A gear speed reducer is a representative example of speed changers, and presently used products could be categorized by the kind of gears, shaft positions and set up of gears into (1) equipment reducer with parallel axes, (2) gear reducer with orthogonal axes, (3) equipment reducer with perpendicular nonintersecting axes, and (4) gear reducer with coaxial axes.

Types and mechanisms of equipment reducers with parallel axes
The apparatus reducers with parallel axes use spur gears, helical gears, or herringbone gears. Their input and result shafts are parallel. For decrease ratios, 1/1 – 1/7 for one-stage shafts, 1/10 – 1/30 for two-stage shafts, and 1/5 – 1/200 for a lot more than three-stage shafts are commercially offered. The overall characteristics of gear reducers with parallel axes are as follows :

For high precision gears, the transmitting efficiency is quite high. (98 to 95% for one-stage equipment reducer)
When correctly lubricated, it can be utilized for a long period.
Can be produced relatively cheaply since standardized gears are used.
Gear reducers with spur gears are used for increasing swiftness.
The sizes of gear reducers with spur gears are is generally large. planetary gearbox Compared to worm equipment reducers with the same speed ratio, their outer designs are huge, and the number of parts increases resulting in constructional disadvantages. Consequently, it can be used for devices with high rotation on the strain side, or which require higher output rotation compared to the primary movers (for increasing quickness). The gear types are proven in Table 2.1.

The gear reducers with parallel axes usually use helical gears. They are used in steel facilities, ships, cranes, elevators, and conveyors. As for automation machines, these equipment reducers are also known for geared motors which are equipment reducers with directly connected motors.