four point angular contact ball bearing QJ1988N2MA for Mill

Characteristic:
1, bearing the universal distribution group
Universally matchable bearings are specially processed, when the bearing is installed close to each other, any combination can achieve the established internal clearance or preload, and the average load distribution, without the use of shims or similar devices.
Paired bearings in: When there is insufficient load carrying capacity of a single bearing (using blow-linked configuration) or when to bear combined load or effect of axial load in both directions (using back to back or face to face configuration).
2, the basic design bearings (can not be used universally matchable) for single bearing configuration
Single row angular contact ball bearings are mainly applied basic design is only one bearing arranged at each position. Its width and the projecting amount of Normal tolerances. Therefore not suitable for the two single row angular contact ball bearings against the installation.

Structural deformation Category
Double row angular contact ball bearings can be characterized withstand the combined load of radial and axial load, axial displacement limit both axes. Compared with the two-way thrust ball bearings, which bearing high speed limit, the contact angle of 32 degrees, rigid, and can withstand the overturning moment large, widely used in cars in the front wheels (some models also use the same size double row tapered roller bearings).
Structural deformation double row angular contact ball bearings, there are four:
A Type: 90mm outside diameter less than or equal to the standard design of the bearing. No ball gap, so it can withstand the equivalent of two-way axial load. The use of lightweight glass fiber reinforced nylon 66 cage, the bearing temperature rise is very small.
A Type: 90mm outside diameter greater than the standard design of the bearing. Side of the ball gap, with z steel stamping cage or brass cage.
E-type: the case of enhanced structure, the side with filling slots, you can install more of the ball, so the higher carrying capacity.
Both sides with a dust cover and sides with a ring-type, A-type and E-type design design double row angular contact ball bearings can be on both sides with a dust cover (non-contact) or seals (contact). Sealed bearings are filled with rust lithium grease, generally between -30 degrees to 110 degrees operating temperature. Without re-lubrication during use, prior to installation is no longer heated.
When the double row angular contact ball bearing installation should be noted that although two-way bearings can withstand axial load, but if one side of the ball gap, it should be careful not to let the main axial load through the notched side of the gutter.