What is a gearbox in a car and what is its role?
The gearbox is one of the most crucial parts of a car. Without it, your car cannot move.
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The automatic transmission control lever on the 2017 Toyota Fortuner. |
A car is made up of thousands of interconnected parts. However, some of those thousands of parts are more important than the rest, and the gearbox is one of them. Without it, your car cannot move.
What is a gearbox?
The gearbox is the component that transmits power from the engine to the drivetrain. It's used to change the gear ratios, thereby altering the torque at the wheels and adjusting the vehicle's speed to match external resistance.
The engine (black section) and gearbox (silver section) on a Lamborghini Aventador. |
In theory, internal combustion engines only produce maximum power and torque within a narrow engine speed range. The gearbox allows the gear ratio between the engine and the drive axle to change as the vehicle accelerates and decelerates, shifting gears so that the engine always operates below its limit and close to its ideal RPM.
Ideally, the gearbox would maintain the gear ratio so that the engine always operates at its optimal RPM.
Gearbox function
- The gearbox is used to change the gear ratio in order to change the torque at the vehicle's drive wheels, and at the same time change the vehicle's speed to match external resistance.
- Change the direction of the vehicle's movement (forward and backward).
- Disconnect the engine from the powertrain for an arbitrary period of time without turning off the engine or disengaging the clutch.
- Providing external power supply to the working parts of specialized vehicles.
- The gearbox must have a sufficient and appropriate number of gear ratios to improve the fuel economy and dynamics of the car.
- The gearbox must have high power transmission efficiency, operate quietly, and shift gears smoothly without generating impact forces on the gears.
