Automatic Transmission

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Automatic transmission is a type of gearbox, especially used in the automobile industry for changing gear ratios automatically. It does not require manual shifting of gears. The gearbox has a set of selected gear range.

The system is hydraulically operated and makes use of a torque converter and a set of planetary gears.

Parts of an Automatic Transmission System

An automatic transmission consists of the following parts :

•     Torque Converter : It is a device connecting engine and transmission. The instrument takes place of a mechanical clutch, allowing the engine to remain running. A torque converter that provides a variable amount of torque multiplication at low engine speeds.
•     Planetary Gearbox Set : The bands and clutches of this gear set are actuated with the help of hydraulic servos controlled by the valve body, thereby providing two or more gear ratios.
•     Valve Body : The system receives pressurized fluid from a main pump operated torque converter. The pressure coming from this pump is regulated and used to run a network of spring-loaded valves, check balls and servo pistons. The valves make use of pump pressure and the pressure from a centrifugal controller on the output side.

Use of Automatic Transmission

•     Automobiles
•     Forklift trucks
•     Lawn mowers