Dummies Guide To Miniature Radial Ball Bearings And Their Types

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In this article we will see in details about the roller/radial bearings, and its types and dimensions.

Parts in Bearing

Radial Bearing Exploded View

##Seals and Shields To help retain bearing lubrication and prevent contamination from the environment a seal (contact) or shield (non-contact) can be employed.

Often no seal (Open) is required when the bearing will be housed and externally lubricated or when operated in a vacuum.

Seal Identification

Comparison of shield, sealed and no-seal bearing

Type Symbol Properties Cost Description
Shield Z They have fair dust resistance and poor water resistance. Shields are good to around 350 F. Lowest in price, hence good for prototyping and low end application The Z type shield is a metal shield that typically is non-removable after installation as is it pressed in. There is a small gap about .005 inches between the shield and inner race. There is no contact so obtainable speeds and torque are not effected as in a contact type seal. Lubricant leakage can occur and contamination can enter through this gap.
Seal RS Generally the speed rating is reduced about 35% that of the Z type or open and torque is increased. Temperature range is 15 F to 220 F Costlier than Z type The RS type seal is a rubber seal that makes contact with the inner race. Most commonly made of Buna-rubber. They are removable. They offer the best sealing against contamination and lubricant leakage.
Seal V Speed rating is not reduced and is comparable to that of the Z type or open. There is no seal induced torque increase. Temperature range is 15 F to 220 F Costlier than RS type Seal is a non-contact type rubber seal that does not contact the inner race, but rides in groove machined in the inner races creating a labyrinth effect. Its performance falls between a metal shield and contact type rubber seal. Most commonly made of Buna-rubber. They are removable. They offer the good sealing against contamination and lubricant leakage.
Seal T High temperature capability of 500 F Availability is rare and very costly The seal is made of glass reinforced Teflon. This type of seal is removable and easily replaced. In most configurations the seal is held in place by a snap ring. The level of contact (sealing) can be adjusted to meet application requirements all the way from non-contact to heavy contact.

Dimensions of Miniature Bearings

Radial/Roller Bearing Dimensions

Bearing No Bore Dia (d) mm Outer Dia (D) mm Width (B) mm
601X 1.5 6 3
602 2 7 3.5
602X 2.5 8 4
603 3 9 5
623 3 10 4
604 4 12 4
624 4 13 5
605 5 14 5
625 5 16 5
606 6 17 6
626 6 19 6
607 7 19 6
627 7 22 7
608 8 22 7
628 8 24 8
609 9 24 7
629 9 26 8
6000 10 26 8
6001 12 28 8
6002 15 32 9
6003 17 35 10
6004 20 42 12
6005 25 47 12
6006 30 55 13
6007 35 62 14
6008 40 68 15
6009 45 75 16
6010 50 80 16
6011 55 90 18
6012 60 95 18
6013 65 100 18

Bearing Identification

Based on the number of number of the shields/seals and size the bearings are named,

For example 608 number specifies the dimension (refer Dimensions section) of a bearing, following letters/numbers says its seal/shield type.

Number Meaning
608 Z Shield on single side only, other side is open
608 ZZ Shields on both side
608 RS Seal on single side only, other side is open
608 2RS Seals on both side

Still there are more you can read about bearing on wikipedia.org



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