Why Spherical Bearings Are Essential in Flight Control Systems

Flight control systems are imperative for an aircraft’s maneuverability, governing the position of surfaces like ailerons, rudders, flaps, and stabilizers. To function effectively, these systems must move with precision while enduring constant stresses, which spherical bearings often aid in. To help you understand why spherical bearings are regularly employed in flight control systems in particular, this blog will discuss their design, variations, and distinct benefits they bring to the table.

What Are Spherical Bearings?

A spherical bearing is composed of an inner ring with a spherical, convex surface and an outer ring with a corresponding concave inner surface. Unlike ball or roller bearings that depend on rolling elements, spherical bearings mainly rely on sliding contact between its mating surfaces. This sliding mechanism is the defining feature of these bearings, though the way it is implemented can vary across designs.

Aerospace spherical bearings may be manufactured from many different materials, spanning from standard steels to lightweight alloys like titanium. Some spherical bearings also include a self-lubricating liner made from PTFE or another advanced polymer that reduces friction and wear while minimizing the need for periodic lubrication and servicing. In addition, the outer ring may be adapted with mounting elements like shoulders, threads, or flanges to help them remain correctly positioned within control linkages, actuator assemblies, or structural interfaces.

Varieties of Spherical Bearings

Swaged Spherical Bearings: In this design, the outer race is deformed around the spherical inner ring, creating 80 to 100% surface contact. This results in very high static load capacity and excellent distribution of forces across the contact surfaces. However, swaged spherical bearings tend to offer less precise regulation of internal clearance.
Split-Ball or Split-Race Spherical Bearings: These bearings are built so that either the inner ring or the outer race is split. Because of this, split-ball and split-race bearings are not as robust as other types, but they are invaluable in retrofit or maintenance scenarios where surrounding components or structures may otherwise need to be removed.
Loader-Slot Spherical Bearings: Loader-slot spherical bearings are manufactured with machined slots in the outer race that allow the inner portion to be inserted during assembly. This enables users to better tailor radial clearance and achieve tighter tolerances than with swaged bearings, although these variants do not deliver as much static load capacity.

Why Spherical Bearings Are Preferred

Spherical bearings offer a few advantages over other options when used in flight control systems, which include:

Multi-Axis Articulation: Spherical bearings facilitate angular motion in tight spaces without inducing binding.
Vibration Damping and Misalignment Tolerance: Their sliding contact design absorbs vibration and accommodates slight misalignments, extending the lifecycle of both the bearing and connected components.
High Static Load Capacity: In swaged designs, nearly the full contact area bears the load to support heavy components reliably.

With these capabilities, spherical bearings are particularly prized in the following areas:

Control Surface Actuators: Ailerons, rudders, flaps, spoilers, slats, and stabilizers all tend to rely on spherical bearings at actuator joints to achieve undisturbed movement.
Structural and Powertrain Pivots: Landing gear actuator pivots, engine and gearbox mounts, and other structural attachment points use spherical bearings to accommodate misalignment while supporting high static loads.
Helicopter Rotor Systems: Rotor heads, swash plates, and vertical stabilizer trunnions incorporate spherical bearings to allow complex rotational and tilting motions without compromising stability under vibration.

Secure Quality Spherical Bearings on Automatic Aerospace

In summary, by presenting smooth articulation, accommodating angular misalignment, and enduring high loads, spherical bearings are uniquely suited for actuators and linkages in aircraft. If you are hoping to source these bearings or any others that must perform reliably in aerospace applications, always work with a dependable procurement partner.

As a platform owned and operated by leading distributor ASAP Semiconductor, Automatic Aerospace is ready to connect customers with thousands of products that are made for aerospace use. Beyond our extensive and high-quality selection, we also strive to deliver a seamless procurement experience with an easy to navigate website, competitive procurement options, and exceptional service. If you are ready to experience our unrivaled solutions for yourself, be sure to check out our website and connect with our staff today.