A fundamental part of the angular contact bearings is the contact angle. These bearings can only take axial load in one direction unless they are used in sets (see universal sets).

Popular Contact Angles:

Standard Precision 15°

                                25°

High-Speed            18°

                                25°

Thrust                      30°

                                40°

Ball Screw Support  60°

As the contact angle increases, the axial load capacity increases but the speed and life decrease. Angular contact bearings with small contact angles are more suitable for high-speeds and radial loads.

Effect of Contact Angle – Standard Designations

For high-speed products; 18° has been adopted as the lowest standard contact angle. This has been shown to be more effective at high-speeds in terms of bending stiffness compared to 15°. An 18° contact angle provides better axial stiffness than 15°, but less radial stiffness. However, as seen from the spindle diagram, bending stiffness is more important.

For high-speed applications using motorised spindles, the internal heat generation can be much higher than belt driven spindles; this can reduce the bearing internal clearance and sometimes cause failure at high-speed. For these applications it is more beneficial to select a 25° contact angle because this has a greater radial internal clearance compared to the 18° contact angle and can more easily accommodate a reduction in internal clearance due to thermal movement.

Examples of Contact Angle – High-Speed and Thrust Designations

25BGR10STDUELP2 = 15° Robust High-Speed Grinding Applications

30BNR10STDBELP = 18° Robust High-Speed

30BER10STDBELP3 = 25° Robust High-Speed

30BAR10STYNDBELP3 = 30° Robust Thrust

30BTR10STYNDBELP3 = 40° Robust Thrust

30TAC62BDFC9PN7A = 60° Ball Screw Support