How To Gearbox Works

Gear Box Working Principle

Here you can get Gearbox. Here we provide Gearbox working principle, Advantages and Disadvantages etc.

Internal-combustion engines run at high speeds, so a reduction in gearing is necessary to transmit power to the drive wheels, which turn much more slowly. The gearbox provides a selection of gears for different driving conditions: standing start, climbing a hill, or cruising on level surfaces.

High torque is required to start the vehicle from rest, accelerating, hill climbing, pulling a load and facing other resistances. But the IC engine operates over a limited effective speed range which produces a comparatively low torque.  In such a situation, the engine is responsible for the stall and the vehicle rests if the speed falls below the limit.

What Is Gearbox

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

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, the term ‘Transmission’ usually refers to the car’s gear box. Some car designs integrate the gear box and differential assembly into a single unit called ‘Transmission’ or ‘Trans-Axle.’

Gear Box Working Principle

Gear Box Working Principle

A Gear Box is an assembly consisting of 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 in it. The gearbox is a part of the ‘transmission’ system as the gears play an important role in transmitting the engine power to the wheels.

Gearbox Working

A gear box contains gears of different sizes.  This is mainly because of the car’s various needs in terms of the torque required at the wheels depending upon the road, terrain & load. E.g., if a vehicle is hiking a slope, it wishes better torque than cruising on a straight road.

The first gear is the most important in length in a tools field and gives maximum torque output even as generating minimal speed. Hence, it’s miles used whilst hiking slopes.  All the gears between 1st and closing tools range in length, in a reducing ratio. Thus, it gives a various mixture in phrases of pulling ability and speed. So, the car can be pushed easily with none drop in its acceleration. The tools field essentially improves the vehicle’s driveability in all conditions.

Types of Gear Box

In general, an automotive gearbox is mainly two types

1.Manual gearbox

Basically, a manual transmission is a gear box that permits the driver to select among distinctive gear ratios to pressure the car. Lower gear ratios provide extra torque, however much less speed, whilst better tools ratios provide much less torque, however better speed. Different gear ratios are regularly referred to as “speeds,” so a “six-speed” manual transmission has six forward tools ratios.

At its simplest, the manual transmission includes 3 shafts with constantly-intermeshed gears of various sizes. The input shaft connects to the engine, thru the clutch. The countershaft is constantly meshed with the input shaft and has more than one gears. The output shaft connects the countershaft to the driveshaft and subsequently the wheels. In four-wheel force and all-wheel force vehicles, the output shaft connects to the switch case first. Reverse gear is generally on a fourth shaft to impact a alternate in direction.

Types of Manual Gearbox

There are 3 types of manual gearboxes used since the introduction of the transmission that are-

  • Sliding Mesh Gearbox

Sliding Mesh Gearbox is the oldest type of gear box used. In thistype of gearbox shifting occurs by the sliding of gears over the splined main-shaft in order to mesh with the appropriate gear on the lay-shaft whose one gear is in constant mesh with the clutch shaft gear in order to carry rotational motion for the conversion(high torque or high speed)as required by the drive, this gearbox requires special technique for the shifting that is usually known as double-declutching and also the meshing was so noisy and harsh ,that gives rise to the development of new gearbox system.

Note-They were usually came with max of 3-speed manual shifts.

  • Constant Mesh Gearbox

Constant Mesh Gearbox is the modified version of the later which was introduced to over the limitations of the later, in this type all the gears on the main-shaft, lay-shaft and clutch-shaft are in constant mesh with each other and the selection of the appropriate gear is done by the special meshing devices known as dog clutches which slides over the splined main-shaft in order to select the appropriate gear as need by the drive.

Constant Mesh Gearbox system flushes away the double-de-clutching problem and made the drive less noisy as the spur gears of the sliding mesh is replaced with the helical or bevel gears , but the shifting of gear is still not smooth and also there is a lot of wear and tear of the dog clutches due to the different rotational speed of the shafts while meshing, which leads to the high maintenance.

Note – They came with 4 or 5-speed 1-reverse manual shift configuration.

  • Synchromesh Gearbox

Synchromesh Gearbox is the latest type of gearbox used from decades as this system overcomes all the limitations provided by the constant mesh gearbox or sliding mesh gearbox and also improves the output capabilities of the manual transmission system, in this type the dog clutches from the constant mesh gearbox is replaced by the synchromesh devices which first bring the main-shaft and lay-shaft at same speed by the frictional contact, then meshing of the appropriate gear occurs which makes the system smooth and also decreases the maintenance of the gearbox, today this system usually comes with 5-speed 1-reverse manual transmission configuration.

Note- They are coming with 5-speed 1-reverse configuration.

2.Automatic gearbox

An automatic transmission is a multi-speed transmission used in motor vehicles that does not require any driver input to change gears under normal driving conditions. The most common type of automatic transmission is the hydraulic automatic, which uses a planetary gearset, hydraulic controls, and a torque convertor.

The traditional automatic transmission is likewise referred to as torque converter automatic and it’s far the regularly used self-shifting technology across maximum vehicles. It makes use of a hydraulic fluid coupling or a torque converter to do the process of converting gears in preference to a clutch.

Types of Automatic Transmission

Automatic Transmission is four types flowing below points.

  • Automated Manual Transmission (AMT)

You might be quite familiar with this name as it is one of the most common Automatic Transmission available in India. The most successful in the Indian market but it doesn’t make it the best.

Automated Manual Transmission uses a myriad of hydraulic systems linked to an ECU which changes gear depending on the current RPM of the car. It as being a manual transmission that works on its own, hence the name. Most cars offer you the choice of ignoring the automated gearshift and allow you to change the gear manually. 

Using the same system as a manual transmission makes it both cheaper and less complicated to work with. The ECU then operates the hydraulic systems present inside the engine. The ECU with its factory set reading of gear shift at certain RPM makes the hydraulic systems work thus shifting the gears.

  • Continuously Variable Transmission (CVT)

Continuously Variable Transmission is the up and coming Automatic transmission system in India. Having infinite gear ratio is its biggest advantage over other transmission options.

Continuously Variable Transmission or continuously variable transmission employs the use of belts and pulleys to have an infinite gear ratio. In the case of Continuously Variable Transmission, fuel efficiency is the best in class as the engine is always working at the RPM where it’ll be efficient due to infinite gear ratio changing themselves whenever necessary.

  • Dual Clutch Transmission

With its multiple clutches, shafts, and gears, Dual Clutch Transmission might be one of the extra complicated transmission systems. It gives each high-pace gear shifts along the performance equal to a guide transmission Dual Clutch Transmission has been slowly growing in the Indian market. Given different names by different companies using it, Dual Clutch Transmission is the basic names it’s known by. Volkswagen calls it DSG, Porsche PDK.

Dual Clutch Transmission in simple terms can be described as two manual transmissions that are automatically controlled. The working is far more intricate so let’s get to it.

  • Intelligent Manual Transmission (iMT)

Another variant of Automated Manual Transmission the Intelligent Manual Transmission (that’s the call it’s now no longer a typo) additionally makes use of guide transmission as its base and makes it automatic. In the case of an Intelligent Manual Transmission, you’re in manipulate of the gearbox as a normal manual transmission but you manipulate the gears at the same time as the auto controls the clutch.

If you remember the biggest issue about AMT was its random gear changes. Intelligent Manual Transmission, however, picks this fault and provides you with full control over the gear shifting. This common ground between manual and automatic is sure to please any manual transmission lover.

With the help on an Intention sensor on the gear shift stick the Hyundai’s iMT knows when you are about to switch gears. When the sensor gets a reading from the TGS it actuates the clutch thus preparing itself for a gear shift. This allows the driver to shift gears without taking care of the clutch as its automatically pressed by the car itself. 


  • The instantaneous transmission ratio is constant and the working stability is high;
  • The non-circular gear is adopted, and the instantaneous transmission ratio can be designed according to the required change rule;
  • Wide range of transmission ratio variation, suitable for decelerating or increasing speed transmission;
  • The peripheral speed range of gear is large.
  • The transmission efficiency is high, especially the cylindrical gear pair with high precision.
  • Easy to maintain.


  • Vibration, impact and noise during operation, and generate dynamic load.
  • No overload protection.
  • When the precision of gear cutting is required to be high or with special tooth shape, high precision machine tools, special cutters and measuring instruments are needed to ensure that the manufacturing process is complex and the cost is high.


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