How A Gearbox (Transmission) Works? What’s Gear Ratio?

Gearbox Working Principle:

A gearbox comprises various gears, synchronizing sleeves, and a gear-shifting mechanism fitted inside a metal housing. The metal housing, usually made of aluminum/iron casting, accommodates all the gears. The gearbox is a part of the ‘transmission’ system. The gears play an important role in transmitting the engine power to the wheels.

What is Transmission?

All the drive-train components that help transmit the engine power to the wheels are a part of the ‘Transmission’ system. Of which the gearbox is an integral part. These components include the clutch, gearbox, couplings, propeller shaft, axle shafts, and differential. In general, ‘Transmission’ usually refers to the car’s gearbox. However, some car designs integrate the gearbox and differential assembly into a single unit called ‘Transmission’ or ‘Trans-Axle.’

What is the Gear Ratio?

The gear ratio is the ratio between the input and output gears. The driving gear and driven gears in a gearbox define the gear ratios. The input gears get the engine’s drive and rotate the output gears, which, in turn, drive the wheels. The ratio of the number of rotations of output gear to the number of rotations of input gear is called the Gear Ratio.

How does a Gearbox work?

A gearbox contains gears of different sizes. It is mainly because of the vehicle’s varying demands for the torque required at the wheels depending upon the road, terrain & load. E.g., if a vehicle is climbing a slope, it needs higher torque than cruising on a straight road. Furthermore, the first gear is the biggest in a gearbox and provides maximum torque output while producing minimum speed. Hence, the drivers use it when climbing slopes. All the gears between 1st and last gear vary in size, in a decreasing ratio. Thus, it provides a varying combination of pulling ability and speed. So, you could drive the vehicle smoothly without any drop in its acceleration. The gearbox, basically, improves the vehicle’s driveability in all conditions.