Key Questions to Ask When Ordering Angular Contact Ball Bearing

Angular contact bearings

Angular contact bearings have one ring shoulder partially or totally removed. This allows a larger ball complement than found in comparable deep groove bearings, hence a greater load capacity. Speed capability is generally higher along with greater rigidity and accuracy. Angular contact bearings are assembled to a contact angle by varying the radial clearance. The smaller angle delivers better radial capacity and rigidity, the larger angle is better for axial rigidity. Separable and nonseparable types are readily available.

For more information, please visit Rimao.

Selecting angular contact ball bearings:

In order to select angular contact ball bearings a few application details have to be known.
a) Minimum and maximum shaft speed
b) Intended method of lubrication, i.e. oil drip mechanism, oil mist, grease only etc
c) Maximum Axial and radial loads
d) Life requirements
e) Shaft dimensions and shaft material
f) Housing dimensions and housing material
g) Contamination possibilities
h) Ambient temperature and local working temperature
i) Maximum shaft deflection / movement

From this information the following can be ascertained.

1) ring sizes and materials and precision
2) cage type
3) ball material
4) contact angle
5) set up, i.e. back to back, face to face, triplex set up etc.
6) complimentary lubricant requirement.
7) preload method (if any) i.e. match ground, spacers, sprung washers etc

Selecting an angular contact bearing for an application can be relatively straight forward. Replacing an angular contact ball bearing with an alternate brand is sometimes more difficult. Switching brands is possible and may well be inevitable at some stage in a machine's life due to original bearing supply problems. Over the years AHR International have specialised in offering alternative angular contact solutions. We only use reputable brands such as RHP Precision, Fafnir, SNFA, SNR, NTN, Barden, FAG, INA, IRB etc. Most of these brands have a high degree of product overlap and it should be possible to find alternate brand matches which are suitable for your application.

Care has to be taken with contact angles, cage materials, ball compliment, precision etc and each customer case is individually assessed.
Here are a few typical questions we are often faced with concerning angular contact bearings.

Can I replace my angular contact with a higher precision?

Yes, but beyond ABEC 7 (ISO P4) this could be an expensive option. Whilst you can increase precision you should never decrease precision as running accuracy could be detrimental to the performance of your machineries.

Can I use a grease instead of oil lubrication?

If your machinery is set up to use an oil drip feed, oil bath or oil mist system then you should NOT change this method of lubrication. Oil systems allow a bearing to achieve higher rpm values. Oil allows for efficient cooling of the bearing and is sometimes used for removal of waste material.

I've heard of sealed angular contact bearings. Can I use these?

Either ask AHR or your OEM. It may be possible but please bear in mind that most sealed angular contact ball bearings have some form of heavy oil or grease lubrication inside which may not be suitable for your application.

Can I use a bearing with a higher or lower contact angle than my existing bearing?

Either ask AHR or your OEM. Whilst increasing the contact angle will give more thrust load capacity it will be at the expense of radial load capacity and shaft speed. It is possible your application could withstand this but consultation should take place before making such a move.

Can I mix single angular contact bearings with match ground bearings?

No, match ground bearings are as the name suggests, had their faces ground to match one or more other bearings. This precision grinding allows this matched ste to be fitted and run with a pre-ground preload.

Can I use a different preload value than the one originally specified on my bearing?

As a rule no you cannot. The preload originally specified is important to your application and changing this to a higher or lower value could have serious consequences to the running accuracy and/or life of your equipment. Although in cases of short supply it is possible to get the bearings re-ground to change their preload but only from lighter to heavier.

There are quite a few manufacturers who make angular contact bearings, how do I know how to compare like for like?

This can be time consuming. We have a nomenclature reference system which you are welcome to look at. Alternatively why not just ask us?

Will ceramic balls increase the life of my bearings?

Ceramic balls are primarily used for high speed applications. Their lower mass gives lower centrifugal forces thus higher speed capabilities. Their stability over wide temperature ranges is very high allowing them to work in extreme hot and cold environments.

Can I have a full complement angular contact?

Yes, although high speeds are normally out of the question due to the ball to ball contact, i.e. for a given speed of 50,000 rpm the ball to ball contact speed is 100,000 rpm.

I have a match ground triplex set of bearings and one of the bearings has failed. Can I replace just the failed bearing?

No, as the name suggests these are match ground. If you introduce another bearing which is not ground to suite the others in your applications you could end up with more problems than just a broken bearing! Always replace as a set.

Can I change lurbicant types?

Only under advice from your OEM. Please bear in mind any warantee you may have on your equipment before making any form of modification.

Can I switch cage types?

Most angular contacts have some form of phenolic cage. Their are many cage types and materials avialable and both should not be changed from the original specification.

I have a bearing which has failed but I know it not to be the original OEM item. How do I get back to the true specification?

You have to either put your hands up and go back to the OEM or give us all the application data as stated at the top of this page along with all detials of the fialed bearing. Use our technical enquiry form to make life easier.

How can I find out why my bearing has failed?

Use our bearing failure analysis page. It covers most eventualities.

See also: Deep groove  |  Angular contact  |  Taper roller  |  Sphericals plain  | Rod ends  | Needle rollers  |  Slewing rings  |  Housed bearings | Self lube units | Spherical roller | Cylindrical roller

Contact us now and let us show you exactly what we can do for you.

© ARN Trading Ltd t/a AHR International All rights reserved

 There are many different types of bearings available today with very little information on the differences between them. Maybe you’ve asked yourself “which bearing will be best for your application?” Or “how do I choose a bearing?” This bearing selection guide will help you answer those questions.

First off, you need to know that most bearings with a rolling element fall into two broad groups:

1. Ball bearings
2. Roller bearings

Within these groups, there are sub-categories of bearings that have unique features or optimized designs to enhance performance.

In this bearing selection guide, we’ll cover the four things you need to know about your application in order to choose the right type of bearing.

Find the Bearing Load & Load Capacity

Bearing loads are generally defined as the reaction force a component places on a bearing when in use.

When choosing the right bearing for your application, first you should find the bearing’s load capacity. The load capacity is the amount of load a bearing can handle and is one of the most important factors when choosing a bearing.

Bearing loads can either be axial (thrust), radial or a combination.

An axial (or thrust) bearing load is when force is parallel to the axis of the shaft.

A radial bearing load is when force is perpendicular to the shaft. Then a combination bearing load is when parallel and perpendicular forces produce an angular force relative to the shaft.

To learn more about axial and radial ball bearings, contact our team of engineers!

How Ball Bearings Distribute Loads

Ball bearings are designed with spherical balls and can distribute loads over a medium-sized surface area. They tend to work better for small-to-medium-sized loads, spreading loads via a single point of contact.

Below is a quick reference for the type of bearing load and the best ball bearing for the job:

• Radial (perpendicular to the shaft) and light loads: Choose radial ball bearings (also known as deep groove ball bearings). Radial bearings are some of the most common types of bearings on the market.
• Axial (thrust) (parallel to the shaft) loads: Choose thrust ball bearings
• Combined, both radial and axial, loads: Choose an angular contact bearing. The balls contact the raceway at an angle which better supports combination loads.

Roller Bearings & Bearing Load

Roller bearings are designed with cylindrical rollers that can distribute loads over a larger surface area than ball bearings. They tend to work better for heavy load applications.

If you are looking for more details, kindly visit Angular Contact Ball Bearing.

Below is a quick reference for the type of bearing load and the best roller bearing for the job:

• Radial (perpendicular to the shaft) loads: Choose standard cylindrical roller bearings
• Axial (thrust) (parallel to the shaft) loads: Choose cylindrical thrust bearings
• Combined, both radial and axial, loads: Choose a taper roller bearing

Bearing Runout & Rigidity

Bearing runout is the amount a shaft orbits from its geometric center as it rotates. Some applications, like cutting tool spindles, will only allow a small deviation to occur on its rotating components.

If you are engineering an application like this, then choose a high precision bearing because it will produce smaller system runouts due to the tight tolerances the bearing was manufactured to.

Bearing rigidity is the resistance to the force that causes the shaft to deviate from its axis and plays a key role in minimizing shaft runout. Bearing rigidity comes from the interaction of the rolling element with the raceway. The more the rolling element is pressed into the raceway, causing elastic deformation, the higher the rigidity.

Bearing rigidity is usually categorized by:

• Axial rigidity
• Radial rigidity

The higher the bearing rigidity, the more force needed to move the shaft when in use.

Let’s look at how this works with precision angular contact bearings. These bearings typically come with a manufactured offset between the inner and outer raceway. When the angular contact bearings are installed, the offset is removed which causes the balls to press into the raceway without any outside application force. This is called preloading and the process increases bearing rigidity even before the bearing sees any application forces.

Bearing Lubrication

Knowing your bearing lubrication needs is important for choosing the right bearings and needs to be considered early in an application design. Improper lubrication is one of the most common causes for bearing failure.

Lubrication creates a film of oil between the rolling element and the bearing raceway that helps prevent friction and overheating.

The most common type of lubrication is grease, which consists of an oil with a thickening agent. The thickening agent keeps the oil in place, so it won’t leave the bearing. As the ball (ball bearing) or roller (roller bearing) rolls over the grease, the thickening agent separates leaving just the film of oil between the rolling element and the bearing raceway. After the rolling element passes by, the oil and thickening agent join back together.

For high-speed applications, knowing the speed at which the oil and thickener can separate and rejoin is important. This is called the application or bearing n*dm value.

Before you select a grease, you need to find your applications ndm value. To do this multiply your applications RPMs by the diameter of the center of the balls in the bearing (dm). Compare your ndm value to the grease’s max speed value, located on the datasheet.

If your n*dm value is higher than the grease max speed value on the datasheet, then the grease won’t be able to provide sufficient lubrication and premature failure will occur.

Another lubrication option for high-speed applications are oil mist systems which mix oil with compressed air and then inject it into the bearing raceway at metered intervals. This option is more costly than grease lubrication because it requires an external mixing and metering system and filtered compressed air. However, oil mist systems allow bearings to operate at higher speeds while generating a lower amount of heat than greased bearings.

For lower speed applications an oil bath is common. An oil bath is when a portion of the bearing is submerged in oil. For bearings that will operate in extreme environments, a dry lubricant can be used instead of a petroleum-based lubricant, but the lifespan of the bearing is typically shortened due to the nature of the lubricant’s film breaking down over time.

There are a couple of other factors that need to be considered when selecting a lubricant for your application, see our in-depth article “How to Choose the Correct Ball Bearing Lubricant".

For more F607 Bearinginformation, please contact us. We will provide professional answers.