Angular Contact Bearings Guide: Types, Uses & Preload

Angular contact bearings are essential for high-speed, high-precision applications.

They are particularly suitable for machine tool spindles, aerospace equipment and precision machinery.

Their unique design enables the bearings to maintain high rigidity and stability under heavy loads.

This guide covers the key types, common applications, preload methods, and practical selection tips to help you choose the right bearing for your needs.

What Is an Angular Contact Bearing?

Angular contact bearings are ball bearings where the inner and outer raceways are set at an angle to each other.

This design allows the bearing to support both radial and axial loads in a single direction.

It also enables high-speed operations and maintains high precision.

One key advantage of angular contact ball bearings is their ability to handle axial loads.

This capacity increases as the ball bearing contact angle increases.

Basic Components of Angular Contact Bearings

• Outer ring

• Inner ring

• Inner Raceway

• Outer Raceway

• Balls

• Cage

How Angular Contact Bearings Work

Contact Angle

The contact angle is a key feature in angular contact bearings.

It refers to the angle between the line connecting the contact points of the ball and the raceways.

This line is compared to another line that is perpendicular to the bearing axis. (Typically 15°, 25°, 30°, 40°)

Bearing contact angle determines how the bearing handles axial loads.

Load Transfer Path

When under load, the force travels through the balls along the contact angle, transferring between the raceways.

This allows the angular contact ball bearing to support both axial and radial loads.

It enhances load adaptability, stability, and precision during rotation.

Types of Angular Contact Bearings

Single Row Angular Contact Ball Bearings

Features:

• Increased Load Capacity

• Smooth and Stable Operation

• Simple Installation with Universal Matching

Single Row Angular Contact Ball Bearing: 7200 BECBP

High rigidity uses:

• Compressors

• Material Handling Systems

• Screw Chillers

• Industrial Pumps & General-Purpose Pumps

• Elevator Hoists

• Electric Motors

Note

Miniature Angular Contact Bearings are compact, high-precision versions of standard single row angular contact bearings.

Angular contact bearings typically have bore sizes under 10 mmand are optimized for space-constrained, precision-critical applications.

Matched/Duplex Angular Contact Ball Bearings

Duplex angular contact ball bearings, also known as matched angular contact ball bearings, are precision pairs.

They handle combined loads and specific mounting arrangements. Here are three common types:

Back-to-back (DB)

Back-to-back angular contact bearings have the following features:

• Handling both radial and axial loads in either direction. Axial loads from both directions are accommodated, but each is carried by only one bearing.

• With a large distance between the load centers, providing high moment load capacity.

• Allowing only a small degree of misalignment.

• Offering a bearing configuration with high rigidity.

• Withstanding tilting or overturning moments.

• Extending load paths outward from the axis of the bearing.

Face-to-face (DF)

Face-to-face angular contact bearings are characterized by:

• Handling radial and axial loads in either direction, with each axial load carried by a single bearing

• Reducing moment load capacity because of shorter distance between load centers

• Allowing greater misalignment compared to back-to-back arrangements

• Offering lower rigidity than back-to-back configurations

• Converging load paths toward the bearing axis centerline

Tandem (DT)

Tandem angular contact bearings offer advantages such as:

• Used when the load-bearing capacity of a single bearing is insufficient.

• Distributes radial and axial loads equally between the bearings.

• Features parallel load paths.

• Accommodates axial loads in only one direction.

• If axial loads are applied in both directions, a third bearing must be added, positioned against the tandem pair.

Double row angular contact ball bearings

A doublerow angular contact ball bearing consists of two single-row angular contact ball bearings.

These angular contact bearings are arranged back-to-back in a single assembly.

Key Features:

• Requiring less axial installation space

• Providing a compact alternative to back-to-back single-row angular contact bearings that require more axial space

• Handling both radial and axial loads in both directions

• Withstanding tilting or overturning moments

• Providing a high-rigidity bearing configuration

Uses:

• Electric motors

• Pumps and compressors

• Machine tool spindles

• Gearboxes

• Conveyors and AGVs

• Textile Industry

Double row angular contact ball bearing: 3200 ATN9

Double row angular contact ball bearings with sealed and shielded designs offer superior protection, durability, and reliability in demanding applications.

They come with either rubber seals or metal shields based on application needs.

Rubber seals suit humid, dusty environments, while metal shields work best in clean, high-speed conditions.

Four-point Contact Ball Bearings

Fourpointcontactbearing features a 30° contact angle and a split inner ring design.

when subjected to radial loads, the balls establish four-point contact with both the inner and outer rings.

This unique design allows a single bearing to handle axial loads in both directions.

Under pure/heavy axial loads, the load is shared at two contact points, similar to standard angular contact bearings.

Four-point Contact Ball Bearing: QJ 202 N2MA

Features:

• Supports axial loads in both directions

• Space-saving axial design

• Enhanced load capacity

• Convenient separable structure

• Optimized lubrication

• User-friendly handling

Uses:

• Tractor Transmissions

• Robot Gearboxes

• Servomotors

• Industrial Gear Units

• Aerospace Applications

How to Select Angular Contact Bearings

The selection of angular contact bearings requires careful consideration of various application parameters.

These include speed, load direction, and rigidity requirements.

Other factors such as contact angle, materials, and pairing arrangements are also important.

Determine Basic Application Parameters

• Target Operating Speed (rpm)

• Type of Load

• Required Rigidity

• Dimensional Constraints

• Space Limitations

• Operating Environment

Understand Speed Limits

Three Types of Speed Definitions

• Limiting Speed: Theoretical maximum speed a bearing can reach under ideal conditions—optimal lubrication, load, and alignment.

• Reference Speed: Recommended upper limit for long-term stable operation under normal operating conditions.

• Actual Operating Speed: The equipment's running speed under normal conditions.

Recommended Speed Reference Table

Tip: When selecting bearings, ensure that the reference speed ≥ target speed, maintaining a safety margin of 10-30%.

Factors Affecting Reference Speed

• Bearing Pairing

• Preload Type

• Lubrication Method

• Cage Material

Understand Load Requirements

• Angular contact bearings support combined radial and axial loads, ideal for high-rigidity or multi-load applications.

• Single-row angular contact bearings support axial forces in only one direction. To handle forces in both directions, they are usually used in pairs, like DB (back-to-back) or DF (face-to-face) setups.

• Double-row and four-point contact contact bearings can directly support axial forces in both directions. They are often used in applications that require precise axial positioning or carry large thrust loads.

• For high load applications, it is recommended to choose bearings with a large contact angle, such as 40°. Multi-row configurations are also effective for increasing load capacity.

Choose the Right Contact Angle

Different contact angles are suitable for different speed and axial load requirements.

Refer to the table below for initial selection guidance.

When selecting bearings, it’s also important check the angle codes used by different brands. (e.g., NSK angular contact bearing A5 = 25°).

Select Materials & Cages

Consider Preload in Selection

For high-speed, high-precision applications such as spindles and servo motors, preload is an important factor to consider.

It helps improve rigidity and reduce vibration. Preload should be carefully addressed during the bearing selection process.

Preload is closely related to the contact angle and bearing pairing arrangement.

The specific preload method—such as using springs or spacers—is usually determined during installation.

It depends on the operating conditions and performance requirements of the application.

Choose Bearing Arrangement (DB/DF/DT)

Materials of Angular Contact Bearings

Materials for Rings and Rolling Elements

Chrome Steel

Standard Grades:

Characteristics:

• High hardness and wear resistance

• Good machinability.

• Suitable for most standard industrial applications.

Typical Applications:

• Electric motor bearings, general machinery drive systems.

• Machine tools, automotive transmissions, high-speed rotating parts.

• Bearings for various industrial equipment.

Various Alloy Steels (Treated with Nitriding and Other Processes)

Example Materials:

• X30CrMoN15-1 (X30)

• Cronidur 30 (Nitrided Stainless Steel)

Characteristics:

• Nitriding layer enhances surface hardness, increasing lifespan;

• Excellent fatigue resistance and wear resistance;

• Operates stably in extreme temperatures (from -70°C to +250°C).

Typical Applications:

• Aerospace, precision instruments.

• High-speed spindle bearings, aerospace gyroscopes.

• Military, nuclear power, and detection equipment.

Stainless Steel

Common models:

AISI 440C, AISI 316L, AISI 304

Characteristics:

• Good corrosion and rust resistance

• Suitable for wet, high humidity, or chemical environments

• Slightly lower hardness compared to GCr15, ideal for light to medium load applications

Typical Applications:

• Medical equipment, laboratory instruments

• Food processing machinery

• Marine equipment, cleaning systems

Ceramic

Features: High hardness, low friction coefficient, excellent corrosion resistance, and high-temperature performance.

• Hybrid Ceramic: Commonly used in high-speed and precision machinery, such as aerospace and automotive applications.

• Full Ceramic Bearings: Suitable for high-temperature, vacuum, or chemically corrosive environments.

Cage Materials

Mounting & Preload of Angular Contact Bearings

Preload Basics

Preloadrefers to applying a small amount of force to the bearing in advance.

This is done before the angular contact bearing is subjected to any external loads.

This ensures that the rolling elements remain in contact with the raceways.

Even when no external loads are applied, the bearing maintains internal stability.

Function:

• Increasing rigidity

• Reducing vibrations

• Improving accuracy

• Enhancing load distribution

Preload Methods:

• Constant Preload: This is achieved by using components like springs or spacers to maintain a fixed preload force.

• Variable Preload: Preload is adjusted according to the operational conditions, typically achieved using mechanical devices like shims or adjusters.

Installation Methods

Preload Adjustment Methods

• Shims: Thin washers used for adjusting preload by adding or removing layers.

• Spacers: Keeping a fixed distance between bearing parts to control preload.

• Springs: Providing constant preload for steady bearing pressure, placed between rings or the bearing and housing.

• Tapered Washers: Applying axial preload in paired bearings, with angled shapes for precise adjustment.

Installation Considerations

• When adjusting preload, it is essential to avoid over-constraining the bearing rings. This can cause excessive friction, heat buildup, and premature bearing failure.

• Proper alignment and clearance should be maintained to prevent uneven loading on the bearing elements.

Preload Recommendations

Angular Contact Bearings vs Deep Groove

Conclusion

Angular contact bearings are crucial for high-speed, high-precision applications, handling both radial and axial loads simultaneously.

Choosing the right bearing involves considering speed, load, and size.

After selecting the structure, visit the angular contact ball bearing manufacturer's website to verify model, dimensions, and installation methods for compatibility.

Contact Lily Bearing today.