Speed reducers are used on machine tools to provide a various range of speed settings. Common types of speed reducers are pulley pairs of different diameters, gearboxes, and stepped electric motors, etc. Speed reducers are commonly used in machine tools, automobiles, transmission products, cranes and hoists, etc. Common types of gear boxes are: worm gear reducers, bevel gearboxes, helical gear reducers, parallel shaft gear reducers, planetary gear reducers, in-line helical reducers, and right angle reducers, etc. Speed reducers can help to slow down machinery that may begin to operate too fast or too hard. These devices are used in machines in many different types of industries. Gearboxes use precision hardened and ground or toughened shaved gears that run smoothly and with the least loss in power. The gears are mounted in a housing using shafts and bearings. Input is taken from the drive electric motor shaft. The gears that are used are different sizes, have a different number of teeth and have a different diameter. A set of levers and clutches allows a different combination of gears to mesh. This allows the speed to be varied in fixed steps. Output from the gearbox is taken from the output shaft. The whole system needs to be thoroughly lubricated to make sure it runs smoothly. A worm gear is a right angle gear reducer that is designed to provide maximum speed reduction in small area. Worm and gear reducers are precision devices and must be procured from expert producers. A wrong selection or fitting can cause the machine on which it is installed to fail. Another type of gear reducer is a helical gear reducer. These devices are quite efficient and durable. Helical reducers are inline reducers and the generally cost less than right angle devices. The amount of teeth that are in the large gear of a speed reducer is divided by the amount of teeth in the smaller gear. This process will give you the ratio in a helical and bevel gear set. If there are 28 teeth in the large gear and 14 in the small one, then the ratio of the gear set would be 2: 1. However, gear ratios in worm gears are figured out differently as the amount of teeth in the gear is compared to the amount of threads on the worm. If there are two threads on the worm and a mating gear with 60 teeth, then the ratio of the gear set is 30: 1. Source: industrial101.com
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