TABLE OF CONTENTS A two-stage, step-up gearbox drives a compressor and has a lubrication pump mounted on one of the gear shafts, Fig. 1. Tables 1, 2, and 3 show the spur-gear data, tolerances for tooth errors, and polar moments of inertia for the masses in the compressor drive. All gears in the drive have 20 pressure angles. The gears are made of steel; the compressor is made of cast iron. A 50-hp (37.3-kW) motor drives the gearbox at 3550 rpm. What are the dynamic loads on this gearbox?
| Number of teeth, N | Pitch radius | Face width | Lewis form factor, y | |||
|---|---|---|---|---|---|---|
| R (in) | mm | F (in) | mm | |||
| Gear 1 | 133 | 3.325 | 84.5 | 1.25 | 31.8 | 0.276 |
| Gear 2 | 47 | 1.175 | 29.8 | 1.25 | 31.8 | 0.256 |
| Gear 3 | 116 | 2.90 | 73.7 | 1.00 | 25.4 | 0.275 |
| Gear 4 | 64 | 1.60 | 40.6 | 1.00 | 25.4 | 0.264 |
| Tolerance for tooth profile error e p | Tolerance for tooth spacing error e s | |||
|---|---|---|---|---|
| in | mm | in | mm | |
| Gear 1 | 0.0010 | 0.0254 | 0.0007 | 0.0178 |
| Gear 2 | 0.0009 | 0.0229 | 0.00065 | 0.0165 |
| Gear 3 | 0.0010 | 0.0254 | 0.0007 | 0.0178 |
| Gear 4 | 0.0009 | 0.0229 | 0.00065 | 0.0165 |
| Diameter, D | Length, L | Polar moment of inertia, I o | |||
|---|---|---|---|---|---|
| Element | in | mm | in | mm | in 2 lb s 2/ft |
