Design considerations

Free space on both sides of the bearing
To prevent interference between rotating bearing parts and stationary machine parts, free space (Ca) should be provided as indicated in fig. 1. The requisite width of the free space depends on:
  • the actual misalignment
  • lubricant space requirements
The requisite free space should be at least 20 times the minimum value of the radial internal clearance in the unmounted bearing:
Abutments for sealed bearings
The diameter of the shaft abutment should not exceed da max (→ product table), certainly for the 1 to 2 mm closest to the bearing, to prevent interference with the seal (fig. 2). If the bearings are to be located axially on the shaft by a lock nut, SKF recommends using a KMFE lock nut (fig. 3) or fitting a spacer ring (fig. 4) between the bearing and the lock washer to prevent interference with the seal.
Bearings on sleeves
Spherical roller bearings with a tapered bore can be mounted with:
  • an adapter sleeve on plain or stepped shafts (fig. 5 or fig. 6):
    • SKF adapter sleeves are supplied complete with a locking device.
    • Use appropriate SKF adapter sleeve assemblies for sealed bearings (fig. 7) to prevent the locking device interfering with the seal (→ product table). Alternatively, a spacer ring can be inserted between the bearing and the lock washer.
  • a withdrawal sleeve on stepped shafts (fig. 8)
For additional information about sleeves, refer to Bearing accessories.
Appropriate bearing housings
The combination of a spherical roller bearing, appropriate sleeve (where needed), and an appropriate SKF bearing housing provides a cost-effective, interchangeable and reliable solution that fulfils the demand for easy maintenance. The comprehensive assortment of SKF bearing housings is provided in the following tables:
  • split plummer (pillow) block housings (table 3)
  • non-split housings (table 4)
  • application-specific housings (table 5)
For additional information, refer to Bearing housings.
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