ball bearing

Schaeffler Group’s member FAG Aerospace has developed a new aircraft engine ball bearing that is claimed to make engines more efficient.

The bearing uses minimal cooling oil quantities, and is said to exceed the speed parameter of four million millimetres per minute.

It features integrated oil damping of vibration loads and performance-enhanced, duplex-hardened raceways that offer strength and wear-resistance, while reducing the rolling contact loads.

The technology is claimed to help lower the global passenger aircraft fleet’s fuel by 200,000t year.

The ball bearing has been developed as part of the ‘Effective Oil System’ collaborative project under the Aviation Research Program (LuFo), which is supported by the Federal Ministry for Economic Affairs and Energy.

Schaeffler and project partner MTU Aero Engines have evaluated the technology on a test stand in a simulated flight cycle environment.

Using the same quantities of oil as for conventional bearings, the new design facilitates tuning maximum-permitted ring temperatures, thereby achieving around 70% higher speed parameters, the company said.

"The higher efficiency and reliability of the new ball bearing is also due to direct cooling of the outer ring and the ceramic balls."

If the speed parameters are constant and smaller quantities of cooling oil are used, the bearing’s temperature will be around 25°C lower, with power losses reduced by up to 25%.

FAG Aerospace said in a statement: "The higher efficiency and reliability of the new ball bearing is also due to direct cooling of the outer ring and the ceramic balls that help to reduce friction and weight.

"Bearings in aerospace applications need to work with the utmost reliability even under the most critical operating conditions."

During take-off, the engine bearings achieve speed parameters of up to 2.4 million millimetres per minute.

Mechanical and thermal efficiency of aircraft engines need to be enhanced to meet the future needs of airlines, the company said.

Image: FAG Aerospace’s new performance-enhanced engine ball bearing. Photo: courtesy of Schaeffler Group USA Inc.