Common Parts of an Automatic Transmission

Last Updated on January 16, 2019

A car that uses automatic transmission there are a number of unfamiliar term such as automatic transmission vacuum modulator. Actually a car with an automatic system uses a hydraulic control system of an automatic transmission which has several components such as clutch friction, steel bands, hydraulic pistons, spring-loaded valve, sensors and engine load shift valve. In this article will explain the function of each component of the above:

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  1. Clutch Friction

Clutch Friction becomes a liaison between the drive shaft and the shaft is driven by a gear-gear planetary gear. The clutch friction designed complex so each gear can be connected with a driven shaft and countershaft.

One gear using 4 the clutch friction to regulate the performance of gear, a clutch friction actuated by a piston which is equipped with a spring, this piston worked by hydraulic oil pressure, if the pressure is sufficient, the piston will be actuated and if the pressure is low, the piston will return to the starting position with the aid of a spring inside.

  1. Bands

Bands are serves to lock the gear planetary gear on a stationary position or be silent. As well as the clutch, is actuated by a piston bands who also works on the basis of the hydraulic oil pressure in the supply it. If piston actuated, the ribbon of steel that is wrapped around the gear wheels will lock gears and associated transmission system so that the body gears are in stationary position.

  1. Spring-Loaded valve

Spring-loaded valve are serves as the output shaft rotation speed sensor that is connected to the drive wheels. The faster the rotation axis, the greater the valve opening, thus supply the hydraulic oil pressure to the larger system. If the rotation axis of the more slowly, the valve will be shut assisted by a spring that is inside.

  1. Sensor

Automatic transmission system need to know how heavy working machines, in order to transfer the transmission ratio can be in accordance with the engine load encountered. So that the load sensor is used in two ways, the first was is by using a cable that is connected between the positions of the gas pedal to the transmission system. If the gas pedal is pressed deeper and deeper, the pressure on the cable also increased. The second way is to use a vacuum modulator, by connecting the intake manifold to the transmission system. The greater the load on the engine, then the vacuum modulator will read the conditions of getting the vacuum system.

  1. Shift Valve

Shift valve is a component of the duty to regulate the hydraulic oil supply will lead to the clutch actuator piston and bands. Every movement of the transmission ratio takes one shift valve, for the ratio 1 and 2 for example is a shift valve, as well as the displacement. Each shift valve has a different working pressure, the higher the position shift valve, the higher working pressure transmission ratio depends hydraulic. So that displacement hydraulic working pressure is regulated by a spring loaded valve in accordance  with the rotation speed of the axle, which in turn will actuate the shift valve at certain pressure points.

Read also: Some symptoms of automatic transmission problems


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