SNLN 30 plummer block housings

SNLN 30 plummer block housing
SNLN 30 plummer block housings are split housings designed for spherical roller bearings in the 230 series. They are intended for grease lubrication. They consist of a cap and base, with a eye-bolt in the cap and two cast holes for attachment bolts. They follow ISO 113. SNLN plummer block housings are dimensionally interchangeable with earlier SN 30 housings.

Features and benefits

SNLN 30 plummer block housings have the following features and benefits:

Stiff housing

Stiff housing
Fig. 1
The housing base is reinforced with ribs and has extra material surrounding the holes for attachment bolts (fig 1). The attachment bolts can be preloaded to locate the housing without deforming the housing base or bore.

Good heat dissipation

Good heat dissipation
Fig. 2
The centre cross reinforcement in the housing base (fig. 2) increase the contact area between the housing base and support surface, to improve the heat flow from the bearing outer ring to the support surface.

Grease guiding system

Grease guiding system
Fig. 3
For more efficient relubrication from the side, SNLN 30 housings have an integrated flange that guides the grease from the grease fitting directly into the bearing (fig 3). This feature is available for housings up to and including size 3038.

Caps and bases individually marked

Caps and bases individually matched
Fig. 4
The housing cap and base are matched during manufacturing and are not interchangeable with caps and bases of the housings. To prevent mismatches, a unique serial number is marked on both the housing cap and base (fig. 4).

Dimples to locate accessories

Dimples to locate accessories
Fig. 5
Dimples cast into the housing cap indicate where grease fittings and condition monitoring sensors can be mounted for maximum effectiveness (fig. 5).

Simple mounting

Simple mounting
Fig. 6
To simplify mounting and make alignment more accurate, lines indicating the centre of the bearing seat and the housing bore axis are cast into the housing base. Dimples indicate the position for dowel pins (fig. 6). Mounting instructions are supplied with each seal pack, except for housings from size 3024 to 3032, with seals in the 200 series, which has to be ordered separately. Housings from size 3028 are supplied with an eye-bolt on top for safe and easy handling.

Many sealing solutions

SNLN 30 plummer block housings are available with different standard sealing solutions
  • four-lip seals (TSN .. L)
  • V-ring seals (TSN .. A)
  • felt seals (tsn .. C)
  •  labyrinth seals (TSN .. S)
  • taconite heavy-duty seals (TSN .. ND) (TNF ..)

Four-lip seals

Four-lip seals
Fig. 7
Four-lip seals (fig 7) replace the former double-lip seals (TSN .. G). The seals provide a better sealing effect and reduce friction torque, while enabling increased circumferential speeds up to 13 m/s. Four-lip seals are horizontally split and simple to mount.

V-ring seals

V-ring seals
Fig. 8
V-ring seals (fig. 8) consist of a V-ring and a sheet steel sealing washer with a vulcanized rubber lip. V-ring seals can accommodate circumferential speeds up to 7 m/s. For higher speeds between 7-12 m/s the seals needs to be axially located on the shaft and for speeds above 12 m/s a support ring must be used to prevent the seal from lifting.

Felt seals

Felt seals
Fig. 9
Felt seals (fig. 9) are simple and effective. At circumferential speeds above 4 m/s, a small gap forms between the felt and shaft, transforming the contact seal into a non-contact, gap-type seal.

Labyrinth seals

Labyrinth seals
Fig. 10
For applications where there are high speeds or extreme temperatures, SKF recommends using labyrinth seals (fig. 10). The labyrinth rings form a multi-stage labyrinth seal with the seal grooves in the housing. A hollow, silicone rubber cord holes the labyrinth ring in place on the shaft.

Taconite heavy-duty seals

Taconite heavy-duty seals with radial labyrinth
Fig. 11
Taconite heavy-duty seals with axial labyrinth
Fig. 12
For bearing arrangements that must operate under highly contaminated conditions, such as those encountered in mining, taconite heavy-duty seals, which can be filled with grease, are recommended. Grease enhances the sealing effect and extends the service life of the seals. Taconite heavy-duty seals are labyrinth seals combined with a V-ring seal.
SNLN 30 housings from size 3023 to 3032 accommodate taconite seals with a radial labyrinth (TSN .. ND) (fig. 11). SNLN 30 housings from size 3034 to 3056 accommodate taconite seals with an axial labyrinth (TNF ..) (fig. 12). Both can be relubricated via a grease fitting in the main body of the seal.

Prepared for relubrication

Prepared for relubrication small housing
Fig. 13
Prepared for relubrication large housings
Fig. 14
SNLN 30 housings enable relubrication of the incorporated bearings and seals and have two drilled and tapped holes (fig 13 and 14) in the centre of the cap for relubrication via the outer ring (in W33 groove) and for relubricating from side (for CARB toroidal roller bearings).
For more information about SNLN 30 plummer block housings contact SKF application engineering service.
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