Gear Reduction Unit Research Articles

Tools for the Workshop

THE need for effective washing equipment for acro‐engine parts is more important today than it has ever been. The apparatus shown in Fig. 1 is for washing engines taken from crashed aeroplanes before they are dismantled prior to re‐assembly. The same machine can also be used for washing quantities of component parts if necessary. This machine is 33 ft. 6 in. in length; 10 ft. 6 in. in width and 12 ft. 6 in. in height; its approximate loaded weight being 30 tons. The engines (or components) are placed in large swing carriers which are swung on two heavy mild‐steel roller chains. The conveyor runs very slowly, driven by a 2 h.p. motor, through a 14,400 to 2 reduction gear unit.

Measurement and Frequency Analysis of Sound from Large Reduction Gear Units

In order to determine noise specifications in absolute units for a certain type of large reduction gear measurements were made of the sounds produced by ten machines in operation at a large central generating station. An average weighted total intensity, and a frequency analysis were made of the noise of each machine. It appears that these data are suitable and sufficient for absolute noise specifications on this type of machine. It was found that 1 db. represents an important difference in loudness in these machines which places quite rigorous requirements on the apparatus and the methods of measurement in order to eliminate errors due to wave patterns, location, load, speed, etc. Data on these points are given. A very close check was obtained between the observed frequencies of the various notes, and the movements of certain parts of the machine. By a comparison of the frequency analyses of the different machines it was possible to locate which part of the machine was responsible for the noise, and something of the nature of the defect producing the noise.