ELECTROMECHANICAL RESTORATION OF SHAFT SEATS UNDER ROLLER BEARINGS

The problem of ensuring the durability of shaft seats for roller bearings and the search for optimal ways to improve their reliability is an urgent task. This study explains the reasons for the low durability of shaft seats for roller bearings associated with the mechanism of bearing wear and insufficient physical and mechanical properties of the surface layer of manufactured and reconditioned machine parts. Based on the analysis of existing methods for restoring shaft seats for roller bearings with wear of less than 0.1 mm, the authors propose a technology of electromechanical reduction hardening, which allows to increase the diameter and hardness of the surface layer of parts in one stroke of the tool. The paper presents the results of comparative wear tests of cylindrical samples of steel 40X coupled with roller bearings 180206AK-6206. After electromechanical hardening recovery, the hardness of the surface layer of samples was 52...58 HRC, at a depth of 0.8 mm with an initial hardness of 19...22 HRC. The outer diameters of the samples before and after each test stage was changed with a lever bracket at an accuracy of 0.001 mm in two mutually perpendicular directions. The inner diameter of the roller bearings before and after each test cycle was controlled with a limit gauge-stopper. The research was carried out as follows: assembling fit-tight joints with a hydraulic press, holding for 60 seconds, pressing out the sample, visual inspecting, measuring the diameter of a sample lever bracket, controlling the inner ring of the bearing using a limit gauge. Ten operations of the assembly and disassembly of connections were taken for the test basis. The wear test results of the samples indicate the high efficiency of the electromechanical hardening recovery technology. The implementation of research results made it possible to use the developed technology for remanufacturing the gearbox of "Volga", "Gazel", "Sobol", and "Barguzin" car families and gear shafts of power reduction gears.