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The performance of high-speed helical geartrains is of particular importance for tiltrotor aircraft drive systems.
These drive systems are used to provide speed reduction/torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High-Speed Helical Geartrain Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double-helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp).
Also two lubrication, system-related, variables were tested: oil inlet temperature (160–250° F) and lubricating jet pressure (60–80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling-off temperatures
(radially and axially). Also, all gear systems were tested with and without shrouds around the gears.
For several months, many economists have
been using the “R” word when it comes to
manufacturing. They say we’ve been in a global manufacturing recession since some time in the fourth quarter of
last year.
Gearing is an essential component
in conveyors. The material handling industry appears divided between those who favor high-end three-stage helical bevel gearboxes and those who rely on less expensive worm gearing. But there’s an often over-looked alternative, the two-stage helical bevel gearbox.
As gear efficiency is improved in small steps, it is important to be able to distinguish actual improvements from scatter that can occur while testing. An FZG back-to-back gear test rig was used
to investigate how the assembly and re-assembly of the same test setup affects the measurements. A spread in torque loss between one assembly and another of the same test setup were observed. Rig conditions also affected the spread in input torque. With knowledge of how the spread in torque loss varies due to assembly, test results could be distinguished between changes due to assembly and
actual differences between tests.
As with just about everything else
in the manufacturing world — and
all which that universe entails — it
depends. After all, that’s why the art
of manufacturing is a process — not
a one-system-fits-all discipline. Yes,
once that process has been properly
designed and correctly implemented
for a given manufacturing production
need, it may well run like the astest,
smoothest cookie-cutter-type operation
ever devised.