College of mining, NUST MISIS, Moscow, Russia:

Yu. F. Nabatnikov, Head of Chair, Professor, Doctor of Engineering Sciences, kaftmr@mail.ru

Powered roof supports employed in coal cutting contain several hundreds of the same-type hydraulic legs. The functional faces that govern the life of each leg are the internal surface of hydraulic cylinders and external surface of pistons. It is of critical importance to manufacture hydraulic legs so that to ensure sustainability of their preset life. The quantitative relationship is revealed between the preset life of hydraulic legs and the quality and accuracy of assembly of their functional joints, which allows determining the joint assembly accuracy capable to provide its preset life. The accuracy of joints can be ensured using different methods. The choice of a method governs the manufacturing procedure of parts of joints and, thus, the manufacture cost. It is important the selection of a method to ensure accuracy of joints is substantiated by the evaluation of the joint quality–life relation. The scope of the article encompasses also the aspect of manufacture of highly accurate joints in hydraulic legs by selective assembly in small-scale production without extra equipment and technology investment. For small-scale production in mining machine building, it is typical that sizes of shafts and holes disagree. Manufacturers lean towards larger sizes when making shafts and towards smaller sizes when making holes. Therefore, for the selective assembly in small-scale production, it is required to reduce or eliminate the influence of the statistical law of size on fabrication of mismatched parts. This problem is solved at the Moscow Mining University by development of the method of inter-group compatibility. The feature of such method of assembly is that each size group of cylinders (holes) is collated with a number of size groups. In this case, the probability of mismatch of parts is minimized, and the assemblage is independent on the size distribution law, i.e. on random components of part manufacturing process. The developed assembly technique essentially contributes to pursuing the goal of import substitution in the area of expensive high-precision equipment and technologies for manufacture of joints.

1. GOST R 55729-2013. Mining Equipment. Hydraulic Props for Roof Supports. General Specifications. Introduced: 01.09.2014. Moscow : Standartinform, 2013. 23 p.
2. Gabov V. V., Zadkov D. A., Stebnev A. V. Evaluation of structure and variables within performance rating of hydraulically powered roof support legs with smooth roof control. Eurasian Mining. 2016. No. 2. pp. 37–40. DOI: 10.17580/em.2016.02.09
3. Kantovich L. I., Merzlyakov V. G. Machines and Equipment for Underground Mining: Text Edition. Moscow : MGGU. 2014. 408 p.
4. Radkevich Ya. M., Skhirtladze A. G. Metrology, Standardization and Certification, Moscow : Yuriat. 2014. 813 p.
5. Nabatnikov J. F. Selective assembly of machine parts in mining machinery manufacturing. Gornyi informatsionno-analiticheskii byulleten. 2014. No. 8. pp. 159–164.
6. Elser H., Heutmann T., Lindemann M., Schmitt R. Hellsehen in vier Schritten. Data Analytics für das digitale Qualitätsmanagement. Qualität und Zuverlässigkeit. 2018. Vol. 63, No. 2. ss. 31–33.
7. Schmitt R., Göppert A., Hüttemann G., Lettmann P., Rook-Weiler K. et al. Frei verkettete wandlungsfähige Montage. Internet of Production für agile Unternehmen : AWK Aachener Werkzeugmaschinen-Kolloquium. Aachen, 2017. ss. 339–368.
8. Matalion A. A. Machine Engineering Technology. Moscow : Lan. 2016. 512 p.
9. Suslov A. G. Foundations of Machine Engineering Technology: Textbook. Moscow : KnoRus. 2018. 288 p.
10. Szurgacz D. Electrohydraulic control systems for powered roof supports in hazardous conditions of mining tremors. Journal of Sustainable Mining. 2015. Vol. 14, Iss. 4. pp. 157–163.
11. Verzhansky A.P., Nabatnikov Yu.F., Ostrovsky M.S. Accuracy of joints of mining machine parts and this accuracy ensuring method. Gornyi informatsionno-analiticheskii byulleten. 2013. Special Issue № 1. Proceedings of international scientific symposium: Miner’s Week-2013. pp. 461–485.
12. Wenking M., Benninghaus C., Groggert S. Die Zukunft von Manufacturing Data Analytics: Implikationen für eine erfolgreiche Datennutzung im produzierenden Umfeld. Industrie 4.0 Management: Gegenwart und Zukunft industrieller Geschäftsprozesse. 2017. Vol. 33, No. 4. ss. 33–37.
13. Nabatnikov Yu.F. Assembly modeling of the machines details connections through the use of the computer. Automation and Modern Technology. 2013. No. 2. pp. 6–15.