Kinematic Nonuniformity of the Rotation of a Toothed Belt Transmission with a Composite Pulley
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matic Nonuniformity of the Rotation of a Toothed Belt Transmission with a Composite Pulley Zh. Mukhamedova, *, V. M. Turdalieva, and A. A. Kosimova aNamangan
Engineering Construction Institute, Namangan, Uzbekistan *e-mail: [email protected]
Received September 26, 2019; revised October 10, 2019; accepted October 25, 2019
Abstract—Existing drive transmissions are analyzed. A toothed belt transmission with a driven pulley that includes an elastic rubber bush is proposed. Formulas are presented for the kinematic nonuniformity of rotation of the driven pulley, its velocity, and its angular displacement as a result of bush deformation. Keywords: toothed belt transmission, pulley, pulley velocity, kinematic nonuniformity, nonuniform rotation, torque, elastic modulus, rigidity, load DOI: 10.3103/S1068798X20090130
In manufacturing, various types of transmissions are employed: in particular, gear, chain, and belt transmissions. Gear transmissions have a precise gear ratio, permit large gear ratios, and withstand high loads, but they are only used with small distances between the shafts. With large distances between the shafts, chain or belt transmissions are employed [1–5]. In chain transmissions, the chain engages with a sprocket. A significant deficiency of such transmissions is that impact loading appears at small gear ratios [6–9]. Therefore, they are suitable for low speeds. In a chain transmission, two rigid elements are in contact: the chain and a wheel. In a belt transmission, the belt engages with a pulley: in other words, a rigid element is in contact with a soft element. In the case of two rigid elements, precise engagement is required, without a gap or tightness. However, if a rigid element and a flexible element are in tight engagement, their interaction is more effective and no impact loads appear [10]. As a rule, a belt transmission relies on friction (in a V belt) or simple engagement (in a toothed belt). Frictional transmissions are employed at large loads. The flexible element in such transmissions is made of an elastic material, such as rubber or plastic. In that case, elastic slip and elastic deformation are unavoidable. In frictional transmissions, elastic slip in the frictional pair occurs at any load, as established in [11‒13]. A refined method of determining a coefficient taking account of the load and operating conditions was proposed in [14]. The inverse problem was solved in [15]: given the specified belt life, to determine the maximum stress of the driving branch and the stress corresponding to the initial tension, the azi-
muthal force, and the cross sectional area ensuring specified life. Calculation of the life of belt transmissions was considered in [16–18]. A toothed belt transmission has a precise gear ratio and is designed so that precise engagement of the belt with the sprocket rules out slip of the belt and idle rotation of the pulley. However, this design is only suitable for small loads. The reliability of a toothed belt transmission is determined by the reliability of the toothed
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