How to Choose Deep Groove Ball Bearing?

 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.

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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.

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.

You will get efficient and thoughtful service from Rimao.

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".

Opting for deep groove ball bearings in your industrial setting is often straightforward due to their widespread effectiveness across diverse industries. However, selecting the appropriate type for your precise requirements can be challenging, given the multitude of factors to evaluate and the various options available to match those needs accurately. 

Working with NSK's engineering team and using our online product selection guide can ensure you find the right deep groove ball bearing to keep your application functioning optimally.

Factors to Consider When Selecting Deep Groove Ball Bearings

Deep groove ball bearings are suitable for many different applications, so the range of operating conditions and application needs is large and varied. When designing, many factors must be considered when selecting the right deep groove ball bearings for your application. 

Depending on your installation space and needs, load capacity needs, speed, alignment issues, vibration and noise tolerance, precision and accuracy concerns, and operating environment, different materials, configurations, and customizations can be made to ensure the right fit for your manufacturing, automation, or operating system.

Installation Space

The installation space is typically fixed within the application, so any deep groove ball bearing that will be used needs to fit. Assess the available space to determine the bore size, outer diameter, and width.

Load Rating

Once you have determined the available space, look for bearings with load ratings that will fit your needs. If the bearing cannot support the load, the lifespan of the bearing and the system as a whole can be significantly reduced. Double-row deep groove ball bearings have higher load capacities than single-row deep groove ball bearings and may be the better choice for applications with a high load capacity.

Speed

The bearing, size, cage style, and lubrication will all impact the speed at which a deep groove ball bearing can operate. When choosing a deep groove ball bearing for your application, make sure to take the speed needs into consideration. Deep groove ball bearings are typically able to achieve the highest permissible speeds.

Misalignment

The inner and outer rings are always slightly askew but should not be tilted. If the shaft is deformed due to overloading or errors in the design of the complete automation system, this must be addressed. Different deep groove ball-bearing options can be used when more skewing is required.

Rigidity

When high rigidity is needed, the bearing needs will often change. The relationship between the bearing load and the elastic deformation of the inner and outer rings and rolling elements is called bearing rigidity. Preloading deep groove ball bearings can increase rigidity for applications that demand a higher level.

Running Noise

Deep groove ball bearings are recommended for use in applications where minimal running noise and vibration are a concern. Many electric motors and measuring devices have low tolerances for running noise and vibration, making deep groove ball bearings a good fit for these applications.

Accuracy

Many applications require a high degree of precision and accuracy during operation. There are several ways to determine how accurate deep groove ball bearings will run. When higher levels of precision are required, deep groove ball bearings are often the best choice.

Installation Concerns

Installation and maintenance methods will vary depending on where and how the system is installed. Bearings that can be taken apart are easier to install and remove, whereas other bearing types require more skill to mount.

Deep Groove Ball Bearing Options

Selecting deep groove ball bearings offers different options. They can be customized to meet the needs of many different applications.

Single-Row or Double-Row

Single-row deep groove ball bearings are typically used in applications where low friction, low running noise, and high speeds are the primary requirements. The bearing will operate in an extreme environment, such as high heat conditions. Double-row deep groove ball bearings are used where load capacity is the more significant concern, and the design space is relatively small compared to the load needs. 

Lubrication 

Self-lubricating deep groove ball bearings, particularly with a high-quality lubricant, will not only allow the bearings to operate most efficiently but will also significantly increase the system's longevity and reduce maintenance requirements, which will ultimately reduce system downtime.

Materials and Sealing Options

Although high-quality, ultra-clean steel with a pressed steel cage is the standard for deep groove ball bearings, there are other options that can be used when operating conditions demand it. Bearings can be coated with an aluminum-based ceramic material, plasma sprayed to ensure appropriate bonding, and then finished with an acrylic resin for moisture resistance. 

Size

Different sizes are available to fit different systems. Online sizing guides can help determine the correct deep groove ball-bearing size.

When choosing a deep groove ball bearing to work within your current system, ensure you have identified your application's needs, especially load capacity, operating environment, precision needs, and installation concerns. NSK engineers will work with you to find the deep groove ball bearing that best fits your specific application.

Why Choose NSK?

Discover the power of NSK's deep groove ball bearings for your system needs. With a diverse range suitable for various industries, NSK offers superior performance, longevity, and cost-effectiveness. Our bearings thrive in any operating environment, ensuring optimal functionality with minimal maintenance.

Partner with NSK  to customize a system tailored to your industry and application requirements. Our team will collaborate with yours to deliver a reliable solution. Unlock your system's potential with ]deep groove ball bearings manufactured by NSK.