Aircraft Landing Wheels and Bearings
When an aircraft lands on a runway or ground surface, it relies on its landing wheels and gear to sufficiently withstand the load and force transmitted from the airframe. As many commercial aircraft may reach upwards of 500-tons in weight, travel at speeds ranging up to 170+ MPH, face fluctuating temperature extremes, and generate intense heat while braking, the landing wheels are designed with robustness and advanced technologies. In this blog, we will discuss the landing wheels and landing wheel bearings found on aircraft, allowing you to better understand their functionality and importance.
With a wheel and tire assembly, the aircraft wheels take on the entire weight of the aircraft during its taxi, landing, and takeoff procedures. Many modern wheel assemblies are constructed from aluminum alloy, allowing them to be lightweight yet strong. Despite early wheel assemblies being one-piece constructions, modern designs regularly utilize two-piece sets to achieve the stiffness and absorption properties necessary for the conditions that such equipment face.
The two wheel sections are often bolted together, utilizing an O-ring seal for the benefit of tubeless tires. The bead seat area is an important section of the wheel, serving as the location where the tire contacts the wheel and where most tensile loads are transferred. During the production stage, the bead seat area is often rolled to prestress it with a compressive stress load.
Each half of the aircraft wheel is unique in its design, the inboard half intended to accept and drive the aircraft brake rotors through mounting. In order for the bearing to be implemented on the tire, a cavity is formed in the center. Generally, the most common bearing types used include steel bearing cups, tapered roller bearings, and grease retainers. If a retaining clip is required to maintain placement, then the tire may be machined to accommodate such parts.
As temperatures may reach extreme highs during the braking process, more modern aircraft regularly implement thermal plugs on the inboard half. With a low melting point alloy, the thermal plugs are designed to melt and deflate the tire in an emergency setting, preventing the chance that the wheel and tire assembly explodes under heat. Heat shields are also useful, ensuring that temperatures remain low to avoid the necessity for thermal plug operations.
The outboard wheel half is the section where the tire itself is mounted to the wheel, and bolting ensures the two halves are secured together with ease. Similar to the inboard half, the outboard wheel section also features an area where a bearing cup and bearing assembly may be received. As bearing components are often at risk of losing performance or facing wear when exposed to contaminants and moisture, the bearing assembly is sealed off with the use of a wheel bearing seal or cap. Generally, the seal wheel bearing component is placed at the outer bearing and the end of the axle. If the aircraft utilizes tubeless tires, a valve stem may extend from the outboard wheel half for inflation and deflation. In other instances, the valve stem may pass from the inner half to the outer half.
When procuring various bearings and bearing sealants for a particular aircraft, it is important to ensure that they are of high quality and meet all the requirements of the application at hand. Often, bearings for aircraft will be designed to FAA quality standards, or meet various other performance specifications. Generally, the bearings used for aircraft wheels need to have tightened tolerances, the ability to undertake repeated spike loads, and have reduced wear and tear over time.
When it comes time to procure the top quality ring wheel bearing components, inboard and outboard half parts, and other various landing gear products that you require, Cogent Sourcing is your one-stop shop with our unrivaled supply of items. Take the time to explore our vast offerings at your leisure, and we can provide you with a competitive quote for your comparisons quickly and easily when you submit a completed RFQ form through our website. Due to our unmatched dedication to quality control and rigorous export compliance measures, we proudly conduct operations with AS9120B, ISO 9001:2015, and FAA AC 00-56B certification and accreditation. Give our team members a call or email today and see how Cogent Sourcing can help you fulfill all your operational needs quickly and easily.