Screw Conveyor End Bearings

Nomenclature Flanged Roller Bearing Flanged Ball Bearing Pillow Block Roller Bearing Pillow Block Ball Bearing

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End bearings provide support at one or both ends of a screw conveyor and must be designed to handle radial and thrust loads as well as shaft runout.

Radial load as measured at the end bearing is half the weight of the last screw section. Radial loads act at right angles to the shaft centerline or bearing axis of rotation. Radial loads are typically negligible at the screw conveyor end shaft. However, end bearings located at the drive end of a screw conveyor are subject to higher radial loading due to the weight of the gear reducer and motor or overhung loads from chain and sprocket drives.

Thrust load is the reaction through the conveyor screws from the movement of a bulk material. Thrust loads are also called axial loads and act parallel to the shaft centerline or bearing axis of rotation. The end bearing on the drive end must prevent axial movement of the screw. Any axial movement of the screw could allow contact with the hanger bearings or trough ends. KWS recommends locating the drive unit and thrust bearing at the discharge end of a screw conveyor, placing the screws in tension and preventing misalignment when the conveyor is heavily loaded.

Shaft runout occurs when the shaft rotates in an eccentric pattern about the centerline axis. Shaft runout is caused by the minor amount of “bend” inherent in any screw due to the manufacturing process. Shaft runout must be accounted for at the bearings to avoid premature bearing failure. KWS recommends using a fixed thrust bearing at the drive end and a ball or spherical roller bearing at the tail end.

Nomenclature

Roller Bearing Flange Unit

* KWS Stock Component

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Ball Bearing Flange Unit

* KWS Stock Component     – All Flange Bearings Include 1/8″ Alemite Fitting

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Roller Bearing Pillow Block

• Uses a 4 bolt base instead of 2.

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Ball Bearing Pillow Block