An angular contact ball bearings concepts:

(Angular Contact Ball Bearings) both radial and axial loads. In high speed work. Larger the contact angle, the higher the axial load capacity. High-precision and high-speed bearings usually take the contact angle of 15 degrees. In the axial force, the contact angle will increase.
     Single row angular contact ball bearings can withstand axial load in one direction, the radial load, will cause additional axial force. And the only limit shaft or housing in a direction of axial displacement. Angular contact ball bearing contact angle of 40 degrees, so you can bear large axial load. Angular contact ball bearing non-separation Taper bearing  inner and outer rings on both sides of the shoulder uneven. Bearings for high load capacity, which would lower side of the shoulder machined, so that the ball bearings can be put more.
Pairs of double ball bearings
     If paired mounting, making a pair of bearing outer ring is relatively wide side face of wide and narrow side facing the narrow end. This can avoid additional axial force, but also in both directions so that the shaft or housing to limit axial clearance range.
     Angular contact ball bearings because of inner and outer ring raceway can be relative displacement on the horizontal axis, so it can bear radial load and axial load - combined load (single row angular contact ball bearings can withstand axial load in one direction, so often used in pairs).
     Retainers are made of brass, synthetic resins, etc., according to individual bearing features and application conditions.
     More angular contact ball bearings are manufactured abroad, bearing manufacturers, domestic imports of equipment used in such large angular contact ball bearings 3204RS, etc.
Properties.