AUTOMATIC TRANSMISSION

[summer project pal]

AUTOMATIC TRANSMISSION
PRESENTED BY
ARUN CHANDRA A C
ROLL NO: 7

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INTRODUCTION
Two types- manual and automatic transmissions
Manual transmission- needs frequent shift between gears
Automatic transmission
- no clutch pedal
- automatic shifting between gears
- most suitable for beginners
HISTORY
First transmission in 1832 by W.H.James
First automatic transmission introduced in 1939
1940 Oldsmobile features a hydra-matic automatic transmission
First hydraulic automatics were introduced by GM,Chrysler and Borg-Warner in early 1950’s
Greater developments in 1990’s

AUTOMATIC TRANSMISSION

Mercedes-Benz CLK, automatic transmission, cut-away model


Main components of automatic transmission are
Torque converter
Planetary gear system
Hydraulic system
Clutches
Bands
Seals and gaskets
Governor
Modulators
Electronic controls
TORQUE CONVERTER
PRINCIPLE:
Main components of torque converter are;
Pump

Turbine and

Stator


Dismantled view of torque converter



PLANETARY GEAR SYSTEM
Planetary gear system has got three main components
Ring gear

Sun gear

Planet gear

Left to right: the ring gear, planet carrier, and two sun gears





CLUTCH PACK
The main components are;
Clutch plates

Clutch discs

Drum

Piston and seal


One of the clutches in a transmission


The clutch plates
BANDS
Used for holding or releasing the drum
HYDRULIC SYSTEM
Most complex part of the transmission

Purposes - shift control
- general lubrication
- transmission cooling





Hydraulic system of a 1960 model vehicle

OIL PUMP
Gear type oil pump

Responsible for producing oil pressure

Keeps circulating the oil
GOVERNOR
Fitted to the transmission output shaft

Speed sensing valve


VALVES AND MODULATORS
Mainly three types of valves;
Throttle valve or modulator

Manual valve

Shift valve
VALVE BODY
Collection of channels and passages
Made of two or more number of pieces
SEALS AND GASKETS
Used between two mating parts

Two main external seals: front seal and rear seal

Seals: between parts having relative motion between them

Gasket: between two stationary parts
ELECTRONIC CONTROLS
Common in most modern cars
Electronic control monitors;
-vehicle speed
-engine speed
-brake pedal position
-throttle position
-ABS

Electronically controlled transmissions can do things like:
Downshift automatically when going downhill


Upshift when braking on a slippery surface


Inhibit the upshift when going into a turn on a winding road

WORKING:
CONCLUSION
The automatic transmission technology has advanced a lot and it is slowly making its presence felt even in developing countries. The automatic transmission is going to stay in the scene for a long time and in future it may phase out the manual transmission for ever.
THANKS