Study On Bearing Raceway Crown And The Method For Its Electrochemical Mechanical Machining

Roller bearing is a widely applicable basic element, which plays important roles inmechanical equipments. The performance of all kinds of equipments such as precision,capability, life and reliability is closely laid on property of bearing. Comparing with foreignsimilar products, domestic cylindrical roller bearing products have obvious gap inperformance, which restrict the development level of domestic equipment manufactureindustry. According to the structural characteristics and performance requirements of rollerbearing, a new processing technique for bearing manufacture is proposed to enhance theprecision and process quality, which is benefit to short the gap between the domestic productsand the overseas equivalents. It has a great reality meaning for improving the life andperformance of bearing.Life, vibration and noise of bearing are the synthetical reflection of the bearing’s quality.According to the previous theoretic research and finite element analysis (FEA) for bearingcontact stress, a crown generator of cylindrical roller bearing raceway with a smooth surfacewhich replaces the flat generator can improve the physical mechanics, elevate rotationprecision and durableness, improve the contact stress distribution, decrease vibration andnoises, avoid early fault, enhance the life of bearing. Compared with some limitations of thetraditional bearing raceway grinding, such as tool worn, poor surface quality, complicatedshaping operation, uncontrollable crown value, and low efficiency, electrochemicalmechanical machining (ECMM) has the advantages of good surface quality, fine surfacemicro-topography, machinability of super-hardness metal, low cost and great efficiency.Aiming at the key issue of raceway surface quality and profile which affects the life and theperformance of bearing, ECMM is proposed in this dissertation to process the bearingraceway in order to finish and crown the raceway at the same time.Experimental study about the key issue of raceway machining by ECMM is executed inthis dissertation. Two type of machining about unequal gap cathode and equal gap cathode areput forward and put in practice for crowning the bearing raceway. For the unequal gapmachining, the removal of anode is controlled by inter-electrode gap. For the equal gapmachining, the removal of anode is controlled by machining time.