PRESENTED BY:
Sunil Kumar Sharma
Himanshu Maheshwari

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An Introduction
1.What is Transmission?
The transmission is a device that is connected to the back of the engine and sends the power from the engine to the drive wheels.
2.What is Automatic Transmission?
An automatic transmission is one type of motor vehicle transmission that can automatically change gear ratios as the vehicle moves, freeing the driver from having to shift gears manually.
Need of Automatic Transmission.
 a manual transmission is especially painful in stop-and-go traffic.
 shifting transmission takes some of your attention away from the actual driving, which is dangerous.
 The basic idea of design is to use a differential to transmit the drive in such a way, that if the resistance of the output grows, it will at certain point trigger the gearbox to switch to lower gear.
 once it’s done the gearbox will switch back to the higher gear.
Main Parts of 2 Speed Automatic Gear Box
 Differential.
 Shaft.
 Lever.
 Gears
Differential
A differential is a device, usually but not necessarily employing gears, capable of transmitting torque and rotation through three shafts.
Working of Differential
Input torque is applied to the ring gear (blue), which turns the entire carrier (blue). The carrier is connected to both the side gears (red and yellow) only through the planet gear (green) . Torque is transmitted to the side gears through the planet gear. The planet gear revolves around the axis of the carrier, driving the side gears. If the resistance at both wheels is equal, the planet gear revolves without spinning about its own axis, and both wheels turn at the same rate.
With Resistance (Lower Gear)
When the resistance is applied at the end of the output, differential rotate and the gear which is meshed with the housing of the differential also rotate. Due to rotation of the gear, the lever which is mounted on the gear axle also starts to rotate. Rotation of small lever cause to translator motion of the big lever. Now this big lever is rigidly mounted on the middle shaft, so motion of lever cause to motion of middle shaft. Due to motion of middle shaft the smaller gear on the middle shaft mesh with the bigger gear of the output shaft. Thus the triggering of gear takes place.
No resistance (Higher Gear)
In this case no resistance is there so the power transmission takes place from input shaft to middle shaft and then output shaft. Here the gear ratio between middle shaft and output shaft is 1:1, and the gear ratio between the middle and output shaft is 1:1. So the complete power will be transmit by the shaft
Advantages
 Convenience
 Strength
 Acceleration
 Torque Multiplication
Disadvantages
 Complex Design
 Lower Gas Mileage
 Higher Maintenance
 Use of A Rubber Band
 Cost