A worm gear design method taking into account the uneven rotation of a driven shaft

A new method of designing worm gears is suggested. The method takes into account the influence of the deformation of bearings on the tolerances of the gear parameters. The existing worm gear design methods account for dynamic loads only at peripheral speeds V > 3 m/s. However, studies have shown that dynamic loads in worm gears can be significantly higher than the design loads even at low circumferential speeds. This is due to the fact that they depend not only on the accuracy of gearing and the peripheral speed, but also on the type of bearings mounted on the shafts and manufacturing and assembly errors of bearing units, which is ignored by conventional techniques. The proposed technique allows for the engagement and assembly errors, the type and deformation of bearings, their vibration, and the resulting uneven rotation of the driven shaft. The developed technique implies the calculation of the speed variation function of the worm gear slow-speed shaft. The adequacy of the obtained theoretical results is confirmed by the test bench experiments. This technique makes it possible to check the accuracy of the parameters chosen, which is important because they affect the spectrum of the speed variation function and the level of loads acting on the drive as a whole. The results of research have shown that the effect of vibrations on the bearing loads is within 15...30 %, which reduces the gear accuracy degree by unity. To decrease gear vibrations and acting loads, it is desirable to use roller bearings because the convergence of rings in ball bearings can exceed the manufacturing tolerance. The results of the study will be useful in the design of worm gears that are widely used in general engineering drives.

References

[1] Ivanov M.N., Finogenov V.A. Detali mashin [Machine parts]. Moscow, Vysshaia shkola publ., 2005. 408 p.

[2] Lelikov O.P. Valy i opory s podshipnikami kacheniia. Konstruirovanie i raschet: spravochnik [Shafts and bearings with rolling bearings. Design and calculation: a handbook]. Moscow, Mashinostroenie publ., 2006. 640 p.

[3] Skvortsov D.F., Sushko A.E., Uspenskii D.A. Povyshennaia vibratsiia rotornogo oborudovaniia i sposob ee ustraneniia [Increased vibration rotating equipment and how to fix it]. Mir tekhniki i tekhnologii [The world technics and technologies]. 2002, no. 8, pp. 20–22.

[4] Anur’ev V.I. Spravochnik konstruktora-mashinostroitelia: v 3 tomakh [Reference Design-Machinist: in 3 volumes]. Moscow, Mashinostroenie publ., 2006. 728 p.

[5] Pchelintsev D.O., Ignat’ev S.A. Avtomatizirovannoe raspoznavanie lokal’nykh defektov poverkhnostei kacheniia kolets podshipnikov pri vikhretokovom kontrole s ispol’zovaniem veivlet-preobrazovaniia [The automated recognition of local defects of surfaces of bearing rings rolling at eddy current control with wavelet-transformation use]. Vestnik SGTU [Herald SSTU]. 2009, no. 3(40), pp. 70–77.

[6] Barkov A.V., Barkova N.A., Azovtsev A.Iu. Monitoring i diagnostika rotornykh mashin po vibratsii [Monitoring and diagnosis of rotary machinery vibration]. Sankt-Peterburg, SPbGMTU publ., 2000. 159 p.

[7] Zakharov S.I. Novyi podkhod k spektral’nomu analizu vibratsii s avtomaticheskoi otsenkoi sostoianiia vrashchaiushchikhsia detalei mashin [New approach to spectral analysis of vibration with an automatic estimation of the rotating components state]. Vestnik mashinostroeniia [Russian Engineering Research]. 2009, no. 4, pp. 93–94.

[8] Al-Ghamdi A.M., Cole P., Such R., Mba D. Estimation of bearing defect size with acoustic emission. Insight, 2004, vol. 46, no. 12, pp. 758–761.