Applicability of fs-all-metal self-lock nuts for railway rolling stock of 1520 mm gauge
Authors: R. Кreis, V. S. Lisnychyi
Number of views: 324
Purpose. One of key requirements for rolling stock of next generation is essential increase of warranty period or running between maintenance depots and in periods between programming repair works. This will lead to a reduction of costs to maintenance and repair during service life of rolling stock. In this regard, the industry aspires to use (during construction, repairs, modernization of rolling stock) a modern screw joints in structures for fixing parts. These screw joints could provide a high reliability under the action of vibration load. FS-hexagon all-metal self-lock nuts of multiple use, Flaig + Hommel GmbH company meets these requirements. Therefore, there is the need to consider the results of tests to confirm the reliability of FS-nuts in the new environment. Methodology. Test complex of developed programs and methods was carried out on railway rolling stock for functional demonstration of screw joints with FS-nuts. These tests include: 1) proof test and locking moment test as specified in ISO 2320 under normal climatic conditions and after low temperatures impact; 2) running test for rolling stock, secured the most load condition and according to supervised operation of next generation cars on the railway. Findings. Results of the tests testify that FS-all-metal self-lock nuts meet the requirements of international standards and confirm the reliability of the next generation rolling stock during its operation on the railway of 1520 mm gauge. Namely, locking moment and tightening torque is maintained in screw joints both on spring-suspended and unspring parts of freight car bogies by the action of vibration load under multiple use of FS-nuts. Originality. The developed software and methods was improved by conducting additional tests after exposure of screw joints with FS-nuts to low temperatures, as well as by control operations for assessing the condition of screw joints with FS-nuts, in the conditions of controlled operation of rolling stock. It fully allows confirming the reliability of the FS-nuts on the rolling stock of 1520 mm gauge railways.Practical value. Application of FS-nuts makes it possible to stop using secondary members in screw joints of railway rolling stock of 1520 mm gauge. These secondary members are used for reaction to slacking under vibration and consist of castle nuts, retaining washers, locking washers, serrated washers, check plates, disposable clamps. Using FS-nuts allow providing the rating rules for next generation of rolling stock. Besides the modern technologies of FS-nuts production provide their prolonged running time under the conditions of pollution, humidity, differential temperature and other adverse factors.