What are ball bearing cages and retainers?

A ball bearing is a common form of rolling-element bearing, featuring balls placed between races to maintain separation. With the use of such products, rotational friction between moving surfaces can be mitigated while axial and radial loads are supported. With the use of ball bearing cages, also known as retainers, the bearings may be held together while balls are separated from one another. Coming in numerous types, such bearing elements are crucial for standard operations and may act as a reservoir or supplier of oils for lubrication. In this blog, we will discuss ball bearing cages and retainers, allowing you to better understand their functionality and common types.

Cages or retainers are often guided by surfaces between inner and outer rings, the outer diameter often having influence on how bores slide or are guided. While the cage or retainer of the ball bearing is paramount for proper assembly and functionality, their design often causes frictional force that rubs against other elements. As a result, the starting and running torque of a ball bearing is increased with the presence of the cage. To ensure proper operations for a given application, multiple types of cages and retainers have come about to benefit higher speeds, torque sensitive applications, environmental extremes, and more. While there are various types available, the most common are the J-type, W-type, RJ-type, and TW-type cage.

The J-type cage is discernible for its two-piece ribbon that consists of two halves. These halves are then connected with fold down tabs that ensure they are secured together. J-type cages are guided by the balls, and loose clinch types may be procured for lower torque. Often, such cages are most common for low to moderately high-speed applications.

The W-type cage features a one-piece steel crown, and such components are most often used for small bearings. Guided by the inner ring, the W-type cage may be snapped in from one side over the balls. W-type retainers excel in low torque, low speed applications, rarely being used for high-speed applications.

The RJ-type cage is best for larger bearings that exhibit bore diameters that exceed 10mm. For their construction, such cages are a two-piece ribbon that come in halves which are riveted together. Due to their method of connection, such cages are guided by the balls of the bearing and may withstand high levels of vibration and acceleration.

The final major variation is the TW-type, those of which are molded nylon cages. Guided by the balls, the TW-type cage is well suited for high-speed applications and may reduce fluctuations of running torque. Their standard operating temperature ranges from -30 degrees Celsius to 120 degrees Celsius, and more robust glass fiber reinforced nylon may be used for increased capabilities.

In order to achieve an optimal ball fitting or bearing fitting, there are a few factors to consider. Generally, tighter fits are better for increased loads, and the direction, type, and magnitude of loads is important to look over. Additionally, ring rotations will affect performance, some applications requiring looser fits while others need tighter fits. Alongside such factors, other important considerations to make include the bearing size and type, mating component tolerances, environmental temperatures, and accuracy requirements.

Whether you are in search of a ball bearing or other bearing components that are new, used, obsolete, or hard-to-find, Purchasing Synergy is your sourcing solution with our unmatched offerings. Explore over 2 billion listings on our website at your leisure, all of which have been sourced from top global manufacturers that we trust. If there are particular items that you would like to procure, you may receive a personalized quote at any time through the submission of a completed RFQ form. At Purchasing Synergy, we are your sourcing solution for all your operational requirements and needs.


February 15, 2023
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