Koyo 2308-2RS Self-Aligning Ball Bearing, Contact Sealed (2RS), 40 x 90 x 33 mm

This Koyo self-aligning ball bearing (contact sealed (2RS), 22 and 23 series) has two rows of balls running on a spherical outer ring raceway. The centre of curvature of that raceway meets that of the bearing, so the inner ring, balls and cage keep rotating and align themselves if they become misaligned within design limits. It suits applications where the shaft and housing centres are likely to be displaced, or where shaft deflection is likely. It carries a contact rubber seal (2RS type) on each side.

The range has 5 sizes, with bores from 35 to 50 mm, boundary dimensions to JIS B 1512 and tolerances to JIS B 1514-1 class 0. Koyo bearings are made by JTEKT Corporation.

Where this product is used

• Power transmission shafts of woodworking and spinning machines
• Plummer blocks
• Shaft and housing arrangements where shaft deflection or misaligned mounting is likely

Features

• Spherical outer ring raceway: the inner ring, balls and cage align themselves if the shaft and housing are misaligned within design limits
• Allowable aligning angle: 0.026 rad (1.5°)
• Contact rubber seals (2RS) on both sides, with a reduced allowable aligning angle of 0.026 rad (1.5°) compared with the open type
• Boundary dimensions to JIS B 1512, tolerances to JIS B 1514-1 class 0, radial internal clearance to JIS B 1520
• Standard cage: pressed steel, staggered type
• Basic dynamic load ratings 22.7 to 43.4 kN and static 7.85 to 14.1 kN depending on size

Key specifications

Available sizes

Selecting the right option

Select by bore d first, then check the outside diameter D and width B in the table against your housing.

The allowable aligning angle is 0.026 rad (1.5°) for this range. It is set by the series: 12 and 22 series allow 0.044 rad (2.5°), 13 and 23 series 0.052 rad (3°), and the sealed 22...2RS and 23...2RS series 0.026 rad (1.5°).

Dynamic equivalent radial load is Pr = X Fr + Y Fa. When Fa/Fr is e or less, X is 1 and Y is Y1. When Fa/Fr is greater than e, X is 0.65 and Y is Y2. Static equivalent radial load is P0r = Fr + Y0 Fa. The values of e, Y1, Y2 and Y0 for each size are in the variant specification.

Compare the limiting speed for your size with the shaft speed. The speeds shown are the grease lubrication limits.

The sealed type has a contact seal on each side, so the limiting speed is lower than the open bearing of the same size. Check the figure shown for your size.

Fitting and use

Check the mounting dimensions in the variant specification: the shaft shoulder diameter da, housing shoulder diameter Da and fillet radius ra give the shoulder sizes and radius limits for the mating parts.

Keep the misalignment within the allowable aligning angle for the series. Beyond it, the bearing is no longer working within its design limits.

Related products

Also available from Koyo: the 2200 series cylindrical bore range and the 2200 series tapered bore range.