How does flange mount bearing help securely position

Standard housings include both cast iron and thermoplastic materials and come with built-in grease nibs. On external housings, flanges are used with bearings to help securely position them for reliable operation. Though problems can arise when high speeds or heavy loads create shaft flex, vibrations or axial load. Bearings that are mounted within a flanged housing are used when the bearing mounting surface is perpendicular to a shaft axis. They are commonly available in two, three, or four-hole configurations.  Four-bolt flanged ball bearing units have a square shape with 4 holes for mounting to accomodate higher loads than two-bolt flanges. 3-bolt flanged bearing units and 4-bolt flanged bearing units can be moved and aligned to accomodate long shafts better.