Theoretical analysis of passive rail grinding

Abstract

Introduction. There are different rail machining technologies designed to eliminate defects on the tread surface and extend the life cycle of rails. The most used is the technology of grinding rails with rotating grinding wheels using rail-grinding trains. Its main disadvantage is the low working speed of the grinding train that requires the organization of track possessions with stopping the movement of trains along the haul. To perform preventive rail grinding with minimal metal removal from the rail head, passive grinding technologies using grinding wheels have become widespread in last years. Passive grinding is when there is no power on the grinding wheel to rotate it actively. Such methods make it possible to achieve high speeds of the grinding train, and the work can be carried out in the train schedule without closing the stage. Currently, passive grinding technologies are relatively new and do not have the necessary scientific basis for optimizing the machining process. The aim of the work is to perform theoretical studies of kinematic and force analyzes of two methods of rail passive grinding: the periphery and the end face of the grinding wheel. Methodology of the work is kinematic and power calculations of rail grinding schemes. Results and discussion. Within the framework of theoretical studies, a kinematic and force analysis of two methods of passive grinding are carried out, on the basis of which the optimal conditions for its implementation are determined. It is established that the method of passive grinding by the periphery of the wheel has a 20 % higher productivity and energy efficiency of the process before end passive grinding due to the higher rotation speed of the grinding wheel with equal forces of pressing it to the rail. At the same time, passive grinding with the end of the wheel is distinguished by a twice greater range of change in both the speed of the grinding wheel rotation and the force of its pressing that makes it possible to achieve greater metal removal at equal speeds of the grinding trains. In conclusion, promising tasks for further research in the field of passive rail grinding are formulated.