Koyo 30305DJR Tapered Roller Bearing, 25 x 62 x 18.25 mm

This is the Koyo Tapered Roller Bearing, Metric, Steep Angle (DJR), 30300 Series.

This Koyo single-row tapered roller bearing (metric series, 30300 series) has tapered raceways on the inner and outer rings and tapered rollers, with the apexes of the three surfaces meeting at a common point on the bearing axis. It carries radial load and axial load in one direction at the same time and suits heavy loads and impact loads. The outer ring and the inner ring assembly separate, so mounting is easy. Radial load produces an axial component of force in this bearing type, so it is normally used in a facing pair or as a matched set. This range has the steep contact angle (supplementary code DJ, 28° 48' 39"). The larger the contact angle, the greater the bearing's resistance to axial load.

The range has 15 sizes, with bores from 25 to 95 mm. Boundary dimensions are to JIS B 1512 and tolerances to JIS B 1514-1. The supplementary code J means the outer ring width, contact angle and outer ring small inside diameter conform to ISO 355, and R is the high load capacity design. Koyo bearings are made by JTEKT Corporation.

Where this product is used

• Automobile front and rear wheels
• Transmissions and differential pinions
• Machine tool spindles
• Construction equipment
• Large size agricultural equipment
• Railway rolling stock speed reduction gears
• Rolling mill roll necks and speed reducers

Features

• Radial load and axial load in one direction in a single bearing, suited to heavy loads and impact loads
• Separable: outer ring and inner ring assembly are mounted separately
• Single-row bearings are normally used facing one another in pairs, or as matched sets
• Steep contact angle (DJ, 28° 48' 39"), for greater resistance to axial load
• J suffix: outer ring width, contact angle and outer ring small inside diameter to ISO 355
• R: high load capacity internal design
• Pressed steel cage as standard
• Allowable misalignment 0.0009 rad (3')
• Basic dynamic load ratings 39.8 to 319 kN and static 42.5 to 391 kN depending on size

Key specifications

Available sizes

Selecting the right option

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

Dynamic equivalent radial load for a single-row bearing is Pr = Fr when Fa/Fr is e or less, and Pr = 0.4 Fr + Y1 Fa when Fa/Fr is greater than e. Static equivalent radial load is P0r = 0.5 Fr + Y0 Fa, and P0r is taken as Fr when it works out lower than Fr. The values of e, Y1 and Y0 for each size are in the variant specification.

When two single-row bearings are used together facing one another, radial load produces an axial component of force in each. Allow for it when calculating the dynamic equivalent radial load.

When the load is too small, slippage between the rollers and raceways can cause smearing. This also applies to matched pairs when Fa/Fr is greater than e. Consult JTEKT for use under those conditions.

Fitting and use

Check the mounting dimensions in the variant specification: the shaft and housing shoulder diameters, shoulder widths and fillet radii (da, db, Da, Db, Sa, Sb, ra, rb) give the shoulder sizes and radius limits for the mating parts.

Single-row bearings have an axial component under radial load, so set the clearance or preload between the facing pair to suit the application.

Related products

Also available from Koyo: the 30200 series metric range, the 30300 series metric range, the 32000 series rubber seal range, the 32000 series metric range and the inch series range.

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