Types and Classification of Spherical Bearings
1. Spherical bearings are classified according to the direction of the load they can bear or the nominal contact angle:
a) Radial bearings — mainly used to bear radial loads, with a nominal contact angle of 0°≤τ≤30°. According to different nominal contact angles, they can be further divided into:
1) Radial contact spherical bearings — bearings with a nominal contact angle τ=0°. Suitable for bearing radial loads and also capable of bearing small axial loads in any direction;
2) Angular contact radial spherical bearings — bearings with a nominal contact angle 0°<τ≤30°. Suitable for combined loads with both radial and axial components.
b) Thrust bearings — mainly used to bear axial loads, with a nominal contact angle of 30°<τ≤90°. According to different nominal contact angles, they can be further divided into:
1) Axial contact thrust spherical bearings — thrust bearings with a nominal contact angle τ=90°. Suitable for bearing axial loads in a single direction;
2) Angular contact thrust spherical bearings — thrust bearings with a nominal contact angle 30°<τ<90°. Mainly suitable for bearing axial loads, but can also bear combined loads.
2. Spherical bearings are classified according to the structure of the outer ring:
a) One-piece outer ring spherical bearing;
b) Single-split outer ring spherical bearing;
c) Double-split outer ring spherical bearing;
d) Two-piece outer ring spherical bearing.
3. Spherical bearings are classified according to whether they are attached to a rod end:
a) (General) spherical bearings;
b) Rod end spherical bearings, with multiple classification methods:
1) According to the parts that mate with the rod end:
— Assembled rod end spherical bearing: rod end with a cylindrical bore, with a radial spherical bearing installed in the bore, with or without a bolt;
— One-piece rod end spherical bearing: rod end with a spherical inner bore, with the bearing inner ring installed in the bore, with or without a bolt;
— Ball-head bolt rod end spherical bearing: rod end with a ball seat, into which a ball-head bolt is installed.
2) According to the connection characteristics of the rod end shank:
— Internal thread rod end spherical bearing: rod end shank is a straight rod with internal threading;
— External thread rod end spherical bearing: rod end shank is a straight rod with external threading;
— Rod end spherical bearing with welded base: rod end shank has a flange seat, square seat, or cylindrical seat with positioning pins, which is fixed to the rod end by welding;
— Rod end spherical bearing with locking seat: rod end shank has an internal threaded slot with a locking device.
4. Spherical bearings are classified according to whether they require re-lubrication and maintenance during operation:
a) Maintenance-lubricated spherical bearings;
b) Maintenance-free self-lubricating spherical bearings.
5. Spherical bearings are classified according to the combination of materials used for the sliding surfaces:
a) Steel/steel spherical bearings;
b) Steel/copper alloy spherical bearings;
c) Steel/PTFE composite spherical bearings;
d) Steel/PTFE fabric spherical bearings;
e) Steel/reinforced plastic spherical bearings;
f) Steel/zinc-based alloy spherical bearings.
6. Spherical bearings are classified according to the units used for dimensions and tolerances:
a) Metric spherical bearings;
b) Imperial spherical bearings.
7. Spherical bearings are comprehensively classified according to the direction of loads, nominal contact angle, and structural type:
a) Radial spherical bearings;
b) Angular contact spherical bearings;
c) Thrust spherical bearings;
d) Rod end spherical bearings.
Spherical bearings can also be divided into various structural types according to their structural shape (e.g., presence or absence of sealing devices, the structure of lubrication grooves and holes, the structure of lubricant distribution grooves, the number of retaining ring grooves, the rotation direction of rod end threads, etc.).
Post time: Apr-07-2026
