Master of Science, The Ohio State University, 2018, Mechanical Engineering

An experimental study is conducted to investigate individual contributions of components to the total spin power loss of a high-speed, aerospace gearbox operating under realistic lubricant flow conditions. An experimental test setup capable of operating the test gearbox containing double-helical gears at desired speeds, temperatures and lubrication conditions is designed and fabricated. Dedicated measurement systems to monitor bearing and oil temperatures as well as the torque loss of the gearbox are devised, and accompanying data analysis systems are developed. A test matrix consisting of two different lubricant flow conditions is defined, each covering a wide range of input speed. These tests are performed with the gearbox having variations of hardware content to separate gear drag, gear mesh pocketing, and bearing power losses from each other. These baseline tests show that the power losses increase with increased lubricant flow rates. They further demonstrate that all three power losses are comparable to each other, and hence, must be considered in evaluating spin power loss of such systems. An auxiliary parametric study is designed to further investigate the effect of the trapped volume in the gear mesh on pocketing power loss. A family of gears having different addendum coefficients are meshed with the same gear forming different root clearance values. The results of these tests are compared to quantify the influence of root clearance on resultant pocketing power loss.

Committee: Ahmet Kahraman Dr. (Advisor); Davie Talbot Dr. (Committee Member) Subjects: Mechanical Engineering

Master of Science, The Ohio State University, 2013, Mechanical Engineering

In this study, load-independent (spin) power losses of a gearbox operating under dip-lubrication conditions are investigated experimentally. A family of final drive helical gear pairs from an automotive transmission is considered as the example for this investigation. A dedicated gearbox is designed and fabricated to operate a single gear or a gear pair under given speed conditions. The test gearbox is incorporated with a high-speed test bed with power loss measurement capability. A test matrix that consists of sets of tests with (i) single spur, helical gears, or disks with no teeth, and (ii) helical gear pairs of varying gear ratios is executed with three different transmission fluids at various temperatures and immersion depths. Power losses from single gear and gear pair tests at identical operating conditions are compared to break down the total spin loss to its main components, namely gear drag loss, gear mesh pocketing loss, and bearing/seal loss. In addition, the space around the gears within the gearbox will be altered to quantify any influences of enclosures and peripheral shrouds on the spin losses of a rotating gear.

Committee: Ahmet Kahraman Dr. (Advisor); Donald Houser Dr. (Committee Member) Subjects: Mechanical Engineering