Gear Decrease. … The rotary machine’s result torque is improved by multiplying the torque by the apparatus ratio, less some performance losses. While in many applications gear reduction reduces speed and increases torque, in other applications gear decrease is used to improve swiftness 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 electric motor needs the output speed reduced and/or torque improved, gears are commonly utilized to accomplish the desired result. Gear “reduction” particularly refers to the swiftness of the rotary machine; the rotational velocity of the rotary machine can be “decreased” by dividing it by a gear ratio higher than 1:1. A gear ratio greater than 1:1 is certainly achieved whenever a smaller gear (decreased size) with fewer number of teeth meshes and drives a larger gear with greater quantity of teeth.
Gear reduction gets the opposite effect on torque. The rotary machine’s result torque is improved by multiplying the torque by the gear ratio, less some performance losses.
While in many applications gear reduction reduces speed and boosts torque, in additional applications gear decrease is used to increase speed and reduce torque. Generators in wind generators use gear decrease in this manner to convert a comparatively slow turbine blade swiftness to a higher speed capable of producing electricity. These applications use gearboxes that are assembled reverse of these in applications that reduce acceleration and increase torque.
How is gear reduction achieved? Many reducer types are capable of attaining gear reduction including, but not limited by, parallel shaft, planetary and right-angle worm gearboxes. In parallel shaft gearboxes (or Stainless Steel Chain reducers), a pinion gear with a particular number of tooth meshes and drives a more substantial gear with a greater number of teeth. The “decrease” or gear ratio is calculated by dividing the amount of tooth on the large gear by the amount of teeth on the small gear. For example, if a power motor drives a 13-tooth pinion equipment that meshes with a 65-tooth gear, a reduced amount of 5:1 is achieved (65 / 13 = 5). If the electric motor speed is definitely 3,450 rpm, the gearbox reduces this swiftness by five situations to 690 rpm. If the engine torque is certainly 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 often contain multiple gear units thereby increasing the apparatus reduction. The total gear decrease (ratio) is determined by multiplying each individual equipment ratio from each equipment established 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). In our example above, the 3,450 rpm electric engine would have its swiftness decreased to 57.5 rpm by using a 60:1 gearbox. The 10 lb-in electric engine torque would be increased to 600 lb-in (before performance losses).
If a pinion equipment and its mating equipment have the same amount of teeth, no reduction occurs and the gear ratio is 1:1. The gear is named an idler and its own major function is to improve the path of rotation rather than decrease the speed or boost the torque.
Calculating the apparatus ratio in a planetary gear reducer is less intuitive since it is dependent upon the amount of teeth of the sun and band gears. The planet gears act as idlers and do not affect the apparatus ratio. The planetary gear ratio equals the sum of the amount of teeth on sunlight and ring gear divided by the amount of teeth on sunlight gear. For instance, 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 pieces can achieve 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 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).
Whenever a rotary machine such as an engine or electric electric motor cannot provide the desired output velocity or torque, a gear reducer may provide a good solution. Parallel shaft, planetary, right-position worm drives are normal gearbox types for achieving gear reduction. Contact us with all your gear reduction questions.