Types of Bearing

When considering bearings, the main factor to consider is the type of load required for the bearing to withstand, the two main types are radial and thrust.


For use in the turning mechanism of the crane, a large thrust load and very small radial load will be applied to the bearing.

Plain Bearing


This is the most simple type of bearing, which simply consists of two surfaces that move past each other with no other mechanism. Often one or both of the surfaces is coated in a non-stick layer as well as being lubricated to further reduce the friction. This type of bearing has a very high load carrying capacity but also creates a lot of friction. They have a fairly high radial and relatively low thrust capacity.


Ball Bearing


Ball bearings have both a high radial and thrust capacity, and are found in a large range of applications where the load is small. Any load applied is focused onto a very small area, which makes it run smoothly and quietly, however this creates high internal pressures which may deform the balls should the bearing be overloaded.


Roller Bearing


Roller bearings are similar to ball bearings in the way they are made, having the key difference that they contain cylindrical rollers instead of balls. The rollers distribute the internal forces over a larger area, which reduces the internal pressure, making the components less likely to deform and vastly increasing the radial load capacity. Although the radial load performance is increased, this type of bearing has a very low thrust load capacity comparatively.


Magnetic Bearing


Magnetic bearings are ideal for high speed applications as they support the load using magnetic levitation which has zero friction and requires no maintenance. These bearings require a constant power supply as well as a sensor circuit to keep the inner and outer rings at a constant distance. This means that often a set of backup bearings is required in the event that a power loss to the device occurs. They have a relatively low radial load and extremely low thrust load capacity, and are most suited to continuous low load applications such as power generation or machine tooling.


Ball/Roller Thrust Bearing


This type of bearing is similar to ball and roller bearings in the way which they work, however the layout of the components allows a far greater thrust load capacity. This type of bearing is well suited to high thrust load applications, where radial load requirements are low. Rollers have the benefit of increased total load capacity, while ball bearings are smoother and run a lot more quietly as a result of decreased friction.