Flange mounted bearings are used when a shaft axis is perpendicular to the
bearing mounting surface. Available in 2, 3, or 4-hole configurations, flange mounted bearings provide a method of accurate
mounting fits and load support. 2-bolt flanged bearings have a diamond shaped flange with 2 mounting holes. Most 3-bolt
flanged bearings have a circular mounting flange with three, equally spaced mounting holes. Other hole configurations,
such as an offset pattern, are also available. 4-bolt flanged bearings have a square or round mounting
flange with four mounting holes. Selection of the appropriate bearing can be accomplished with knowledge of the shaft
size and radial and thrust load requirements.
Bearing type choices for flange mounted bearings include ball bearing, needle roller bearing, plain
bearing, and roller bearing. In a roller bearing the rolling element is a ball. Ball bearings are used to provide
smooth, low friction motion in rotary applications. Construction consists of an inner and outer ring, balls, and usually
a cage or ball separator. In a needle roller bearing the rolling element is a needle roller. Needle roller bearings
are designed for radial load applications where a low profile is desired. Bushings / sleeve bearings, also called journal
or plain bearings, are used to constrain, guide, or reduce friction in rotary or linear applications. They work by means
of sliding action as opposed to the rolling action used by ball, roller and needle bearings. As in all bearings, proper
lubrication is required to reduce wear and friction. Terms such as fluid film, self-lubricated, hydrostatic, and hydrodynamic
are commonly designations for plain bearings. In a roller bearing the rolling element is a roller. Roller bearings
are used to provide smooth, low friction motion in rotary applications. Construction consists of an inner and outer
ring, rollers, and usually a cage or roller separator. The principal types of roller bearings are cylindrical, spherical,
and tapered. The most common type of flange mounted roller bearing is a spherical roller bearing, which is a self-aligning,
double row, combination radial and thrust bearing.
Important dimensions to consider for flange mounted bearings are shaft size and
overall height from the mounting surface. Shaft size specifies the maximum diameter of the shaft or the bore diameter
of the bearing. Overall height above mounting surface is important to take into consideration for low clearance applications.
Housing material choices for flange mounted bearings include pressed steel, stainless steel, cast iron, and plastic.
Bearing material choices include steel, stainless steel, sintered bronze, graphite or metal alloy, sintered iron, and plastic.
The choices for shaft securing method for flange mounted bearings include none, setscrew, and locking collar. Lubrication
choices include relubricatable and self-lubricating.
Pillow block bearings are mounted bearings that are used to provide load
support for a rotating shaft’s axis. Their mounting surface is on a line parallel to the axis of the shaft. Elongated
bolt holes in the base or feet of pillow block bearings permit adjustment and easy mounting. Product categories include plain
bearings, ball bearings, cylindrical-roller bearings, needle-roller bearings, tapered-rolling bearings, hydrodynamic bearings,
and more. With pillow block bearings, product selection is based on shaft size, radial and thrust load requirements, and dimensions
Shaft diameter, shaft height, and the distance between bolt holes are the main dimensions for pillow
block bearings. Shaft diameter must be matched with the appropriate bore dimensions of the bearing unit. Properly-sized pillow
block bearings easily slide onto the shaft and into position, ready to be secured by the locking device. Shaft height
or backing height is determined by measuring the distance from the base of a pillow block bearing to the center of the shaft. The
distance between bolt-hole centers is taken from the center of one elongated bolt-hole to the center of the housing’s