What is the preload of angular contact ball bearings related to and what should we pay attention to?

The preload of angular contact ball bearings is a critical factor that influences the performance and functionality of the bearing arrangement. Preload refers to the axial force applied to a bearing before it is mounted or installed in a machine. It is essential for achieving proper operating conditions and maximizing the performance of angular contact ball bearings. The preload is related to several important aspects, and attention should be paid to the following factors:

1. Elimination of Clearance

The primary purpose of applying preload is to eliminate the internal clearance within the bearing. Angular contact ball bearings typically have some internal clearance, which can lead to issues such as vibration, noise, and reduced precision in applications where minimal play is required.

2. Rigidity and Stiffness

Preloading increases the rigidity and stiffness of the bearing system. This is particularly important in applications where high precision, accuracy, and resistance to deflection are critical, such as machine tool spindles and other precision equipment.

3. Axial and Radial Stiffness Balance

The amount of preload applied needs to strike a balance between achieving the desired axial and radial stiffness. Excessive preload can result in increased friction, heat generation, and potential damage to the bearing, while insufficient preload may lead to insufficient stiffness and reduced performance.

4. Operating Temperature

Preloading affects the operating temperature of the bearing. Excessive preload can result in higher temperatures due to increased friction, potentially leading to premature wear and reduced lubricant life. Proper preload selection helps maintain optimal operating temperatures.

5. Bearing Life and Fatigue

The fatigue life of angular contact ball bearings can be influenced by preload. Improper preload can lead to increased stress levels and reduce the bearing’s fatigue life. It’s essential to consider the intended application and load conditions when determining the appropriate preload.

6. Mounting Arrangement

The method of mounting the bearing, whether it’s face-to-face, back-to-back, or tandem arrangement, can affect the preload requirements. Different arrangements may have different preload specifications.

7. Application Specifics

Consider the specific requirements of the application, such as speed, load, accuracy, and operating conditions. Different applications may have different preload needs based on these factors.

8. Type of Preload

There are various methods to apply preload, including axial spring preload, spacers, and using a pair of bearings in opposition. Each method has its advantages and limitations, and the choice depends on the application requirements.

9. Manufacturer Recommendations

Manufacturers of angular contact ball bearings provide guidelines and recommendations for preload values based on their designs. It’s important to refer to the manufacturer’s specifications and guidelines when selecting and applying preload.

10. Testing and Verification

After installation, it is essential to test and verify the preload to ensure it aligns with the design specifications. This may involve measuring axial displacement or using specialized tools for preload verification.

In summary, preload in angular contact ball bearings is related to eliminating clearance, increasing rigidity, and optimizing operating conditions. When selecting and applying preload, careful consideration of application requirements, bearing type, and manufacturer recommendations is crucial to achieving optimal performance and longevity. Consulting with bearing experts or referring to relevant standards and guidelines can aid in the proper selection and application of preload for specific applications.