1. Start with the load direction

According to the product description, a single row of tapered rollers is guided by the large rib of the inner ring. It can carry radial loads together with axial load in one direction, and it has a high load capacity. Under radial load it also produces an additional axial force. For this reason, taper roller bearings are generally mounted in pairs, facing each other (a duplex arrangement).

Questions to answer before you request a quote:

• Does the shaft carry combined radial and axial load? If so, a taper roller bearing is a reasonable candidate.
• Does the axial load act in one direction or both? For single row bearings, plan on two opposed bearings, or on a multi-row type.
• Is the load mainly radial with almost no thrust? A different roller bearing type may suit better (see section 5).

The source also says that large-taper-angle bearings are intended mainly for single-direction axial loads and are not suitable for radial loads alone.

2. Single row, double row or 4 row taper roller bearing

The product range is described by contact angle (general, medium and large cone angle) and by the number of roller rows. Double row and four row versions are described as carrying heavy radial loads plus part of the axial load in either direction. In these versions, spacer rings sit between the inner rings and between the outer rings. Clearance is set by changing the width of those spacers.

If you are specifying a 4 row taper roller bearing, send the supplier your spacer and clearance requirements together with the load data.

The description also mentions an E series, which uses larger and more numerous rollers to raise load capacity.

3. Plan for clearance adjustment and mounting

The bearings are a separable design. The outer ring can be removed separately from the inner ring and roller assembly. According to the description, axial and radial clearance can both be adjusted during mounting. When two bearings are used in opposition, clearance is set by adjusting the axial spacing between the inner rings or between the outer rings. The description notes that pressed steel cages are generally used.

For buyers, this means that the required clearance or preload, and the way it will be set during assembly, are part of the purchase specification. They are not left until installation.

4. Read the taper roller bearings catalogue values

The confirmed catalogue table lists each bearing by its new number and old number. For each size it gives dimensions in mm (d, D, T, B, C, chamfers), basic load ratings in kN (Cr, Cor), Grease and Oil speed columns, mounting dimensions, calculation factors (e, Y, Y0) and mass. Some rows from the table:

The table shows that bearings with the same boundary size do not always have the same ratings. For example, 30313 and 31313 share d = 65 mm, D = 140 mm and T = 36 mm. However, 31313 lists a lower Cr (172 vs 205 kN), a higher e factor (0.83 vs 0.35) and different Y factors. Choosing between them depends on the ratio of axial to radial load in your application, not on the envelope size alone. Check the following:

1. Envelope: bore d, outside diameter D and overall width T must match the shaft and housing.
2. Load ratings: compare Cr and Cor with your calculated loads.
3. Factors e, Y, Y0: use the catalogue values for the exact bearing number in your equivalent-load calculation.
4. Mounting dimensions: check shoulder diameters (da, db, Da, Db) against your shaft and housing design.
5. Interchange: quote both the new and old numbers when replacing an existing bearing.

5. When taper roller bearings are not the right fit

The same range of roller bearings includes other types whose confirmed descriptions point to different duties:

• Mainly radial load, higher speed: the Cylindrical Roller Bearings are described as mainly carrying radial loads, with low friction at the rib and suitability for high-speed rotation. Types without ribs can act as free-end (floating) bearings.
• Shaft deflection or misalignment: the Spherical Roller Bearings are described as self-aligning, with an allowable angular misalignment of 0.5° to 2°. They are suited to heavy and impact radial loads, but not to pure axial loads.
• Axial load only: the Thrust Roller Bearings are described as carrying axial loads only, not radial loads, and as suitable for low-speed rotation. They are used together with radial bearings.

What to send with an enquiry

To get a usable recommendation, include:

• radial and axial loads and the direction of the axial load
• shaft speed and lubrication method (grease or oil)
• shaft and housing dimensions, or the bearing number currently fitted
• whether you need a single row pair, or a double row or four row arrangement
• the required clearance or preload

The figures in this article come from the published catalogue excerpt. Prices, delivery times, certifications and sizes outside the table above are not covered here and should be confirmed directly with XINGTAI WEIZI BEARING CO., LTD.