Russian State Agrarian University – Moscow Timiryazev Agricultural Academy (Moscow, Russia)

O. A. Leonov, Dr. Eng., Prof., oaleonov@rgau-msha.ru
N. Zh. Shkaruba, Dr. Eng., Prof., shkaruba@rgau-msha.ru
Yu. G. Vergazova, Cand. Eng., Associate Prof., vergazova@rgau-msha.ru

Transmission of torque through the coupling connections with dowels must be ensured by interference of a halfcoupling with a shaft, while dowels should act as a safety lock in case of overloads. However, an analysis of regulatory documents showed that transitional fits and clearance fits in most cases are recommended in these connections, it is stipulated by simplicity of assembling. Therefore, in order to ensure reliability and durability when designing drives of cylindrical joints with dowels, it is necessary to calculate the maximum and minimum interference, while material of half-coupling and shaft manufacturing is one of the most important factors having the effect on the maximum interference. Therefore, a situation arises when the following combinations of materials are possible in the “shaft – coupling hole” joint: steel – cast iron, cast iron – cast iron, steel – steel and cast iron – steel. In this regard, it is necessary to evaluate the effects of various combinations of materials of the connected parts on formation of maximum and minimum interference and types of fits for the “shaft – coupling hole” joints. Based on the classical theory of strength of materials, the dependencies of the largest and smallest calculated interference were obtained, as well as formulas for correcting these stresses for real assembly conditions. It can be seen from the obtained calculations, that the highest values of the fit tolerances correspond to the joints of a steel shaft with a steel half-coupling, as well as a cast-iron shaft – with a cast-iron half-coupling. The fit tolerance is also affected by the assembly method G when connecting by heating a bush sleeve, and tolerance in upsetting operation is larger. Thus, based on the position of forming rational tolerances and fits, it is recommended to choose a steel coupling if a the shaft is made of steel; it allows expanding expand the fit tolerance and reducing the cost of shaft processing. When making the shaft from cast iron, the coupling should also be chosen from cast iron. Steel shaft joints with a cast-iron coupling are also possible, but at the same time, the requirements for shaft processing accuracy are more strict.

1. Grakov S. A. Elastic couplings for lowering dynamic loads in machine drives. Dinamika system, mekhanizmov i mashin. 2018. Vol. 6. No. 1. pp. 40–44.
2. Zhilrsov A. P., Melezhik R. S., Vlasenko D. A. et al. Substantiation of parameters and industrial mastering of elastic pin coupling with elastic disk-type element in the drive of four-roll crusher. Izvestiya vysshikh uchebnykh zavedeniy. Mashinostroenie. 2022. No. 12 (753). pp. 3–13. DOI: 10.18698/0536-1044-2022-12-3-13
3. Ramteke H. P., Mehta G. D. Flexible Coupling – A Research Review. Machines. Mechanism and Robotics. 2019. pp. 887–892. DOI: 10.1007/978-981-16-0550-5_81
4. Godzhaev Z. A., Shekhovtsov V. V., Lyashenko M. V. et al. Technical solutions for elastic coupling of drive transmissions in traction and transportation machines. Fundamentalnye i prikladnye problemy tekhniki i tekhnologii. 2024. No. 5 (367). pp. 211–224. DOI: 10.33979/2073-7408-2024-367-5-211-224
5. Tadeo A. T., Cavalca K. L. A Comparison of Flexible Coupling Models for Updating in Rotating Machinery Response. Journal of the Brazilian Society of Mechanical Sciences and Engineering. 2003. Vol. 25 (3). pp. 235–246.
6. Melnyk V., Vlasovets V., Konoplianchenko I., Tarelnyk V., Dumanchuk M., Martsynkovskyy V., Semirnenko Y., Semirnenko S. Developing a system and criteria for directed choice of technology to provide required quality of surfaces of flexible coupling parts for rotor machines. J. of Physics: Conf. Series. 2021. Vol. 1741. p. 012030. DOI: 10.1088/1742-6596/1741/1/012030
7. Khidir T. C. Design and Analysis of Bushed Pin Flexible Coupling. International Journal of All Research Education and Scientific Methods. 2017. Vol. 5. No. 4. pp. 38–44.
8. Melezhik R. S., Vlasenko D. A. Load simulation and substantiation of construction parameters of elastic pin coupling with elastic disk-type element. Gornye nauki i tekhnologii. 2021. Vol. 6. No. 2. pp. 128–135. DOI: 10.17073/2500-0632-2021-2-128-135
9. Leonov O. A., Shkaruba N. Z., Vergazova Y. G. et al. Analysis of the Accuracy of Manufacturing of Shaft Surfaces and Cylindrical Keyed Joint Holes. J. Mach. Manuf. Reliab. 2023. Vol. 52 (Suppl. 2). pp. 126–131. DOI: 10.1134/S1052618823100084
10. GOST 12080-66. Cylindrical shaft ends. Main dimensions, allowing torques. М.: Izdatelstvo standartov. 1994. 16 pс.
11. GOST 20742-93. Chain couplings. Parameters and dimensions. М.: IPK Izdatelstvo standartov. 1996. 16 p.
12. Yakishev A. I., Bezhelukova E. F., Plutalov V. N. ESDP tolerances and fits for smooth cylindrical components (calculation and selection). М.: Izdatelstvo standartov. 1978. 256 p.