Sealing solutions

SONL housings are equipped with non-contact labyrinth seals (fig. 1). These seals retain the lubricating oil and prevent contaminants from entering the housing. The oil retaining effect is enhanced by oil traps that return oil that has passed through the labyrinth back to the oil reservoir. Table 1 provides an overview of the seal characteristics and suitability. This information should be used as a guideline and does not substitute for testing the seal in its application.
A labyrinth seal consists of a shaft sleeve and a labyrinth ring, to form a multi-stage labyrinth. The sleeve has a clearance fit on the shaft while the labyrinth ring is stationary and mounted in the housing with an O-ring. To guide the oil pick-up ring, one shaft sleeve is provided with a groove.

The shaft sleeve can be locked onto the shaft in different ways:

  • Shaft sleeves for bearings on an adapter sleeve (TSO 5..) are locked by grub screws in the shaft sleeve.
  • Shaft sleeves for bearings on a cylindrical seat (TSO 2..) must be locked by an adapter ring, end plate or similar component (not supplied by SKF) on the shaft. Details for locking are shown in the product table.

Seal kits

The seals for SONL housings are supplied as kits and must be ordered separately.
Seal kits for housings for a through shaft, designation TSO (fig. 2), include:
  • 2 labyrinth rings with O-rings
  • 2 shaft sleeves, one of them for the oil pick-up ring
  • 1 oil pick-up ring
  • 1 oil level gauge
  • 1 magnetic plug
  • mounting instructions
Seal kits for housings for a shaft end, designation TSO .. A (fig. 3), include:
  • 1 labyrinth ring with O-ring
  • 1 shaft sleeve
  • 1 end cover with O-rings
  • 1 oil pick-up ring
  • 1 oil level gauge
  • 1 magnetic plug
  • mounting instructions
Both the oil level gauge and the oil pick-up ring can be supplied separately.
For bearings mounted on a cylindrical seat on plain shafts, a kit with the designation TSO 2../VZ643 must be used. The seal kit includes two shaft sleeves with the same bore diameter.

End covers

Housings at the end of a shaft should have an end cover that fits into the seal groove in the housing (fig. 4).
End covers, which are made of grey cast iron, are installed with two O-rings that hold the cover in place.
Details of the permissible length of the shaft end are listed in the product tables for bearings on an adapter sleeve and for bearings on a cylindrical seat.
End covers are supplied as a part of the TSO .. A seal kit, but can also be ordered separately.

High-temperature seals

SKF can supply sealing solutions for high operating temperatures. For additional information, contact the SKF application engineering service.
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