Self-Aligning C3W33 Spherical Roller Bearing Mining Conveyors

The 22218/C3W33 is a double-row spherical roller bearing with a 90 mm bore, 160 mm outer diameter, and 40 mm width. It features a cylindrical bore, C3 radial clearance, and a W33 lubrication arrangement consisting of an annular groove in the outer ring with three lubrication holes. Manufactured from through-hardened GCr15 bearing steel, the bearing meets P5 running accuracy standards and is supplied without seals, allowing for relubrication during service.

Spherical roller bearings of the 22218 type incorporate two rows of barrel-shaped rollers running between a common sphered outer ring raceway and two inner ring raceways inclined at an angle to the bearing axis. This geometry provides self-aligning capability, allowing the bearing to accommodate shaft deflection and misalignment of up to approximately 1.5° without significant increase in friction or operating temperature. The C3 clearance designation indicates a radial internal clearance greater than the C0 normal class, making this variant suitable for applications where thermal expansion of the shaft may reduce operating clearance, or where interference fits on both rings are specified.

22218/C3W33 Bearing Specifications

Design Features of 22218/C3W33 Spherical Roller Bearings

Self-Aligning Geometry

The sphered outer ring raceway enables the inner ring assembly to pivot relative to the outer ring, compensating for shaft deflection, housing bore misalignment, and mounting errors. This characteristic reduces edge loading on the rollers and raceways that would otherwise occur in misaligned conditions.

W33 Relubrication System

The W33 designation refers to an annular groove machined into the outer ring OD with three radial lubrication holes spaced evenly around the circumference. This arrangement allows grease or oil to be introduced through the housing into the bearing interior during operation, extending service intervals in contaminated or high-temperature environments.

C3 Radial Clearance

With C3-class internal clearance, the 22218/C3W33 provides greater radial play than the standard C0 clearance. This is specified for applications where operating temperatures cause the shaft to expand more than the housing, or where the bearing is mounted with heavy interference fits on both rings.

P5 Running Accuracy

P5 precision class means the bearing is manufactured to tighter dimensional and running tolerance limits than the standard P0 class, including reduced radial runout and axial runout values. This level of precision supports smoother operation and lower vibration levels in medium-speed machinery.

22218/C3W33 Bearing Industrial Applications

The 22218/C3W33 spherical roller bearing is specified across industrial sectors where heavy radial loads, moderate axial loads in both directions, and misalignment tolerance are required. Common applications include conveyor systems in mining and material handling, gearboxes for wind turbine yaw drives, vibrating screens and feeders in aggregate processing, paper machine dryer sections, and shaft supports in steel mill continuous casters. The relubrication feature makes this variant suitable for installations where periodic maintenance access is available but extended service life under heavy loads is desired.

FAQ

What does the C3 clearance designation mean for 22218 bearings?

C3 indicates a radial internal clearance greater than the normal (C0) class. For a 90 mm bore spherical roller bearing, C3 clearance provides additional internal play to accommodate thermal growth of the shaft, heavy interference fits, or applications where the bearing runs at elevated temperatures.

How does the W33 lubrication feature work on the 22218/C3W33?

The W33 feature consists of a circumferential groove machined into the outer ring outer diameter, connected to three radial lubrication holes. Grease or oil is fed through the housing into this groove, which distributes the lubricant through the holes into the bearing interior, supporting relubrication without disassembly.

What applications are 22218/C3W33 bearings suitable for?

This bearing is commonly used in mining conveyors, vibrating screens, gearboxes, paper machinery, and steel mill equipment where heavy radial loads, bidirectional axial loads, and potential shaft misalignment are present. The C3 clearance and W33 lubrication options suit medium-to-heavy duty industrial environments with periodic maintenance schedules.