Angular Contact Ball Bearings

Listing ID #4344897

Single row angular contact ball bearings are manufactured in various constructive versions, with various contact angles, depending on the application. Bearings series 72B and 73B for general applications have a contact angle a = 40?. Bearings series 718,719,70 and 72 generally used for tool-holders, have phenol resins (textolite) cages or machined brass cages. Those with bore diameters up to d = 100 mm are manufactured to tolerance classes P5, P4 and P2 and have a contact angle of 15? (C) and 25? (A) respectively.

Single row angular contact ball bearings can take only one direction axial loads. When being radially loaded, in bearing occurs an axially acting load which has to be compensated. For this reason, a bearing or paired bearings are mounted on each shaft end. Single row angular contact ball bearings with B suffix have a contact angle a = 40? and are suitable in case of heavy loads. These bearings are not dismountable and their use at relatively high speeds is allowed. Pair mounting of bearings as shown in figures on page 119 is used when the load carrying capacity of a single bearing is inadequate (tandem arrangement), respectively when axial loads have to be taken in both directions (DB or DF arrangements). In case of DT tandem arrangement , the contact lines are in parallel. Radial and axial loads are uniformly distributed on both bearings. The bearing pair can take axial loads in only one direction. Therefore, a third bearing should take axial loads in the opposite direction. In case of DB arrangement, the contact lines diverge towards the bearing axis and form letter “O”. Axial loads are taken in both directions, but only by one single bearing for each direction. DB arrangement is considered to be a relatively stiff arrangement and can also take tilting moments. The contact lines of DF arrangement converge towards the bearing axis and form letter “X”. Axial loads are taken in the same way as in case of DB arrangement, but the arrangement is not so stiff and it is less suitable for taking tilting moments

Universal design

Single row angular contact ball bearings of universal design are suitable for DB, DF and DT arrangements. Bearings of universal design are manufactured to more accurate tolerance classes and can be matched if the mounting conditions UA, UO and UL are observed. The values of clearance or preload are obtained when the shaft is manufactured to tolerance class j5 and the housing bore to tolerance class J6.

Dimensions

Main dimensions of bearings given in tables are in accordance with ISO 15.

Misalignment

In case of single row angular contact ball bearings the conditions regarding the permissible error of alignment of the outer ring relative to the inner ring are as complex as for single row deep groove ball bearings. When the bearings are paired in DB arrangement, angular misalignments of the outer ring in relation to the inner ring can only be accommodated between the balls and raceways by force, leading to a reduction in bearing life.

Tolerances

Single row angular contact ball bearings of series 72B and 73B, with a contact angle a = 40? (B) are generally manufactured to the normal tolerance class. At request, they also can be manufactured to normal tolerance classes P6 and P5. Single row angular contact ball bearings of high accuracy, series 70C, 72C, 70A and 72A, with a contact angle a = 15? (C) and a = 25? are manufactured to tolerance classes SP, P4, UP and P2. The deviations of bore diameter, outside diameter and width of high accuracy single row angular contact ball bearings of universal design (UL) are given in table 1. In case of single row angular contact ball bearings manufactured and delivered in sets of 2, 3 or 4 bearings, outside and bore diameter should be chosen considering the mean tolerance values, which are given on the package.

Contact angle

In case of single row angular contact ball bearings, the efforts between rings and rolling elements (contact points of rolling elements/ outer or inner ring) are transmitted at an angle a (< 90?) to a plane perpendicular to the bearing axis. The value of this angle depends on the magnitude of the raceway radius, rolling element diameter and radial clearance in bearing, when the curvature centres of the raceways in the outer or on the inner ring are in the same plane. The contact angle a can be calculated and verified in accordance with the specifications on page 118.

Axial clearance – preload

Axial clearance or preload can be obtained only when single row angular contact ball bearing is mounted in the assembly and depends on the location of the second bearing which assures the shaft axial guiding. Single row angular contact ball bearings series 72B and 73B, paired mounted in DB and DF arrangements are manufactured with normal axial clearance CB, smaller than normal, CA, larger than normal, CC, or with light preload, GA, moderate preload GB, or heavy preload, GC, according to the values given in table 2.

Cages

Single row angular contact ball bearings series 72B and 73B are generally fitted with pressed sheet cages. High precision single row angular contact ball bearings series 70C, 72C, 70A and 72A are fitted with textolite cages (textile fibre reinforced phenol resins). At special request (high speeds, large sizes), bearings series 70C, 72C, 70A and 72A are fitted with machined brass cages. Cages of glass fibre reinforced polyamide 6.6 are also used with good results if operating temperature doesn’t exceed +120?C. Cages design and some technical data are given in table 4

Equivalent dynamic radial load
For single row angular contact ball bearings series 72B and 73B, single and in tandem arrangement the following equations are used:

For bearings in DB or DF arrangement

Pr = Fr + 0,65Fa, kN, when Fa/Fr 1,14

In case of paired bearings, Fr and Fa are the loads acting upon the bearings pair. As the load is transmitted from one raceway to the other under a certain angle to the bearing axis, the actual load will cause an axial load. This has to be considered when calculating the equivalent dynamic load, in case of two single bearings or tandem arrangements. The equations needed for calculation are given in table 5, for various arrangements and loading versions. These equations are available for bearings mounted without clearance and without preload (clearance equal to zero).

For single row angular contact ball bearings series 70C and 72C with a contact angle a= 15? (C), single or in DT arrangement, the following equations are available:

Pr = Fr, kN, for Fa/Fr e

The values of factor Y depend on the values of the ratio f0 i Fa/C0r and are given in table 6. Factor fo can be found in diagram in page 179 as a function of dimensions series and bearing mean diameter, “i” represents the number of bearings or bearing pairs in a bearing joint. For bearings in DB and DF arrangements, the following equations are available:

Pr = Fr + Y1Fa, kN, for Fa/Fr e

The values of factors Y1 and Y2 depend on the ratio Fa/Cor and are given

Pr = Fr, kN, for Fa/Fr 0,68

For bearings in DB and DF arrangement, the following equations are available:

Pr = Fr + Y1Fa, kN, for Fa/Fr e

Values for Y1 and Y2 are given in table 6.

Equivalent static load

For single row angular contact ball bearings series 72B and 73B with a contact angle a = 40?, single and in DT arrangement, the following equation is available:

P0r=0,6Fr+0,26 Fa, kN if P0r < Fr, then we consider P0=Fr

For bearings in DB and DT arrangement, the following equation is available:

P0r=Fr + 0,52Fa, kN

For single row angular contact ball bearings series 70C and 72C, with a contact angle a = 15?, single and in DT arrangement, the following equation is available:

P0r = 0,5 Fr + 0,46 Fa, kN

For bearings in DB and DE arrangement, the following equation is available:

P0r = 0,5 Fr + 0,92 Fa, kN

For single row angular contact ball bearings series 70A and 72A with a contact angle a = 25?, single and in DT arrangement, the following equation is available:

P0r = 0,5 Fr + 0,38 Fa, kN

For bearings in DB and DE arrangement, the following equation is available:

P0r = Fr + 0,76 Fa, kN

Two “V” scratches are marked on the outside surface where the runout is maximum, i.e. where the outer ring thickness is maximum, so that the bearings of a set can be mounted in the manufacturing order. The place of maximum runout is marked on the chamfer between the inner ring bore and side face. Thus, the possible fit ovalnesses on the shaft can be compensated. Every set is delivered as an unit, separately packed. In each unit, bearings are singly packed. If distance rings are necessary to be mounted between bearings, they have not to be adjusted when being mounted. There is only one condition to be observed: the inner distance ring width should be equal to that of the outer ring, the side faces being parallel to each other. This can be easily done if both distance rings are simultaneously ground on a grinding and lapping machine. If bearings are mounted with distance rings, the mounting is also done observing the “V” marked as mentioned above. The cone vertex should be on the ring side opposite to that one on which the load acts (see next figure).

Basic dynamic load of paired bearings

Basic dynamic load given in bearing tables is valid for each single bearing. Basic dynamic load of a paired bearings set can be determined according to the specifications on page 26.

Basic static load of paired bearings

Basic static load of paired bearings can be similarly determined, multiplying the values of Cor in the tables by 2, 3 and 4 respectively.
Bearing speed limit

Single row angular contact ball bearings are used at high speeds. High precision bearings allow operation at higher speeds than those in the catalogue, depending on the oil lubrication system (oil bath, dropping lubrication, oil spot, with oil cooling). The values of speeds for bearings series 72B and 73B, normal tolerance class, without preload are given in this catalogue. In case of preloaded bearings, forsinglemounted bearing and bearings in DB, DFor DTarrangements, speeds should be multiplied by the coefficients in table 7. For bearings series 70C, 72C, 70A and 72A, speeds are given for the tolerance class P4 and light preload. In case of bearings with other values of preloads or arrangements of 3 or 4 bearing sets, the speeds of the bearing of basic design should be multiplied by the values of the coefficients in table 7.

Abutment dimensions
For a proper location of bearing rings on the shaft and housing shoulder respectively, shaft (housing) maximum connection radius ru max should be less than bearing minimum mounting chamfer r1min,r1min Shoulder height should also be properly sized in case of bearing maximum mounting chamfer. The values of the connection radii and support shoulder height are given in table 8.