Improving the Quality of Manufacturing of Locomotive Body Frames

Abstract

The paper describes the process of manufacturing the frame of locomotive bodies, which is a complex step-by-step process of assembling (welding) elements. It has been established that internal stresses cause welding deformations, while the deviation from the straightness of the sidewalls of the electric locomotives body frames of 2ES6, 2ES10, 2ES7 series (manufactured by Ural Locomotives LLC) can reach up to 25 mm with a tolerance of 5 mm. The results of internal stress analysis for linear displacements of 25 mm sidewalls showed that the maximum stress values can reach up to 45 MPa. To improve the accuracy of parameters, the operation of straightening by local heating is introduced into the body frame manufacturing technology. The paper describes the main characteristics of the existing straightening technology in production, shows the main disadvantages. Studies of technical solutions for straightening methods have been carried out. The results show that there are ample opportunities to replace thermal straightening with mechanized vibrational processing, which reduces residual stresses in the product material. The efficiency of vibration treatment largely depends on the selected mode parameters: frequency, amplitude, duration of vibration exposure, as well as the optimal frame vibration treatment scheme. The paper proposes an original scheme for straightening the body frame of electric locomotives in production environment. It is indicated that in order to minimize the forces of static bending, it is necessary to suspend the frame under constraints and move the vibrator(-s) along the length of the frame, dividing it into approximately 3 equal parts. To work out the straightening technology, it is proposed to use PXI Platform equipment with the LabVIEW application. The cost of the straightening operation can be reduced by at least 20%, which will affect the cost of the electric locomotive as a whole.