Angular contact ball bearings – single and double row for combined loads

What are angular contact ball bearings and what are they used for?

In an angular contact ball bearing, the raceways of the inner and outer rings are offset in the axial direction. The ball therefore contacts the rings at a defined angle, known as the contact angle. A larger contact angle means a higher axial load capacity, while a smaller one provides more favourable conditions at higher speeds.
A single row angular contact bearing carries axial force in one direction only. It is therefore normally mounted in a pair with a second bearing that takes up the force in the opposite direction. A double row bearing has two rows of balls with contact angles in opposite directions, so it carries axial forces in both directions.
Angular contact ball bearings are used wherever radial and axial forces act on the shaft simultaneously:

• in centrifugal pumps and compressors,
• in gearboxes with helical and worm gears,
• in machine tools and spindles,
• in fans, mixers and separators,
• in agricultural machinery and conveying equipment,
• in bearing positions that require precise axial guidance of the shaft.

Main features of angular contact ball bearings

Angular contact ball bearings are intended for bearing positions where a standard ball bearing is not sufficient for the axial load.
Key features include:

• transmission of combined radial and axial loads,
• higher axial load capacity than deep groove ball bearings,
• can be mounted in pairs for axial guidance in both directions,
• greater stiffness of the bearing arrangement with appropriate preload,
• suitable for higher speeds than roller bearings of similar dimensions,
• designs with different cage materials,
• double row designs with seals on both sides, greased at the factory.

Angular contact ball bearings are sensitive to misalignment between shaft and housing, so they require precise machining of the bearing seats and correct adjustment.

Types of angular contact ball bearings in the M&M Intercom range

Our range is divided into single row angular contact ball bearings and double row angular contact ball bearings. Both groups are represented in roughly equal numbers.

Feature	Single row bearing	Double row bearing
Direction of axial load	one direction	both directions
Mounting	normally in pairs	individually
Most common series	72, 73, 70, 718	32, 33, 52, 53, 38
Protection	mostly open	open, 2RS, 2Z, ZZ

Single row angular contact ball bearings

Single row bearings in our range are mainly in dimension series 72 and 73, for example 7205 B, 7310 B or 7314 B. Bearings of series 70 and 74 and thin-section bearings of series 718 are also available.
With many manufacturers, the letter B in the designation indicates a 40° contact angle, intended for higher axial loads. For FAG bearings, the designation XL indicates the X-life design.
For single row bearings, the cage material is also important:

• TVP – glass fibre reinforced polyamide cage,
• MP – solid brass cage for more demanding operating conditions,
• JP – pressed steel cage.

Our range also includes smaller single row angular contact bearings, such as BO 17, L 20 or M 20, which are used in smaller devices and special applications.

Universally matchable single row bearings

Single row angular contact bearings are often mounted in pairs. Universally matchable bearings are intended for this type of mounting; the manufacturer produces them so that the two bearings in a pair have a predefined clearance or preload.
For FAG bearings, the suffix UA indicates a small axial clearance in the pair, UO a pair with zero clearance and UB a light preload. Precision designs are also available with the suffix P5, which indicates a higher accuracy class.
Universally matchable bearings can be mounted in an O, X or tandem arrangement:

• O arrangement (back-to-back) – greater stiffness against tilting moments,
• X arrangement (face-to-face) – lower sensitivity to misalignment,
• tandem – higher axial load capacity in one direction.

Double row angular contact ball bearings

In design terms, a double row angular contact bearing corresponds to a pair of single row bearings in an O arrangement, but it is narrower. It carries radial loads, axial loads in both directions and tilting moments.
Our range mainly includes double row bearings of series 32 and 33, for example 3206, 3306 or 3310. Bearings of series 52 and 53, used by some manufacturers, and thin-section bearings of series 38 are also available.
Double row bearings are available in several designs:

• open bearings for lubrication from the housing,
• bearings with seals on both sides, 2RS or 2HRS,
• bearings with metal shields on both sides, 2Z or ZZ,
• bearings with increased radial clearance C3,
• designs with a brass cage, identified by the suffix M.

For FAG bearings, the designation BD indicates a double row angular contact bearing design and TVH a polyamide cage.

Angular contact ball bearings with seals and shields

Double row angular contact ball bearings are often available in a closed design. Such bearings are filled with grease at the factory and are suitable for bearing positions without additional lubrication.

Design	Description	Typical application
Without seal	bearing is lubricated from the housing	gearboxes, oil-lubricated pumps
2Z, ZZ – metal shield	non-contact protection on both sides	cleaner environments, higher speeds
2RS, 2HRS – elastomer seal	contact seal on both sides	dusty and damp environments

Seal designations vary between manufacturers. When replacing a bearing, we therefore always compare the complete bearing designation.

Contact angle and its influence on selection

The contact angle is the most important parameter of an angular contact ball bearing. A larger angle allows higher axial forces to be transmitted, while a smaller one allows higher speeds and less heat generation.
In general industrial bearings of series 72 and 73, the most common contact angle is 40°. Smaller contact angles are used mainly in precision bearings for machine tool spindles. You will find these in the spindle bearings category.

Angular contact ball bearings for pumps and compressors

In centrifugal pumps and compressors, the shaft is subjected to a radial force and an axial force resulting from the action of the liquid or gas. For such bearing positions, a pair of single row bearings of series 72 or 73 with a brass or polyamide cage is often used. When replacing them, we keep the same arrangement and the same suffix for paired mounting.

Angular contact ball bearings for gearboxes and drives

Helical gearboxes, worm gearboxes and other drives generate axial forces that standard ball bearings cannot carry reliably enough. Double row bearings of series 32 and 33 are suitable where little space is available in the axial direction. Our power transmission range can be found in the gearboxes category.

Mounting and adjustment of angular contact bearings

When mounting single row bearings in pairs, the correct arrangement and the correct setting of clearance or preload are important. Excessive clearance causes rough running, while excessive preload causes heat generation and a shorter service life.
The bearing is mounted so that the force acts on the ring with the tight fit and not through the balls. For mounting and dismounting, we use suitable bearing tools, and for axial fastening, bearing locknuts.

Lubrication of angular contact ball bearings

Open bearings are lubricated with oil or grease in the housing. At higher speeds, it is important that the quantity of lubricant is not excessive, as this causes heat generation. Closed double row bearings with seals or shields on both sides are greased at the factory and normally require no additional lubrication.
Suitable greases for bearing positions are available in the greases and pastes category.

How to choose the right angular contact ball bearing?

When selecting a bearing, we first determine whether it must carry axial force in one or both directions. We then determine the dimensions and design that suit the operating conditions.
Important selection data include:

• bore diameter, outside diameter and bearing width,
• magnitude and direction of the radial and axial loads,
• speed,
• mounting method: single, in pairs or as a double row bearing,
• required clearance or preload of the pair,
• cage material,
• protection by seals or shields,
• lubrication method and operating temperature.

When replacing a bearing, the most reliable information is the complete designation of the existing bearing, including the suffixes for contact angle, cage, paired mounting and clearance. Where the bearing position carries mainly radial loads, a standard deep groove ball bearing is more suitable. Where axial force in both directions predominates and space is limited, a four-point contact ball bearing may also be considered.

Angular contact ball bearings at M&M Intercom

At M&M Intercom, we offer 1,400+ angular contact ball bearings for pumps, compressors, gearboxes, machine tools and general maintenance. Our range includes single row bearings for individual and paired mounting, universally matchable bearings and double row bearings in open design, with seals or with metal shields.
Bearings from FAG INA, ROLLWAY, Nachi, NTN/SNR and other manufacturers are available. For a complete bearing arrangement, our range also includes bearing housings and bearing accessories.
If you need help selecting or replacing an angular contact bearing, send us the designation of the existing bearing or details of the application. We will help you choose the right design.

 

Frequently asked questions about angular contact ball bearings

1. What is an angular contact ball bearing?
An angular contact ball bearing is a rolling bearing in which the balls transmit force at an angle to the bearing axis. It therefore carries radial loads and higher axial loads simultaneously.
2. What is the difference between an angular contact ball bearing and a standard ball bearing?
A standard deep groove ball bearing carries mainly radial and moderate axial loads. An angular contact bearing has a higher axial load capacity, but the single row design carries axial force in one direction only.
3. Why are single row angular contact bearings mounted in pairs?
A single row bearing carries axial force in one direction only. By mounting two bearings in an O or X arrangement, the shaft is guided axially in both directions, while a tandem arrangement increases the load capacity in one direction.
4. What does the letter B in the designation mean, e.g. 7205 B?
With many manufacturers, the letter B indicates a 40° contact angle. Such bearings are intended for bearing positions with higher axial loads.
5. What do the suffixes UA, UB and UO mean?
For FAG bearings, these suffixes indicate universally matchable bearings. UA means a small axial clearance in the pair, UO a pair with zero clearance and UB a light preload of the pair.
6. What is the difference between a single row and a double row angular contact bearing?
A double row bearing has two rows of balls with contact angles in opposite directions. It carries axial forces in both directions and tilting moments, while taking up less space than a pair of single row bearings.
7. Are double row angular contact bearings available with seals?
Yes. Our range includes double row bearings with rubber seals on both sides, 2RS or 2HRS, and with metal shields, 2Z or ZZ. Such bearings are greased at the factory.
8. Which cage material should I choose?
The TVP polyamide cage is lightweight and suitable for most general applications up to the temperature limit of the material. The MP brass cage is more suitable for more demanding operating conditions, larger bearings and higher temperatures.
9. Can I replace an angular contact bearing with a standard ball bearing?
As a rule, no. A standard ball bearing cannot carry the same axial load, so the bearing position would wear faster. Replacement is only possible if the design and loading of the bearing position permit it.
10. How do I choose the right angular contact ball bearing?
We take into account the direction and magnitude of the load, dimensions, speed, mounting method, cage, protection and lubrication. When replacing a bearing, the complete designation of the existing bearing is the most reliable reference. At M&M Intercom, we will help you choose the right design based on the designation or application data.