Gear Ratio of a Multistage Gear Drive
An example of a simple two-stage gear train comprised of helical gears is shown in Figure 18.1. Gear trains of this kind are typical for industrial reducers. A multistage gear drive that has three to ve stages is common for industrial gearboxes as well as other applications. Longer gear trains (more than ve stages in total) are used as well. Another example of a gear train is illustrated in Figure 18.2. This is a multistage gear train capable of a changeable gear ratio between the input and output shaft. The actual value of the gear ratio of the gear train (Figure 18.2) depends on which gear pairs are engaged in mesh.