Koyo 1200 series, 25 x 52 x 15

This Koyo self-aligning ball bearing (tapered bore, 1200 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. The tapered bore (taper 1:12) lets the bearing be fitted to the shaft with an adapter assembly.

The range has 14 sizes, with bores from 25 to 100mm, 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: 0.044 rad (2.5°)
• Tapered bore (taper 1:12), fitted to the shaft with an adapter assembly
• 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 12.1 to 69 kN and static 3.3 to 29.7 kN depending on size

Key specifications

Available sizes

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.

Choosing the right option

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

The allowable aligning angle is 0.044 rad (2.5°) 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. Both grease and oil lubrication limits are shown.

The K suffix means a tapered bore with a 1:12 taper. Match the shaft, adapter assembly and bearing as a set, and the adapter size before ordering.

Also available from Koyo: the 1200 series cylindrical bore range, the 1300 series tapered bore range, the 2200 series tapered bore range.