Agear reducer, also known as a speed reducer or a gearbox, is a mechanical transmission device consisting of a gear or a series of gears placed between machinery and its motor to reduce the output rotational speed and increase the torque created by the motor.
The motor provides a very high rotation speed but minimal torque. A speed reducer is required to reduce the speed and increase the load capacity. Multiplying the torque produced by the motor leads to increased serviceable power to the machine connected. Gear reducers are used to improve the efficiency of any operation.
Principle of gear reducers
As mentioned above, a gear reducer consists of one or more pairs of gears, and each pair consists of a larger driven gear and a smaller driver gear. The gear ratio is a way of measuring how different sizes of gears interact to transfer energy. The ratio of the number of teeth on the driven gear to the number of teeth on the driver gear decides the reduction ratio of the pair.
For example, there’s a driven gear with 75 teeth and a driver gear with 25 teeth. In this case, the single reduction gearbox has a ratio of 75/25, which is 3:1. This concludes that the input shaft must rotate four times to fully rotate the output shaft once.
If the electric motor speed is 3,000 rpm, the gearbox reduces this speed by three times to 1000 rpm. If the motor torque is 15 lb-in, the gearbox increases this torque by three times to 45 lb-in (before subtracting out gearbox efficiency losses).