No abstract

No abstract

No abstract

The development of constructive recommendations aimed at increasing the service life of roller bearings of axle boxes of railway cars is described. The elastic volumetric stress-strain state of the bearing elements of the bearings under consideration is analyzed. Numerical analysis of the corresponding mathematical models was carried out using the finite element method in the NX NASTRAN software environment. It is shown that near the edge of the roller with chamfer-rounding, a stress concentration arises, caused by insufficient smoothness of the contour line of the axial section of the roller. It is noted that this concentration is caused by the fact that the line of the contour under consideration has a finite specified curvature in the section corresponding to the chamfer and almost zero curvature in the adjacent straight section corresponding to the cylindrical surface of the roller. It is shown that the use of smoother contour lines for the marginal zone of a roller more than doubles the maximum value of the stress intensity in the boundary zone under consideration and accordingly increases the cyclic life of the bearing. The proposed smoothing of the line of the considered circuit allows one not only to unload the edge of the roller but also to reduce the contact pressure in its middle part. At the same time the stress-strain state of the roller becomes more uniform by increasing the smoothness of the contour line in the area of the roller’s edge and simultaneously reducing the degree of bombing (barrel-shaped) its cylindrical surface.

The possibility of the car dynamic performance improvement is studied through structural changes (modernization) of the passenger bogie. Based on the calculations of the natural oscillations of the car, the critical values were determined and rational values of the damper resistance coefficient were chosen for vertical and lateral vibrations. It was concluded that with the forced spatial fluctuations of a carriages on KCCW-CRI bogies the required damping value of the vertical oscillations should be twice as large as for the lateral ones; important factors in damping of the car oscillations are the central suspension dampers. The rational angle of installation of the hydraulic damper in the central suspension and the use of separate action in the central suspension of hydraulic dampers are justified. The proposed version of the modernization of the bogie can improve the smoothness indicators of the car by 25-30%.