Spherical roller bearings
Characteristics of spherical roller bearings
The spherical roller bearing is a special design of rolling bearing, which has various advantages. For example, this type of bearing can support a combination of radial and axial loads (combined loads) and also has enormous load capacity. Furthermore, spherical roller bearings have a high load carrying capacity and can support shock-type loads. But the main advantage over other types of rolling bearings is that spherical roller bearings can compensate for static and dynamic misalignments up to a maximum misalignment of 2°. This property results from the spherically ground raceways, which allows the rows of rolling elements to oscillate about the axis of rotation. The advantages of a spherical roller bearing are basically offset by a few disadvantages. When using this type of bearing, it should be noted that it is rather unsuitable for high speed requirements. In addition, spherical roller bearings are only suitable to a limited extent for supporting purely axial loads.
The universality of the spherical roller bearing makes it one of the most widely used bearing designs of all. Spherical roller bearings combine unique design features that make them indispensable for many demanding bearing arrangements. Numerous variants of individual elements of the bearing give the spherical roller bearing additional application possibilities in special areas, such as in paper and printing machines or rail vehicles.
Structure of spherical roller bearings
Spherical roller bearings consist of two symmetrically arranged, barrel-shaped rows of rollers with a common spherical raceway in the outer ring and two grooves inclined to the bearing axis in the inner ring. Practically all spherical roller bearings are supplied with a cylindrical or tapered bore. In this case, the roller geometry is matched to the groove, which leads to a favourable load distribution over the entire roller length and prevents edge stresses and stress peaks at the roller ends. This raceway design enables balancing and misalignment of the shaft to be compensated. This makes spherical roller bearings ideal for applications with shock-like and dynamic loads that occur increasingly in the radial direction. Steel window cages are mainly used for spherical roller bearings, as they allow larger quantities of grease in the bearing interior than brass cages. Solid brass cages are the standard design only for larger bearings.
Lubrication of spherical roller bearings
In most cases, spherical roller bearings are lubricated by a centre groove and lubrication holes in the outer ring. This enables an even distribution of oil or grease in the roller rows. Especially when supporting shafts with a vertical axis, it is essential to ensure that the bearings are reliably supplied with lubricant. Oil lubrication is advantageous for such cases.
Certain bearing types are also available in sealed form. It should be noted that the permissible adjustment angle of sealed bearings is smaller than that of open bearings. The angular adjustability of sealed bearings is 0.5° from the centre position. Up to this value, the sealing function is not impaired in the event of misalignment. Sealed spherical roller bearings are maintenance-free for most applications. Whether a bearing needs to be relubricated during its service life depends on the specific operating conditions, such as temperatures. The respective sealing concepts depend on the size of the bearing.
Axial spherical roller bearings
Axial spherical roller bearings are single row, self-aligning bearings that can compensate for misalignments between the shaft and housing due to the hollow spherical contour of the shaft and housing locating washer and the asymmetrical barrel rollers. Spherical roller thrust bearings can support high to very high axial loads at relatively high speeds. In spherical roller thrust bearings, the loads are transmitted from one groove to the other at an angle to the bearing axis. Due to this characteristic, this type of bearing can support radial loads with simultaneously acting axial loads. Axial spherical roller bearings are characterised by extremely high robustness and are insensitive to high shock-type loads.
PACH Systems offers you a wide product range of different spherical roller bearings. For this purpose, we work together with our long-standing partners. Please let us know your requirements via our contact form. We will be happy to provide you with a non-binding offer or contact you to discuss the details.