Minimum Load-Cylindrical Roller Bearings

In order to keep bearings working in good condition, a minimum load must be imposed on bearings, particularly on bearings working at high speeds, high accelerations, or with the load direction changing frequently, because under these working conditions, inertial force of balls and cage and lubricant friction will have bad influence on the rotation of bearings, and detrimental sliding movement may be caused.

The minimum load of a cylindrical roller bearing can be obtained from

Where

n - Working speed, r/min

nr -(0.8～0.9)Limiting speed, r/min

dm - Mean bearing diameter dm=0.5(d+D), ,mm

Kr - Minimal load factors,the values are

When bearings are started at low ambient temperatures or in the condition that the viscosity of the lubricant is very high, bigger minimum load is required. Usually, the weight of the bearing supporting parts plus the load on the bearing have been over the required minimum load. If the weight cannot be up to the minimum load, extra radial load must be exerted on this type of bearing in order to meet the requirement of minimum load.