Assignment #5. Designing a gear set.

For assignment #5, a gear set with a speed ratio e=0.2 was designed. The speed ratio is defined as the product of the driving teeth divided by the product of the driven teeth. In this case since there was only one driving gear, (the pinion), and one driven gear, (the gear), e=N2/N3. The steps in designing gears are as follows:

Pick the number of teeth of one of the gears.
Pick a suggested diametrial pitch (P).
Pick a suggested pressure angle.

After these three variables are defined, the remaining parameters of the gear such as the involute profile, base diameters, pitch diameters, and addendum and dedendum distances are all easily solved for using trigonmetry and algebra. A MathCad work sheet with all the derivations including X and Y coordinates of the involute profile is included with this report

The next step was to export the X and Y coordinates to Excell and create a spreadsheet. The spreadsheets were saved as text file with comma delimited format, and imported into Autocad as points. The points were connected and mirrored over the Y axis. The base circle and addendum circle were added, and the gear tooth was formed by trimming and adding fillets and rounds as necessary. After the gear tooth was formed, it was rotated and copied about the origin forming the gear.

The pinion and gear were then to be exported in DXF format to Working Model and the resulting gear train was to be simulated. However, the equations used to define the involute profile were incorrect and the larger of the two, (the gear), did not seem to form correctly, therefore, to complete the assignment in a reasonable amount of time the pinion gear was recopied and pasted next to its self allowing for a decent simulation.