drylin® R - Design information

floating bearing for shaft guide

drylin®® series 03 linear plain bearings offer major advantages in applications with parallel shafts. Due to their geometry, they compensate for misalignment and parallelism errors and should be used on the shaft further away from the drive.

The design provides a crowned area on the outer jacket of the aluminium bearings for self-alignment. This prevents a reduction in the load rating due to self-adjustment, as the shaft always rests on the entire projected surface. The even distribution of the load over the entire bearing means that edge pressure does not occur with the self-aligning drylin®® linear bearings. To compensate for deviations in the parallelism of two shafts, the outer diameter is 0.2 to 0.3 mm (depending on size) smaller than the housing bore. These bearings have an elastic bearing seat due to the fitted O-rings. The oversize specifies the maximum permissible deviation in parallelism.

The self-aligning bearings from the drylin®® range are supplied hard-anodised. This surface guarantees the highest wear resistance when the aluminium bearing moves in the housing during balancing movements.

The housing bearings of the OJUM06 LL and RJUM-06 LL series are another variant. The bearing design allows parallelism compensation between the shafts of ±3 mm. The unique suspension of the supporting housing on an axis running in the z-direction enables angular misalignment compensation of up to 3.5°.

Compensation for misalignments

Series	Equalisation
RJUM-03/OJUM-03 series	+/- 0,5°
RJUM-06 LL / OJUM-06 LL series	+/- 3,5°

Compensation of parallelism errors

Series	Equalisation
RJUM-03/OJUM-03 series	+/- 0.1 mm
RJUM-06 LL / OJUM-06 LL series	+/- 3 mm

Eccentric forces

A few recommendations must be observed for the successful use of maintenance-free drylin® linear bearings: If the distance between the driving force and the fixed bearing is more than twice the bearing distance (2:1 rule), a static friction coefficient of 0.25 theoretically leads to jamming of the guidance.

The principle is not dependent on the load or the drive force. It is a product of friction and always relates to the locating bearing. The further away the drive is from the guide bearing, the greater the wear and the drive force required.

If the 2:1 rule is not observed when using linear plain bearings, the result is uneven movement or even blocking of the system. This can often be remedied with relatively simple modifications.

If you have any questions about the design and/or installation, please contact our application consultants.

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