Axial-radial cylindrical roller bearings are precision machine elements that can provide long service life, provided they are mounted and maintained properly. Proper mounting requires experience, accuracy, a clean work environment and the appropriate tools.
Mounting instructionsFor general information about mounting bearings, refer to Mounting and dismounting.
When mounting axial-radial cylindrical roller bearings the inner ring can be unsupported (fig. 1) or supported (fig. 2). When a support ring is used, it should support the inner ring over its entire width. The support ring should be approximately twice the thickness of the flange.
CAUTION:To reduce the risk of damaging the bearing, do not apply any force through the rolling elements. Force should only be applied directly through the ring that is being mounted.
- Coat all mating surfaces on the shaft and inner ring with a thin layer of light oil.
- Loosen the retaining bolts (used to secure the bearing during transportation) ½ a turn.
- Mount the bearing onto the shaft, loose flange first, aligning the attachment bolt holes in the bearing with the tapped holes in the shaft. To facilitate this process, an induction heater can be used and/or a guide stud can be inserted into one of the attachment bolt holes in the shaft. SKF does not recommend heating axial-radial cylindrical roller bearings above 80 °C (175 °F).
- Once the bearing (and support ring where applicable) is in position against the shaft abutment and the assembly is at ambient temperature, insert the attachment bolts and tighten them “finger tight” while rotating the outer ring. This procedure helps to settle the rollers and centre the inner ring assembly.
- With the inner ring centred, gradually tighten each attachment bolt in a criss-cross pattern in three stages (fig. 3), tightening the bolts to 35%, then 70% and then 100% of the recommended torque values listed in the product table.
- After the bearing is fitted, the retaining bolts must not be left loose. Either retighten them to the recommended torque values or remove them completely.
- A similar procedure can be applied for fitting the outer ring. Coat all mating surfaces in the housing and on the outer ring with a thin layer of light oil.
- Mount the bearing/shaft assembly into the housing (fig. 4).
- Insert and tighten the attachment bolts “finger tight” while rotating the bearing/shaft assembly. Tighten each attachment bolt in a criss-cross pattern in three stages (fig. 5), as described in step 5.
Checking running accuracy and friction
Once mounting is complete, the running accuracy and friction need to be checked. In cases where friction is particularly high, there are three potential explanations:
- The mating parts are not machined according to specification.
- The attachment bolts are over-tightened.
- There is too much grease in the bearing.
To eliminate possible stresses that may have occurred during mounting, loosen all attachment bolts and retighten them in a criss-cross pattern using the three stage process described above.