Gear Reduction. … The rotary machine’s result torque is increased by multiplying the torque by the gear ratio, less some efficiency losses. While in many applications gear reduction reduces speed and raises torque, in other applications gear decrease is used to increase rate and reduce torque.
On the surface, it could appear that gears are being “reduced” in quantity or size, which is partially true. Whenever a rotary machine such as an engine or electric motor needs the output speed decreased and/or torque improved, gears are commonly used to accomplish the desired result. Gear “reduction” particularly refers to the acceleration of the rotary machine; the rotational velocity of the rotary machine is usually “decreased” by dividing it by a equipment ratio higher than 1:1. A gear ratio greater than 1:1 is usually achieved when a smaller gear (reduced size) with fewer number of 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 efficiency losses.
While in lots of applications gear reduction reduces speed and improves torque, in various other applications gear reduction is used to increase acceleration and reduce torque. Generators in wind turbines use gear reduction in this manner to convert a comparatively slow turbine blade velocity to a high speed capable of generating electricity. These applications use gearboxes that are assembled reverse of these in applications that decrease acceleration and increase torque.
How is gear decrease achieved? Many reducer types can handle attaining gear decrease 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 “decrease” or equipment ratio can be calculated by dividing the amount of the teeth on the large gear by the number of teeth on the small gear. For instance, if a power motor drives a 13-tooth pinion gear that meshes with a 65-tooth gear, a reduction of 5:1 can be achieved (65 / 13 = 5). If the electrical motor speed is definitely 3,450 rpm, the gearbox reduces this swiftness by five times 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 effectiveness losses).
Parallel shaft gearboxes often contain multiple gear models thereby increasing the gear reduction. The total gear reduction (ratio) depends upon multiplying each individual gear ratio from each gear arranged stage. If a gearbox consists of 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 engine would have its speed 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 performance losses).
If a pinion gear and its mating equipment have the same amount of teeth, no decrease occurs and the apparatus ratio is 1:1. The gear is called an idler and its own primary function is to change the path of Leaf Chain rotation rather than reduce the speed or increase the torque.
Calculating the gear ratio in a planetary equipment reducer is much less intuitive since it is dependent on the amount of teeth of sunlight and ring gears. The earth gears act as idlers and do not affect the gear ratio. The planetary gear ratio equals the sum of the number of teeth on sunlight and ring gear divided by the number of teeth on the sun gear. For instance, a planetary arranged with a 12-tooth sun gear and 72-tooth ring gear includes a gear ratio of 7:1 ([12 + 72]/12 = 7). Planetary gear models can achieve ratios from about 3:1 to about 11:1. If more gear reduction is needed, additional planetary stages can be used.
The gear decrease in a right-angle worm drive would depend on the amount of threads or “starts” on the worm and the amount of teeth on the mating worm wheel. If the worm has two begins and the mating worm wheel offers 50 tooth, the resulting equipment ratio is 25:1 (50 / 2 = 25).
When a rotary machine such as an engine or electric engine cannot supply the desired output quickness or torque, a equipment reducer may provide a great choice. Parallel shaft, planetary, right-angle worm drives are normal gearbox types for achieving gear reduction. Contact us with all of your gear reduction questions.