A SEMINAR ON AUTOMATIC TRANSMISSION Presented By Guided By Debraj Biswal Prof. Ashok Pradhan Branch:Mechanical Dept. of mech.engg.

Introduction Device which changes gear ratios automatically Deliver maximum efficiency Difference between automatic and manual transmission Easier to drive because they do not have a clutch,pedal or gearshift lever There are two type of automatic transmissions

CLASSIFICATION AUTOMATIC TRANSMISSIONS USING PLANETARY GEARS CONTINUOUSLY VARIABLE TRANSMISSION(CVT)

AUTOMATIC TRANSMISSIONS USING PLANETARY GEARS Components PLANETARY GEAR SYSTEM TORQUE CONVERTER HYDRAULIC SYSTEM GOVERNOR COMPUTER CONTROLS

Sun gear 2. Planet gear 3. Ring gear 4. Planetary carrier PLANETARY GEAR SYSTEM

PLANETARY GEAR SYSTEM (SIDE VIEW)

HOW PLANETARY GEARS WORK Power transfer can only take place when one of the members is held at rest or if two of the members are locked. Input Output Stationary Calculation Gear Ratio A Sun (S) Planet Carrier (C) Ring (R) 1 + R/S 3.4:1 B 1 / (1 + S/R) 0.71:1 C -R/S -2.4:1 Gear Input Output Fixed Gear Ratio 1st 30-tooth sun 72-tooth ring Planet carrier 2.4:1 2nd 36-tooth sun 2.2:1 0.67:1 Total 2nd 1.47:1 3rd 30- and 36-tooth suns 1.0:1 OD Reverse -2.0:1

TORQUE CONVERTOR takes the place of the clutch found on standard shift vehicles large doughnut shaped device that is mounted between the engine and the transmission it uses oil or transmission fluid to transmit power three internal elements that work together to transmit power to the transmission.

TORQUE CONVERTOR

THE HYDRAULIC SYSTEM complex maze of passages and tubes that sends transmission fluid under under pressure to all parts of the transmission and torque converter. Transmission fluid serves in shift control, general lubrication and transmission cooling. Keeps the transmission at normal operating temperature OIL PUMP VALVE BODY SHIFT VALVES BANDS

GOVERNER provides the inputs that tell the transmission when to shift connected to the output shaft and regulates hydraulic pressure based on vehicle speed

COMPUTER CONTROLLS Detect such things as throttle position, vehicle speed, engine speed, engine load,etc. to control exact shift points Downshift automatically when going downhill, to control speed and reduce wear on the brakes. Up shift when braking on a slippery surface to reduce the braking torque applied by the engine. Inhibit the Up shift when going into a turn on a winding road.

CONCLUSION Automatic transmissions contain mechanical systems, hydraulic systems, electrical systems and computer controls. All working together in perfect harmony

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