The NPB bearing unit is a combination of a radial ball bearing, seal, and a housing of high-grade cast iron or pressed steel, which comes in various shapes. The outer surface of the bearing and the internal surface of the housing are spherical, so that the unit is self-aligning. The inside construction of the ball bearing for the unit is such that steel balls and retainers of the same type as in series 62 and 63 of the deep groove ball bearing are used. A duplex seal consisting of a combination of an oil-proof synthetic rubber seal and a flinger is provided on both sides. For the application with serious contamination, bearings with triple seal also can be supplied.
Pillow blocks with bearings mounted in rigid housings of simple construction are the most common bearing units. They are extensively used for various kinds of transmission equipment and machinery.
Square Flanged Units
These bearing housings have square flange which can be
easily attached to a machine with four bolts.
With its simple mounting face, this bearing unit is widely used.
Oval Flanged Units
These bearing housings have oval flanges which can be
easily installed onto a machine with two bolts.
This type of bearing unit is suitable where mounting space is limited or where it is necessary to minimize the distance between shafts. The distance between bolt holes of an oval flange type is generally equal to the distance between bolt holes diagonal position of square flange type.