1、Ball bearings have higher limit speed and rotational accuracy than roller bearings, so ball bearings should be preferred in high speed.
2, in the same conditions of the inner diameter, the smaller the outer diameter, the smaller the rolling body, the smaller the centrifugal inertia force on the peripheral raceway when running, and therefore also suitable for higher speed work. Therefore, in high speed, it is appropriate to use the same diameter series in the outer diameter of the smaller bearing. If the bearing with a smaller outside diameter and the bearing capacity does not meet the requirements, can be installed with the same bearing, or consider using a wide series of bearings.
3、The material and structure of the cage have great influence on the bearing speed. Solid cage allows higher speed than pressed cage, bronze solid cage allows higher speed.
In general, deep groove ball bearings, angular contact bearings and cylindrical roller bearings are suitable for higher speed work; in lower speed work, tapered roller bearings can be used. The limit speed of tapered roller bearings is generally about 65% of deep groove ball bearings, 70% of cylindrical roller bearings and 60% of angular contact ball bearings. The limit speed of thrust ball bearings is low and can only be used in lower speed situations.
Depending on the type and brand of lubricant. Some lubricants may have some good performance but not suitable for high speed rotation. Therefore, if the speed of the bearing exceeds 80% of the limiting speed stated in the dimension table, please contact the bearing manufacturer.
The limiting speed of a bearing is the speed limit at which frictional heat does not cause burns and at which continuous rotation is possible. Therefore. The limiting speed of a bearing depends on various factors such as shaft type, size, tolerance, lubrication, quality and quantity of lubricant, material and type of cage, and load conditions.
All kinds of bearings with grease lubrication and oil lubrication (oil bath lubrication) when the limit speed are contained in each bearing size table whose values indicate the standard design of bearings in general load conditions (C/P ≥ 16, Fa/Fr ≤ 0.25 or so) under the limit speed.
Experience shows that even if the bearings operate under the most favorable load and friction conditions, the maximum speed should not be exceeded for technical reasons or because the cost required to maintain stable operating conditions for a certain period of time is too high.
The limiting speeds listed in the product list apply to the basic bearing design. In cases where the limiting speed is higher than the reference speed, the operating temperature may be significantly higher than the reference value. Under these conditions, appropriate measurements (whether the cage, seals, preload and lubricant can withstand high temperatures) may be required. If these measurements are not sufficient, the internal clearance of the bearing and the accuracy of the housing and journal need to be verified and adjusted appropriately to meet the more demanding operating conditions.
For grease, other factors should be considered, such as the lubrication conditions of the cage guiding surface at operating temperature and the consistency of the grease.
Some open ball bearings have very low friction and the reference speeds listed in the product table may be higher than the limiting speed. It is therefore necessary to calculate the adjusted reference speed and compare it with the limiting speed, and then take the lower value between the two. In some special cases, for example for some cylindrical roller bearings, if other cages are selected, the bearings can be operated at higher than the standard limiting speed listed in the table.
If the bearing is required to operate at a higher speed than the limit speed listed in the product list, some factors that impose limits on the speed must be improved. If modifications are to be made to the bearing, lubrication system or application. The modifications made may include improving the rotational accuracy of the bearing; changing the cage material and structure, lubrication conditions and heat dissipation methods, etc.
