The rated dynamic load of the bearing can be understood as the maximum load that the bearing can bear when it rotates 654.38+0 million revolutions, and the basic rated static load refers to the load corresponding to a certain contact stress between the bearing roller and the raceway.
Generally speaking, the bearing model can be selected according to the relationship between the rated dynamic load and the actual load, and the service life and grease life of the bearing can be predicted.
Extended data
Rolling bearing performance
Alignment performance
The ability of bearing to work normally when the center line of important official is inclined relative to the center line of bearing seat hole. Double-row radial ball bearing and double-row radial roller bearing have good self-aligning performance. Roller bearings and needle bearings are not allowed to tilt the axes of inner and outer rings relatively. The allowable inclination angles of various rolling bearings are different, such as single-row radial ball bearing 8 ′ ~16 ′, double-row spherical ball bearing 2 ~ 3, tapered roller bearing ≤ 2 ′.
Limit speed The maximum speed allowed by a bearing under certain load and lubrication conditions. Limit speed and bearing type, size and accuracy? Clearance, cage, load and cooling conditions. The working speed of the bearing should be lower than the limit speed. Selecting high-precision bearings, improving the structure and material of cage, using oil mist lubrication and improving cooling conditions can all improve the limit speed.
Bearing lubrication
There are mainly grease lubrication and oil lubrication. Grease lubrication is not easy to leak, easy to seal, long in service time, simple in maintenance and high in oil film strength, but the friction torque is greater than that of oil lubrication, which is not suitable for high speed. The amount of grease in the bearing should not exceed 1/2 ~ 1/3 of the bearing space, otherwise the bearing will be overheated due to too much stirring lubricant.
Oil lubrication has a good cooling effect, but the sealing and oil supply devices are more complicated. The viscosity of oil is generally 0.12 ~ 0.2cm/s. When the load is high and the working temperature is high, the oil with high viscosity should be selected, and when the rotating speed is high, the oil with low viscosity should be selected. Lubrication methods include oil bath lubrication, dripping lubrication, oil mist lubrication, oil injection lubrication and pressure oil supply lubrication.
During oil bath lubrication, the oil level should not be higher than the center of the lowest roller. If the bearing is designed according to the theory of elastic hydrodynamic lubrication and the viscosity of lubricant is selected, the contact surfaces will be separated by oil film. At this time, under the action of stable load, the bearing life can be improved many times.
Modern machines, instruments and other equipment are developing in the direction of high speed, heavy load, precision and light weight, which puts forward many new requirements for rolling bearings, such as reducing the size while maintaining or even increasing the rated load, improving the process by adopting new technologies, improving the manufacturing accuracy and reducing the cost.
Universal rolling bearings are difficult to meet various requirements. For mechanical equipment with large production capacity, special bearings should be designed and manufactured. While strengthening standardization, we should increase varieties and expand the proportion of special bearings. The development of modern industry also needs special bearings working under special working conditions, such as bearings working in high speed, high temperature, low temperature, strong magnetic field or acid, alkali and other media.
References:
Baidu encyclopedia-rolling bearings