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Bearing Geometry Technical Information and Design Factors || Dynaroll

TECHNICAL PAPERS

TECHNICAL PAPERS

DESIGN FACTORS WHEN USING SMALL BEARINGS, PART 1: BEARING GEOMETRY (Page 2)


Common radial play values are given in the table below:

STANDARD RADIAL PLAY RANGES AND APPLICATIONS
DYNAROLL CODE MIN DESCRIPTION MAX
RADIAL PLAY RANGE
APPLICATION
MC2
Tight
1(3)
3(8)
 Low backlash gear systems with
predominantly radial loading.
MC3
Standard
2(5)
4(10)
 Low speed electric motors.
MC4
Standard
3(8)
5(13)
 Gears, belt drive, tape guides, synchros, servos.
MC5
Loose
5(13)
8(20)
 High speed electric motors, tape Guides, radial and axial loading.

Note: final radial play after assembly is the important operating condition, therefore, compensation for interference must be made in the bearing specification.

Note that bearing manufacturers’ radial play values are given as a range. Tighter tolerance of the radial play may be specified, but it will increase the cost of the bearing since a sorting process is used to select specific radial play values.

Preload and Axial Play

In an application where accurate rotation is needed, the radial play must be removed from the bearing. Unless this is done, the races can bounce around relative to each other. The radial play is normally removed by using a pair of bearings which are preloaded to remove the play by pressing the races together axially until the balls are in firm contact with the raceways.
O-Type Preload Stiffer
X-Type Preload Less Stiff

 

Note that in the examples above, preload is achieved by pressing the inner races together (or outer races apart) to give O-type preload or by pressing the outer races together (or inner races apart) to give X-type preload. The O and X refer to the shape formed by the contact angle lines in the diagrams.


Bearing Geometry, Page 3: Contact Angle and Axial Play link