Transmission is a system of gears within the vehicle that transmits engine power through gears and gear trains. When the acceleration increases or decreases, the gear changes according to the engine load requirements for optimum vehicle performance (1).
Although transmission is a simple system of gears, many important components function for the vehicle’s optimum performance, this article has highlighted some important transmission parts.
Important Transmission Parts
Importance of Torque Converter
The torque converter is an important component of the automatic transmission system and is similar to fluid coupling. This part is responsible for spinning the engine. It transmits the torque to the driving load. Also, it develops the connection between the power sources to the load. The torque converter comprises five components impeller, turbine, stator, clutch, and fluid. The impeller has a fan shape the tilted blades—the movement of the impeller results in the movement of the transmission fluid.
This torque production at this point almost becomes zero as the impeller and the turbine is locked at this stage. At this point, the stator begins to rotate towards the direction of the impeller and turbine. The torque converter is useful as it transmits energy from the engine to the input shaft of the transmission system (1). Moreover, it helps in operating the pump of the transmission system and helps in multiplying the torque produced in the engine and then transferring it to the transmission components.
The function of a Torque Converter
The flow of the transmission fluid depends upon the speed of the impeller. Then, the transmission fluid enters the turbine opposite the impeller. Next, the transmission fluids contact the turbines’ blades and operate the engine’s transmission shaft and pump. The transmission fluid is then thrown back toward the impeller. The stator is another part of the torque converter, and the blades are set at a particular angle so that the direction of the transmission fluid can be reversed easily. Further, a clutch is responsible for simultaneously locking up the impeller and turbine at high speed. This helps in improving the overall fuel efficiency of the vehicle.
This means that energy is transmitted only to the impeller. At this stage, the speed of the impeller is much greater than the speed of the turbine. Therefore, in acceleration mode, the torque production is reduced as the turbine speed gradually increases in the acceleration mode.
Importance of Oil Pump
The oil pump is also considered one of the most important parts of the transmission system, and its main purpose is to rotate the engine. The oil pump is present inside the gearbox (1).
The function of an Oil Pump
The oil pump’s role is to pressurize the automatic transmission fluid system.
The main purpose of the oil pump is to develop the required pressure for the hydraulic system. Other than it, the oil pump provides the exact oil pressure to the torque convertors. Also, it removes the excess amount of heat from the torque converter. Moreover, the oil pump plays a beneficial role in reducing the emission of carbon components by 5%.
Planetary Gear Set
Importance of Planetary Gear
In an automatic transmission system, the planetary gear set has an important role as the gear ratios during the transmission can be changed easily without interfering with the torque flow (2).
The function of Planetary Gear
When the gear changes, the clutches and band brakes hold one gear and transmit the power from the components. This planetary gear set is useful as it maximizes the transmission process, reducing noise and vibrations in the vehicle system. Moreover, it helps the vehicle to accelerate properly because torque transmission is not delayed.
Importance of Clutch
Through the help of the clutch, power is transmitted to the vehicle’s wheels. This results in the movement of the vehicle (1). And when the clutch is not in operational mode, and the engine is even in operational mode, the vehicle cannot move as power is not transferred to the wheels.
Function of Clutch
This results in the transmission of power am the components. The main role of the clutch is to transmit power to the torque converter. It helps in reducing the vibrations in the vehicle (2). Also, this component is useful as it avoids the engine’s overheating and releases an extra amount of heat.
Importance and Function of Output Shaft
The output shaft is another component of the transmission system and is used to establish the connection between the gearboxes and the wheels of the vehicle (2).
It is a good part as it helps transmit power from the engine to the wheels of the vehicle and helps maintain speed.
Importance of Transmission band
The Transmission bands are made up of steel, and a frictional material is present on the internal surface of the transmission band (1). Transmission bands are present in the planetary gear set: the clutch and the frictional disc control it.
The function of the Transmission band
The main purpose of the Transmission band is to block the functioning of the gear sets for a very short period. The hydraulic system usually operates this function (3). The hydraulic system is responsible for rotating or blocking the function of the Transmission bands. The Transmission bands have two ends. One end of the Transmission band is attached to the transmission case, and another is attached to the piston. The transmission band gets tightened when the hydraulic oil is pushed towards the band with high pressure. The rotation of the Transmission band stops when hydraulic oil is pushed.
It immediately cools down the lubricating fluid and improves the transmission system’s performance.
Importance of Oil Pan
This oil splashing in the vehicle impacts the overall transmission process to protect the engine parts from excessive oil (3). This is because the baffle stops the movement of oil during the vibrations. The dipstick is another component in the oil pan and is used to determine the level of the oil in the internal combustion engine.
The function of Oil Pan
The transmission oil pan is also an important part of the transmission system and is responsible for storing the transmission fluid.
Therefore, it is necessary to maintain the health of the transmission pan. This is because the oil pan plays an essential role in the transmission system. The main function of the oil pan is to provide storage for the automatic transmission fluid. Besides this, the transmission pan also has a drainage plug. The drain plug helps clean the dirt and debris from the transmission fluid. Thus, this part helps maintain the overall transmission process (4). Initially, the transmission pan was made of steel, but with modernization in technology, the pan is now made of aluminum. This is because aluminum has more durability and less exposure to rust and damage. Moreover, aluminum is also light in weight.
The transmission fluid is transferred from the oil pan to the combustion engine by determining the oil level. Another component of the oil pan is the windage tray that is used to prevent the transmission fluid from entering the crankshaft (4). The last component of the oil pan is the drain plug. A drain plug helps in removing dirt particles and metal components from the transmission fluid. Finally, the oil pan is used in the lubrication of the system.
Importance of Valve Body
There are two types of valve bodies, i.e., electronic valve body and hydraulic valve body. The solenoid is operated through the electronic control unit in the electronic valve body. The ECU determines the fluid level and allows it to flow, and the valve opening and closing are controlled electrically (4). In a hydraulic valve system, the opening and closing of the valves depend upon the hydraulic pressure.
The function of an Oil Valve
There are multiple paths and passages in the valve bodies. These paths direct the flow of transmission fluid and lubricate the metal parts and bearings. The valves allow or block the flow of the transmission fluid as per the requirement (5). The vehicle’s electronic control unit controls the valves’ opening and closing.
Importance of Propeller Shaft
This propeller shaft transfers the energy to those parts that cannot be connected. The Propeller shaft consists of multiple components, i.e., u-joint, tube, center bearing, mid-ship shaft, end yoke, slip yoke, and flanges. The U-join is used in the propeller shaft to develop a connection between the rotating shafts (5). The tube in the propeller shaft keeps the rare end in its place so that the vibrations are not produced during the acceleration process. The Centre bearing is another component of the propeller shaft and is used to establish the connection between the two parts of the drive shaft. This helps in limiting the vibrations when the vehicle is in acceleration mode. The propeller shaft’s end yoke limits the vehicle’s noise and vibrations. Finally, the drive shaft is linked with hydraulic pumps through the help of flanges.
The function of the Propeller Shaft
There are different types of propeller shafts in vehicles, i.e., single, piece propeller shafts and 2-3 piece propeller shafts. Single-piece propeller shafts are used in those vehicles where the distance is shorter between the engine and axles. The 2-3 propeller shafts are used where there is a long distance between the engine and the axles.
Importance of Gear Box
The clutch shaft is used to establish the connection through the clutch. The clutch helps in the rotation of the shaft. The engine’s RPM equals the crankshaft speed when the single gear is a single mode. The countershaft is used to make contact between the counter shafts. The countershaft can be rotated even if the engine RPM is low (5). The main shaft in the gearbox produces the required amount of torque in the engine. The output shaft is adjusted at an angle so the gear can engage or disengage easily. The bearings in the gearbox limit the friction. The last component of the gearbox is the gear is to transmit the power from one shaft to the other shaft. The torque transfer from one shaft to another depends upon the gear size. The larger the gear size, the more power will be transferred through the shafts.
The function of Gear Box
The gearbox is an essential component of the transmission system as it helps maintain the engine’s speed. The automatic transmission system operates in two modes, i.e., hydramatic transmission and torque converter transmission.
The gearbox is made of aluminum because of its durability and long life. This part breaks the connection between the driving wheels and the engine. Moreover, it also establishes the engine’s connection with the driving wheels without producing vibrations. Also, the speed of the wheels can be varied easily.