With the development of various industries, bearing product plays a more and more crucial part. A bearing can be defined as a member specifically designer to support moving machine components. It is a device to allow constrained relative motion between two or more parts, typically rotation or linear movement. The use of bearings is essential to all types of machines, in that they provide the function of supporting another piece or component in a desired position. Moreover, they can also be used to supporting a rotating object or shaft.
As we know that bearing types are various, when compared to common types such as ball bearings and roller bearings, the magnetic bearings may not be very popular. They can support a load using magnetic levitation. They can be used in many specific places such as electric power generation, petroleum refining, and natural gas pipelines and so on.
Although magnetic bearings are not as common as some other types, they have their own advantages. First of all, they are free of lubrication which avoids servicing and also enables use in clean room environments. And due to the absence of surface wear, maintenance is also decreased. There could even be no maintenance as long as the control system functions as intended. Secondly, they are contact-free in that the magnetic force is used to support the object as opposed to contact between two surfaces. Thirdly, the magnetic properties of the materials used are highly resistive or immune to changes in temperature, pressure, and the presence of chemicals, therefore, they can be used in highly sensitive applications and in extreme conditions.
Except for those advantages, of course, they also have some disadvantages. For example, their costs are much higher compared to traditional bearings because of the large amount of effort and time required for development and the increase in the number of components. Besides, their complexity is also a disadvantage to use them.
The magnetic force used in magnetic bearings can be divided into two categories of how the force is created: reluctance force and Lorentz force. The former is resulted from a difference of permeabilities between two materials, while the latter is resulted from the movement of charges in a magnetic field. The classical active magnetic bearing and the permanent magnetic bearing both employ the use of the reluctance force in conjunction with ferromagnetic material.
All in all, magnetic bearing is also an important kind of bearing; thus, you should also pay attention to it to learn more about its functions and operations.