VISTA Technology Knowledge: Assembly Technology of Double Row Angular Contact Ball Bearing

Hot tags: double row angular contact ball bearing(1), assembly(1), protrusion(1), measure(1)

The measurement and assembly method of double row angular contact ball bearing is proposed.

Abstract: according to the structure and characteristics of double row angular contact ball bearing, taking the inner ring separation bearing as an example, the measurement and assembly method of double row angular contact ball bearing is proposed. Aiming at the problem that the preload required for assembly is greater than the measurement load range of protrusion measuring instrument, which leads to the problem that cannot be measured, the modified measurement and calculation method is introduced, which solves this problem well.

Key words: double row angular contact ball bearing; Assembly; Protrusion; measure

 

Double row angular contact ball bearings are generally of inner ring separation type or outer ring separation type, which is equivalent to two sets of single row angular contact ball bearings assembled in back-to-back (DB) or face-to-face (DF) mode and used together in pairs. When the bearing is installed, the axial preload is applied to eliminate the supporting radial clearance of the bearing and realize the preload of the bearing. After installation, for the double row angular contact ball bearing without spacer in the middle, the final preload is determined by the tightness of the non reference end face close to the two inner rings (inner ring separation type) or two outer rings (outer ring separation type); For the double row angular contact ball bearing with spacer in the middle, the final preload can be adjusted by the width of the spacer.

 

double row angular contact ball bearing 

 

It can be seen that the double row angular contact ball bearing, like the single row angular contact ball bearing, should be assembled under a certain preload according to the user's requirements, so as to give full play to the advantages of the double row angular contact ball bearing.

 

1.Assembly technology of double row angular contact ball bearing

When assembling double row angular contact ball bearings, it is also necessary to accurately measure the protrusion of the assembled bearings under a certain preload in advance. The measurement of the projection of angular contact ball bearing is carried out on the high-precision bearing projection measuring instrument. Similarly, the double row angular contact ball bearing must also be measured with the help of the measuring instrument.

 

Because the structure of double row angular contact ball bearing is different from that of single row angular contact ball bearing, the positioning and centering mode during measurement is completely different from that of single row angular contact ball bearing, and the positioning and outer diameter centering must be based on the outer ring end face; Moreover, it is impossible to directly obtain the protrusion value of the two matched surfaces through one measurement on the instrument. Only first measure the protrusion value of the two reference end faces of the outer ring respectively, and then convert it to the non reference end faces of the two matched inner rings (Fig. 1a). Finally grind the width of one inner ring or the non reference end faces of the two inner rings of the bearing as needed to ensure that the specified preload is obtained after the bearing is installed, The assembly process is much more complex than that of single row angular contact ball bearing. During measurement, it is also necessary to replace the accessories of the instrument according to the structure of double row angular contact ball bearing to meet the measurement requirements.

 

The measurement principle of projection of double row angular contact ball bearing is shown in Fig. 1b. The measuring principle is as follows: place the reference ring (not shown in the figure, at the measured bearing position in Figure 1b) in the combination of the centering ring and the centering seat, make the end face of the reference ring contact with the end face of the positioning seat, apply the preload F0 to the reference ring in the axial direction through the main shaft and the combination of the measuring instrument, place the pointer of the measuring instrument at zero and lock it, take out the reference ring, and take out the selected group of steel balls Measure the maximum protrusion F0 of the inner ring and the outer ring of the bearing assembly through the instrument, and put them into the inner ring of the bearing assembly to measure the maximum protrusion F0 of the inner ring and the outer ring of the bearing assembly, and put them into the inner ring of the bearing assembly to measure the maximum protrusion F0 of the inner ring and the outer ring of the bearing assembly δI. then take out the tested bearing, turn the bearing outer ring upside down (rotate 180 °), install another set of steel balls, cage and another inner ring II into the channel on the other side of the bearing outer ring, and repeat the above measurement process to obtain the projection value measured for the second time δ II (Fig. 1a). Then the sum of the grinding amount of the non reference end face width of the two inner rings of the double row angular contact ball bearing is

Δ = C ( B1 + B2 ) ( δ+ δ)          ( 1)

 

C is the actual width of the outer ring; B1 is the actual width of inner ring I; B2 is the actual width of inner ring II.

 

According to the above measurement method and the calculation results of formula (1), grind one inner ring or the non reference end face of two inner rings of the bearing on MG7340 high-precision horizontal shaft round table surface grinder (if the reference end faces of both inner rings are polished, the sum of the total grinding amount is Δ) After grinding, the bearing parts shall be cleaned, and the bearing shall be assembled according to the installation sequence during measurement, that is, the assembly of double row angular contact ball bearing shall be completed.

 

It should be pointed out that at present, the theoretical maximum measuring load of high-precision bearing protrusion measuring instrument is 2 kN. When the preload of the paired double row angular contact ball bearing does not exceed 2 kN, it can be measured and paired directly according to the above method. When the preload required for the assembly of double row angular contact ball bearing is much greater than 2 kN, it is beyond the measurement range of the current instrument, and the actual protrusion value of the bearing cannot be measured directly on the instrument. In this regard, the actual measurement shall be carried out with a small measuring load (not exceeding the range of instrument measuring load), and then the difference between the deformation of a single set of bearing under the action of paired preload and measuring load can be corrected. The calculation formula of the sum of the grinding amount of the width of the non reference end face of the two inner rings of the bearing is

Δ =  C ( B1 + B2 ) (  δ  +  δ ) 2(  δ 0   δ 0a )     ( 2)

 

δ 0a, δ 0 is the deformation of a single set of bearing under measured load and preload.

δ 0a and δ 0 is calculated by the following formula:

δ a = 0.000 436 F2 /3 a Z2 /3 D1 /3 w sin 5 /3  α      (3)

 

δa is axial deformation, mm; Fa is axial load, N; Z is the number of steel balls; DW is the diameter of steel ball, mm; α  Is the bearing contact angle, (°). δ 0a and δ0 can be programmed to speed up the calculation.

 

It should be pointed out that the contact angle of the bearing will change under the action of axial load. According to the actual calculation, the double row angular contact ball bearing with the original contact angle of 60 ° is obtained from the actual contact angle under the action of axial load δ 0a and δ 0 and obtained from the original contact angle δ 0a and δ0. The difference is very small and can be ignored. Therefore, carry out δ 0a and δ 0 the influence of the change of contact angle can be ignored in the calculation. However, for bearings with a contact angle less than 45 °, the smaller the initial contact angle is, the greater the change of the actual contact angle under different axial loads. If the initial contact angle is directly substituted into formula (3) for calculation δ 0a and δ 0 will produce a large error with the actual measurement results. Therefore, for bearings with contact angle less than 45 °, the actual contact angle should be substituted into formula (3) for calculation.

 

2. Example calculation

The dimension of double row angular contact ball bearing ZYSF2575-2RS is Φ 25 mm  × Φ 75 mm  ×  28 mm;  The width deviation of inner and outer rings is Δ C = 20  μ mΔ B1 = 30  μ mΔ B2 = 35  μ m;  Dw = 7.144Z = 15F0 = 9 410 Nα =  60°.

 

The measured load F0a = 1000 N is selected, and the protrusions measured on both ends of the bearing outer ring under the measured load are δ  = 20  μ m,  δ  = 32  μ m;  Under the action of measured load F0a = 1000 N and preload F0 = 9410 n, it is calculated by computer program δ 0a = 4.7  μ mδ 0 = 21.1μ m.

 

Then the total grinding amount of the non reference end face width of the two inner rings

Δ = -20 - (- 30-35) - ( 20 + 32) - 2  ×  ( 21.1 - 4. 7) = - 39.8  μ m

 

In order to simplify the process and improve efficiency, only 39.8μ m of the non reference end face width of one inner ring needs to be polished μ m. After the bearing is assembled, the specified preload can be obtained.

 

After the bearing assembly is completed, the following assembly can be carried out as required, that is, the two-way assembly of double row angular contact ball bearings, as shown in Figure 2.

 

3.Conclusion

Double row angular contact ball bearings are equivalent to two sets of single row angular contact ball bearings assembled and matched back-to-back or face-to-face. Therefore, double row angular contact ball bearings, like single row angular contact ball bearings, must follow the general technical conditions of single row angular contact ball bearing assembly. When the preload of the paired double row angular contact ball bearing is within the load range measured by the protrusion measuring instrument, the grinding protrusion can be calculated directly according to formula (1) in this paper. When the preload required for assembly completely exceeds the load range measured by the protrusion measuring instrument, the corrected formula (2) can be used to calculate the protrusion to be polished. This paper introduces the assembly of inner ring separated double row angular contact ball bearing. This method is also applicable to the assembly of outer ring separated double row angular contact ball bearing and other similar bearings.

 

More about VISTA High-quality Double Row Angular Contact Ball Bearing

The sealing system of  double row angular contact ball bearings prevents the ingress of dirt and ensures an optimal service life. They parallel, in structure and function, to a pair of single-row angular contact ball bearings with a back to back arrangement.

Features and benefits:

Less axial space 

Can be used for applications where two single row angular contact ball bearings arranged back-to-back take up too much axial space. 

Accommodates radial as well as axial loads in either direction

Accommodates tilting moments

Stiff bearing arrangement


double row angular contact ball bearing 


As a angular contact ball bearing manufacturer, Vista supplies single row angular contact ball bearing, double row angular contact ball bearing and four point angular contact ball bearing for customers.

 

angular contact ball bearing 

 

Applications: Machine tool, Precise instrument, Automobile, Fluid conveying machinery, Light industry machinery, etc.

 

 

 


2022-05-10

Vista Bearing

Shanghai.ChinaVictoria.AustraliaCalifornia.USA
© 2020 VISTA Bearing All rights reserved. | Sitemap