Common spindle speed dn value

Common spindle speed dn value (dn value is the average diameter of the spindle radial clearance (mm) and the limit speed (r / min) the product of the spindle) to measure the speed spindle often refers to the value of the spindle dn 1.0 × 106 or more. With the development of bearing technology, lubrication technology, the spindle speed to improve year by year. The data show that in the 1980s, spindle bearing grease lubrication dn values ​​under conditions of maximum reach 0.5 × 106, but after the oil lubrication device developed, dn values ​​rapidly increased to 1.0 × 106, using angular contact ceramic ball bearings after, dn value of the spindle bearings further increased to 2.0 × 106.