Custom Gearboxes
Barber-Nichols, Inc. (BNI) has been engineering, manufacturing, and testing custom gearboxes since 1969. BNI develops spur, helical, and worm gears in accordance with American Gear Manufactures Association (AGMA) 2002 standards. In addition to oil, Barber-Nichols has experience using unorthodox lubricants such as light hydrocarbons, refrigerants, and water at pitch line velocities up to 125 m/sec (417 ft/sec).
Bearing selection and design are critical for successful gearbox design. Bearing selection is performed concurrently with gear design to ensure proper bearing load capacity and gear alignment. Antifriction or fluid film bearings can also be used.
Gearbox windage and oil drainage receive special attention during the design and development phases to reduce parasitic power loss. Calculations are performed to estimate the loss and optimize clearances between the rotating components and the housing. BNI has special expertise in this area and has helped several clients reduce parasitic power losses in their gearboxes. Some of the applications include:
Case Study 1:
Barber-Nichols designs and manufactures custom turbocompound units for diesel engines. A turbocompund extracts waste energy from a vehicle's exhaust, turns it into useable energy, and returns it to the vehicle's crankshaft, thereby increasing engine efficiency. A turbine is attached to the exhaust system downstream from the turbocharger and typically rotates at 50,000 to 100,000 rpm. An integrated high-speed custom gearbox then reduces the speed and a fluid coupling delivers the useable energy back to the crankshaft via. the flywheel.
Case Study 2:
BNI designed an extremely compact, high-torque shoulder joint gearbox for NASA's Johnson Space Center. The custom gearbox is 0.9 meters (three feet) in diameter and transfers 447,414 N-m (330,000 ft/lbs) of torque. Additionally, the gearbox requirements called for near zero backlash and high stiffness. The gearbox was incorporated into a ground based robotic arm that is used to train astronauts.
Case Study 3:
Barber-Nichols designed and manufactured a compact, high power, ultra high-speed turbine driven gearbox for the U.S. Navy's Countermeasure Anti-Torpedo (CAT). The gearbox is a compound star epicyclical configuration and spur gears were used for simplicity and cost reduction.