Gear Reduction. … The rotary machine’s output torque is increased by multiplying the torque by the gear ratio, less some performance losses. While in many applications gear reduction reduces speed and boosts torque, in other applications gear reduction is used to increase speed and reduce torque.
On the surface, it may seem that gears are being “reduced” in quantity or size, which is partially true. When a rotary machine such as an engine or electrical motor needs the result speed reduced and/or torque increased, gears are commonly used to accomplish the desired result. Gear “reduction” specifically refers to the rate of the rotary machine; the rotational acceleration of the rotary machine is usually “reduced” by dividing it by a equipment ratio higher than 1:1. A gear ratio greater than 1:1 can be achieved whenever a smaller gear (decreased size) with fewer quantity of the teeth meshes and drives a larger gear with greater quantity of teeth.
Gear reduction has the opposite effect on torque. The rotary machine’s output torque is increased by multiplying the torque by the gear ratio, less some performance losses.
While in many applications gear decrease reduces speed and improves torque, in various other applications gear decrease is used to increase velocity and reduce torque. Generators in wind generators use gear decrease in this fashion to convert a relatively slow turbine blade quickness to a higher speed capable of producing electricity. These applications use gearboxes that are assembled reverse of these in applications that reduce quickness and increase torque.
How is gear decrease achieved? Many reducer types are capable of attaining gear reduction including, but not limited to, parallel shaft, planetary and right-position worm gearboxes. In parallel shaft gearboxes (or reducers), a pinion gear with a certain number of teeth meshes and drives a more substantial gear with a greater number of teeth. The “reduction” or gear ratio is definitely calculated by dividing the number of teeth on the large equipment by the number of teeth on the tiny gear. For instance, if a power motor drives a 13-tooth pinion gear that meshes with a 65-tooth equipment, a reduced amount of 5:1 is usually achieved (65 / 13 = 5). If the electrical motor speed is certainly 3,450 rpm, the gearbox reduces this acceleration by five instances to 690 rpm. If the motor torque is 10 lb-in, the gearbox boosts this torque by one factor of five to 50 lb-in (before subtracting out gearbox efficiency losses).
Parallel shaft gearboxes many times contain multiple gear sets thereby increasing the gear reduction. The total gear reduction (ratio) depends upon multiplying each individual equipment ratio from each gear arranged stage. If a gearbox includes 3:1, 4:1 and 5:1 gear models, the total ratio is 60:1 (3 x 4 x 5 = 60). Inside our example above, the 3,450 rpm electric electric motor would have its speed reduced to 57.5 rpm by using a 60:1 gearbox. The 10 lb-in electric motor torque would be risen to 600 lb-in (before efficiency losses).
If a pinion gear 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 main function is to change the path of rotation instead of reduce the speed or raise the torque.
Calculating the apparatus ratio in a planetary equipment reducer is much less intuitive as it is Transmission Chain dependent upon the number of teeth of the sun and ring gears. The earth gears become idlers , nor 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 example, a planetary arranged with a 12-tooth sun gear and 72-tooth ring gear includes a equipment 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 necessary, additional planetary stages can be used.
The gear decrease in a right-angle worm drive is dependent on the number of threads or “starts” on the worm and the amount of teeth on the mating worm wheel. If the worm has two starts and the mating worm wheel provides 50 tooth, the resulting equipment ratio is 25:1 (50 / 2 = 25).
When a rotary machine such as for example an engine or electric electric motor cannot supply the desired output speed or torque, a equipment reducer may provide a good solution. Parallel shaft, planetary, right-position worm drives are common gearbox types for achieving gear reduction. Contact us with all your gear reduction questions.