Gearbox and its Function

What is a gearbox?


A speed reducer is an arrangement of gears in an enclosed housing. The reducer contains shafts, bearings and some other parts. The gears are mounted on shafts and the bearings support the shafts. The reducer housing generally contains some form of lubricant (e.g. oil or grease) to lubricate the gears and bearings. Reducers come in a wide range of shapes and sizes to accommodate a broad range of uses.

Reasons for using a gearbox:

  • Less expensive to manufacture motors at higher speed rather than lower speed, for the same amount of power.
  • Most machines require a lower speed than the motors produced.
  • Gears are compact in size for the amount of power they can transmit and are also quite durable. They do not slip like belts for example.
  • The correct amount of lubricants can be controlled and at the same time kept clean.
  • The housing serves as a safety guard, bearing support and lubricant reservoir.

Functions of a gearbox:

  • Most commonly being used to change the speed from the input shaft to the output shaft – the speed can be either reduced or increased.
  • When speed is reduced, torque is increased and vise versa.
  • It can be used to change the direction of a shaft, e.g. worm gear for right angle application.
  • It may be used to change the direction of shaft rotation, from clockwise to counter-clockwise.