| Railway is developping fast in our country, but the high speed and overloaded railway bearings are still need imported. The domestic bearing industry is accelerating the development of highspeed and overloaded railway bearing, and developed the complete precise grinding equipments of railway bearings’ inner and outer ring which have positive influence of promoting the localization our country’s highspeed and overloaded bearings. Internal grinder of railway bearing ring is a precise grinding equipment for the outer ring’s raceway and inner ring’s inner hole of railway bearing, and it’s important to develop internal grinder of railway bearing ring which has great thermal characteristics in order to improve the machining precision of bearing ring. The main contents of this paper are as follows:(1)3D digital model and thermal model of the internal grinder of railway bearing ring are established. Energy flow model of grinding machine is established based on the heat transfer theory, and energy transfer pathes and heat-dissipating methods of internal grinder is given by the energy flow model.(2)The heat source and thermal boundary conditions of some main components such as the motorized spindle, workpiece spindle system are worked out, and also done is the finite element analysis (FEA) of the temperature field and thermal deformation of the main components. Cutting fluid is studied as a "secondary heat source" on the thermal characteristic of lathe bed.(3) Thermal characteristics of internal grinder under the influence of factors such as motorized spindle, workpiece spindle system and cutting fluid are researched, and the grinding error under these facters are also analyzed.(4)Thermal characteristics of internal grinder under the working condition is studied, the grinding accuracy of internal grinder under the working condition is calculated. The reasonable thermal design of internal grinder is done according to the results of theoretical analysis above.The results showed that:The radial grinding error of the internal grinder of railway bearing ring is mainly from the cutting fluid, therefore the focus of the thermal structure design is to reduce the heat transfer from the cutting fluid to the bed. After adding insulation materials on the cutting fluid runner of lathe bed, the radial grinding error of the internal grinder reduced to 4μm, reduced about 94.4%. |
