Speed of bearing
Each bearing model has its own limit speed, bearing which is determined by physical characteristics such as size, type and structure. The limit speed refers to the maximum working speed of the bearing (usually R / min). Exceeding this limit will lead to the increase of bearing temperature, the drying of lubricant and even the seizure of the bearing.
The speed range required for the application helps to determine what type of bearing to use. The product catalogue of most bearing manufacturers provides the limit speed value of their products. Practice has proved that it is better to work under 90% of the limit speed.
The limit speed of grease lubricated bearing is lower than that of oil lubricated bearing, and the oil supply mode of bearing has an impact on the attainable limit speed. It must be noted that for grease lubricated bearings, the limit speed is generally only 80% of the limit speed when the bearing adopts a high-quality repeated circulation oil system, but for oil mist lubrication system, the limit speed is generally 50% higher than the same basic lubrication system.
The design and structure of the cage also affect the limit speed of the bearing, because the rolling element is in sliding contact with the surface of the cage. The cage made of expensive, reasonably designed, high-quality and low friction materials can not only separate the rolling element, but also help to maintain the lubricating oil film in the sliding contact area.
However, low-cost cages such as stamping cages usually only keep the rolling elements separated. Therefore, they are prone to accidents and distressing sliding contact, resulting in lower limit speed.
Generally speaking, deep groove ball bearing, angular contact bearing and cylindrical roller bearing should be selected in the workplace with high speed; Tapered roller bearings can be used in low speed working situations. The limit speed of tapered roller bearing is generally about 65% of deep groove ball bearing, 70% of cylindrical roller bearing and 60% of angular contact ball bearing. The limit speed of thrust ball bearing is low, so it can only be used at low speed.
For the same type of bearing, the smaller the size, the bearing higher the allowable speed. When selecting bearings, pay attention to make the actual speed lower than the limit speed.
