Exploration of a strategy for reducing gear noise in planetary transmissions, and, Evaluation of laser vibrometry as a means for measuring transmission error.

摘要

Researchers have already demonstrated that vibration in a simple planetary gear train can be reduced by properly indexing the planet pinions so that their spacing errors tend to cancel. Their kinematic analysis applied only to the special case of planet spacing errors in the form of runout. The present research expands on that concept by considering a general kinematic solution, that is, for all spacing errors. It is hypothesized that by this technique one can reduce the kinematic transmission error attributable to vibration and noise. The first part of this research is a feasibility study evaluating whether this technique, based upon a kinematic analysis for reducing the spacing error, will tend to reduce gear noise.; The equations are first developed for the simple planetary where the planets may be simply indexed to produce the minimum net transmission error. Then the technique is expanded to the compound planetary. In the latter case the gears must be timed so the planets cannot be simply indexed, but must be exchanged with other gears. This is called planet matching. The analyses are conducted at "snapshots" by advancing the gear train by one tooth increments. The goal is to find the planet assembly combination which produces the minimum peak to peak net transmission error.; Transmission error is well accepted as the greatest source of gear noise in simple gear pair systems. In the planetary gear train, however, transmission error is a much more complex concept and has no universally accepted definition. I postulate that it is the overall train error, entitled net transmission error, which should be minimized.; The gear noise reduction strategy was tested by experiment. In support of the experimental work, net transmission error was measured across the planetary in a fully functioning industrial transmission by means of laser vibrometry. The second part of this research evaluates the application of rotational laser vibrometers as applied to transmission error measurement.