19FTM26 - Sizing of Profile Modifications for Asymmetric Gears

Sizing of Profile Modifications for Asymmetric Gears19FTM26 Today, the benefits of asymmetric gears are being extensively discussed. They have yet to be widely adopted, but investigations are ongoing as to whether gear reducers can be improved with such techniques. The geometric definition of asymmetric gears is shortly described. The strength calculation of such gears can be calculated according to ISO standards, but the method for the bending stress must be adapted. This permits the...
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Sizing of Profile Modifications for Asymmetric Gears19FTM26 Today, the benefits of asymmetric gears are being extensively discussed. They have yet to be widely adopted, but investigations are ongoing as to whether gear reducers can be improved with such techniques. The geometric definition of asymmetric gears is shortly described. The strength calculation of such gears can be calculated according to ISO standards, but the method for the bending stress must be adapted. This permits the power capacity of asymmetric gears to be calculated and compared with symmetric gears. In specific cases, when using asymmetric gears, the power capacity of a gear pair can be increased by up to 30%.The power capacity of a gear pair is critical, but the noise and vibration behavior is also highly relevant. With appropriate profile modifications, gears can be significantly improved. A modification of the gear profile will change the load distribution during a meshing cycle, therefore changing transmission errors, contact pressure and power losses. Additionally, with tip and/or root relief, the contact shock at the beginning and the end of the meshing can be removed, substantially reducing the vibration and noise of the gear mesh.The selection process of a steel gear with asymmetric teeth is discussed in detail. With a well selected profile modification, the noise excitation and Hertzian pressure can be reduced. The behavior of the critical parameters was verified for different torque levels and for helix and profile errors due to manufacturing tolerances.ISBN: 978-1-64353-065-9Pages: 16Author: Ulrich Kissling