The use of wheel bearing did not start today. They have been in existence for a long time. Their existence is almost as old as a wheel itself. A wheel bearing makes it possible for a wheel to rotate freely without the interference of friction. In this article, we will be looking at some of the parts that make up a wheel bearing. We will also be taking about the differences that exist between various bearing types.
Types of bearings
Ball bearings: They are round and metallic. They can be found in a wide range of applications such as bearing assemblies of a vehicle, electric motors, skateboards, and some household equipment. Ball bearings handle different load types (radial and thrust) because their shape permits them to spin in different angles. However, their contact area is very small and this means they are not suitable for heavy load applications.
Straight roller bearings: They are cylindrical in shape. They are also characterized by uniform diameter across the board. Unlike ball bearings, they are perfect for heavy-duty applications. This is because they allow the radial load to be spread across a wider contact point. However, they are not able to handle thrust load because of their shape. An example of where straight roller bearings are used is a gearbox since it has a tight space.
Tapered roller bearings: The shape of this bearing type is also cylindrical. However, its side is tapered. Tapered roller bearings are able to handle thrust loads, radial pressure, and hard shocks expertly. They are commonly found in the wheel bearing assembly in wheel hubs. It can be used as a single entity or in pairs, with each one facing opposite directions.
Some bearing assembly components
Race: It is a ring-like component made from metal. Races have inner and outer surfaces. It creates a surface for bearings to rotate against. If the bearing assembly is new, a race will likely include but you’d have to check to be sure. If it is absent, you will have to purchase it separately. Avoid the temptation of using an old race with a new bearing no matter how well it looks.
Bearing cage: This is a form of race that is characterized by perforations. It creates an inner surface for the bearing to rotate against. They are sold together with bearings since they are not separated from the assembly.
Bearing seal: It is usually round with an O-shape. It helps to protect the bearing assembly from moisture and grease. It can be bought separately in case it is not included in your new bearing assembly purchase. There are sometimes referred to as bearing retainers because of the role they play.
Bearing snap ring: It is metallic, rigid and circular in shape. It does the job of keeping the bearing assembly in position by clipping it. It can be removed or installed by making use of a snap ring removal tool.
Wheel hub: This is a piece of metal that an automobile is mounted upon. It is embedded in a wheel hub where it permits rotation without restriction around a spindle or an axle shaft. A wheel hub bearing assembly is one that mounts inside a wheel hub. The features of a wheel hub bearing assembly depend on individual manufacturers. Some are made with integral bearing assemblies and this means if a fault occurs, the entire wheel hub will have to be replaced.
Wheel hub/bearing O-rings: This is often found in older vehicles such as vans and 4×4’s. They provide a support and defense system against leaking grease from a wheel bearing assembly.
Bearing grease: This acts as a lubricant. It is synthetic or petroleum-based grease that helps to minimize frictional forces. It has a high viscosity and this allows it to remain thick and sticky even under high and extreme temperatures. This is a characteristic that distinguishes it from motor oil and gear oil. When working on a bearing, it is important to have clean grease on standby. If the grease has been left uncovered for some time, do not use it as it may have attracted dust and dirt. If you discover that the cover of the container that holds the grease has been compromised, do well to replace it.
Bearing grease packer: It has a center shaft and it is a perfectly shaped receptacle. It houses an O-shaped bearing assembly comfortably. When placed inside the packer, the bearing assembly stays on lubricating grease and as pressure is applied, it is immersed into the thick and viscous grease. After it is fully immersed, there would be no gap or opening between bearings, cage, and race. It is the most practicable way of ensuring most of the bearing areas are covered in grease. Applying another layer of grease on the bearing assembly after it is removed from a grease packer is a good practice.
Bearing dust cap: The job of the bearing dust cap is to prevent dirt from entering the bearing dust cap. It also ensures lubricating grease sinks into the bearing very well. Bearing dust caps are metallic and they can be pressed over the outer edge of a wheel hub bearing assembly.
A bearing does not work the same way in a front-, rear-, and all-wheel-drive system. Often times, the variation depends on which of the wheels are drive wheels. In a drive wheel, the bearing is referred to as an “axle bearing” whether front- or rear-. This is because of where the wheels are mounted which is usually the axle shaft.
If it is front- or rear non-driven axle, the bearing assembly will be referred to as “wheel bearing”. Usually, they are mounted between a simple spindle shaft and a wheel hub. Four axle bearings are used in an all-wheel-drive system.