High-Pressure Angle Gears: Comparison to Typical Gear Designs

A preliminary study has been completed to determine the feasibility of using high-pressure angle gears in aeronautic and space applications. Tests were conducted in the NASA GRC Spur Gear Test Facility at speeds up to 10,000 rpm and 73 N m (648 in. lb) for 3.18, 2.12, and 1.59 module gears (8, 12, and 16 diametral pitch gears), all designed to operate in the same test facility. The 3.18 module (8-diametral pitch), 28 tooth, 20 deg pressure angle gears are the NASA GRC baseline test specimen. Also, 2.12 module (12-diametral pitch), 42 tooth, 25 deg pressure angle gears were tested. Finally, 1.59 module (16-diametral pitch), 56 tooth, 35 deg pressure angle gears were tested. The high-pressure angle gears were the most efficient when operated in the high-speed aerospace mode (10,000 rpm, lubricated with a synthetic turbine engine oil) and produced the lowest wear rates when tested with a perfluoroether-based grease. The grease tests were conducted at 150 rpm and 71 N m (630 in. lb).