Four-point contact bearings are a special form of single-row angular contact bearings. Their high raceway shoulders and the large number of balls enable them to absorb high axial forces on both sides. Their ability to withstand radial forces is low, however.
A minimum axial load is essential in order to achieve low friction (particularly at high speeds).
Four-point contact bearing up to bore Ø 710 mm.
Four-point contact bearings come in two different versions:
- QJ - with split inner ring and a contact angle of 35°
- Q - with split outer ring and a contact angle of 23°
The split inner and outer rings allow a large number of balls to be accommodated. The bearings are also easy to assemble because the respective ring (outer or inner ring) is installed separately with the ball and cage assembly and the respective ring halves. There is little scope for adjusting the angle.
Four-point contact bearings in the standard version are manufactured with a normal bearing clearance (C0 or CN – no suffix added to the bearing designation).
The four-point contact bearings are manufactured with solid brass cages or plastic cages (glass fibre reinforced polyamide 66). If a bearing with plastic cage is used, the operating temperature is max. + 120 °C.
In the standard version four-point contact bearings are heat treated so that they are generally dimensionally stable up to max. + 150 °C (bearings above an outer diameter of 120 mm up to + 200°C).
In the case of bearings with plastic cages the permitted operating temperatures must be noted.