Linear Bearing Guide
What is a linear bearing?
A linear bearing is the bearing that is linear in the outer shape, which helps reduce friction produced when the drive mechanism is operated and work in axial directions. Depending on the requirements of different applications, the linear bearings are made as different compositions with varied materials.
A bearing is an element that is wrapped in between two moving parts of a drive mechanism, which moves relative to the motion of the moving parts in order to prevent the two parts from producing too much friction that may lead to overheating. It works by reducing the contacting surfaces as when the two parts directly contact each other.
Why are linear bearings important?
The reason why the bearings are important for the drive mechanisms is to reduce friction. Friction is made when two parts come in contact and move relatively to each other. During this process, not only friction but also heat would be produced between the two parts. If these occurrences are not well-controlled, it may result in the malfunctioning of the mechanism or dangers that are caused by the heat on the working sites.
Although there is coolant that can be provided for the lubrication of the working sites, the adoption of the bearings can help achieve the best efficiency of the works. Besides, the linear bearings cover the different types of bearings at a wide range, as they serve for the most basic linear motion of the compatible applications, which makes them be commonly utilized for a variety of applications, such as the automatic control machine robots, medical equipment, and machine tools, etc.
What are linear bearings made of?
A linear bearing can be made of materials like hardened steel, plastic, or ceramic, which own different properties or features respectively that make them suitable for different applications.
● Hardened steel bearings
Linear bearings that are made of hardened steel provide optimal stiffness and rigidity, and their high load capacity allows them to be stable even when they are withstanding heavy loads from their applications. It is the stability and the longer lifespan that this type of material that makes these bearings more suitable for being used in hardened axles.
● Plastic bearings
Most of the linear bearings as the hardened steel bearings have the rolling elements inside the bearings, while the plastic bearings, which are made of plastic materials, do not include these rolling elements. In other words, these plastic bearings can be free from the contamination of dirt or debris, etc. In addition, compared to other materials, plastics are relatively cheaper choices.
● Ceramic bearings
This type of bearings is made of ceramic material, which is known for providing quiet and smooth operation for compatible applications. However, unlike the ones that contain rolling elements, these bearings may not have room for lubrication, which is often a primary concern when choosing this type of linear bearings.
Different types of linear bearing
Considering the configuration of the bearing, the linear bearings may come in either open or closed form. The open form offers an opening and is adopted when the additional supports for its compatible applications are required. As for the closed form, which doesn’t have openings, is another type that is more commonly seen on the configuration of bearings.
In addition to the different materials that make up the linear bearings and whether they have openings or not, depending on the variation in construction, they can be differentiated into rolling linear bearings and plain linear bearings.
● Rolling linear bearings
The rolling linear bearings are the bearings that contain the rolling elements like balls and rollers, which are arranged in rows and roll inside the bearings when they are in operation. These two formations are called the linear ball bearings and the linear roller bearings.
The difference between the balls and the rollers is the shapes them. Despite the same arrangement of them, the former is the ball-shape elements, and the latter are crisscrossed, in order to provide more load capacity than the balls with stability control. Whether the balls or the rollers, they are both stored in the cages and covered by two layers of rings around the bearing. One is the inner ring and the other is the outer ring, and the two layers make races, where the balls and rollers travel through.
● Plain linear bearings
Another type of linear bearings is the plain form. When there are balls or rollers in the bearings, there is room for the lubrication to be fed into when the bearings are in operation. In contrast, the plain bearings do not own this characteristic. In addition, they are less rigid than the type with rolling elements but perform better in resisting the circumstances with a wider range of temperatures.
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