High-speed rotation that exceeds the limit of the spindle bearing itself will cause frictional heat inside the bearing, resulting in temperature rise, and risk of overheating, burns, and damage that affect the performance of the bearing. If such an accident does not occur, the maximum rotation speed for trouble-free operation is called the limit rotation speed. The limit speed varies with bearing model, size, lubrication method and load. The limit speed of the bearing with contact seal ring is affected by the peripheral speed of the contact part between the seal ring and the raceway. The dimension table in this catalog lists the limit speeds for grease lubrication and oil lubrication. The relevant values u200bu200bare reference values u200bu200bwhen lubrication is appropriate under light load and horizontal shaft usage conditions. Generally, there are more than 2 preloads on angular contact ball bearings. At this time, due to the limitation of the limit speed, it is necessary to multiply the correction factor listed in Table 7.1 on the basis of the limit speed in the dimension table. When the limit speed exceeds 75% of the limit speed, if you use grease lubrication, you must correctly select the type and amount of grease; if you use oil lubrication, you must correctly select the type and amount of lubricating oil.