The National Transport University Bulletin

Abstract

The article considers the issue of increasing the reliability and durability of planetary gearboxes. The indicator which can be used as the complex characteristic of these parameters is defined. As such an indicator, it is proposed to take the coefficient of uneven load distribution between satellites Ω. The object of research is a single-stage planetary gearbox. The purpose of the study is to establish experimentally the confidence interval of the mathematical expectation of the maximum values of the coefficient of non-uniformity of the load distribution between the satellites for the batch of planetary gearboxes based on the test results of one sample. The method of experimental research is given in the work. The strain gauges were glued to the axis of the satellites, which simplified the process of current collection. The use of three pairs of resistors on each axis also made it possible to obtain information on the nature of the load distribution along the length of the teeth. Student's t-test and bootstrap method were used to determine the confidence interval of the mathematical expectation of the maximum values of the coefficient of uneven load distribution between satellites. As a result of testing the original sample, it was not possible to prove that its members are distributed according to the normal law, which, in turn, is the main condition for the successful use of the t-test. The confidence interval obtained by this method had an inflated range, the limit values of which did not correspond to the results of other observations. The confidence interval of the mathematical expectation calculated by the bootstrap method had a smaller range and its limit values coincided with the results of other studies. Thus, it can be argued that the nonparametric bootstrap method allows to obtain statistical results that agree well with the real process, with a small number of members of the original sample, regardless of the law of their distribution. The conducted researches allowed to define the basic directions of increase of technical level of planetary gearboxes.

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