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

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

Cylindrical joints are widely used in mechanical engineering, where cast iron (sprockets of chain gears, gears, pulleys, etc.) act as the material for making holes, and steel is used for shafts. As a rule, these joints work in the conditions of dry and boundary friction and, in some cases, they have a key. The analysis showed that the wear of such joints occurred mainly due to the discrepancy between the accuracy standards, which, along with the strength standards, determine the durability and reliability of the joints. And if the strength standards are laid down by the designer, then the accuracy standards are usually assigned by analogy, based on the previous experience of using such constructions, with the use of software, when designer inserts standard deviations of shaft and hole as well as fit in electronic drawings. The main factors determining the margin of safety are such characteristics of the material as the maximal stresses on the cut, crumpling, bending, twisting, etc. To determine the margin of accuracy, it is necessary to set such parameters as the largest functional clearance or interference. Currently, there is no method for calculating the maximum functional clearance for joints with boundary or dry friction. The authors obtained dependence for determining the maximal functional clearance by the criterion of exceeding the allowable normal pressure on the contacting surfaces. An example of calculating the accuracy parameters for connecting a shaft made of steel with a malleable cast iron sprocket is considered, for which the maximal functional clearance is determined and fits are assigned – the first of the preferred series, and the second according to the criterion of reducing the cost of finishing processing of the components.

1. Erokhin M. N., Leonov O. A., Shkaruba N. Z. et al. Assessing the Relative Interchangeability in Joints with Preload. Russian Engineering Research. 2020. Vol. 40. No. 6. pp. 469–472. DOI: 10.3103/S1068798X2006009X
2. Zhuravlev A. V., Egorova R. V., Egorov M. S. Prediction of contact fatigue life of heavy loaded friction pairs, which are strengthened by induction facing by hard alloy powders. Metallurg. 2023. No. 4. pp. 93–98.
3. Stepakin I. N., Pozdnyakov E. P., Kuis D. V. Contact wearing of semi-heat-resistant die steels Kh12M and Kh12MF with a surface-modified layer. Trenie i iznos. 2019. Vol. 40. No. 1. pp. 5–11.
4. Grebnev Yu. V., Karpova E. Yu., Gabekchenko N. I. Study of possibility of wear resistance increase for the components of cleaning equipment made of chromium cast iron. Izvestiya Volgogradskogo gosudarstvennogo tekhnicheskogo universiteta. 2019. No. 7 (230). pp. 54–58.
5. Yonghao J., Xiulong Ch., Lianzhen Zh., Chengsi N. Dynamic characteristics and reliability analysis of parallel mechanism with clearance joints and parameter uncertainties. Meccanica. 2023. 58 (4). pp. 813–842. DOI: 10.1007/s11012-023-01650-9
6. Leonov O. A., Shkaruba N. Zh. Calculation of Fit Tolerance by the Parametric Joint Failure Model. Journal of Machinery Manufacture and Reliability. 2020. Vol. 49. No. 12. pp. 1027–1032.
7. Leonov O. A., Shkaruba N. Z., Vergazova Y. G., Khasyanova D. U. Justification of Keyed Joint Fits. Journal of Machinery Manufacture and Reliability. 2022. Vol. 51 (6). pp. 548–553.
8. Shuai J., Lin Y., Jianan L., Linjing X., Shuaishuai Z. Dynamics Optimization Research and Dynamics Accuracy and Reliability Analysis of a Multi-Link Mechanism with Clearances. Machines. 2022. Vol. 10 (8). pp. 698. DOI: 10. 698. DOI: 10.3390/machines10080698
9. Jinge W., Junfu Zh., Xiaoping D. Hybrid dimension reduction for mechanism reliability analysis with random joint clearances. Mechanism and Machine Theory. 2011. Vol. 46 (10). pp. 1396–1410. DOI: 10.1016/j.mechmachtheory.2011.05.008
10. Liu Y., Tan C., Zhao Y. Dynamic effect of time-variant wear clearance on mechanical reliability. Acta Aeronautica et Astronautica Sinica. 2015. Vol. 36 (5). pp. 1539–1547. DOI: 10.7527/S1000-6893.2014.0129
11. Boutoutaoua H., Bouaziz M., Fontaine J. F. Modeling of Interference Fits Taking form Defects of the Surfaces in Contact into Account. Materials & Design. 2011. Vol. 32. No 7. pp. 3692–3701.
12. Chigrik N. N. Quantitative estimation of uncertainty of the average clearance and interference in joints of intermediate and marginal dimension groups of the same name. Computational Nanotechnology. 2023. Vol. 10. No. 1. pp. 11–29. DOI: 10.33693/2313-223X-2023-10-1-11-29
13. Repcic N., Saric I., Muminovic A. Software for Calculation and Analysis of ISO System of Tolerances, Deviations and Fits. 23^rd International DAAAM Symposium on Intelligent Manufacturing and Automation – Focus on Sustainability. 2012. pp. 0195 – 0198.
14. Ordiz M., Cuadrado J., Cabello Ulloa M. et al. Prediction of fatigue life in multibody systems considering the increase of dynamic loads due to wear in clearances. Mechanism and Machine Theory. 2021. 160. p. 104293. DOI: 10.1016/j.mechmachtheory.2021.104293
15. Yakushev A. I., Beluzhkova E. F., Plutalov V. N. Allowances and fits of USTF of the Council of mutual economic assistance (CMEA) for smooth cylinder components: calculation and selection. Moscow : Izdatelstvo standartov. 1978. 284 p.
16. Gafner S. L., Verkhov E. Yu. Calculation of contact stresses in slide bearings with dry friction. Tekhnika i tekhnologiya: novye perspektivy razvitiya. 2016. No. XX. pp. 5–8.
17. Slepchenko E. V., Mineeva A. S. Determination of the contact square in slide bearings. Uspekhi sovremennogo estestvoznaniya. 2011. No. 7. pp. 199–200.