Four-point bearings are single-row angular contact ball bearings and can accept high axial forced in both directions. However, only low radial forces can be accepted. A minimum axial load must be applied in order to achieve low friction. This is applicable in particular to high speeds
SLF produces two designs of four-point bearings:
-with split inner ring as design QJ and
-with split outer ring as design Q.
Due to the split inner and/or outer ring it is possible to accommodate a high number of balls. The relevant ring (outer or inner ring) with the ball race and the relevant ring halves can be installed separately. Only low angles can be set.
The bearings of the QJ version have a contact angle of 35° and in the Q version a contact angle of 23°.
Tolerances, bearing clearance
The standard designs of the bearings have standard tolerances and standard bearing clearances. Bearings with different clearances can be supplied on request.
Tolerances: Radial bearings,
Axial clearance: Four-point bearings,
The four-point bearings are produced with solid brass cages or fiber-glass reinforced polyamide 66. For the possible standard design please refer to the overview of products. For deviations please contact the manufacturer. The temperature of use of the polyamide cage is max. 120 °C.
Four-point bearings have been heat treated so that they can be used up to an operating temperature of 150 °C and in bearings with an outer diameter over 120 mm up to 200 °C while maintaining the accurate dimensions and with due consideration given to the cage used.
Dynamic equivalent loading
P = Fr+ 0.66 Fa [kN] for Fa/ Fr= 0.95
P = 0.6 Fr+ 1.07 Fa [kN] for Fa/ Fr> 0.95
To minimize the friction in the bearing the axial force should be selected such that the ball contact only at two points. This is the case if Fa is > 1.2 Fr.
Angular contact ball bearings (four-point bearings) DIN 628-4
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