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Mounting and dismounting

Insert bearings and ball bearing units are reliable 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 methods and tools.

Failure to carefully follow applicable mounting instructions can result in premature bearing failure or improper performance. For detailed information, contact the SKF application engineering service.

The method used for mounting a ball bearing unit depends on:
  • the overall machine design
  • the insert bearing housing design
  • the method by which the unit is locked onto the shaft
Leave the insert bearing, housings for insert bearing or ball bearing units in their original packages until immediately prior to mounting so that they are not exposed to any contaminants.
Before mounting a ball bearing unit, check that the shaft and support surfaces or machine rails are clean and free of any burrs. Also be sure that the shaft seat is within tolerance (table 1) and that for the support surfaces the flatness is within the IT7 tolerance grade and the roughness Ra ≤ 12,5 µm or the machine rails have appropriate dimensions to fit into the housing piloting grooves.

Tools

To mount or dismount ball bearing units, the following tools are required:
  • a hexagonal key or torque key to tighten the grub (set) screws in the inner ring or the eccentric locking collar as specified in the product tables
  • a hook spanner with a stud to tighten or loosen the eccentric locking collar
  • a hook spanner to tighten adapter sleeve lock nuts as specified in the product table
  • a torque wrench or hexagonal key to tighten the attachment screws, bolts or nuts

Grub screws / adapter sleeve lock nuts should be tightened to the torque values / tightening angles listed in the product tables. The tightening angles, listed for bearings on an adapter sleeve, are to be used as guideline values only, as it is difficult to establish an exact starting position.

Hook spanners are part of the comprehensive SKF assortment of high quality mounting and maintenance products. For information about SKF maintenance products, refer to Maintenance products.

For additional information about mounting and dismounting insert bearing and assembling ball bearing units, refer to the SKF bearing maintenance handbook.

Attaching ball bearing units to the support base

To reduce vibration and enable heat to dissipate from the unit, the housing must be firmly attached to the support base. To attach ball bearing units to the support surface, SKF recommends using 8.8 class bolts or studs and a washer in accordance with ISO 7089:2000 or 7090:2000 and a spring washer. Hexagonal head bolts in accordance with ISO 4014:2011 are appropriate. Alternatively, hexagonal socket head cap screws in accordance with ISO 4762:2004 can be used (fig. 1)

Appropriate fastener sizes are listed in the product tables.

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