Analysis of clearance of tapered roller bearings

In response to common misunderstandings about the clearance of tapered roller bearings during assembly, an analysis of the clearance of tapered roller bearings was conducted through diagrams and calculations. The analysis results showed that there were errors in the radial clearance of tapered roller bearings compared to the clearance formed by the inner diameter of the outer ring and the outer diameter of the rollers. The reasonable and accurate way to adjust the clearance of tapered roller bearings is to adjust the axial clearance.

1. Introduction

About 25% of the motion pairs in our company's production equipment are equipped with tapered roller series bearings. Accurately adjusting the clearance of such bearings is one of the methods to ensure the healthy operation and service life of the equipment and bearings.

2. Example analysis

Taking a single row tapered roller bearing as an example, the single row tapered roller bearing has an outer ring, and its inner ring and a set of tapered rollers are enclosed by a cage to form an inner ring component. The outer ring can be separated from the inner ring components. Usually, the cone angle of the outer raceway of a single row tapered roller bearing is between 10 ° and 19 °, and there are also bearings with a large cone angle outer raceway of 25 ° to 29 °, which can withstand both axial and radial loads simultaneously. In addition, the clearance of single row tapered roller bearings can be adjusted during installation.

During equipment installation and maintenance, it is often necessary to recheck, measure, and adjust the clearance of this type of bearing. Maintenance personnel usually use a feeler gauge to measure the clearance between the inner diameter of the outer ring and the outer diameter of the roller (see H in Figure 1) as the radial clearance of the bearing.

The clearance of rolling bearings is divided into radial clearance and axial clearance. They respectively represent the amount of movement of one sleeve from one extreme position to another in the radial and axial directions when one sleeve is fixed.

As shown in Figure 1: Ur - radial clearance, Ua - axial clearance, H - clearance between outer ring inner diameter and roller outer diameter.

Figure 1 Bearing Structure

3. Calculation

In Figure 1, the outer ring of the bearing was first pre tightened and then placed outward at a position of 0.30mm. Draw a triangle from the enlarged image of I.

According to the trigonometric function, Ur=tga • Ua, H=cosa • Ur, where a is taken as 10 °, 19 °, and 27 ° respectively, and Ua=0.30mm. The calculation results are shown in Table 1.

Table 1 Calculation Summary Table

The summary shows that Ua>Ur>H, that is, when a is between 10 ° and 29 °, at the same degree, the axial clearance Ua of the tapered roller bearing is greater than the radial clearance Ur, and the radial clearance Ur is greater than the clearance H between the inner diameter of the outer ring and the outer diameter of the roller.

4. Conclusion

(1) There is an error in the radial clearance Ur and the gap H formed by the inner diameter of the outer ring and the outer diameter of the roller.

(2) The clearance adjustment of tapered roller bearings is more reasonable and accurate to adjust the axial clearance.

5. Adjustment method

The axial clearance adjustment method for tapered roller bearings should be as follows:

(1) Firstly, with the help of external pressure covers or other specialized tools for tapered roller bearings, use bolts or other tools to press the outer ring of the bearing tightly, so that the inner diameter of the outer ring is in close contact with the outer diameter of the roller, i.e. H=0.

(2) Measure the relevant dimension L relative to reference A using a depth gauge or caliper.

(3) Loosen the bolts or other tools, and adjust the thickness of the gasket to move the outer ring of the bearing. The relevant dimensions relative to reference A are equal to L ± u, achieving the expected value.

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