Housing designs

Cast iron take-up housings are used in the ball bearing unit series listed in table 1.

Cast iron take-up housings, available in the TU .. M and TUJ series, enable insert bearing units to be relubricated through a grease fitting. This makes them especially suitable for bearing arrangements that operate under any of the following conditions:

• high levels of contamination
• high speeds
• high temperatures
• relatively heavy loads

Composite take-up housings for the SKF Food Line are used in the ball bearing unit series listed in table 2. The units incorporate stainless steel insert bearings or insert bearings with zinc-coated rings, both types filled with a food-grade grease. The housings cannot be ordered as separate products.

The composite housings for the SKF Food Line are strong, yet lightweight and chemically resistant. Their hygienic design features make them particularly well-suited for following the highest food safety standards.

The housings remain highly stable dimensionally and maintain their expected physical properties, despite repeated operational and washdown cycles. Particularly in wet environments, the housings are more reliable compared to other materials.

The composite material is reinforced polypropylene, chosen for its dimensional stability and chemical resistance to detergents and contaminants (table 3). Importantly, polypropylene is hydrophobic, distinguishing it from conventional composite housing materials.

The housings feature 40% long glass fibre reinforcement, to reduce the tendency of the housings to creep under temperature and load.

The external surface finish is comparable to food industry requirements for the internal surface finish on hygenic tubing and piping.

To protect the bearing arrangement at the end of a shaft, and to avoid the possibility of an accident caused by an exposed shaft end, depending on their design take-up housings are able to accommodate one of the following end cover designs:

• TU .. M series
  → ECY end cover (fig. 3)
• WSTUC series
  → ECB end cover (fig. 4)

If not used with sealed units (designation suffix DFH), end covers are supplied as accessories and must be ordered separately. The designations together with the distance A₅ that the end cover protrudes from the housing (fig. 5, fig. 6) are listed in the product tables:

• Take-up housings for insert bearings
  
• Ball bearing take-up units

The complete assortment of end covers for insert bearing housings and units is listed in the product table.

ECY end covers are made of polypropylene (PP), have good resistance to most chemicals and can withstand operating temperatures up to 100 °C (210 °F). They are mounted by snapping them into the recess of the housing.

ECB end covers are made of thermoplastic polyurethane (TPU), have good resistance to most chemicals and can withstand operating temperatures up to 100 °C (210 °F). They are installed in the interlocking areas of the housing (→ End covers).

To protect the bearing arrangement from shaft-side contamination, composite take-up housings for the SKF Food Line can accommodate back seals. These back seals are only available with sealed units (designation suffix DFH), which already have an end cover (fig. 7).

fig. 3

fig. 4

fig. 5

fig. 6

fig. 7