In brief
A spherical roller bearing is a double-row, self-aligning rolling bearing with barrel-shaped rollers for very high loads and shaft misalignment.
Contents
What is Spherical roller bearing?
Spherical roller bearings have two rows of barrel-shaped rollers that roll on a common sphered raceway in the outer ring. This allows the inner ring to tilt relative to the outer ring. The bearing thus compensates for misalignment and shaft deflection without creating additional edge stresses. At the same time, it carries very high radial loads and axial forces in both directions.
Versions with a cylindrical and with a tapered bore are available. Bearings with a tapered bore are mounted on a tapered seat or, using an adapter or withdrawal sleeve, on a cylindrical shaft; the bearing clearance is deliberately reduced as the bearing is driven up. Key ratings are dimension series, bore type, clearance, cage design and, where applicable, a lubrication groove with holes in the outer ring. Sealed variants are also available. For housed bearing arrangements, spherical roller bearings are frequently installed in plummer block or flanged housings with their own seals.
Typical applications are vibrating screens, crushers, fans, conveyor systems, paper machines, continuous casting plants and large gearboxes. Causes of failure are mainly lack of lubricant, contamination, insufficient residual clearance after mounting and false brinelling caused by vibration at standstill. Vibration monitoring often detects damage early.
In practice: maintenance and procurement
For bearings with a tapered bore, the matching adapter or withdrawal sleeve together with nut and locking device belongs in the enquiry. Clearance class, cage type and any special versions, for example for vibratory applications, must also be stated.
Synonyms and abbreviations: SRB · self-aligning roller bearing · spherical roller radial bearing · barrel roller bearing
Frequently asked questions
What is the difference between a spherical roller bearing and a barrel roller bearing?
Strictly speaking, a barrel roller bearing is a single-row bearing with barrel-shaped rollers that mainly carries radial loads. The spherical roller bearing is double-row and additionally carries considerable axial forces in both directions. In everyday usage the two terms are sometimes used interchangeably, but for a replacement the exact design must be correct.
What does the K in the designation of a spherical roller bearing mean?
The suffix K usually stands for a tapered bore. Such bearings are mounted on the shaft with an adapter sleeve or withdrawal sleeve, or directly on a tapered seat. A bearing with K cannot be replaced by one with a cylindrical bore without changing the fastening. The taper must match the existing sleeve.
What information is needed to replace a spherical roller bearing?
Important are the full designation with dimension series and bore code, the bore type, the clearance, the cage and any suffixes for a lubrication groove or suitability for vibration. For sleeve mounting, the sleeve, nut and lock washer are included. For housed bearings, the housing designation is also helpful.
How is a spherical roller bearing mounted with an adapter sleeve?
The bearing is placed on the shaft with the sleeve and driven up using the nut until the specified clearance reduction is reached. The residual clearance is measured with a feeler gauge or via the axial drive-up distance. Driving it up too far removes the operating clearance, while too little allows the inner ring to creep. The target values are provided by the bearing manufacturer.