Movement always involves friction, but bearings reduce that friction to essentially nothing, allowing for a wide range of movement. They are what make a washing machine’s spin possible, and a car’s drive wheels able to rotate. Without bearings, machinery fails. Knowing how to best apply the different types of bearings means the difference between easily repairable or replaced components and a costly breakdown.
The most common type of bearing is the ball bearing. These consist of steel balls contained in a ring which allows for rotational movement with low frictional contact. They are effective for use with high speeds and moderate loads. You can find ball bearings almost anywhere, from a skateboard to an electric motor. Ball bearings are easy and cheap to make and so are abundant in almost every product.
Roller bearings are similar to ball bearings in concept, but instead use cylindrical rollers to support a larger contact area, making them appropriate for applications requiring higher load capacities. However, they do so at the cost of supporting loads at lower speeds than ball bearings. Roller bearings are often used in conveyor systems, gearboxes, and heavy vehicles because the load is substantial and needs to be distributed evenly along the length of the roller as opposed to being concentrated at a point.
Next, tapered roller bearings can handle both radial and axial loads. For example, wheel hubs need to support weight from the car pressing down and also lateral forces from cornering and braking. For this reason, tapered bearings are usually a pair with one facing each direction.
One type of bearing useful in industrial settings is a split roller bearing. They are unique from other bearings because the outer housing and the rolling elements are manufactured separately and joined together. An application for bearings made this way is to facilitate the installation or removal of a bearing on a long shaft. In conjunction with that, it will allow the installation or removal of a bearing that was previously covered by a disassembled part of the machinery. Engineers use split roller bearings in large fans, pumps, and conveyor drives, since removing the part covering the bearing would otherwise mean unnecessary and prolonged machinery downtime.
The questions to consider when selecting a bearing are largely practical. How much weight will it need to support, in what direction will that load be acting, and how fast do you need it to rotate? What type of environment will it be operating in, considering the presence of dirt, moisture, and potentially extreme temperatures? Answering these questions correctly will prevent expensive and time-consuming premature failures and a resulting trip to your supplier. This is especially frustrating as a machine or vehicle sits idle while you wait for a replacement part.
Proper bearing selection is crucial, but so is maintenance. In most cases, bearing failures can be attributed to lack of lubrication, contamination, or insufficient maintenance, rather than normal bearing wear. Time and resources spent on a bearing’s maintenance, including seals and adequate lubrication and/or load, will increase the bearing’s useful lifespan. A simple visual inspection can identify issues that would otherwise lead to more costly repairs. Bearing wear is often noticeable not just through routine maintenance checks, but also by listening for unusual sounds and feeling for excessive heat or looseness.
If you ever have trouble identifying which bearing works best for your application, consulting a specialist supplier is always better than a guess. An inappropriate selection may mean that the bearing fails prematurely and takes other components along with it. The cost of a minor failure versus the expense of a breakdown, or even unanticipated repairs, should easily be recouped by a brief discussion with the salesperson or a phone call.
Bearings are boring, but without them, the rest of the machine won’t work. Whether it’s a small appliance or a large industrial drive, you need to consider the load, speed, and pressure on the bearing, and treat it accordingly for it to serve you well. Neglected bearings will lead to extra costs and a lot of difficulties that could have been avoided in the first place.