The limiting speed of the bearing is the highest speed that the bearing can reach when the bearing is running. It mainly depends on the relationship between the heat generated by friction and the heat discharged when the bearing is running, and the bearing material, structural size, clearance, load, and cage material. It is closely related to factors such as structure and guiding method, lubrication method, lubricant amount, and cooling condition of the bearing.
Under normal circumstances, the bearing samples have given the limit speed of a single set of bearing grease lubrication and oil lubrication. The applicable conditions are: open bearings with standard structure, ordinary level accuracy, and basic group clearance; sufficient lubrication conditions ; Equivalent dynamic load is less than 10% of the rated dynamic load of the bearing; at an ambient temperature of 20℃, the temperature rise of the bearing is 50℃; the radial bearing only bears radial load, and the thrust bearing only bears axial load. If the actual operating conditions are different from the above applicable conditions, the actual maximum operating speed will be lower than the reference limit speed value given in the catalog. The limit speed of double or triple bearing can generally reach 60%-80% of single bearing.
Improving bearing accuracy and appropriately increasing bearing clearance can increase the limit speed of the bearing to a certain extent, but the specific increase is difficult to quantify; the cage is made of lightweight materials or the cage with a special structure is designed, and more effective lubrication is adopted. The method can greatly increase the limit speed of the bearing, up to 3 to 4 times the limit speed given in the sample.