The limiting speed of a bearing is related to its type, load, precision, dimensions, lubrication, clearance, cage, and cooling conditions. However, the most important factors are the allowable operating temperature of the bearing material and the lubricant. The limiting speeds of various bearing models are listed in the bearing dimensions and performance tables of the "Rolling Bearing Product Catalog." These are determined under oil lubrication and grease lubrication conditions, and their applicable ranges are:
1. Standard (G) grade tolerance bearings; 2. Radial bearings only bear radial loads, and thrust bearings only bear axial loads; 3. P ≤ 0.1C (C is the basic dynamic load rating of the bearing); 4. Rigid shaft and bearing housing; 5. Normal lubrication and cooling conditions.
When a bearing operates under a load condition where P ≥ 0.1C, the increased contact stress between the raceway contact surface and the rolling elements causes the bearing operating temperature to rise, and the performance of the lubricant to deteriorate relatively. Therefore, the limiting speed of the bearing will decrease accordingly.