Have you ever noticed the types of cage guidance of your bearings? 

Basically, there are 3 types: outer-ring-rib guidance, inner-ring-rib guidance, and rolling-element guidance.

Unfortunately, big part of Chinese factories, including big brands, don’t put their eyes on cage guidance. 

They believe various types of cage guidance are interchangeable. You may get NU2310 with MA brass cage with outer-ring-rib guidance, even though you order “NU2310M” with clear requirement of rolling-element guidance. 

In some cases, it may lead to a serious claim.

All these 3 types of cage guidance probably appear in various types of bearings, with performance reasons, bearing design reasons and manufacturing reasons. Attention should be paid to the different performances of different types of cage guidance. 

The performance difference of these 3 types of cage guidance is mainly reflected in the speed performance under different lubrication conditions.

During our research on cage guidance, we got to know something interesting as extra:

1.     Brass cage is widely used in high-speed application.

2.     There are 4 kinds of gaps between components: 

radial clearance (Gr), roller gap (△), cage guidance gap (Cr), cage axial gap (Ca), respectively. 

These gaps are defined as the maximum possible displacements between relative components in radial/axial direction.

[At the time we got to understand the requirement “max. axial displacement” in some drawings of cylindrical roller bearing.]

3.     According to the general design guideline of rolling bearings, Ca>△, T (pocket clearance)>Cr, Cr>Gr, usually. 

These rules ensure that the rollers contact with raceways directly.