Bearings are mechanical components designed to guide a rotating assembly. They are found in everything from dental tools to roller blades and can seem relatively simple to understand. Finding the right replacements for broken or worn bearings can be a challenge, but less so if you keep in mind your needs for rotation speed as well as what kinds of axial and radial loads they will be subjected to.
Some bearings are designed for higher rotation speeds than others. For instance, Myonic bearings are designed to withstand the high rotation speed of dental equipment, while cylindrical bearings are used in skateboard wheels because they can handle heaver loads at lower speeds.
Axial load is parallel to the axis of rotation. For instance, the bearings helping your chair turn face axial load because the weight of the seat and occupant is directed vertically downwards, and the axis of the bearings also runs in this direction. Many loads that bearings face will be both axial and radial, so both are usually listed in the specifications of the items.
Radial load is perpendicular to the axis and is found in wheels of all types. To continue the above example, the bearings in the wheels of your chair face radial load because they are mounted perpendicular to the to direction the weight of the chair and occupant is directed towards. Since many applications of bearings need to factor both axial and radial load as well as rotation speed, it is a good idea to compare the specifications of the bearings you are replacing with the ones you are looking at to get the right type.
Although there are bearings in most things that move, there are also many different types designed for specific applications. To choose the right one for your needs, it is a good idea to check out the specifications for the ones you already have and check them against the ones you are considering. Keeping in mind rotation speed, axial load and radial load can help you narrow down your choices.