Bearing Parts Descriptions and Terminology
Ball Bearings Components
The figures below illustrate an assembled Ball Bearing and the terms used to describe each component:
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 Shield type |
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 Flange type |
 External Retaining Ring type |
About Ball Bearing Parts
When discussing ball bearing components, it's important to understand that the main parts of the ball bearing are the races and the balls. There is an outer race, which goes into a bore, and the inner race, in which the shaft rides. The balls are placed in between these two parts to create the rolling properties of the ball bearing. Without these basic parts, there is no ball bearing. That being said, there are other bearing parts to consider, like shields, cages, and flanges. Here you can find a description of some of these types of parts that are available through NMB.
Retainers/Cage
The following retainers are available in most of our Ball Bearings.
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Ribbon Retainer/Cage (Symbol R)It is composed of two press molded steel parts. The balls are held between the two steel parts, and the tabs of one of the steel parts are bent over the second steel part to unite them together. This is the most common type. |
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Crown Retainer/Cage (Symbol H)It is composed of a press molded steel part. The small difference in inner and outer diameters of the retainer allows them to be used for thin type and very small ball bearings.
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Plastic Retainer/Cage (Symbol MN etc.)It is composed of a molded and cut plastic part. The plastics include Polyamide, Polyacetal, and so on. It is used for high speed rotation and low noise level. |
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Shields and Steels (Enclosures)
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