Machine concepts with long distances between the bearing positions, such as tube dryers, plastic or paper calenders are, beside
the huge shaft deflection also exposed to a process-induced high thermal expansion of several millimeters. KRW developed the ACB series for these applications.


KRW ACB Self-Aligning Cylindrical Roller Bearings

ACB bearings are double row, full complement cylindrical roller bearings. They are available as fixed and floating bearings with cylindrical or conical bore. All versions are fitted on both sides with non-contact seals and thus provide reliable protection against contamination and leakage of the grease.

All ACB series bearings have a self-retaining design. If treated carefully and impacts are avoided, inner and outer ring can be handled and fitted separately.


KRW Self-Alingning Cylindrical Roller Bearings "ACB" are ideal for compensating angular misalingments of up to 2°. At the same time, the units sealed on both sides, in contrast to designs with spherical roller bearings, ensure that the shaft in the bearing has almost no linear expansion.



Bearing Design

KRW ACB Self-Aligning Cylindrical Roller Bearings fixed bearing

Fixed bearing ACB 05 (E-performance-enhanced version):


sealed, aligning cylindrical roller bearing with cylindrical bore

KRW ACB Self-Aligning Cylindrical Roller Bearings floating bearing

Floating bearing ACB 06 (E-performance-enhanced version):


sealed, aligning cylindrical roller bearing with cylindrical bore

KRW ACB Self-Aligning Cylindrical Roller Bearings floating bearing

Fixed bearing ACB 07:


sealed, aligning cylindrical roller bearing with conical bore 1:12

KRW ACB Self-Aligning Cylindrical Roller Bearings fixed bearing

Floating bearing ACB 08:


sealed, aligning cylindrical roller bearing with conical bore 1:12

The locating bearing unit 05 has two self-centering loose ribs; the tapered version 07 has a rigid rib and a self-centering loose rib. The axial forces that can be absorbed correspond to those of conventional cylindrical roller bearings. In the event of static dimensioning the limiting factor could be the ability of the housing to accommodate thrust loads. In this case, please contact KRW application technology department.


The floating bearing units 06 and 08 have two external retaining rings which keep the inner ring from sliding away accidentally. The locating bearing units 05 and 07 are not secured in this way.

Bearing Clearance and Tolerances

In the standard version, all bearings are supplied with internal clearance CN and in the tolerance class PN. Non-standard versions can be defined while using the following suffix table.

General Suffix List

Admissable Operating Temperatures

The admissible operating temperature of a bearing is limited by cage material, dimensional stability of the bearing components (ball race and rolling elements), as well as lubrication. By default, KRW bearings are stabilised up to 200°C (S1). KRW provides roller bearings for higher operating temperatures on request.


Plummer Block Housings

All bearings in the ACB series 05 to 08 have a spherical outer ring, which ensures angular alignment in conjunction with the KRW SLG01 series plummer block housing. As an alternative, it is also possible to develop a customized bearing seat suitable for integration into your own design.


The matching series SLG01 plummer block housings for KRW self-aligning ACB bearings consist of two parts and ensure an uncomplicated fitting and dismantling of the bearing. The upper and lower parts of the housing are pinned and bolted together.The standard KRW SLG01 housings are made of EN GJL-200 (GG20) cast iron. For special requirements, other materials can be requested.

All fitting plummer block housings can be found in our brochure "Self-Aligning Cylindrical Roller Bearings".


Fitting, Dismantling and Lubrication

As with all roller bearings, when fitting and dismantling ACB series bearings it is important to make sure that forces are not exerted on the rolling elements or flanges. The retaining ring of the floating bearing can remain in the bearing during operation. However, it is important to ensure that the floating bearing is positioned in that way that no contact between the flange and the retaining rings can occur during the maximum axial displacement of the shaft.

When fitting the bearing series 07 and 08 with tapered bore on the matching adapter sleeves from KRW product line, bear in mind that, due to the reduction in clearance, a higher clearance class must be chosen. Position the bearing in the housing in that way that the lubrication hole in the housing coincides with a lubrication hole in the outer ring of the bearing. Otherwise, it could lead to excessive pressure during lubrication.

In conventional applications, the bearings are completely filled with grease in order to ensure an optimal sealing effect. At speeds greater than 25 rpm, the amount of grease should be gradually reduced depending on the bearing size. Please contact us regarding the required amount of grease. On deli-very KRW series ACB bearings are preserved and ungreased.



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KRW ACB Self-Aligning Cylindrical Roller Bearings
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