【文章內(nèi)容簡(jiǎn)介】 haft is braked using an electrical Optimization of gears Noiseoptimized dropbox gears were designed by choosing macroand microgeometries giving lower transmission error than the original(reference) gear geometry was chosen to yield a low transmission error for the relevant torque range, while also taking into consideration variations in the microgeometry due to manufacturing optimization of one gear pair is described in more detail in Paper error is considered an important excitation mechanism for gear [1] defines it as “the difference between the actual position of the output gear and the position it would occupy if the gear drive were perfectly conjugate.” In this project the aim was to reduce the maximum predicted transmission error amplitude at gear mesh frequency(first harmonic of gear mesh frequency)to less than 50% of the value for the reference gear first harmonic of transmission error is the amplitude of the part of the total transmission error that varies with a frequency equal to the gear mesh torque range of 100 to 500 Nm was chosen because this is the torque interval in which the gear pair generates noise in its design to Welbourn [1], a 50% reduction in transmission error can be expected to reduce gearbox noise by 6 dB(sound pressure level, SPL).Transmission error was calculated using the LDP software(Load Distribution Program)developed at the Gear Laboratory at Ohio State University [3].The “optimization” was not strictly design was optimized by calculating the transmission error for different geometries, and then choosing a geometry that seemed to be a good promise, considering not only the transmission error, but also factors such asstrength, losses, weight, cost, axial forces on bearings, and choosing microgeometric modifications and tolerances, it is important to take manufacturing options and cost into goal was to use the same finishing method for the optimized gears as for the reference gears, namely grinding using a KAPP VAS 531 and CBNcoated grinding a specific torque and gear macrogeometry, it is possible to define a gear microgeometry that minimizes transmission example, at no load, if there are no pitch errors and no other geometrical deviations, the shape of the gear teeth should be true involute, without modifications like tip relief or involute a specific torque, the geometry of the gear should be designed in such a way that it pensates for the differences in deflection related to stiffness variations in the gear , even if it is possible to define the optimal gear microgeometry, it may not be possible to manufacture it, given the limitations of gear must also be given to how to specify the gear geometry in drawings and how to measure the gear in an inspection many applications there is also a torque range over which the transmission error should be that manufacturing tolerances are inevitable, and that a demand for smaller tolerances leads to higher manufacturing costs, it is important that gears be other words, the important characteristics, in this case transmission error, must not vary much when the torque is varied or when the microgeometry of the gear teeth varies due to manufacturing [3] was used to calculate the transmission error for the reference and optimized gear pair at different torque robustness function in LDP was used to analyze the sensitivity to deviations due to manufacturing “min, max, level” method involves assigning three levels to each Optimization of transmission housing Finite element analysis was used to optimize the transmission optimization was not performed in a strictly mathematical way, but was done by calculating the vibration of the housing for different geometries and then choosing a geometry that seemed to be a good was not the sole consideration, also weight, cost, available space, and casting were simplified shell element model was used for the optimization to decrease putational model was checked against a more detailed solid element model of the housing to ensure that the simplification had not changed the dynamic properties too modal analysis was also used to find the natural frequencies of the real transmission housing and to ensure that the model did not deviate too much from the real shafts and bearings were modeled as point masses and model was excited at the bearing positions by applying forces in the frequency range from 1000 to 3000 force amplitude was chosen as 10% of the static load from the choice could be justified because only relative differences are of interest, not absolute finite element analysis was performed by Torbj246。rn Johansen at Volvo author’s contribution was the evaluation of the results of different housing number of measuring points were chosen in areas with high vibration each measuring point the vibration response due to the excitation was evaluated as a power spectral density(PSD) goal of the housing redesign was to decrease the vibrations at all measuring points in the frequency range 1000 to 3000 Results of the noise measurements The noise and vibration measurements described in section were performed after optimizing the gears and transmission total sound power level decreased by 4 Discussion and conclusions It seems to be possible to decrease the gear noise from a transmission bydecreasing the static loaded transmission error and/or optimizing the the present study, it is impossible to say how much of the decrease is due to the gear optimization and how much to the housing this question would have required at least one more noise measurement, but time and cost issues precluded would also have been interesting to perform the noise measurements on a number of transmissions, both before and after optimizing the gears and housing, in order to determine the scatter of the noise of the though the goal of decreasing the gear noise by 10 dB was not reached, the goal of reducing the gear noise in the wheel loader cab to 15 dB below the overall noise wa