Koyo HK2218-RS sealed drawn cup bearing, 22 x 28 x 18 mm

These Koyo HK RS sealed drawn cup needle roller bearings have caged needle rollers, open ends and a lip contact seal on one side. Drawn cup needle roller bearings support radial loads and reduce friction between rotating components, with a drawn steel outer cup that serves as the raceway for the needle rollers. The small cross-section gives high load-carrying capability in minimum space, and the bearing is installed with a press fit in the housing.

Drawn cup bearings suit compact, economical designs where it is not practical to harden and grind the housing bore, or where the housing material has low rigidity, such as cast iron, aluminium or plastics. The seal lip makes light, constant contact with the inner raceway across the range of mounted bearing clearances, which gives positive sealing with low friction. The seals retain grease or non-pressurised oil and keep contaminants out of the raceway area. The stamped lip of an HK RS bearing is at the seal end.

The range has 8 metric sizes with needle roller complement bore diameters from 8 to 22 mm. Koyo bearings are made by JTEKT Corporation.

Where this product is used

• Transmissions and transfer cases
• Engines and valve trains
• Steering and braking systems
• Axle supports
• Outboard engines
• Power tools
• Copiers, fax machines and paper-moving equipment
• Appliances

Features

• Caged needle rollers with a lip contact seal on one side to retain grease and keep contaminants out
• Drawn steel cup raceway pressed into the housing: compact cross-section and economical mounting without a hardened, ground housing bore
• Basic dynamic load rating C 2.9 to 13.1 kN and basic static load rating C0 2.73 to 20.9 kN
• Grease lubrication speed rating 8,800 to 20,000 min-1
• Seals suitable for -30 to +100 °C, supplied with lithium soap-based general-purpose grease
• Matching JR series inner rings are available in the Koyo range where the shaft cannot be hardened and ground

Key specifications

Available sizes

Selecting the right option

Choose the size from the shaft (the needle roller complement bore diameter Fw), the housing bore (outside diameter D) and the width C. Use the HK.2RS series if you need a seal on both sides, or the open-end HK series if sealing is not needed.

Drawn cup needle roller bearings accommodate radial loads only. The maximum dynamic radial load P should be less than Cr/3, where Cr is the basic dynamic load rating, and the static load safety factor f0 (C0 divided by the maximum applied static load P0) should be greater than 3.

Fitting and use

For a one-piece heavy-section steel or cast iron housing, the catalogue recommends a shaft tolerance of h5 (or h6) and a housing bore tolerance of N6 (or N7). For housings of low rigidity, use R6 (or R7) for the housing bore. Where the outer ring rotates relative to the load, use f5 (or f6) for the shaft and R6 (or R7) for the housing bore, and for oscillating motion use j5 (or j6) for the shaft. The shaft surface should be 58 HRC or equivalent.

The standard lip contact seals are compatible with common lubricating oils and petroleum-based fuels, but they are adversely affected by certain fire-resistant hydraulic fluids and most common solvents. Sealed bearings are normally filled with a high-quality lithium soap-based general-purpose grease, and the seal material and grease limit the operating temperature to between -30 and +100 °C. Details of shaft design for sealed bearings are given in the Koyo catalogue engineering section.

Press the bearing into the housing with an installation tool used with a standard press. The tool must be coaxial with the housing bore, and the stamped end of the bearing (the end with the identification markings) goes against the angled shoulder of the tool. Do not hammer the bearing into place, even with a mandrel, and do not press it tightly against a shoulder.

Do not inspect an unmounted drawn cup bearing by measuring its outside diameter, because the thin cup can go out of round during heat treatment and becomes round and correctly sized when pressed into a true housing or ring gage. Remove a bearing by pushing it through a straight housing, and do not reuse it after extraction.

Where the shaft cannot meet the raceway hardness, case depth and surface finish requirements, use a Koyo JR series inner ring with a loose transition fit on the shaft (g5), clamped against a shoulder.

Related products

Also available from Koyo: the Koyo HK.2RS sealed drawn cup bearing range, the Koyo HK drawn cup bearing range and the Koyo BK drawn cup bearing range.