The Experimental Study Of Oil-air Lubrication For High-speed Motorized Spindle Bearing

In recent years, with the development of high-speed motorized spindle technology, although the tradition grease lubrication has the advantage of simple structure and don’t need to change,The grease lubricated bearing is so poor in cooling that the temperature rise is high. Under the action of circulating cooling water in motorized spindle, the temperature of bearing outer ring get lower, however, the temperature of bearing inner ring is still high, making a bigger difference between bearing internal and external temperature, so the bearing’s service life is reduced greatly. Oil-air lubrication as a new way of cooling and lubrication, not only provide effective lubrication for bearing, also can take away the most heat generated by bearing, so as to reduce the temperature both in bearing outer ring and bearing inner ring. The double role of oil-air lubrication, makes it a broad application prospect in high speed motorized spindle. At present, the research of oil-air lubrication technology mainly focus on:1) the formation mechanism and flow state in pipeline of oil-air lubrication; 2) the thermal simulation analysis for bearing with the oil-air lubrication.; 3) the minimum oil quantity of oil-air lubrication bearing with the method of experiment. Experimental study of oil-air lubrication for bearing, predecessor only considering bearing’s temperature rise, in this paper, both bearing temperature rise and vibration as the evaluation criteria to judge bearing performance under difference lubricant, oil supply, air pressure and nozzle diameter, and study the combined effect of the oil supply, air pressure and nozzle diameter for bearing at the speed of 20100r/min and axial load of 30 N with the orthogonal test.Firstly, choose three lubricants according to the working condition of bearing and the principle of oil selection(MOTOREX COREX HLP-D 68、MOTOREX SPINDLE LUBE 68 �'� MOTOREX SPINDLE LUBE 46). Using the rolling bearing performance analysis software to analysis the film thickness and the length and width of the bearing contact region under the three lubricants, and make appropriate correction for film thickness. Using Dowson minimum oil film thickness calculations to analysis and calculation the oil supply at different working condition of bearing. Theoretically analyzes the pressure loss of compressed air from air source to lubrication point, which provice a reference to the minimum air supply pressure to guarantee a certain positive pressue chamber.Then, oil-air lubrication test rig for high-speed bearing were set up. Which has the functions of axial load and frequency control, and can monitor the temperature of bearing outer ring, vibration and current of test system. after that, verifying the experiment station to analysis the repeated accuracy.Finally, research the influence to bearing temperature and vibration with different oil-air parameters; and with the method of orthogonal experiment to study the combined effect of oil supply, air pressure and nozzle diameter, to obtain the influence level of the three factors on bearing temperature rise and vibration.