This is the newest series developed in SKF High Precision Bearings. It has ball size smaller than the other two series and it is specifically developed to be equipped with non-contacting seals.
These bearings belong to the series 70 FB (DB) and 719 FB (DB).

Centrifugal forces from contact between the balls and the outer ring raceway are therefore further reduced, as is also the contact pressure.
Because of the very small balls, the rings are also thicker; this means that any form error of shaft or housing bore have less influence on the roundness of the bearing rings. As a result the running accuracy is further enhanced.
The sealed version eliminates the need to develop the application with labyrinths or sealing systems.

The suffix FB indicates that the angular contact ball bearing has a contact angle equal to 18 degrees.
It is manufactured according to 719 and 70 series.

This contact angle value keeps the possibility to carry remarkable axial loads keeping a high rotational speed capacity.

The suffix DB indicates that the angular contact ball bearing has a contact angle equal to 25 degrees.
It is manufactured according to 719 and 70 series.

This contact angle value increases the possibility to carry axial loads keeping a fairly good rotational speed capacity.
In spindle applications they are usually fitted on the front side of the shaft to support the biggest portion of the working loads.

Drawing (click to enlarge)

 

Seal

no

 
 

bearing internal diameter range

d [mm]

50-79

 
 

bearing internal diameter

d [mm]

50

0

-0,006

 
 

bearing external diameter

D [mm]

80

0

-0,007

 
 

bearing width

B [mm]

16

0

-0,12

 
 

d1

[mm]

61,4

 
 

D1

[mm]

68,4

 
 

r1, r2

[mm]

1

 
 

r3, r4

[mm]

1

 
 

contact angle

α [°]

18

 
 

a

[mm]

19

 
 

da

[mm]

54,6

 
 

db

[mm]

54,6

 
 

Da

[mm]

75,4

 
 

Db

[mm]

75,4

 
 

ra

[mm]

1

 
 

rb

[mm]

1

 
 

oil nozzle position

dn [mm]

61,8

 
 

Speed rating with grease

[1/min]

20 000

 
 

Speed rating with oil

[1/min]

34 000

 
 

dynamic load rating

C [N]

13 300

 
 

static load rating

Co [N]

13 400

 
 

fatigue load limit

Pu [N]

570

 
 

calculation factor

[fo ]

9,7

 
 

Light preload

Class A [N]

37

 
 

Medium preload

Class B [N]

74

 
 

Heavy preload

Class C [N]

145

 
 

mean diameter

P [mm]

64,6

 
 

ball diameter

dw [mm]

5,56

 
 

ball number

[Z ]

27

 
 

Bearing materials

All-steel

 
 

Mass

[kg]

0,28