on an axis cause torsional vibrations about the axis of rotation. In this mainly experimental study we investigate the influence of the finishing method of gears and the deviations of gears in the noise of gearbox. Eleven pairs of different test gears were fabricated using three different finishing methods, as well as different modifications and deviations of the gear tooth. The surface finish and the geometry of the flanks of the gear tooth were measured. The transmission error was predicted and measured, which is considered an important mechanism of excitation for gear noise.
LDP software from Ohio State University was used for transmission error calculations. A specially built test equipment was used to measure the noise of the gearbox and the vibration of the different pairs of test gears. Measurements show that dismantling and reassembling the gearbox with the same gear pair can significantly change the measured noise and vibration levels. The rebuilding variations are sometimes in the same order of magnitude as the differences between the different pairs of tested gears, indicating that other factors besides the gears affect the gear noise. Most of the experimental results can be understood and explained in terms of measured and predicted transmission error. However, it does not seem possible to find a single parameter, such as the peak-to-peak transmission error measured, which may be directly related to measured noise and vibration.