Understanding Bearing Cages: Preventing Damage and Ensuring Reliability

Understanding the intricacies of bearing components is key for engineers. This way, as they design applications that rely on bearings they can ensure optimal performance and longevity. The bearing cage is a crucial component in this regard. In this blog, we will delve into what a bearing cage is, its significance in bearing operation, and the potential causes of damage. Additionally, we will provide a list of possible problems, their typical root causes, as well as offer solutions to assist engineers in designing applications that use bearings more effectively.

What is a Bearing Cage?

Bearing cages, also known as bearing retainers or separators, are a critical component in many rolling element bearings, such as ball bearings and roller bearings. Their primary function is to maintain uniform spacing between the rolling elements (balls or rollers) and guide them within the bearing raceways. This essential role prevents contact between rolling elements, reducing friction, wear, and the risk of failure. The cages also help in evenly distributing lubrication, contributing to the overall efficiency and reliability of the bearing.

A bearing cage from a ball bearing. The retainer is made of two pieces of steel that are riveted together.

What Could Cause Damage to a Bearing Cage?

Bearing cages are subjected to various operating conditions and stresses, which can lead to damage if not addressed appropriately. Here are some common factors that can cause damage to bearing cages:

  1. Misalignment: When a bearing experiences misalignment, it can lead to uneven loading on the cage and rolling elements, causing premature wear or deformation of the cage.
  2. Excessive Speed: High rotational speeds can generate significant centrifugal forces, stressing the cage. Excessive speeds can lead to cage distortion, wear, or even failure. 
  3. Severe Vibration: While severe vibration is rare, it is a leading cause of cage failure. When severe vibration is present a special cage is typically required. 
  4. Insufficient Lubrication: Inadequate lubrication can result in increased friction between the rolling elements and the cage. This friction can lead to overheating and accelerated cage wear.
  5. Contaminants: Foreign particles, such as dust, debris, or moisture, can enter the bearing assembly and accumulate within the cage. This can lead to abrasive wear and corrosion of the cage material.
  6. Overloading: Applying excessive axial or radial loads on the bearing can deform or fracture the cage, reducing its effectiveness and the bearing’s overall lifespan.

Common Problems and Solutions

To help engineers design applications that use bearings with foresight, here is a list of possible problems related to bearing cages and their corresponding solutions:

  1. Cage Wear or Distortion: Problem – Cage wear or deformation due to misalignment, insufficient lubrication, or excessive speed and vibration. Solution – Ensure proper alignment of the shaft and housing, use suitable lubrication, and consider higher-quality cages for high-speed applications.
  2. Cage Fracture: Problem – Cage fracture caused by vibration, overloading, or excessive forces. Solution – Select bearings with cages designed to withstand higher loads or consider alternative cage materials.
  3. Cage Corrosion: Problem – Cage corrosion due to exposure to moisture or contaminants. Solution – Implement effective sealing mechanisms, use corrosion-resistant materials, and maintain a clean operating environment.
  4. Cage Jamming: Problem – Jamming of rolling elements within the cage is almost always a catastrophic failure, and can be the result of any of the issues listed in the above section. It is most often due to either lubrication failure or misalignment. Solution – Confirm that lubrication type and amounts meet equipment or bearing manufacturer’s recommendations. Search for and address misalignment issues promptly.


Bearing cages play a vital role in ensuring the smooth operation and longevity of rolling element bearings. Engineers designing applications that rely on bearings should consider potential problems related to bearing cages and implement suitable solutions during the design phase. By understanding the factors that can cause cage damage and applying preventive measures, engineers can create more reliable and durable systems, ultimately saving time and resources in the long run.

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