The weight that can be supported by the bearing area
What is the concept of 4000MPa, the bearing is an area of one square millimeter that can withstand 4000 Nm of force, that is, 400 kg. The area of a fingernail is about 100 square millimeters, can withstand 400X100 = 4000 kg = 40 tons of weight, what is the concept of forty tons, an adult elephant weighs 4 to 6 tons, according to five tons, 40 tons is 8 adult elephants, imagine what is the state of 8 adult elephants standing on your fingernails.
Is not very spectacular, bearings generally contain multiple rolling elements, so the bearing load carrying capacity is very high, here is only a brief introduction to the ultimate bearing capacity of the bearing, as for the dynamic load carrying capacity will be different. So how the bearing withstands high temperatures, first of all, why does the temperature rise, when the bearing works, between the rolling elements and the outer ring, between the rolling elements and the inner ring, there will be contact friction, friction will generate heat, heat absorbed by the bearing parts will increase the temperature. Friction is a source of heat for bearing parts. So is the temperature really high when the bearing is working normally, the answer is no, then the bearing has been working continuously, how to reduce the temperature, first of all, to reduce the heat generation, what to do? Lubrication, reduce the friction coefficient between the contacts, after the friction coefficient is reduced, the heat generated is less, and the bearing work is to add grease or lubricating oil to work. In addition, the heat of the bearing will also be taken away by lubricating oil, and as the temperature of the bearing rises, when the temperature is higher than that of other surrounding components, the heat will be dissipated to other media through two ways: conduction and radiation. The higher the temperature difference, the more heat dissipated through heat conduction and radiation, when the temperature reaches a certain value, the heat generated by friction and the heat emitted are equal, which is the bearing is in a state of thermal equilibrium, that is, the temperature of the bearing is stable and no longer rises.
1) Material design: There are many kinds of bearing steels with high temperature resistance materials, mainly their own materials and layers. This can be found in any data, such as silicon nitride, titanium carbide, etc.; materials generally require high hardness, and their own quality can not be too large.
2) The lubrication system of high-temperature bearings is generally a labyrinth sealing method.
3) The bearing clearance with high temperature resistance should have sufficient design clearance to prevent overload.
Wheel diameter by 500 mm, specific I really don't know, a turn of 1.57 meters, bearing speed according to 360 km / h, equivalent to 100 meters per second, wheel speed of 100/1.57 * 60 rpm, That is, 3821.7 rpm, bearing size takes into account the bearing capacity and wheel size, the diameter will not be too large, the front answer someone said 200 mm, according to this specification, 3821.7 speed is fully adapted, there will not be too high temperature, heat is caused by friction, the bearing in the case of lubrication, the friction coefficient is not very large, 0.02 or 0.004 as if, do not remember, different bearings also have differences.
