planetary wheel drive

The gear decrease 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 starts and the mating worm wheel provides 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 since it is dependent on the number of teeth of sunlight and ring gears. The planet gears act as idlers and do not affect the gear ratio. The planetary gear ratio equals the sum of the amount of teeth on the sun and ring Planetary Wheel Drive equipment divided by the amount of teeth on the sun gear. For example, a planetary arranged with a 12-tooth sun gear and 72-tooth ring gear has a gear ratio of 7:1 ([12 + 72]/12 = 7). Planetary gear units can perform ratios from about 3:1 to about 11:1. If more gear reduction is needed, additional planetary stages can be used.

If a pinion gear and its mating equipment have the same number of teeth, no decrease occurs and the apparatus ratio is 1:1. The gear is called an idler and its principal function is to improve the path of rotation instead of reduce the speed or boost the torque.

Parallel shaft gearboxes often contain multiple gear pieces thereby increasing the gear reduction. The total gear decrease (ratio) is determined by multiplying each individual equipment ratio from each equipment arranged stage. If a gearbox includes 3:1, 4:1 and 5:1 gear pieces, the total ratio is 60:1 (3 x 4 x 5 = 60). Inside our example above, the 3,450 rpm electric engine would have its swiftness decreased to 57.5 rpm by utilizing a 60:1 gearbox. The 10 lb-in electric engine torque would be risen to 600 lb-in (before efficiency losses).