What Is Gearbox?- Definition, Types, and Uses

A gearbox is often called a transmission. A gearbox simply refers to a set of gears and their casing, most commonly found in automobiles. Since most automotive engines have high operating and idle speeds, transmissions allow the machine to run efficiently and also help slow down and stop the machine.

Gearboxes are used to transfer energy from one rotational power source to another and are found in automobiles, turbines, and heavy machinery. In this article, you will learn about gearboxes and their types.

What is a Gearbox?

A gearbox is a mechanical device that is used to increase the output torque or change the speed (RPM) of the motor. The motor shaft is connected to one end of the gearbox and through the internal configuration of the gears of the gearbox, it provides an output torque and a specific speed determined by the gear ratio.

The most basic definition of a gearbox is that it is a mechanical unit or component consisting of a gear train or set of gears embedded in a housing. In fact, the name itself defines it as a box containing gears. In the most basic sense, a gearbox works like a gear system. Change torque and speed between a drive, such as a motor, and a load.

Gears in gearboxes can be one of several types, from bevel and helical gears to worm gears and planetary gears. The gear is mounted on a shaft supported by roller bearings and rotates around it. A gearbox is a mechanical method of transferring energy from one device to another, which is used to increase torque while decreasing speed.

Gearboxes are used in many applications, including machine tools, industrial equipment, conveyor belts, and almost any power transmission application with rotary motion that requires a change in torque and speed.

What Is Gear box

Car Gearbox Functions

As discussed earlier, in general, the gearbox functions to distribute engine power to other parts of the engine so that it can work to run the vehicle. In addition to these main functions, there are several other functions of the gearbox, namely:

  • Changing the twisting moment (twisting moment) to adjust the rotating shaft between stationary or moving, in which power will be transmitted to other car engine components from this shaft.
  • Providing a gear ratio so that it can be adjusted to the vehicle engine load.
  • Allowing rotational movement to occur by producing regular rotation of the engine.
  • Producing and also changing energy so that the feeding process carried out by other components can be accurate.
  • Helping to make the vehicle move forward or backward by adjusting the power or torque.

Parts of a car gearbox

Here are the primary parts of a gearbox.

  • Clutch shaft: It is also known as the drive shaft that uses the force from the engine and sends the power to other parts. A clutch attaches the drive shaft to the engine and other components. When you engage the clutch, the drive shaft starts to rotate.
  • Countershaft: It is the second most prominent gearbox part and includes various gears in different sizes that can produce enough torque to propel the vehicle.
  • Main shaft: It is also referred to as an output shaft. It offers mandatory torque to the vehicle. It has ridges and teeth so the gears can move smoothly.
  • Bearings: It supports the rotating shafts and minimizes friction.
  • Gears: These transfer power from one shaft to another. The torque transferred through the gears depends on the number of ridges and teeth and the gear size.

how does a car gearbox work?

For your engine to send its power to the wheels, it needs to go through the gearbox (also known as a transmission). To do this, power is sent through a shaft that connects the engine and the gearbox.

However, the shaft needs to be disconnected from the engine when changing gear. This is where the clutch comes in, as its components work together to disconnect a shaft from the engine when you press the clutch pedal.

Once you’ve changed gear, releasing the pedal allows the clutch assembly to smoothly reconnect the engine’s power with the gearbox via the shaft mentioned above.

Now that power is being delivered to the gearbox, it turns a series of other shafts, which have gears fitted to them. When you move up or down a gear, a selector fork within the transmission engages the gear you’ve selected through the use of a synchronizer.

Once the gear has been engaged, the gearbox will be able to direct power from the engine through to the driven wheels.

Gearbox: Speed vs. Traction

Driving a car requires both speed and traction. Transmission gears help you choose one or the other depending on your driving situation.

The lower gears, 2nd and 1st, provide the best traction, while the higher gears, 5th and 6th (if available) provide the most acceleration. In addition, the number of gears in the gearbox provides an excellent combination of traction and speed.

So, it helps the driver/rider to choose the most suitable combination to increase efficiency. Therefore, it is very important to choose the right gear according to the road conditions and the load. Shorter gears improve acceleration and pickup, while higher gears improve top speed.

Types of Gearboxes in Cars

The primary types of car gearboxes are manual and automatic. The automatic gearbox is further classified into Torque Converter, CVT (Continuously Variable Transmission), Automatic Manual Transmission (AMT), and DCT (Dual Clutch Transmission). Here’s an overview of car transmissions.

Manual gearbox

A manual gearbox allows the driver to get complete control and choose the gears manually, operating both the gearstick and the clutch. Manual transmissions are affordable and easy to maintain compared to automatic transmissions.

The manual version is a predominant gearbox option in Indian cars due to its low-cost factor and maintenance.

Automatic gearbox

An automatic gearbox is a type of gearbox that automatically shifts gears and doesn’t require manual intervention. It uses electronic sensors to monitor the vehicle’s speed and shifts gears with the help of an Electronic Control Unit (ECU).

Automatic gearboxes are more convenient and easier to use than manual transmissions but are more complex and expensive to maintain and repair. Here is an overview of different types of automatic gearboxes in cars.

Automated Manual Transmission (AMT)

An AMT gearbox is a type of gearbox that automates the manual gearbox by employing a hydraulic to actuate the clutch pedal. It removes the manual effort of using the clutch (physically) and gears since the AMT gearbox uses electronic sensors to perform the task.

The AMT gearbox in cars has revolutionized the car market in India, offering the option of affordable automatic cars. Its biggest highlight is the lower cost factor since it has fewer components compared to pure automatic gearboxes, thereby reducing the overall cost of the vehicle.

Torque Converter Gearbox

The Torque Converter Gearbox is an automatic gearbox that utilises fluid coupling to transfer power from the engine to the transmission. This gearbox doesn’t require a clutch pedal to shift gears like other automatic transmissions.

The torque converter is one of the traditional gearboxes that has witnessed a decline in its popularity in recent times due to its low fuel efficiency and high maintenance cost.

Continuously Variable Transmission (CVT)

A CVT gearbox is a type of automatic transmission that works via a pulley system. It uses several intricate parts to shift between a range of preset gears.

The CVT system includes cones at each pulley linked through a belt and moves to increase or decrease the chain belt diameter to change gear ratios. The CVT is reliable and offers higher fuel efficiency. It is common in Japanese cars such as the Hondas, Nissans and Toyotas.

Dual Clutch Transmission (DCT)

The DCT employs two clutches to shift gears, offering optimum performance. It uses two separate clutches for odd and even gear sets, reducing gear shift lag. This allows for quicker and smoother gear shifts compared to traditional gearboxes.

While one of the clutches is engaged, offering the required power, the other pre-selects the next gear, allowing for faster transitions. DCTs are popular among high-performance and sports cars.

However, it is fast becoming one of the most preferred in the mass-market car segment. Brands such as Volkswagen, Skoda, Audi, and more are offering DCT in their Indian car portfolio.

How to Take Care of a Car Gearbox

A few small changes in the way you operate your motor vehicle can make a big difference for your gearbox.

  • Routinely check your transmission fluid. Your fluid should be bright red and smell sweet. If it’s a muddy color or smells off, it’s time to get a transmission specialist to look at it.
  • Flush your transmission. Take your car into the shop once a year to have your transmission flushed. If your car overheats or you do a lot of driving, you might consider having it flushed more often.
  • Never change gears while driving. If you need to put the car in reverse, you should come to a complete stop. Changing gears while the car is in motion can damage your transmission.
  • Change your transmission filter. Like your oil filter, your transmission filter can get clogged with debris and cause damage to your transmission. Have your transmission filter changed regularly to avoid costly repairs.
  • Annual gearbox inspection. Once a year, you should have a certified mechanic inspect your gearbox to ensure it’s in good working order. They can check your fluid and identify any issues before they become larger, more expensive problems.