Pillow Block Linear Bearings

Pillow Block Linear Bearings

Pillow block linear bearings always have holes for bolts or fasteners; the holes are often elongated for adjustment. Pedestal pillow block bearings are taller, with the center hole further away from the bolts and therefore the mounting surface. The area surrounding the holes is strengthened to minimize the risk of cracking or warping due to over-tightening. Pillow block linear bearings are available in a variety of sizes depending on the diameter of the hole, or bore, and range from a few millimeters to around 5 centimeters. These mounted bearings are used extensively in conveyor systems for the automotive and manufacturing industries as well as on automatic or robotic assembly lines, for die cutting tools, molds, punches and more.

Pillow block linear bearings can be mounted vertically on the wall or horizontally on the ceiling or floor. Some bearings are thicker and wider than others in anticipations of their applications. Though not motorized, pillow block bearings must be able to support heavy load capacities, and the size of the bore and the diameter of the shaft should be carefully matched to ensure the easiest and best fit. If the shaft is too wide, the increased surface area contact will cause more friction and the bearing will require heavy lubrication. Should the shaft be much smaller in diameter than the hole in the bearing, it will not slide through evenly and will add tension on the bearing and casing, causing wear and fatigue. Some styles enable both linear and rotary motion. For pillow block bearings that allow a rotating shaft to pass through, the bearing contains rolling elements called ball bearings that rotate and travel in tracks, called races or raceways. The raceways are often oval in shape and the rolling elements are enough exposed to facilitate free motion of the shaft with low friction. For these bearings, a shaft can move in a straight line—linearly—while also rotating on its radial axis. Depending on the application, the cylindrical holes in pillow block linear bearings can be completely closed or partially open to accommodate a shaft with an attached carriage or load.