Aerospace Bearings Information
Aerospace bearings are designed to meet the rigorous demands of aircraft control and aerospace applications. They are usually manufactured in accordance with U.S. government military specifications (MIL-SPEC) and made from stainless steel or other metals or materials that are resistant to corrosion, shock, and temperature extremes. Aerospace bearings are available in several different shapes and with varying load and axial load capacities. Important measurements for Aerospace bearings include bore size, outside diameter, and overall width. Metric and English or imperial pitch bearings are available. Typically, manufacturers use a standard numbering system for bearings with metric diameter bores. For bore sizes 04 and up, multiplying the size by 5 yields the bore in millimeters. Hexagonal bores are measured across the flats. Tapered bores are measured by the smaller diameter.
Aerospace bearings use several bearing designs. Conrad bearings rotate in a deep groove that is machined into the inner and outer races. They exhibit good radial load capacity, fair axial load capacity, and an adequate ability to resist misalignment. A cage maintains ball space. Double row angular contact ball bearings have two rows of balls in a single inner and outer ring. Spherical roller bearings are self-aligning, double row, combination radial and thrust bearings. As their name suggests, the rolling element is a spherical, or crowned, roller. Spherical roller bearings are unequalled in their capacity for high loads and tolerance to shock loads, but have limited speed capabilities. Another type of bearing, needle rollers, features a cylindrical design with a rolling element that is long and thin relative to its diameter. Needle roller bearings have low cross sections but a high radial load carrying capacity. They have an outer ring, a cage, and an inner ring.
Aerospace bearings are used in a variety of military aircraft, helicopters, and missile systems. They are also used in commercial passenger jets manufactured by companies such as Airbus, Boeing, Cessna, Piper, Learjet, and McDonnell-Douglas. Some manufacturers can modify standard ball bearings for military or civilian applications that include special requirements. For example, Aerospace bearings can be heat-treated or sealed against chemicals or extreme temperatures. Coatings and plating such as dry film, thick or thin dense chrome, zinc nickel, and silver are also available. Lubrication and relubrication options are designed to support devices that operate at high and low temperature extremes.