Housing Materials

Cast Iron Housings

Malleable cast iron housing are another one-piece designed housing, but they are less rigid and therefore less susceptible to fracture than gray iron housings. They are more suitable for applications where shock loads are present.

Pressed Steel Housing

Pressed steel housings are, as their name implies, pressed, or stamped, of plain carbon steel and are much less rigid than either of the cast iron versions previously described. They are generally used for light duty applications.

These units are designed as two-piece housings; the insert bearing is cradled between the two housing sections and the assembled unit is held in place with the bolts that attach it to the application. Although these units do not have the machined bases of the other units, they do provide a relatively stable foundation for the insert bearing while providing the lightest, most economical housing possible.

Some applications using pressed steel housings additionally require a rubber grommet (tire) around the insert bearing’s O.D. This tire serves to dampen noise and is designated by an R. Examples include the RPF and RPP pressed housings.

Cast stainless steel housings are another option and are intended as an additional measure of protection—specifically anticorrosion— against exposure to liquids and other contaminants. They’re most often used in applications in the food and beverage industries where equipment must be kept hygienically clean and is washed down frequently. Ordinary housings when subjected to repeated washing would corrode, but the stainless steel housings resist corrosion from moisture and are often referred to as "wash down units."

Molded plastic housings, a more competitively priced alternative to the stainless steel housings, are another option for moist environments. Manufactured of a glass-filled polyester engineering plastic, these housings not only resist corrosion but offer better water resistance.

Both stainless steel and plastic housed units typically feature insert bearings also made of stainless steel for optimum corrosion resistance. Additional information on these units and on the other housing types offered by NTN is available. Contact your NTN representative for the appropriate catalog.