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 increases torque, in other applications gear decrease is used to Leaf Chain increase velocity and reduce torque.
On the surface, it could appear that gears are being “reduced” in quantity or size, which is partially true. When a rotary machine such as for example an engine or electrical motor needs the output speed decreased and/or torque increased, gears are commonly utilized to accomplish the required result. Gear “reduction” specifically refers to the velocity of the rotary machine; the rotational speed of the rotary machine is “reduced” by dividing it by a gear ratio higher than 1:1. A gear ratio greater than 1:1 can be achieved whenever a smaller equipment (decreased size) with fewer amount of teeth meshes and drives a more substantial gear with greater amount of teeth.
Gear reduction gets the opposite effect on torque. The rotary machine’s result torque is improved by multiplying the torque by the apparatus ratio, less some efficiency losses.
While in lots of applications gear decrease reduces speed and improves torque, in additional applications gear reduction is used to increase rate and reduce torque. Generators in wind turbines use gear decrease in this manner to convert a relatively slow turbine blade velocity to a higher speed capable of generating electricity. These applications use gearboxes that are assembled reverse of those in applications that reduce velocity and increase torque.
How is gear decrease achieved? Many reducer types are capable of attaining gear decrease including, but not limited by, parallel shaft, planetary and right-angle worm gearboxes. In parallel shaft gearboxes (or reducers), a pinion gear with a specific number of teeth meshes and drives a larger gear with a lot more teeth. The “decrease” or gear ratio is definitely calculated by dividing the number of the teeth on the large equipment by the amount of teeth on the tiny gear. For example, if an electric 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 electric motor speed is definitely 3,450 rpm, the gearbox reduces this rate by five moments to 690 rpm. If the engine torque is 10 lb-in, the gearbox raises this torque by one factor of five to 50 lb-in (before subtracting out gearbox performance losses).
Parallel shaft gearboxes often contain multiple gear pieces thereby increasing the gear reduction. The full total gear decrease (ratio) depends upon multiplying each individual equipment ratio from each gear set stage. If a gearbox includes 3:1, 4:1 and 5:1 gear pieces, 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 speed decreased to 57.5 rpm by utilizing a 60:1 gearbox. The 10 lb-in electric electric motor torque would be risen to 600 lb-in (before performance losses).
If a pinion equipment and its mating gear have the same quantity of teeth, no decrease occurs and the gear ratio is 1:1. The gear is called an idler and its own major function is to improve the path of rotation rather than decrease the speed or increase the torque.
Calculating the apparatus ratio in a planetary equipment reducer is much less intuitive as it is dependent upon the amount of teeth of sunlight and band gears. The earth gears become idlers and do not affect the gear ratio. The planetary equipment ratio equals the sum of the amount of teeth on the sun and ring equipment divided by the number of teeth on sunlight gear. For example, a planetary arranged with a 12-tooth sun gear and 72-tooth ring gear has a equipment ratio of 7:1 ([12 + 72]/12 = 7). Planetary gear pieces can perform ratios from about 3:1 to about 11:1. If more gear 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 number of teeth on the mating worm wheel. If the worm has two starts and the mating worm wheel offers 50 the teeth, the resulting gear ratio is 25:1 (50 / 2 = 25).
When a rotary machine such as an engine or electric electric motor cannot supply the desired output velocity or torque, a gear reducer may provide a great choice. Parallel shaft, planetary, right-position worm drives are common gearbox types for achieving gear reduction. Contact us with all of your gear reduction questions.