The bearing cage aim at keeping the balls in place on the circumference of the medium diameter, called primitive. According to applications, there are different types of cages.
Types of common cages
TWO PIECES CAGES, ASSEMBLY BY STRIP DEFORMATION
Code J : Steel
Code Y : Brass
SINGLE PIECE CAGES, ASSEMBLY BY PRESSURE ON THE BALLS
Code W : Steel plate
Code TNH : Polyamide PA66 Max. Temp. 80°C, slow speed
Code T9H : Polyamide PA66 reinforce with fiber glass Max. Temp. 120°C, high speed
CAGE-FREE BEARINGS (full of balls)
Requires slots for balls mounting.
Code V : Higher loads and acceptable accelerations, lower speed limits.