Bearings
Roller bearings
What are roller bearings?
Roller bearings, which are closely related to ball bearings, have the main function of carrying loads with as little friction as possible. Although both types of bearings aim to reduce resistance while moving machine parts, roller bearings are distinguished by their unique form of construction. Instead of round balls that ball bearings use, roller bearings are fitted with cylindrical rollers.
Roller bearings are equipped with single or double rows of rollers, with the double rows offering especially significant increases in radial load carrying capacity. The diversity in shapes and sizes of these bearings allows them to effectively facilitate the transfer of both radial and axial loads, resulting in reduced friction during operations.
What are the characteristics of a roller bearing?
Roller bearings normally consist of an inner and outer ring. The rolling elements (rolling bodies) are located between these rings. Common roll elements are cylinders, barrels, cones, diablos and needles. To ensure that the roller elements are evenly distributed and do not touch each other, they are placed in a cage. With removable bearings, the cage also ensures that the roller elements do not fall out of the bearing.
Why use roller bearings?
Roller bearings are an essential choice for many industrial applications, primarily because of their ability to reduce friction.
This results in several operational benefits:
- Cost savings: The use of roller bearings significantly reduces maintenance and service costs.
- Ease of use: The removable design of roller bearings simplifies assembly and disassembly, saving users time and increasing efficiency.
- Flexibility of use: Roller bearings ease the change of direction of movement without the need for technical modifications.
- Axial movement: They allow axial movement, offering additional versatility in various applications.
Bearing load
The radial and axial loads are important loads in roller bearings. When a force acts perpendicular to an axis, we speak of a radial load. When a force acts in the longitudinal direction of the shaft, we speak of an axial load.
The bearing loads are divided into three categories:
- Low bearing load;
- Medium bearing load;
- Heavy bearing load.
Lifespan
Roller bearings are provided with a line contact. As a result, they will eventually succumb to exhaustion. Standard formulas are available to calculate the life of a roller bearing. However, the environment in which a roller bearing is located can also play a major role in its service life.
More than 90% of the roller bearings are lubricated with grease or liquid lubrication is applied. In some cases, mist lubrication is also used with low-load bearings.
The lubrication film thickness must have a minimum value in order to achieve the usual service life of the rolling element bearing. However, because these are precision materials, the lubricating film thickness can remain extremely thin. In many cases less than 1/50th of a human hair.
Water and moisture have an adverse effect on the life of a roller bearing. In the event of premature failure of a bearing, corrosion caused by water is the cause. Water resistance and corrosion protection are therefore an important part of many lubricating grease specifications.
Dirt, no matter how small the particles, can also significantly shorten the life of a rolling bearing. A rolling bearing often comes into contact with dirt particles because the lubricant was not clean. Lubricating with grease should therefore always be done with a new and clean lubricant.
Tapered roller bearings
Tapered roller bearings differ from other types of rolling bearings in that they can withstand high radial and high one-sided axial loads. The cup, cone and rollers of tapered roller bearings have a conical surface. Its cone faces convert to one point on the centerline of the bearing.
The tapered roller bearings are suitable for applications with a high load or impact load. These bearings are available in metric series and inch sizes. The metric series are suitable for a bore diameter of 15mm – 200mm. The inch series are suitable for a bore diameter of 15,875mm – 200,000mm.
Tapered roller bearings can take combined load in one direction. Since an axial force is generated under radial load, two bearings in X arrangement, or two or more paired bearings are used.
There are standard, medium and highly conical types. These are distinguished by the contact angle. Medium-conical and metric series are indicated by the additional code 'C'. This code is stated as a suffix after the bearing number.
Tapered roller bearings whose width, smallest inner diameter and cup contact angle are designed in accordance with ISO 355 are identified by the additional code 'J'. The cones and cups of these tapered roller bearings are interchangeable with other brands when the numbers of these bearings are the same.
When the code 'J' is mentioned as a prefix, the tapered roller bearing is not designed according to ISO 355, but is produced according to special tolerances.
Product Range
The range of rolling bearings that Neita supplies consists of the following categories:
- 1-row cylindrical roller bearings
- 2-row cylindrical roller bearings
- Multi-row Cylindrical Roller Bearings
- 2-row spherical roller bearings
- 1-row tapered roller bearings
- 2-row tapered roller bearings
- Multi-row tapered roller bearings
- Cup for 1-row tapered roller bearings
- Cone for 1-row tapered roller bearings
