Page 81 - Rollingbearings

Selection criteria
Speed and friction • Bearings with rolling elements made of
ceramics (hybrid bearings) accommodate
The permissible operating temperature of higher speeds than their all­steel
rolling bearings imposes limits on the speed equivalents
at which they can be operated The operating
temperature is determined, to a great extent,
on the frictional heat generated in the bearing,
except in machines where process heat is
dominant
An overview is provided in Suitability of
rolling bearings for industrial applications,
page 72, of the speed capability of various
bearing types
When selecting bearing type on the basis
of operating speed, you should consider the
following:

• Ball bearings have a lower frictional
moment than same­sized roller bearings
• Thrust bearings cannot accommodate
speeds as high as same­sized radial
bearings
• Single row bearing types typically gener­
ate low frictional heat and are therefore
Bearing type and arrangement
more suitable for high ­speed operation
than double or multi­row bearings

Diagram 1
Contact angles of various bearing types
Contact angle = 90°
1 Cylindrical roller thrust bearing (for axial load) 75° 60°
2 Needle roller thrust bearing 45°
3 Thrust ball bearing
4 Angular contact thrust ball bearing 1
5 Spherical roller thrust bearing
6 Single row angular contact ball bearing 2 5 B.2
7 Four­point contact ball bearing
8 Double row angular contact ball bearing
9 Self­aligning ball bearing Medium to
10 Deep groove ball bearing Thrust heavy load
The contact angle depends on load and clearance bearings
11 Tapered roller bearing 3
12 Spherical roller bearing
13 Needle roller bearing 30°
14 CARB toroidal roller bearing 4
medium load
15 Cylindrical roller bearings Light to bearings
Radial
6

7 11
8 15°

Radial load 9 12 15

14
10 13
Contact angle = 0°
Thrust load
(for radial load)

79