FAG double row angular contact ball bearings

FAG double row angular contact ball bearings are particularly suitable where:

• the design envelope is not sufficient under high loads for a pair of single row angular contact ball bearings
• high radial and axial loads are acting simultaneously
• tilting moments must also be supported
• a relatively rigid bearing arrangement is required
• the bearing arrangement is to run quietly in addition to meeting the requirements stated above

FAG double row angular contact ball bearing design

FAG double row angular contact ball bearings are available as:

• FAG bearings of basic design
• FAG bearings with filling slot
• FAG bearings with split inner ring
• FAG X-life bearings

FAG bearings of basic design

Nominal contact angle α = 25° or 30°

Double row angular contact ball bearing of basic design
F_r = radial load
F_a = axial load
α = nominal contact angle

FAG double row bearings correspond in their structure to a pair of single row angular contact ball bearings in an O arrangement, but they are narrower to a certain extent. They differ in the size of the contact angle α and the design of the bearing rings. Due to the manufacturing processes used, open bearings, which are also available with sealing washers or sealing shields, can have turned recesses in the outer and/or inner ring for sealing washers or sealing shields.

FAG double row bearings of series 38..-B(-2RSR, -2Z), 30..-B(-2RSR, -2Z), 32..-B(-2RSR, ‑2Z), 32..-BD(-2HRS), 33..-B(-2RSR, -2Z), 33..BD(-2HRS) are self-retaining. They do not have filling slots in the end faces of the bearings rings. Bearings of series 32..-BD and 33..-BD have an optimised internal construction.

In design terms, FAG double row angular contact ball bearings thus fulfil the requirements for:

• supporting axial loads in both directions and high radial loads
• low-noise running
• versatile application

The nominal contact angle α in B designs is 25°, in the case of the BD variant , this is 30°.

FAG bearings with filling slot

Nominal contact angle α = 35°

FAG angular contact ball bearings of series 32 and 33 are self-retaining. They have filling slots on one end face of the bearing ring for filling the bearings with rolling elements. The nominal contact angle is α = 35°.

Double row angular contact ball bearing with filling slot
F_r = radial load
F_a = axial load
α = nominal contact angle

These series must be fitted such that the main load direction is supported by the row of balls without filling slots under axial load.

FAG bearings split inner ring

Nominal contact angle α = 45°

In FAG angular contact ball bearings of series 33..-DA, the inner ring is split. The inner rings are not self-retaining. Filling the bearings with a large number of balls - in conjunction with the internal design of the bearing and the contact angle of 45° - allows high alternating axial loads to be supported.

Double row angular contact ball bearing with split inner ring
F_r = radial load
F_a = axial load
α = nominal contact angle

The inner ring halves are matched to the particular bearing and must not be interchanged with those of other bearings of the same size.

X-life premium quality

FAG double row angular contact ball bearing of series 32..-BD and 33..-BD are X-life bearings. These FAG bearings exhibit considerably higher performance than standard double row angular contact ball bearings. This is achieved, for example, through the modified internal construction, higher surface quality of the contact surfaces and optimised cage design, as well as through the improved quality of the steel and rolling elements.

Load carrying capacity

Capable of supporting axial loads in both directions and radial loads
In addition to high radial loads, FAG double row angular contact ball bearings can also support axial forces in both directions and tilting moments. They are highly suitable for bearing arrangements with rigid axial guidance.

Contact angle and axial load carrying capacity
The bearings are available with α = 25°, 30°, 35° and 45°. The axial load carrying capacity increases with the size of the contact angle. In bearings without filling slots, it is the same in both directions.

Compensation of angular misalignments

FAG double row angular contact ball bearings are not suitable for the compensation of angular misalignments. In addition, misalignments induce internal forces, which not only lead to higher temperatures, but also to a reduction in the bearing rating life.

Lubrication

Angular contact ball bearings sealed on both sides are maintenance-free

Open bearings and bearings with seals on both sides are greased using a high quality grease. Bearings sealed on both sides are maintenance-free for many applications, i.e. they do not require relubrication.

Open bearings must be lubricated

Angular contact ball bearings without seals and with seals on one side of series 32.., 33.., 33..-DA, 32..-BD and 33..-BD are not preserved or greased. These bearings must be lubricated with oil or grease.

Compatibility with plastic cages

When using FAG bearings with plastic cages, compatibility between the lubricant and the cage material must be ensured if synthetic oils, lubricating greases with a synthetic oil base or lubricants containing a high proportion of EP additives are used.

Observe oil change intervals

Aged oil and additives in the oil can impair the operating life of plastics at high temperatures. As a result, stipulated oil change intervals must be strictly observed.

Sealing

2RS, 2RSR and 2HRS seals are contact designs

Series 38..-B, 30..-B, 32..-B and 33..-B with the suffix 2RS, 2RSR and 2HRS have lip seals in axial contact on both sides and in radial contact. Bearings with the suffix RS, HRS and RSR are sealed on one side with lip seals in axial and radial contact.

2Z sealing shields and 2RZ seals are non-contact designs

FAG bearing series with the suffix 2Z have sheet steel sealing shields on both sides. Bearings with the suffix 2RZ are fitted with rubberised gap seals on both sides.

Open bearings

In the case of unsealed FAG bearings, sealing must be carried out by the adjacent construction. The sealing system should reliably prevent:

• moisture and contaminants from entering the bearing
• the egress of lubricant from the bearing

Cages

Solid cages made from brass and PA66, as well as sheet steel cages, are used as standard

Standard cages and additional cage designs for FAG double row angular contact ball bearings are made from brass, polyamide or steel. Other cages are available by agreement. With such cages, however, suitability for high speeds and temperatures as well as the basic load ratings may differ from the values for the bearings with standard cages.

Internal clearance

Axial internal clearance - FAG bearings with unsplit inner ring

FAG double row angular contact ball bearings with unsplit inner ring of the basic design have the axial internal clearance CN (group N) in accordance with DIN 628-3:2008

Axial internal clearance - FAG bearings with split inner ring

Standard corresponds approximately to C3 for unsplit bearings

FAG bearings with a split inner ring are intended for higher axial loads. As a result, they generally also have a tighter fit than unsplit bearings. Their normal internal clearance corresponds approximately to the internal clearance group C3 for unsplit bearings.

FAG double row angular contact ball bearing nomenclature and suffixes

Structure of FAG bearing designation

Examples of composition of bearing designation. Please refer to FAG bearings nomenclature.

FAG double row angular contact ball bearing of basic design: designation structure

FAG double row angular contact ball bearing with split inner ring: designation structure

Suffixes