The Spur Gear head Motor
Spur gearhead motors begins simply with a standard DC motor. The next major component is the spur gearbox. This consists of a series of small gears that mesh with larger gears, and placed in a rigid frame. The gears are greased to minimize friction and then secured in a gearbox cover to avoid debris from entering and disrupting the gears. Finally, a pair of screws fastens the gearbox on top of the DC motor.
A spur gear can be a disk or cylinder with teeth or cogs pointing out radially along the perimeter. These teeth mesh with another toothed gear to transmit torque. On the spur gearhead motor, the DC motor shaft is connected to the first smaller gear and causes it to turn when the motor is operating. This gear is meshed with a larger gear, thus causing it to turn as well. Since the smaller gear has fewer teeth, it spins faster. For instance, if the smaller gear consists of 12 teeth and the larger one 40, then the smaller gear will spin three and a third times(40/12) while the larger one will spin once. Moreover, if the motor supplied the smaller gear with 6000 RP M, the larger gear wools sustain an RPM of 18000. This is given by the following computation:
Small gear RPM * small gear teeth / large gear teeth = large gear RPM
6000 RPM * 12 teeth / 40 teeth = 1800 RPM
It may seem that there is some “waste" of energy, as 6000 RPM is only being converted to 1800 RPM, but instead what is happening, the larger gear has an increased torque of 3 and 1/3 times. Therefore, by placing a series of small and large gears together, the motor speed decreases as the torque increases.
The last gear in the gearbox is connected to the output shaft. This shaft can be connected to wheels and other such things to operate.