December 25, 2019

The gear reduction in a right-angle worm drive is dependent on the amount of threads or “starts” on the worm and the number of teeth on the mating worm wheel. If the worm has two Planetary Wheel Drive starts and the mating worm wheel offers 50 the teeth, the resulting gear ratio is 25:1 (50 / 2 = 25).

Calculating the gear ratio in a planetary gear reducer is less intuitive as it is dependent upon the amount of teeth of sunlight and band gears. The earth gears become idlers and don’t affect the apparatus ratio. The planetary gear ratio equals the sum of the number of teeth on the sun and ring equipment divided by the amount of teeth on sunlight gear. For instance, a planetary set with a 12-tooth sun gear and 72-tooth ring gear includes a gear ratio of 7:1 ([12 + 72]/12 = 7). Planetary gear sets can perform ratios from about 3:1 to about 11:1. If more equipment reduction is needed, additional planetary stages may be used.

If a pinion equipment and its mating gear have the same quantity of teeth, no reduction occurs and the apparatus ratio is 1:1. The gear is named an idler and its own major function is to change the path of rotation instead of reduce the speed or boost the torque.

Parallel shaft gearboxes many times contain multiple gear models thereby increasing the gear reduction. The total gear decrease (ratio) is determined by multiplying each individual equipment ratio from each equipment established stage. If a gearbox consists of 3:1, 4:1 and 5:1 gear sets, the full total ratio is 60:1 (3 x 4 x 5 = 60). Inside our example above, the 3,450 rpm electric motor would have its quickness reduced to 57.5 rpm by using a 60:1 gearbox. The 10 lb-in electric electric motor torque would be risen to 600 lb-in (before performance losses).