Bearing Units with Dust Covers

Pressed Steel Dust Cover

For protection beyond that provided by the insert bearing’s seals and housing, mounted unit bearings may be fitted with special dust covers. This configuration consists of a bearing unit with external covers which provide extra protection in heavily contaminated operating environments, such as in flour mills, steel mills, foundries, galvanizing plants, chemical plants, and as well in construction and transportation applications. What these applications have in common is that they involve excessive dust, and/or splashes of liquids.

Pressed Steel and Cast Iron Dust Covers

NTN supplies both cast iron and pressed steel dust covers. Pressed steel dust covers are attached to specially designed housings; the outside surface of these housings are machined with a circular groove. The covers snap into the groove and are then ready to provide additional protection in heavily contaminated areas.

Generally, cast iron covers are more rigid and are less likely to be damaged by larger objects, such as rocks, coal and other aggregate materials. Three bolts secure these covers to a specially designed housing; the housings feature three threaded holes.

Each dust cover is fitted with a seal which has two lips that ride on the shaft. The space between the lips is filled with grease. This grease pocket forms an effective seal and provides good lubrication (cooling) to the contacting lips. Generally, cast iron covers provide better seal lip alignment and the most effective seal.

Cast iron covers are designated by attaching prefix C (open end) or CM (closed end) and pressed steel covers by attaching prefix S (open end) and SM (closed end) to the standard mounted unit part number. Examples of complete part numbers are:

Complete units with dust covers

• C-UCP205-100D1 — a 1" pillow block unit with an open end, cast iron cover
• CM-UCP204-100D1 — a 1" pillow block unit with a closed end, cast iron cover
• S-UCP204-100D1 — a 1" pillow block unit with an open end, pressed steel cover
• SM-UCP204-100D1 — a 1" pillow block unit with a closed end, pressed steel cover

Replacement dust covers

• CM-205-100 — a closed end, cast iron cover for a 205 size bearing with 1" shaft
• S-206-104 — an open end pressed steel cover for a 206 size bearing with 1 1/4" shaft

Note: you must specify the bore size (-100) to ensure the seals properly contact the shaft.

Replacement housings

• C-P205 pillow block housing with three drilled holes to accept a cast iron housing (205 insert series)
• S-P205 pillow block housing with a circular groove to accept a pressed steel cover (205 insert series)