SKF
Angular Contact Spherical Plain Bearings
Angular contact spherical plain bearings (GAC series) are designed to carry predominantly axial loads in one direction, combined with a limited radial load. The raceway contact angle shifts the load-bearing path axial, making them suitable for applications like helicopter rotor blade retention, articulation of variable stator vanes in jet engines, and high-load thrust pivots. SKF offers these in steel-on-steel and maintenance-free variants. The sliding contact surfaces are optimised for the axial force direction, providing high axial stiffness and low friction. These bearings must be mounted in opposition if loads reverse direction, or combined with a radial bearing. Proper preload adjustment ensures smooth motion without play.
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Trusted by Industry Leaders
Optimised for Thrust
Contact angle directs load axially, reducing radial space.
High Axial Stiffness
Minimal elastic deflection under heavy thrust.
Aerospace Proven
Materials and precision meet aerospace certification standards.
Maintenance-Free Options
PTFE liners eliminate need for in-flight greasing.
Corrosion Protected
Stainless steel and special coatings for tough environments.
Preload Adjustable
Axial play can be eliminated via matched pairs or shims.
Applications in Helicopter Rotor Systems
Helicopter main rotor blades create enormous centrifugal and oscillating pitch-change loads. Angular contact spherical plain bearings accommodate these combined forces and small, rapid oscillations without fretting, a critical safety function. SKF’s aerospace-grade bearings provide the required reliability.
Mounting Angular Contact Bearings in Opposition Pairs
When axial loads reverse, two angular contact spherical plain bearings are installed back-to-back on a common shaft and housing. The axial clearance or preload is set by shimming between the outer rings. This arrangement delivers precise, stiff thrust articulation.