In a ball bearing, the balls are separated and held in place by which component?

• A. Grease
• B. A retainer
• C. Seal
• D. Cage

Answer: (B)

The spacing and containment of the rolling elements is handled by a retainer, often called a cage. This component sits between the inner and outer races and has pockets for each ball, keeping them evenly spaced so they don’t collide as the bearing rotates. That precise spacing allows the load to be carried smoothly around the circumference and helps maintain lubrication paths around each ball. Grease lubricates but doesn’t hold the balls in place; a seal keeps lubricant in and contaminants out but doesn’t organize the balls. The term cage is sometimes used interchangeably with retainer, but the device’s job is to separate and position the balls, which is described here as a retainer.