Strength analysis of wave gear with intermediate rolling bodies with rotational motion of the output link

Аuthors

Krylov N. V.

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

e-mail: artsunday@mail.ru

Abstract

The purpose of this work is to develop a method to find the forces and stresses in the most loaded places of the wave gear with intermediate rolling bodies — areas of contact of rolling bodies with other elements of the gear, and find the dependence between stresses in these areas and gear geometric parameters based on analysis made by this method.
The method is to determine the deformation of circular spline while the wave generator and circular spline have stopped, and the separator has turned to some small angle. In this case, the rolling bodies and their areas of contact with a circular spline will be moved causing deformation of the circular spline. Since the circular spline obeys Hookes' law, the resulting forces can be found acting by the circular spline on the rolling bodies. These forces are then translated to the percentage distribution of loads in all contact areas, then possibly real forces and stresses are found. Strength criterion is the stress at the most loaded contact area. The method uses the following assumptions: a separator, wave generator and rolling bodies are considered absolutely rigid; friction is small in the contact areas of rolling bodies with other parts, hence there are no gaps in the gear.
A resulting mathematical algorithm for the strength calculation of wave gear with intermediate rolling bodies was compiled. Analysis of results of the calculations was made. A relation was discovered between the radius of the wave generator, the radius of the rolling body and the number of periods of the circular spline, when stresses in the contact areas are distributed more evenly, which allows to reduce weight and volume of the gear and increase durability.
The method developed can be used to calculate the strength of the wave gear with intermediate rolling bodies. Gears of this type have a number of advantages in terms of weight and volume compared to other types of gears, making them a high demand in systems where these parameters are critical, such as in aircraft actuators.

Keywords:

wave gear with intermediate rolling bodies, stress analysis of wave gear with intermediate rolling bodies, stress distribution in wave gear with intermediate rolling bodies, contact strength

References

1. Gerashhenko A.N., Postnikov V.A., Samsonovich S.L. Pnevmaticheskie, gidravlicheskie i jelektricheskie privody letatel'nyh apparatov na osnove volnovyh ispolnitel'nyh mehanizmov (Pneumatic, hydraulic and electric actuators of aircraft based on harmonic drives), Moscow, MAI-Print, 2010, 126 p.
2. Stepanov V.S., Metodika proektirovanija privoda na osnove volnovoj peredachi s telami kachenija (Drive design methodology based on wave gear with intermediate rolling bodies), PhD thesis , 2009, Moscow, 49 p.
3. Birger I.A., Shorr B.F., Iosilevich G.B. Raschjot na prochnost' detalej mashin (Strength analysis of machine parts), Moscow, Mashinostroenie, 1993, 530 p.

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