How to Install a Pillow Block Bearing
What is a Pillow Block Bearing?
A Pillow Block Bearing is a mounted anti-friction bearing that is contained within a solid cast iron, ductile iron or cast steel housing unit. Also referred to as a housed bearing unit, meaning they are self-contained, greased, sealed and ready for installation on the equipment. Pillow Block bearings are typically bolted to a surface, so that the attached shaft runs parallel with the surface. There are two types of housings used for pillow block bearings, solid and split housings. Solid housed bearings are single-piece housings, while split housed bearings are two-piece housings. Pillow block bearings can contain several types of bearings, including ball, roller and tapered. Shaft attachment devices can be set screw, eccentric lock, single or double set collar, concentric lock or tapered adapter. Each device has their own positive and negatives. Seals vary as well, including clearance seals, light contact, heavy contact and auxiliary type seals. Pillow Block Bearings, in most cases, also come in a fixed or expansion version. The expansion bearings allow for shaft growth and can reduce the risk of loading one bearing against the other. Choosing the best shaft mount device and seal will prolong bearing life. When installed properly, pillow block bearings can last years without needing to be replaced. Follow these steps to ensure minimal downtime and a longer service life.
*This procedure is for the most common shaft locking device set screw or set collar, utilizing a fixed and expansion unit, but the general guidelines apply to all bearing installs.
1) Check and Clean the Shaft
First, check your shafting to ensure it is clean, round, straight, free of burrs and nicks and is not undersized or oversized, per the manufacturers specification. Use fine sandpaper or scotch bright to clean the shaft of any rust. Then use a light coat of oil to remove any debris.
2) Position the Bearings on the Shaft
When placing the bearing on the shaft, if it is necessary to tap the bearing into place, use a mallet and a hardwood block or soft steel tube against the inner ring. DO NOT strike or exert pressure on the housing or seals.
3) Lightly Bolt the Housing to the Mounting Structure
Locate the shaft in position by lightly bolting the housing to the mounting structure. Bridge over the housing mounting bolt slots with heavy washers, or heavy spring lock washers. This may help prevent loosening.
4) Establish the Final Mounting Position
Prior to securing the bolts, establish your final mounting position by aligning the bearing units by hand or a rubber mallet.
5) Securely Bolt the Housing to the Mounting Structure
Once the bearing is properly aligned, securely bolt both units to the mounting structure.
6) Ensure the Shaft can Move Axially
Ensure that the shaft can move axially through the bearing bores to confirm proper alignment. If this cannot be done, loosen the housings and realign the shaft.
7) Tighten Both Collar Set Screws
Tighten both collar set screws, and then rotate the shaft and alternately tighten to the manufacturer recommended torque values. If a torque wrench is not available, tighten the set screws until a permanent twist is established with an allen wrench.
8) Expansion Unit*
If you are using an expansion unit, always lock the fixed bearing first. Move the expansion bearing axially to center in the housing. Once centered, alternately tighten the set screws on the expansion unit as you did on the fixed unit.
For full installation manuals and documentation, visit Rexnord.com/documentation. Or Call 1-866-REXNORD for technical and sales support.