Baoji Bjzv Precision Machinery Bearing Co., Ltd.

Case 1: Solving the problems of electrical corrosion and premature failure of bearings in high-voltage motors Applicable equipment: YKK series 1000kW high-voltage asynchronous motors (6 poles,rotational speed approximately 1000 rpm) produced by a domestic large-scale motor manufacturer,used to drive centrifugal water pumps in mines. Industry pain point: There is an axial current issue during the operation of the motor. The parasitic current generated by the high-frequency inverter passes through the bearings,causing electro-corrosion (Fluting),resulting in grooves on the bearing raceways and deterioration of the lubricating grease. On average,bearings need to be replaced every 6-8 months,causing huge losses due to unplanned downtime. Our solution: Insulated bearings: For both the drive end and the non-drive end,deep groove ball bearings (6316/C3 + INSOCOAT) with an aluminum oxide coating on the outer ring are installed,effectively blocking the electrical current path of the shaft. Precise selection: Based on the motor load,speed and temperature rise,the C3 group clearance was recalculated and recommended to better accommodate the thermal expansion during the motor operation. Lubrication recommendation: It is recommended to use polyurea-based lubricating grease with excellent electrical insulation properties. Precise filling volume and re-lubrication cycle guidelines are also provided. Achieved results: The failure of the bearings caused by electrical corrosion has been completely eliminated. The service life of the bearings has been extended to over 3 years,which is in line with the overhaul cycle of the motor. It saves the maintenance cost for each customer's motor by more than 50,000 yuan per year and avoids downtime losses. Case 2: Enhancing the service life of the positioning bearings of the cold rolling machine in a steel plant under heavy load and impact Applicable equipment: The transmission side of the supporting rolls of a large-scale steel group's cold continuous rolling machine (rolling stainless steel,rolling speed 240m/min,rolling force 450KN). Industry pain point: The original positioning bearings used were 60/630M deep groove ball bearings,but the failure rate was abnormally high. The main manifestations were loose cracking of the cage (the original design was a two-part riveted structure),as well as severe peeling of the steel balls and raceways. Analysis revealed that the outer ring of the bearing and the bearing seat had an interference fit,causing the positioning bearings,which were supposed to be floating,to bear additional radial loads,resulting in rapid failure under combined loads. Our solution: Cooperation with optimization: Adjust the outer diameter size of the bearing (make it 50 μm smaller than the national standard),ensure that it has a clearance fit with the bearing housing,completely avoid bearing radial force,and restore its floating positioning function. Inner ring reinforcement: The original riveted inner ring was replaced with a high-strength bolt connection,and an adhesive was used for anti-loosening and external spot welding. This significantly enhanced the structural integrity of the inner ring under impact loads. Design optimization: Increase the curvature radius coefficient of the inner and outer raceways of the bearings,improve the stress distribution,enhance the bearing's ability to withstand axial forces,and make the rotation more flexible. Achieved results: The bearing cage has not experienced any further cracking. The bearing life is matched with the grinding cycle of the rolls,eliminating the occurrence of premature failure and ensuring the continuity of production. Case 3: Protecting the bearings of the vibrating screen of the mining crusher from severe impacts and dust Applicable equipment: Heavy-duty hammer crusher and vibrating screen equipment of a mining enterprise. Industry pain point: During operation,the equipment experiences intense shock and vibration,and the ambient dust concentration is extremely high. The original matching self-aligning roller bearings often fail prematurely due to cage fractures and abrasive wear,requiring frequent replacements,which adversely affects production efficiency and costs. Our solution: Inner ring upgrade: It is recommended to use the solid brass cage self-aligning roller bearing. Its strength,wear resistance and impact resistance are much better than those of the stamped steel inner ring. Sealing innovation: Equipped with "RS2" three-lip contact sealing ring (made of fluororubber FKM),replacing the original single-lip seal,this significantly enhances the sealing reliability in dusty environments. Clearance customization: For the operating conditions of vibration machinery,we offer "C4 group large clearance" bearings to prevent the loss of working clearance or even seizure caused by the combined effect of intense vibration and temperature rise. Achieved results: The bearings operate smoothly and the temperature has decreased by 15 degrees Celsius. The bearing lifespan is matched with the equipment's major overhaul period (approximately 8,000 hours),enabling predictive maintenance and eliminating the occurrence of sudden shutdowns. Although the customer's procurement costs have increased slightly,the overall maintenance costs have decreased by 40%.